Mariculture tailwater poses significant environmental challenges such as water pollution and eutrophication.Photosynthetic bacteria(PSB)have been widely used for pollutant treatment.The integrated aquaculture wastewat...Mariculture tailwater poses significant environmental challenges such as water pollution and eutrophication.Photosynthetic bacteria(PSB)have been widely used for pollutant treatment.The integrated aquaculture wastewater bioremediation system(IAWBS)consists of four key components:sedimentation,biofilm,shellfish,and macro-algae.However,there is still some room for improvement in the treatment efficiency of the IAWBS.In this study,PSB(Rhodopseudomonos,Rhodobacteria,Rhodococcus)were added to the system.High-throughput amplicon of 16S rRNA,PERMANOVA,NMDS and other statistical analyses were used to investigate the impacts of PSB.The results showed that significant removal efficiencies of CODMn,NH_(4)^(+)-N,NO_(3)^(-)-N,NO_(2)^(-)-N,PO_(4)^(3-)-P were 71.42%,91.37%,91.72%,87.20%,and 88.80%,respectively.The impact of PSB on bacterioplankton community(BC)was not affected by the time interval but affected by different units,Proteobacteria,Bacteriodia and Actinobacteria were the most abundant phyla in all the units.Alpha diversity underscored a significant decrease in bacterial community diversity due to the PSB.Notably,the PERMANOVA analysis highlighted a significant interaction between the time interval and treated unit,influencing the composition of the microbial community(R^(2)=0.152;P=0.001).This study provides a better understanding of the role of photosynthetic bacteria in an integrated bioremediation system that can effectively treat mariculture tailwater,which is of great significance for the sustainable development of aquaculture.展开更多
Saline treatment is a low-cost,simple,and effective method to stimulate astaxanthin accumulation in Haematococcus pluvialis,and is proposed to be applied in the second stage of a 2-stage culture since it does not nece...Saline treatment is a low-cost,simple,and effective method to stimulate astaxanthin accumulation in Haematococcus pluvialis,and is proposed to be applied in the second stage of a 2-stage culture since it does not necessitate changing the medium.To understand the effect of salinity on the astaxanthin production of H.pluvialis,the photosynthetic activity and the biocomponents production in 1-and 2-stage cultures in different salinities were investigated.Except for astaxanthin synthesis,which increased at low salinities of 2 and 5-g/L NaCl,most biocomponent yields decreased in 1-stage cultures as salinity increased.At a salinity of 5-g/L NaCl,the 2-stage culture further increased astaxanthin production to 18.41±0.24 mg/L,which was more than 2.0 times that of the control.Saline treatment led to an overall decrease in photosynthetic performance indices of H.pluvialis,and had an impact on five sites of the electron transport chain:the energy connection between antenna and reaction center of photosystemⅡ(PSⅡ),oxygen evolving complex activity on the donor side,the electron transfer from plastoquinone A(Q_(A))to plastoquinone B(Q_(B))and from plastoquinone(PQ)to receptor side of photosystem I(PS I),and the pool size of the end electron acceptors in PSⅠacceptor side.The excitation imbalance between PSⅠand PSⅡcaused by the variance in the electron transfer chain necessitated the synthesis of antioxidants like astaxanthin in order to ensure cell viability.The accumulation of astaxanthin was found to be closely correlated with the stabilized or enhanced the maximum relative electron transfer rate(rETR_(max))and the PSⅡactual quantum yield(QY_(SS))as well as the increased fluorescence yield at J-step(V_(J)).This work offers the novel insight of how saline stress controls H.pluvialis photosynthetic activity and astaxanthin synthesis.展开更多
Macroalgae dominate nutrient dynamics and function as high-value foods for microbial,meio-and macrofaunal communities in coastal ecosystems.Because of this vital role,it is important to clarify the physiological infor...Macroalgae dominate nutrient dynamics and function as high-value foods for microbial,meio-and macrofaunal communities in coastal ecosystems.Because of this vital role,it is important to clarify the physiological information associated with environmental changes as it reflects their growth potential.To evaluate the effects of the changes in salinity and nutrients,the photosynthetic efficiency of a green macroalga Ulva fasciata from the Daya Bay was tested at a range of salinity(i.e.,31 to 10 psu)and nitrogen content(i.e.,5 to 60μmol L^(-1)).The results showed that cellular chlorophyll a(Chl a),carbohydrate and protein contents of U.fasciata were increased due to reduced salinity,and were decreased by interactive nitrogen enrichment.Within a short culture period(i.e.,18 h),the reduced salinity decreased the maximum photosynthetic efficiency(rETRmax and Pmax)derived from the rapid light response curve and photosynthetic oxygen evolution rate versus irradiance curve,respectively,as well as the saturation irradiance(E_(K)).This reducing effect diminished with enlonged cultivation time and reversed to a stimulating effect after 24 h of cultivation.The nitrogen enrichment stimulated the rETRmax and Pmax,as well as the E_(K),regardless of salinity,especially within short-term cultivation period(i.e.,<24 h).In addition,our results indicate that seawater freshening lowers the photosynthetic efficiency of U.fasciata in the short term,which is mitigated by nitrogen enrichment,but stimulates it in the long term,providing insight into how macroalgae thrive in coastal or estuarine waters where salinity and nutrients normally covary strongly.展开更多
This study aimed to decipher the mechanism by which exogenous methyl jasmonate(MeJA)regulated the photosynthesis of Malus spectabilis leaves under ozone(O_(3))stress.The photosynthetic parameters and chlorophyll fluor...This study aimed to decipher the mechanism by which exogenous methyl jasmonate(MeJA)regulated the photosynthesis of Malus spectabilis leaves under ozone(O_(3))stress.The photosynthetic parameters and chlorophyll fluorescence parameters of M.spectabilis‘Hongjiu’seedlings under O_(3)stress were measured by spraying different concentrations of MeJA.The results showed that O_(3)stress significantly reduced the chlorophyll a and total chlorophyll content,net photosynthetic rate(Pn),stomatal conductance(G_(s)),transpiration rate(T_(r)),maximum fluorescence yield(F_(m)),maximum quantum yield of photosystem II(F_(v)/F_(m)),and actual photochemical efficiency of photosystem II(Ф_(PSII)),while increasing the intercellular CO_(2)concentration(Ci).Exogenous MeJA reduced the Ci and original fluorescence yield(Fo),while increasing chlorophyll a,chlorophyll b,and total chlorophyll content,P_(n),G_(s),T_(r),F_(m),F_(v)/F_(m),andФ_(PSII) of the leaves under O_(3)stress.The application of 150μmol/L MeJA showed the best effect.The above results demonstrated that exogenous MeJA could enhance chlorophyll content and photosynthetic capacity,thereby improving the tolerance of M.spectabilis to O_(3)stress.展开更多
Climate changes in cold-temperate zones are increasingly altering the state of climatic constraints on photosynthesis and growth,leading to adaptive changes in plant phenology and subsequent seasonal carbon assimilati...Climate changes in cold-temperate zones are increasingly altering the state of climatic constraints on photosynthesis and growth,leading to adaptive changes in plant phenology and subsequent seasonal carbon assimilation.However,the spatio-temporal patterns of climatic constraints and seasonal carbon assimilation are poorly understood.In this study,the timing of peak photosynthetic activity(DOY_(pmax))was employed as a proxy for plant adap-tive state to climatic constraints on growth to examine the spatio-temporal dynamics of DOY_(pmax).By using multiple remote sensing metrics,DOY_(pmax)was characterized with changes in the solar-induced chlorophyll fluorescence(SIF)and leaf area index(LAI)from 2000 to 2018.Based on SIF,the DOY_(pmax)was generally around day 190,while based on LAI was about 10 d later.Peak photosynthetic activity of forests occurs earlier compared to other vegetation types.Overall,the advanced DOY_(pmax)were observed based on both SIF and LAI,with annual rates of 0.2(P=0.31)and 0.3(P<0.05)d,respectively.DOY_(pmax)dynamics were influ-enced by hot temperature extremes and vapor pressure defi-cits(VPD)during the early growing season,regardless of sub-zone and different vegetation type.The generalized lin-ear mixed model(GLMM)showed the largest contribution by hot extremes to DOY_(pmax)dynamics accounted for 55.5%(DOY_(pmax_SIF))and 49.1%(DOY_(pmax_LAI)),respectively,fol-lowed by VPD(DOY_(pmax_SIF):23.1%;DOY_(pmax_LAI):29.5%).These findings highlight the crucial role of climate extremes in shaping seasonal carbon dynamics and regional carbon balance.展开更多
Layered transition metal hydroxides show distinct advantages in separately co-catalyzing CO_(2)reduction and H_(2)O oxidation at the electron-accumulating and hole-accumulating sites of wrapped heterojunction photocat...Layered transition metal hydroxides show distinct advantages in separately co-catalyzing CO_(2)reduction and H_(2)O oxidation at the electron-accumulating and hole-accumulating sites of wrapped heterojunction photocatalysts,while concurrently preventing side reactions and photocorrosion on the semiconductor surface.Herein,Ni-Co bimetallic hydroxides with varying Ni/Co molar ratios(Ni_(x)Co_(1-x)(OH)_(2),x=1,0.75,0.5,0.25,and 0)were grown in situ on a model 2D/2D S-scheme heterojunction composed of Cu_(2)O nanosheets and Fe_(2)O_(3)nanoplates to form a series of Cu_(2)O/Fe_(2)O_(3)@Ni_(x)Co_(1-x)(OH)_(2)(CF@NiCo)photocatalysts.The combined experimental and theoretical investigation demonstrates that incorporating an appropriate amount of Co into Ni(OH)_(2)not only modulates the energy band structure of Ni_(x)Co_(1-x)(OH)_(2),balances the electron-and hole-trapping abilities of the bifunctional cocatalyst and maximizes the charge separation efficiency of the heterojunction,but also regulates the d-band center of Ni_(x)Co_(1-x)(OH)_(2),reinforcing the adsorption and activation of CO_(2)and H_(2)O on the cocatalyst surface and lowering the rate-limiting barriers in the CO_(2)-to-CO and H_(2)O-to-O_(2)conversion.Benefiting from the Ni-Co synergy,the redox reactions proceed stoichiometrically.The optimized CF@Ni_(0.75)Co_(0.25)achieves CO and O_(2)yields of 552.7 and 313.0μmol gcat^(-1)h^(-1),respectively,11.3/9.9,1.6/1.7,and 4.5/5.9-fold higher than those of CF,CF@Ni,and CF@Co.This study offers valuable insights into the design of bifunctional noble-metal-free cocatalysts for high-performance artificial photosynthesis.展开更多
Straw return has demonstrated significant potential for enhancing carbon(C)sequestration and nitrogen(N)uptake while concurrently promoting plant productivity.However,the specific transport and distribution of C produ...Straw return has demonstrated significant potential for enhancing carbon(C)sequestration and nitrogen(N)uptake while concurrently promoting plant productivity.However,the specific transport and distribution of C produced by photosynthesis and exogenous N within the rice plant-soil system under straw return remains unclear.A long-term straw return pot trial experiment was conducted in a double cropping rice system,incorporating treatments of inorganic fertilizer application with straw removal(F),straw burning and ash return with reducing inorganic fertilizers(SBR),and straw return with reducing inorganic fertilizers(SR)to investigate C sequestration and exogenous N uptake using ^(13)C pulse and ^(15)N isotope tracer techniques.The SR treatment had significantly higher soil ^(13)C abundance,by 24.4 and 25.4%,respectively,^(13)C concentrations in aboveground plant parts,by 18.4 and 35.8%respectively,and ^(15)N concentrations in rice panicles,by 12.8 and 34.3%than the SBR and F treatments.This enhancement contributed to a higher total organic C concentration and increased rice grain yield in the SR treatment.Furthermore,the SR treatment had significantly higher photosynthetic C,by 9.8%,which was directly transferred to soil C.The SR treatment had a higher distribution of photosynthetic C in the leaves and stems,but a lower distribution in the panicle compared to the SBR treatment.This finding is advantageous for sequestering photosynthetic C into the soil through straw return;conversely,opposite trends were observed in ^(15)N distribution.In addition,rice plants in the SR treatment had increased N uptake from urea and soil N sources,enhancing N recovery by 9.2 and 12.5%,respectively,and reducing soil N residues.Correlation analysis showed that the SR treatment increased the concentrations of ^(13)C in leaves and roots while decreasing the ^(15)N abundance in all rice organs,thereby contributing to an increase in rice yield.The partial least square path model suggested that the increase in rice yield under the SR treatment was primarily linked to ^(13)C accumulation within the rice plant-soil system.The results suggest that straw return increases the sequestration of photosynthetic C and exogenous N in the rice plant-soil system and increases N utilization efficiency,which subsequently improves both rice and soil productivity.展开更多
To determine the invasiveness of invasive plants,many studies have compared photosynthetic traits or strategies between invasive and native species.However,few studies have compared the photosynthetic dynamics between...To determine the invasiveness of invasive plants,many studies have compared photosynthetic traits or strategies between invasive and native species.However,few studies have compared the photosynthetic dynamics between invasive and native species during light fluctuations.We compared photosynthetic induction,relaxation dynamics and leaf traits between the invasive species,Tithonia diversifolia and two native species,Clerodendrum bungei and Blumea balsamifera,in full-sun and shady habitats.The photosynthetic dynamics and leaf traits differed among species.T.diversifolia showed a slower induction speed and stomatal opening response but had higher average intrinsic water-use efficiency than the two native species in full-sun habitats.Thus,the slow induction response may be attributed to the longer stomatal length in T.diversifolia.Habitat had a significant effect on photosynthetic dynamics in T.diversifolia and B.balsamifera but not in C.bungei.In shady habitat,T.diversifolia had a faster photosynthetic induction response than in full-sun habitat,leading to a higher average stomatal conductance during photosynthetic induction in T.diversifolia than in the two native species.In contrast,B.balsamifera had a larger stomatal length and slower photosynthetic induction and relaxation response in shady habitat than in full-sun habitat,resulting in higher carbon gain during photosynthetic relaxation.Nevertheless,in both habitats,T.diversifolia had an overall higher carbon gain during light fluctuations than the two native species.Our results indicated that T.diversifolia can adopt more effective response strategies under fluctuating light environments to maximize carbon gain,which may contribute to its successful invasion.展开更多
Simultaneous stresses of salinity and drought often coincide during rice-growing seasons in saline lands,primarily due to insufficient water resources and inadequate irrigation facilities.Consequently,combined salinit...Simultaneous stresses of salinity and drought often coincide during rice-growing seasons in saline lands,primarily due to insufficient water resources and inadequate irrigation facilities.Consequently,combined salinity-drought stress poses a major threat to rice production.In this study,two salinity levels(NS,non-salinity;HS,high salinity)along with three drought treatments(CC,control condition;DJ,drought stress imposed at jointing;DH,drought stress imposed at heading)were performed to investigate their combined influences on leaf photosynthetic characteristics,biomass accumulation,and rice yield formation.Salinity,drought,and their combination led to a shortened growth period from heading to maturity,resulting in a reduced overall growth duration.Grain yield was reduced under both salinity and drought stress,with a more substantial reduction under the combined salinity-drought stress.The combined stress imposed at heading caused greater yield losses in rice compared with the stress imposed at jointing.Additionally,the combined salinity-drought stress induced greater decreases in shoot biomass accumulation from heading to maturity,as well as in shoot biomass and nonstructural carbohydrate(NSC)content in the stem at heading and maturity.However,it increased the harvest index and NSC remobilization reserve.Salinity and drought reduced the leaf area index and SPAD value of flag leaves and weakened the leaf photosynthetic characteristics as indicated by lower photosynthetic rates,transpiration rates,and stomatal conductance.These reductions were more pronounced under the combined stress.Salinity,drought,and especially their combination,decreased the activities of ascorbate peroxidase,catalase,and superoxide dismutase,while increasing the contents of malondialdehyde,hydrogen peroxide,and superoxide radical.Our results indicated a more significant yield loss in rice when subjected to combined salinity-drought stress.The individual and combined stresses of salinity and drought diminished antioxidant enzyme activities,inhibited leaf photosynthetic functions,accelerated leaf senescence,and subsequently lowered assimilate accumulation and grain yield.展开更多
Light levels determine regeneration in stands and a key concern is how to regulate the light environment of different stand types to the requirements of the understory.In this study,we selected three stands typical in...Light levels determine regeneration in stands and a key concern is how to regulate the light environment of different stand types to the requirements of the understory.In this study,we selected three stands typical in south China(a Cryptomeria japonica plantation,a Quercus acutissima plantation,and a mixed stand of both)and three thinning intensities to determine the best understory light environ-ment for 3-year-old Phoebe bournei seedlings.The canopy structure,understory light environment,and photosynthe-sis and growth indicators were assessed following thin-ning.Thinning improved canopy structure and understory light availability of each stand;species composition was the reason for differences in the understory light environ-ment.Under the same thinning intensity,the mixed stand had the greatest light radiation and most balanced spectral composition.P.bournei photosynthesis and growth were closely related to the light environment;all three stands required heavy thinning to create an effective and sustained understory light environment.In a suitable understory light environment,the efficiency of light interception,absorption,and use by seedlings was enhanced,resulting in a higher carbon assimilation the main limiting factor was stomatal conductance.As a shade-avoidance signal,red/far-red radia-tion is a critical factor driving changes in photosynthesis and growth of P.bournei seedlings,and a reduction increased light absorption and use capacity and height:diameter ratios.The growth advantage transformed from diameter to height,enabling seedlings to access more light.Our findings suggest that the regeneration of shade-tolerant species such as P.bournei could be enhanced if a targeted approach to thinning based on stand type was adopted.展开更多
A two-year field experiment was conducted to measure the effects of densification methods on photosynthesis and yield of densely planted wheat.Inter-plant and inter-row distances were used to define ratefixed pattern(...A two-year field experiment was conducted to measure the effects of densification methods on photosynthesis and yield of densely planted wheat.Inter-plant and inter-row distances were used to define ratefixed pattern(RR)and row-fixed pattern(RS)density treatments.Meanwhile,four nitrogen(N)rates(0,144,192,and 240 kg N ha-1,termed N0,N144,N192,and N240)were applied with three densities(225,292.5,and 360×10^(4)plants ha^(-1),termed D225,D292.5,and D360).The wheat canopy was clipped into three equal vertical layers(top,middle,and bottom layers),and their chlorophyll density(Ch D)and photosynthetically active radiation interception(FIPAR)were measured.Results showed that the response of Ch D and FIPAR to N rate,density,and pattern varied with different layers.N rate,density,and pattern had significant interaction effects on Ch D.The maximum values of whole-canopy Ch D in the two seasons appeared in N240 combined with D292.5 and D360 under RR,respectively.Across two growing seasons,FIPAR values of RR were higher than those of RS by 29.37%for the top layer and 5.68%for the middle layer,while lower than those of RS by 20.62%for the bottom layer on average.With a low N supply(N0),grain yield was not significantly affected by density for both patterns.At N240,increasing density significantly increased yield under RR,but D360 of RS significantly decreased yield by 3.72%and 9.00%versus D225 in two seasons,respectively.With an appropriate and sufficient N application,RR increased the yield of densely planted wheat more than RS.Additionally,the maximum yield in two seasons appeared in the combination of D360 with N144 or N192 rather than of D225 with N240 under both patterns,suggesting that dense planting combined with an appropriate N-reduction application is feasible to increase photosynthesis capacity and yield.展开更多
Understanding the relationship between forest management and water use efficiency(WUE)is important for evaluating forest adaptability to climate change.However,the effects of thinning and understory removal on WUE and...Understanding the relationship between forest management and water use efficiency(WUE)is important for evaluating forest adaptability to climate change.However,the effects of thinning and understory removal on WUE and its key controlling processes are not well understood,which limits our comprehension of the physiological mechanisms of various management practices.In this study,four forest management measures(no thinning:NT;understory removal:UR;light thinning:LT;and heavy thinning:HT)were carried out in Pinus massoniana plantations in a subtropical region of China.Photosynthetic capacity and needle stable carbon isotope composition(δ^(13)C)were measured to assess instantaneous water use efficiency(WUE_(inst))and long-term water use efficiency(WUE_(i)).Multiple regression models and structural equation modelling(SEM)identified the effects of soil properties and physiological performances on WUE_(inst)and WUE_(i).The results show that WUE_(inst)values among the four treatments were insignificant.However,compared with the NT stand(35.8μmol·mol^(-1)),WUE_(i)values significantly increased to 41.7μmol·mol^(-1)in the UR,50.1μmol·mol^(-1)in the LT and 46.6μmol·mol^(-1)in HT treatments,largely explained by photosynthetic capacity and soil water content.Understory removal did not change physiological performance(needle water potential and photosynthetic capacity).Thinning increased the net photosynthetic rate(A_n)but not stomatal conductance(g_s)or predawn needle water potential(ψ_(pd)),implying that the improvement in water use efficiency for thinned stands was largely driven by radiation interception than by soil water availability.In general,thinning may be an appropriate management measure to promote P.massoniana WUE to cope with seasonal droughts under future extreme climates.展开更多
Photosynthesis is the most important biochemical reaction on Earth. It has co-evolved and developed with the Earth, driving the biogeochemical cycle of all elements on the planet and serving as the only chemical proce...Photosynthesis is the most important biochemical reaction on Earth. It has co-evolved and developed with the Earth, driving the biogeochemical cycle of all elements on the planet and serving as the only chemical process in nature that can convert light energy into chemical energy. Some heavy oxygen isotopic(^(18)O) labeling experiments have"conclusively" demonstrated that the oxygen released by photosynthesis comes only from water and are written into textbooks. However, it is not difficult to find that bicarbonate has never been excluded from the direct substrate of photosynthesis from beginning to end during the history of photosynthesis research. No convincing mechanism can be used to explain photosynthetic oxygen evolution solely from water photolysis. The bicarbonate effect, the Dole effect, the thermodynamic convenience of bicarbonate photolysis, the crystal structure characteristics of photosystem Ⅱ, and the reinterpretation of heavy oxygen isotopic labeling(^(18)O)experiments all indicate that the photosynthetic oxygen evolution does not exclude the important role and contribution of bicarbonate photolysis. The recently proposed view that bicarbonate photolysis is the premise of water photolysis, bicarbonate photolysis and water photolysis work together with a 1:1(mol/mol) stoichiometric relationship, and the stoichiometric relationship between oxygen and carbon dioxide released during photosynthetic oxygen evolution is also 1:1, has excellent applicability and objectivity, which can logically and reasonably explain the precise coordination between light and dark reactions during photosynthesis, the bicarbonate effect, the Dole effect, the Kok cycle and the neutrality of water and carbon in nature.This is of great significance for constructing the bionic artificial photosynthetic reactors and scientifically answering the question of the source of elemental stoichiometric relationships in nature.展开更多
Drought(water shortage)can substantially limit the yield and economic value of rose plants(Rosa spp.).Here,we characterized the effect of exogenous calcium(Ca^(2+))on the antioxidant system and photosynthesis-related ...Drought(water shortage)can substantially limit the yield and economic value of rose plants(Rosa spp.).Here,we characterized the effect of exogenous calcium(Ca^(2+))on the antioxidant system and photosynthesis-related properties of rose under polyethylene glycol 6000(PEG6000)-induced drought stress.Chlorophyll levels,as well as leaf and root biomass,were significantly reduced by drought;drought also had a major effect on the enzymatic antioxidant system and increased concentrations of reactive oxygen species.Application of exogenous Ca^(2+)increased the net photosynthetic rate and stomatal conductance of leaves,enhanced water-use efficiency,and increased the length and width of stomata following exposure to drought.Organ-specific physiological responses were observed under different concentrations of Ca^(2+).Application of 5 mmol·L^(-1)Ca^(2+)promoted photosynthesis and antioxidant activity in the leaves,and application of 10 mmol·L^(-1)Ca^(2+)promoted antioxidant activity in the roots.Application of exogenous Ca^(2+)greatly enhanced the phenotype and photosynthetic capacity of potted rose plants following exposure to drought stress.Overall,our findings indicate that the application of exogenous Ca^(2+)enhances the drought resistance of roses by promoting physiological adaptation and that it could be used to aid the cultivation of rose plants.展开更多
Controlled-release urea(CRU)releases nitrogen(N)at the same pace that rice takes it up,which can effectively improve N use efficiency,increase rice yield and improve rice quality.However,few studies have described the...Controlled-release urea(CRU)releases nitrogen(N)at the same pace that rice takes it up,which can effectively improve N use efficiency,increase rice yield and improve rice quality.However,few studies have described the effects of CRU application on the photosynthetic rate and endogenous enzyme activities of rice.Accordingly,a twoyear field trial was conducted with a total of seven treatments:CK,no N fertilizer;BBF,regular blended fertilizer;RBBF,20%N-reduced regular blended fertilizer;CRF1,70%CRU+30%regular urea one-time base application;CRF2,60%CRU+40%regular urea one-time base application;RCRF1,CRF1 treatment with 20%N reduction;and RCRF2,CRF2 treatment with 20%N reduction.Each treatment was conducted in triplicate.The results showed that the N recovery efficiency(NRE)of the controlled-release bulk blending fertilizer(CRBBF)treatments was significantly greater over the two years.There were significant yield increases of 4.1–5.9%under the CRF1treatment and 5.6–7.6%under the CRF2 treatment compared to the BBF treatment,but the differences between the reduced-N treatments RBBF and RCRF2 were not significant.Photosynthetic rates under the CRF1 and CRF2treatments were significantly higher than under the other treatments,and they had significantly greater RuBPCase,RuBisCO,glutamate synthase(GOGAT)and glutamine synthetase(GS)enzyme activities.Additionally,the soil NH_(4)^(+)-N and NO_(3)^(–)-N contents under the CRBBF treatments were significantly higher at the late growth stage of rice,which was more in-line with the fertilizer requirements of rice throughout the reproductive period.CRBBF also led to some improvement in rice quality.Compared with the BBF and RBBF treatments,the protein contents under the CRBBF treatments were reduced but the milling,appearance,eating and cooking qualities of the rice were improved.These results showed that the application of CRBBF can improve the NRE,photosynthetic rate and endogenous enzyme activities of rice,ensuring sufficient N nutrition and photosynthetic material production during rice growth and thereby achieving improved rice yield and quality.展开更多
Compared with conventional fertilizers,nano fertilizer has many advantages such as controlled release,controlled or slow release of nutrients,high efficiency of nutrition use,cheap,and little polluting of the environm...Compared with conventional fertilizers,nano fertilizer has many advantages such as controlled release,controlled or slow release of nutrients,high efficiency of nutrition use,cheap,and little polluting of the environment.The use of fertilizers with nanotechnology is a new field in agriculture,and it is a promising and cost-effective substitute for conventional fertilizers to improve the productivity of the world’s food supply.Photosynthesis is an essential biochemical reaction on Earth.Improving photosynthesis,the basic process for light’s transformation into chemical energy is one of the most important areas of research for improving agricultural output and tackling world food security.Nano fertilizers can promote plant photosynthesis,improve crop photosynthetic efficiency,increase plant biomass,improve plant stress resistance,improve nutrient uptake efficiency,and encourage plant growth and development due to their tunable surface properties,special electronic,magnetic,and optical properties,and other characteristics.It can be seen that nano fertilizers and improving photosynthetic efficiency in plants are a hot topic of concern.Therefore,an overview of the effects of nano fertilizers on plant photosynthesis is given in this paper.These effects include the ability to increase biomass,pigment and gas openness,photosynthetic efficiency,and plant resistance to stress.On the other hand,improper use of nano fertilizers can have the opposite effect,inhibiting plant photosynthesis.展开更多
[Objectives]To investigate the effects of 15 distinct citrus rootstock-scion combinations on tree growth,fruit quality,and photosynthetic characteristics under red loam soil conditions and provide a theoretical founda...[Objectives]To investigate the effects of 15 distinct citrus rootstock-scion combinations on tree growth,fruit quality,and photosynthetic characteristics under red loam soil conditions and provide a theoretical foundation for the selection of appropriate citrus rootstock-scion combinations in the Zhaoqing region.[Methods]A total of 15 citrus rootstock-scion combinations were utilized as test materials for a comprehensive analysis of their phenological periods(budding,flowering,and fruiting),tree growth indicators(tree height,crown diameter,and growth),and fruit quality(appearance quality and intrinsic quality).The photosynthetic characteristics of the test materials,including the net photosynthetic rate(Pn),transpiration rate(Tr),water use efficiency(WUE),apparent quantum yield(AQY),and carboxylation efficiency(CE),were analyzed to determine their significance.Additionally,the leaf photosynthetic physiological indicators,such as soluble protein,specific leaf weight,chlorophyll,and carotenoids,were evaluated.[Results]There were notable differences observed in the phenological period,growth potential of trees,fruit quality,and photosynthetic characteristics among various citrus rootstock-scion combinations.The phenological periods exhibited variation contingent on the grafting varieties.In terms of tree growth potential,the Citrus tangerina Tanaka‘Hongju’and C.haniana Hort.‘Suanju’rootstocks demonstrated greater tree height,crown growth,and overall tree strength;however,they were also prone to excessive growth.Conversely,the C.limonia Osbeck‘Hongningmeng’and C.sinensis×P.trifoliata‘Zhicheng’rootstocks displayed medium growth potential,while the Poncirus trifoliate(L)Raf.‘Zhike’rootstock resulted in shorter trees.In terms of fruit quality,the single fruit weight of C.flamea Hort.‘Shatangju’ranged from 33 to 50 g,exhibiting a flat and round shape.The total soluble solids and titratable acid content of‘Shatangju’grafted onto the‘Zhike’rootstock were notably high.In contrast,the single fruit weight of C.haniana Hort.‘Chuntianju’varied between 65 and 81 g,characterized by a high flat round shape.The‘Suanju’rootstock demonstrated a higher sugar and acid content compared to other rootstocks.Additionally,the single fruit weight of C.nobilis Lour.‘Gonggan’ranged from 62 to 145 g,with the fruit shape being either round or oval.The soluble sugar and total soluble solids content associated with the‘Zhike’rootstock was also elevated.In relation to photosynthetic characteristics,the photosynthetic performance of the‘Shatangju’variety was superior when grafted onto the‘Zhike’and‘Hongju’rootstocks.Similarly,the‘Chuntianju’variety exhibited enhanced photosynthetic performance on the‘Zhike’,‘Zhicheng’,and‘Hongju’rootstocks.Furthermore,the‘Gonggan’variety demonstrated improved photosynthetic performance when grafted onto the‘Zhike’and‘Suanju’rootstocks.[Conclusions]Based on the characteristics of the red loam soil in the Zhaoqing region,the rootstocks‘Zhike’and‘Hongju’are conducive to the cultivation of the‘Shatangju’variety.Additionally,the rootstocks‘Zhike’,‘Zhicheng’,and‘Hongju’are optimal for the growth of the‘Chuntianju’variety,while the rootstocks‘Zhike’and‘Suanju’are appropriate for the growth of the‘Gonggan’variety.展开更多
Preserving microbial diversity has become a strategic undertaking. Thus, ex situ microalgal culture conservation results in strategic and functional resource in both biodiversity protection and application domains. Cr...Preserving microbial diversity has become a strategic undertaking. Thus, ex situ microalgal culture conservation results in strategic and functional resource in both biodiversity protection and application domains. Cryopreservation of microalgae has been practiced since the 1960s and is now considered the optimal preservation strategy. Furthermore, the overall monitoring during growth of cultures after freezing/thawing protocols was hardly investigated and there is poor evaluation related to preserve especially the photosystem apparatus. The present study focuses on Stichococcus bacillaris as case study for short-term cryopreservation at −80 °C storage. Various freezing pretreatments using cryoprotective agents, and two thawing methods were compared introducing a novel variable to evaluate viability recovery and assessing growth kinetics of cultures immediately after thawing and after a series batch cultivation. Photosynthetic rate and pigments assessment were proposed to evaluate hidden metabolic cell damage. Results underline cryoprotective agents can increase the kinetic recovery of preserved cells in terms of reduction of lag phase during batch cultivation tests: the use of dimethyl sulfoxide and glycerol granted a growth comparable to unpreserved cells when sudden thawing occurs after 24 hours of storage, but recovery after preservation is less sensitive to cryoprotective agents when gradual thawing and 1 month of storage is considered. However, cells are always able to restore their physiological pathways even without agents, so their kinetic effect has been proved and quantified. Interestingly, both the photosynthetic efficiency and the ratio between total chlorophyll and carotenoids are comparable (0.75 F<sub>v</sub>/F<sub>m</sub>, 2.2 ± 0.25 g/g) to unpreserved cells and they are unsensitive to chosen agents, but the ratio between chlorophyll a and chlorophyll b was clearly altered (up to 10 times), suggesting that photoactive pigments relative proportions can result in similar growth kinetic performances. Long-term studies will be carried out to assess whether the differences found could cause chronic damage to photosystem efficiency of S. bacillaris cultures.展开更多
It is well known that plants have functional equilibrium between their above-ground parts (shoots) and below-ground parts (roots), but whether the above-ground parts of plants have functional equilibrium between their...It is well known that plants have functional equilibrium between their above-ground parts (shoots) and below-ground parts (roots), but whether the above-ground parts of plants have functional equilibrium between their photosynthetic structures (leaves) and non-photosynthetic structures (branches and stem) is unknown. The purpose of this study is to test the hypotheses that: (1) the above-ground parts of plants have functional equilibriums between their photosynthetic structures and non-photosynthetic structures; (2) the maintenance of the equilibriums is guaranteed by the alteration of biomass partitioning to photosynthetic and non-photosynthetic structures. To test these hypotheses, a pruning experiment with four pruning intensities (0%, 20%, 50%, and 70%) were carried out with three subtropical Chinese tree species ( Ficus microcarpa, Ficus virens, Cinnamomum camphora). Pruning treatments were conducted in two successive years. The results were in conformity with the hypothesis, i.e. above-ground parts of trees had functional equilibriums between photosynthetic and non-photosynthetic structures. Pruning decreased instantaneously the mass ratios of photosynthetic structures to non-photosynthetic structures (P/NP) of all three tree species, the reduction in P/NP was strengthened with pruning intensity. However, one year after pruning, the P/NP of all pruned trees increased and were not smaller than those of unpruned trees. In agreement with the expectation, the biomass partitioning of pruned trees was altered, more newly produced above-ground biomass was partitioned to leaf growth and less to branch and stem growth, thus enabled the damaged trees to restore their functional equilibrium between photosynthetic and non-photosynthetic structures. It is clear that the maintenance of functional equilibrium between photosynthetic and non-photosynthetic structures guaranteed by the alteration of biomass partitioning provides plants a good strategy to resist external disturbance and damage.展开更多
The photosynthetic functions and the sensitivity to photoinhibition were compared between two superhigh_yield hybrid rice (Oryza sativa L.) Liangyoupeijiu and X07S/Zihui 100, the newly developed from two parental line...The photosynthetic functions and the sensitivity to photoinhibition were compared between two superhigh_yield hybrid rice (Oryza sativa L.) Liangyoupeijiu and X07S/Zihui 100, the newly developed from two parental lines and traditional hybrid rice Shanyou 63 developed from three parental lines. The results showed that, as compared to Shanyou 63, the net photosynthetic rate of Liangyoupeijiu and X07S/Zihui 100 was 9.1% and 11.9% higher, the transpiration rate was 37.4% and 31.4% lower, and their water use efficiency was 74.2% and 63.5% higher respectively. After strong light (2 000 μmol photons·m -2 ·s -1 ) treatment for 2 h, the photochemical quantum yield and the photochemical quenching increased by 37.0% and 18.0% respectively in Liangyoupeijiu, 28.3% and 46.2% in X07S/Zihui 100, but decreased a little in Shanyou 63. The non_photochemical quenching decreased in Liangyoupeijiu and X07S/Zihui 100 (about 50%) but increased greatly in Shanyou 63 (about 50%). Better photosynthetic functions, higher water use efficiency and stronger resistance to photoinhibition, may be the physiological basis for the super high_yield of the two hybrid rice under study.展开更多
基金financially supported by the National Key R&D Program of China(No.2020YFD0900201)the Ningbo Public Welfare Technology Application Research Project(No.2022S164)the K.C.Wong Magna Fund in Ningbo University。
文摘Mariculture tailwater poses significant environmental challenges such as water pollution and eutrophication.Photosynthetic bacteria(PSB)have been widely used for pollutant treatment.The integrated aquaculture wastewater bioremediation system(IAWBS)consists of four key components:sedimentation,biofilm,shellfish,and macro-algae.However,there is still some room for improvement in the treatment efficiency of the IAWBS.In this study,PSB(Rhodopseudomonos,Rhodobacteria,Rhodococcus)were added to the system.High-throughput amplicon of 16S rRNA,PERMANOVA,NMDS and other statistical analyses were used to investigate the impacts of PSB.The results showed that significant removal efficiencies of CODMn,NH_(4)^(+)-N,NO_(3)^(-)-N,NO_(2)^(-)-N,PO_(4)^(3-)-P were 71.42%,91.37%,91.72%,87.20%,and 88.80%,respectively.The impact of PSB on bacterioplankton community(BC)was not affected by the time interval but affected by different units,Proteobacteria,Bacteriodia and Actinobacteria were the most abundant phyla in all the units.Alpha diversity underscored a significant decrease in bacterial community diversity due to the PSB.Notably,the PERMANOVA analysis highlighted a significant interaction between the time interval and treated unit,influencing the composition of the microbial community(R^(2)=0.152;P=0.001).This study provides a better understanding of the role of photosynthetic bacteria in an integrated bioremediation system that can effectively treat mariculture tailwater,which is of great significance for the sustainable development of aquaculture.
基金Supported by the National Natural Science Foundation of China(Nos.42177459,41776156,41271521)。
文摘Saline treatment is a low-cost,simple,and effective method to stimulate astaxanthin accumulation in Haematococcus pluvialis,and is proposed to be applied in the second stage of a 2-stage culture since it does not necessitate changing the medium.To understand the effect of salinity on the astaxanthin production of H.pluvialis,the photosynthetic activity and the biocomponents production in 1-and 2-stage cultures in different salinities were investigated.Except for astaxanthin synthesis,which increased at low salinities of 2 and 5-g/L NaCl,most biocomponent yields decreased in 1-stage cultures as salinity increased.At a salinity of 5-g/L NaCl,the 2-stage culture further increased astaxanthin production to 18.41±0.24 mg/L,which was more than 2.0 times that of the control.Saline treatment led to an overall decrease in photosynthetic performance indices of H.pluvialis,and had an impact on five sites of the electron transport chain:the energy connection between antenna and reaction center of photosystemⅡ(PSⅡ),oxygen evolving complex activity on the donor side,the electron transfer from plastoquinone A(Q_(A))to plastoquinone B(Q_(B))and from plastoquinone(PQ)to receptor side of photosystem I(PS I),and the pool size of the end electron acceptors in PSⅠacceptor side.The excitation imbalance between PSⅠand PSⅡcaused by the variance in the electron transfer chain necessitated the synthesis of antioxidants like astaxanthin in order to ensure cell viability.The accumulation of astaxanthin was found to be closely correlated with the stabilized or enhanced the maximum relative electron transfer rate(rETR_(max))and the PSⅡactual quantum yield(QY_(SS))as well as the increased fluorescence yield at J-step(V_(J)).This work offers the novel insight of how saline stress controls H.pluvialis photosynthetic activity and astaxanthin synthesis.
基金funded by the National Key Research and Development Program of China(No.20022YFC3102405)the National Natural Science Foundation of China(Nos.42425004,32371665)the Natural Science Foundation of Guangdong Province(Nos.2022A1515011461,2022A1515011831)。
文摘Macroalgae dominate nutrient dynamics and function as high-value foods for microbial,meio-and macrofaunal communities in coastal ecosystems.Because of this vital role,it is important to clarify the physiological information associated with environmental changes as it reflects their growth potential.To evaluate the effects of the changes in salinity and nutrients,the photosynthetic efficiency of a green macroalga Ulva fasciata from the Daya Bay was tested at a range of salinity(i.e.,31 to 10 psu)and nitrogen content(i.e.,5 to 60μmol L^(-1)).The results showed that cellular chlorophyll a(Chl a),carbohydrate and protein contents of U.fasciata were increased due to reduced salinity,and were decreased by interactive nitrogen enrichment.Within a short culture period(i.e.,18 h),the reduced salinity decreased the maximum photosynthetic efficiency(rETRmax and Pmax)derived from the rapid light response curve and photosynthetic oxygen evolution rate versus irradiance curve,respectively,as well as the saturation irradiance(E_(K)).This reducing effect diminished with enlonged cultivation time and reversed to a stimulating effect after 24 h of cultivation.The nitrogen enrichment stimulated the rETRmax and Pmax,as well as the E_(K),regardless of salinity,especially within short-term cultivation period(i.e.,<24 h).In addition,our results indicate that seawater freshening lowers the photosynthetic efficiency of U.fasciata in the short term,which is mitigated by nitrogen enrichment,but stimulates it in the long term,providing insight into how macroalgae thrive in coastal or estuarine waters where salinity and nutrients normally covary strongly.
文摘This study aimed to decipher the mechanism by which exogenous methyl jasmonate(MeJA)regulated the photosynthesis of Malus spectabilis leaves under ozone(O_(3))stress.The photosynthetic parameters and chlorophyll fluorescence parameters of M.spectabilis‘Hongjiu’seedlings under O_(3)stress were measured by spraying different concentrations of MeJA.The results showed that O_(3)stress significantly reduced the chlorophyll a and total chlorophyll content,net photosynthetic rate(Pn),stomatal conductance(G_(s)),transpiration rate(T_(r)),maximum fluorescence yield(F_(m)),maximum quantum yield of photosystem II(F_(v)/F_(m)),and actual photochemical efficiency of photosystem II(Ф_(PSII)),while increasing the intercellular CO_(2)concentration(Ci).Exogenous MeJA reduced the Ci and original fluorescence yield(Fo),while increasing chlorophyll a,chlorophyll b,and total chlorophyll content,P_(n),G_(s),T_(r),F_(m),F_(v)/F_(m),andФ_(PSII) of the leaves under O_(3)stress.The application of 150μmol/L MeJA showed the best effect.The above results demonstrated that exogenous MeJA could enhance chlorophyll content and photosynthetic capacity,thereby improving the tolerance of M.spectabilis to O_(3)stress.
基金supported by the National Key R&D Program of China(2021YFD2200405)the National Natural Science Foundationof China(Nos.U23A2002,31930078,and 31670450)the Fundamental Research Funds for ICBR(1632021023,1632019006,and1630032023002).
文摘Climate changes in cold-temperate zones are increasingly altering the state of climatic constraints on photosynthesis and growth,leading to adaptive changes in plant phenology and subsequent seasonal carbon assimilation.However,the spatio-temporal patterns of climatic constraints and seasonal carbon assimilation are poorly understood.In this study,the timing of peak photosynthetic activity(DOY_(pmax))was employed as a proxy for plant adap-tive state to climatic constraints on growth to examine the spatio-temporal dynamics of DOY_(pmax).By using multiple remote sensing metrics,DOY_(pmax)was characterized with changes in the solar-induced chlorophyll fluorescence(SIF)and leaf area index(LAI)from 2000 to 2018.Based on SIF,the DOY_(pmax)was generally around day 190,while based on LAI was about 10 d later.Peak photosynthetic activity of forests occurs earlier compared to other vegetation types.Overall,the advanced DOY_(pmax)were observed based on both SIF and LAI,with annual rates of 0.2(P=0.31)and 0.3(P<0.05)d,respectively.DOY_(pmax)dynamics were influ-enced by hot temperature extremes and vapor pressure defi-cits(VPD)during the early growing season,regardless of sub-zone and different vegetation type.The generalized lin-ear mixed model(GLMM)showed the largest contribution by hot extremes to DOY_(pmax)dynamics accounted for 55.5%(DOY_(pmax_SIF))and 49.1%(DOY_(pmax_LAI)),respectively,fol-lowed by VPD(DOY_(pmax_SIF):23.1%;DOY_(pmax_LAI):29.5%).These findings highlight the crucial role of climate extremes in shaping seasonal carbon dynamics and regional carbon balance.
文摘Layered transition metal hydroxides show distinct advantages in separately co-catalyzing CO_(2)reduction and H_(2)O oxidation at the electron-accumulating and hole-accumulating sites of wrapped heterojunction photocatalysts,while concurrently preventing side reactions and photocorrosion on the semiconductor surface.Herein,Ni-Co bimetallic hydroxides with varying Ni/Co molar ratios(Ni_(x)Co_(1-x)(OH)_(2),x=1,0.75,0.5,0.25,and 0)were grown in situ on a model 2D/2D S-scheme heterojunction composed of Cu_(2)O nanosheets and Fe_(2)O_(3)nanoplates to form a series of Cu_(2)O/Fe_(2)O_(3)@Ni_(x)Co_(1-x)(OH)_(2)(CF@NiCo)photocatalysts.The combined experimental and theoretical investigation demonstrates that incorporating an appropriate amount of Co into Ni(OH)_(2)not only modulates the energy band structure of Ni_(x)Co_(1-x)(OH)_(2),balances the electron-and hole-trapping abilities of the bifunctional cocatalyst and maximizes the charge separation efficiency of the heterojunction,but also regulates the d-band center of Ni_(x)Co_(1-x)(OH)_(2),reinforcing the adsorption and activation of CO_(2)and H_(2)O on the cocatalyst surface and lowering the rate-limiting barriers in the CO_(2)-to-CO and H_(2)O-to-O_(2)conversion.Benefiting from the Ni-Co synergy,the redox reactions proceed stoichiometrically.The optimized CF@Ni_(0.75)Co_(0.25)achieves CO and O_(2)yields of 552.7 and 313.0μmol gcat^(-1)h^(-1),respectively,11.3/9.9,1.6/1.7,and 4.5/5.9-fold higher than those of CF,CF@Ni,and CF@Co.This study offers valuable insights into the design of bifunctional noble-metal-free cocatalysts for high-performance artificial photosynthesis.
基金supported by the National Natural Science Foundation of China(32160503)the Earmarked Fund for Jiangxi Agriculture Research System,China(JXARS-01)the National Key R&D Program of China(2023YFD2301303).
文摘Straw return has demonstrated significant potential for enhancing carbon(C)sequestration and nitrogen(N)uptake while concurrently promoting plant productivity.However,the specific transport and distribution of C produced by photosynthesis and exogenous N within the rice plant-soil system under straw return remains unclear.A long-term straw return pot trial experiment was conducted in a double cropping rice system,incorporating treatments of inorganic fertilizer application with straw removal(F),straw burning and ash return with reducing inorganic fertilizers(SBR),and straw return with reducing inorganic fertilizers(SR)to investigate C sequestration and exogenous N uptake using ^(13)C pulse and ^(15)N isotope tracer techniques.The SR treatment had significantly higher soil ^(13)C abundance,by 24.4 and 25.4%,respectively,^(13)C concentrations in aboveground plant parts,by 18.4 and 35.8%respectively,and ^(15)N concentrations in rice panicles,by 12.8 and 34.3%than the SBR and F treatments.This enhancement contributed to a higher total organic C concentration and increased rice grain yield in the SR treatment.Furthermore,the SR treatment had significantly higher photosynthetic C,by 9.8%,which was directly transferred to soil C.The SR treatment had a higher distribution of photosynthetic C in the leaves and stems,but a lower distribution in the panicle compared to the SBR treatment.This finding is advantageous for sequestering photosynthetic C into the soil through straw return;conversely,opposite trends were observed in ^(15)N distribution.In addition,rice plants in the SR treatment had increased N uptake from urea and soil N sources,enhancing N recovery by 9.2 and 12.5%,respectively,and reducing soil N residues.Correlation analysis showed that the SR treatment increased the concentrations of ^(13)C in leaves and roots while decreasing the ^(15)N abundance in all rice organs,thereby contributing to an increase in rice yield.The partial least square path model suggested that the increase in rice yield under the SR treatment was primarily linked to ^(13)C accumulation within the rice plant-soil system.The results suggest that straw return increases the sequestration of photosynthetic C and exogenous N in the rice plant-soil system and increases N utilization efficiency,which subsequently improves both rice and soil productivity.
基金financially supported by the National Natural Science Foundation of China(Grant number:32071661)。
文摘To determine the invasiveness of invasive plants,many studies have compared photosynthetic traits or strategies between invasive and native species.However,few studies have compared the photosynthetic dynamics between invasive and native species during light fluctuations.We compared photosynthetic induction,relaxation dynamics and leaf traits between the invasive species,Tithonia diversifolia and two native species,Clerodendrum bungei and Blumea balsamifera,in full-sun and shady habitats.The photosynthetic dynamics and leaf traits differed among species.T.diversifolia showed a slower induction speed and stomatal opening response but had higher average intrinsic water-use efficiency than the two native species in full-sun habitats.Thus,the slow induction response may be attributed to the longer stomatal length in T.diversifolia.Habitat had a significant effect on photosynthetic dynamics in T.diversifolia and B.balsamifera but not in C.bungei.In shady habitat,T.diversifolia had a faster photosynthetic induction response than in full-sun habitat,leading to a higher average stomatal conductance during photosynthetic induction in T.diversifolia than in the two native species.In contrast,B.balsamifera had a larger stomatal length and slower photosynthetic induction and relaxation response in shady habitat than in full-sun habitat,resulting in higher carbon gain during photosynthetic relaxation.Nevertheless,in both habitats,T.diversifolia had an overall higher carbon gain during light fluctuations than the two native species.Our results indicated that T.diversifolia can adopt more effective response strategies under fluctuating light environments to maximize carbon gain,which may contribute to its successful invasion.
基金financed by the National Key Research and Development Program,China(Grant Nos.2022YFE0113400 and 2022YFD1500402)National Natural Science Foundation of China(Grant No.32001466)+3 种基金Scientific and Technological Innovation Fund of Carbon Emissions Peak and Neutrality of Jiangsu Provincial Department of Science and Technology,China(Grant Nos.BE2022304 and BE2022305)Joints Funds of the National Natural Science Foundation of China(Grant No.U20A2022)Postdoctoral Research Foundation of China(Grant No.2020M671628)the Priority Academic Program Development of Jiangsu Higher Education Institutions,China.
文摘Simultaneous stresses of salinity and drought often coincide during rice-growing seasons in saline lands,primarily due to insufficient water resources and inadequate irrigation facilities.Consequently,combined salinity-drought stress poses a major threat to rice production.In this study,two salinity levels(NS,non-salinity;HS,high salinity)along with three drought treatments(CC,control condition;DJ,drought stress imposed at jointing;DH,drought stress imposed at heading)were performed to investigate their combined influences on leaf photosynthetic characteristics,biomass accumulation,and rice yield formation.Salinity,drought,and their combination led to a shortened growth period from heading to maturity,resulting in a reduced overall growth duration.Grain yield was reduced under both salinity and drought stress,with a more substantial reduction under the combined salinity-drought stress.The combined stress imposed at heading caused greater yield losses in rice compared with the stress imposed at jointing.Additionally,the combined salinity-drought stress induced greater decreases in shoot biomass accumulation from heading to maturity,as well as in shoot biomass and nonstructural carbohydrate(NSC)content in the stem at heading and maturity.However,it increased the harvest index and NSC remobilization reserve.Salinity and drought reduced the leaf area index and SPAD value of flag leaves and weakened the leaf photosynthetic characteristics as indicated by lower photosynthetic rates,transpiration rates,and stomatal conductance.These reductions were more pronounced under the combined stress.Salinity,drought,and especially their combination,decreased the activities of ascorbate peroxidase,catalase,and superoxide dismutase,while increasing the contents of malondialdehyde,hydrogen peroxide,and superoxide radical.Our results indicated a more significant yield loss in rice when subjected to combined salinity-drought stress.The individual and combined stresses of salinity and drought diminished antioxidant enzyme activities,inhibited leaf photosynthetic functions,accelerated leaf senescence,and subsequently lowered assimilate accumulation and grain yield.
基金This study was supported by the National Natural Science Foundation of China(Grant No.31870613)Guizhou Province High-level Innovative Talents Training Plan Project(2016)5661.
文摘Light levels determine regeneration in stands and a key concern is how to regulate the light environment of different stand types to the requirements of the understory.In this study,we selected three stands typical in south China(a Cryptomeria japonica plantation,a Quercus acutissima plantation,and a mixed stand of both)and three thinning intensities to determine the best understory light environ-ment for 3-year-old Phoebe bournei seedlings.The canopy structure,understory light environment,and photosynthe-sis and growth indicators were assessed following thin-ning.Thinning improved canopy structure and understory light availability of each stand;species composition was the reason for differences in the understory light environ-ment.Under the same thinning intensity,the mixed stand had the greatest light radiation and most balanced spectral composition.P.bournei photosynthesis and growth were closely related to the light environment;all three stands required heavy thinning to create an effective and sustained understory light environment.In a suitable understory light environment,the efficiency of light interception,absorption,and use by seedlings was enhanced,resulting in a higher carbon assimilation the main limiting factor was stomatal conductance.As a shade-avoidance signal,red/far-red radia-tion is a critical factor driving changes in photosynthesis and growth of P.bournei seedlings,and a reduction increased light absorption and use capacity and height:diameter ratios.The growth advantage transformed from diameter to height,enabling seedlings to access more light.Our findings suggest that the regeneration of shade-tolerant species such as P.bournei could be enhanced if a targeted approach to thinning based on stand type was adopted.
基金supported by the National Key Research and Development Program of China(2022YFD2301402)the National Natural Science Foundation of China(32071903)+2 种基金the Jiangsu Provincial Key Technologies R&D Program of China(BE2019386)the Guidance Foundation of the Sanya Institute of Nanjing Agricultural University,China(NAUSY2D01)the Earmarked Fund for Jiangsu Agricultural Industry Technology System(JATS(2022)468,JATS(2022)168)。
文摘A two-year field experiment was conducted to measure the effects of densification methods on photosynthesis and yield of densely planted wheat.Inter-plant and inter-row distances were used to define ratefixed pattern(RR)and row-fixed pattern(RS)density treatments.Meanwhile,four nitrogen(N)rates(0,144,192,and 240 kg N ha-1,termed N0,N144,N192,and N240)were applied with three densities(225,292.5,and 360×10^(4)plants ha^(-1),termed D225,D292.5,and D360).The wheat canopy was clipped into three equal vertical layers(top,middle,and bottom layers),and their chlorophyll density(Ch D)and photosynthetically active radiation interception(FIPAR)were measured.Results showed that the response of Ch D and FIPAR to N rate,density,and pattern varied with different layers.N rate,density,and pattern had significant interaction effects on Ch D.The maximum values of whole-canopy Ch D in the two seasons appeared in N240 combined with D292.5 and D360 under RR,respectively.Across two growing seasons,FIPAR values of RR were higher than those of RS by 29.37%for the top layer and 5.68%for the middle layer,while lower than those of RS by 20.62%for the bottom layer on average.With a low N supply(N0),grain yield was not significantly affected by density for both patterns.At N240,increasing density significantly increased yield under RR,but D360 of RS significantly decreased yield by 3.72%and 9.00%versus D225 in two seasons,respectively.With an appropriate and sufficient N application,RR increased the yield of densely planted wheat more than RS.Additionally,the maximum yield in two seasons appeared in the combination of D360 with N144 or N192 rather than of D225 with N240 under both patterns,suggesting that dense planting combined with an appropriate N-reduction application is feasible to increase photosynthesis capacity and yield.
基金supported by the National Key Research and Development Program of China(2016YFD0600201)the National Nonprofit Institute Research Grant of CAF(CAFYBB2017ZB003)+1 种基金the National Natural Science Foundation of China(3187071631670720)。
文摘Understanding the relationship between forest management and water use efficiency(WUE)is important for evaluating forest adaptability to climate change.However,the effects of thinning and understory removal on WUE and its key controlling processes are not well understood,which limits our comprehension of the physiological mechanisms of various management practices.In this study,four forest management measures(no thinning:NT;understory removal:UR;light thinning:LT;and heavy thinning:HT)were carried out in Pinus massoniana plantations in a subtropical region of China.Photosynthetic capacity and needle stable carbon isotope composition(δ^(13)C)were measured to assess instantaneous water use efficiency(WUE_(inst))and long-term water use efficiency(WUE_(i)).Multiple regression models and structural equation modelling(SEM)identified the effects of soil properties and physiological performances on WUE_(inst)and WUE_(i).The results show that WUE_(inst)values among the four treatments were insignificant.However,compared with the NT stand(35.8μmol·mol^(-1)),WUE_(i)values significantly increased to 41.7μmol·mol^(-1)in the UR,50.1μmol·mol^(-1)in the LT and 46.6μmol·mol^(-1)in HT treatments,largely explained by photosynthetic capacity and soil water content.Understory removal did not change physiological performance(needle water potential and photosynthetic capacity).Thinning increased the net photosynthetic rate(A_n)but not stomatal conductance(g_s)or predawn needle water potential(ψ_(pd)),implying that the improvement in water use efficiency for thinned stands was largely driven by radiation interception than by soil water availability.In general,thinning may be an appropriate management measure to promote P.massoniana WUE to cope with seasonal droughts under future extreme climates.
基金the Support Plan Projects of Science and Technology Department of Guizhou Province [No.(2021)YB453]。
文摘Photosynthesis is the most important biochemical reaction on Earth. It has co-evolved and developed with the Earth, driving the biogeochemical cycle of all elements on the planet and serving as the only chemical process in nature that can convert light energy into chemical energy. Some heavy oxygen isotopic(^(18)O) labeling experiments have"conclusively" demonstrated that the oxygen released by photosynthesis comes only from water and are written into textbooks. However, it is not difficult to find that bicarbonate has never been excluded from the direct substrate of photosynthesis from beginning to end during the history of photosynthesis research. No convincing mechanism can be used to explain photosynthetic oxygen evolution solely from water photolysis. The bicarbonate effect, the Dole effect, the thermodynamic convenience of bicarbonate photolysis, the crystal structure characteristics of photosystem Ⅱ, and the reinterpretation of heavy oxygen isotopic labeling(^(18)O)experiments all indicate that the photosynthetic oxygen evolution does not exclude the important role and contribution of bicarbonate photolysis. The recently proposed view that bicarbonate photolysis is the premise of water photolysis, bicarbonate photolysis and water photolysis work together with a 1:1(mol/mol) stoichiometric relationship, and the stoichiometric relationship between oxygen and carbon dioxide released during photosynthetic oxygen evolution is also 1:1, has excellent applicability and objectivity, which can logically and reasonably explain the precise coordination between light and dark reactions during photosynthesis, the bicarbonate effect, the Dole effect, the Kok cycle and the neutrality of water and carbon in nature.This is of great significance for constructing the bionic artificial photosynthetic reactors and scientifically answering the question of the source of elemental stoichiometric relationships in nature.
基金supported by the National Key Research and Development Program of China(Grant No.2018YFD1000400)Innovative Program for Graduate Student of Qingdao Agricultural University(Grant No.QNYCX22045).
文摘Drought(water shortage)can substantially limit the yield and economic value of rose plants(Rosa spp.).Here,we characterized the effect of exogenous calcium(Ca^(2+))on the antioxidant system and photosynthesis-related properties of rose under polyethylene glycol 6000(PEG6000)-induced drought stress.Chlorophyll levels,as well as leaf and root biomass,were significantly reduced by drought;drought also had a major effect on the enzymatic antioxidant system and increased concentrations of reactive oxygen species.Application of exogenous Ca^(2+)increased the net photosynthetic rate and stomatal conductance of leaves,enhanced water-use efficiency,and increased the length and width of stomata following exposure to drought.Organ-specific physiological responses were observed under different concentrations of Ca^(2+).Application of 5 mmol·L^(-1)Ca^(2+)promoted photosynthesis and antioxidant activity in the leaves,and application of 10 mmol·L^(-1)Ca^(2+)promoted antioxidant activity in the roots.Application of exogenous Ca^(2+)greatly enhanced the phenotype and photosynthetic capacity of potted rose plants following exposure to drought stress.Overall,our findings indicate that the application of exogenous Ca^(2+)enhances the drought resistance of roses by promoting physiological adaptation and that it could be used to aid the cultivation of rose plants.
基金supported by the Natural Science Foundation of Jiangsu Province,China(BK20220563)the Key R&D Program of Jiangsu Province,China(BE2022338)the Colleges and Universities in Jiangsu Province Natural Science Foundation of China(19KJB210014)。
文摘Controlled-release urea(CRU)releases nitrogen(N)at the same pace that rice takes it up,which can effectively improve N use efficiency,increase rice yield and improve rice quality.However,few studies have described the effects of CRU application on the photosynthetic rate and endogenous enzyme activities of rice.Accordingly,a twoyear field trial was conducted with a total of seven treatments:CK,no N fertilizer;BBF,regular blended fertilizer;RBBF,20%N-reduced regular blended fertilizer;CRF1,70%CRU+30%regular urea one-time base application;CRF2,60%CRU+40%regular urea one-time base application;RCRF1,CRF1 treatment with 20%N reduction;and RCRF2,CRF2 treatment with 20%N reduction.Each treatment was conducted in triplicate.The results showed that the N recovery efficiency(NRE)of the controlled-release bulk blending fertilizer(CRBBF)treatments was significantly greater over the two years.There were significant yield increases of 4.1–5.9%under the CRF1treatment and 5.6–7.6%under the CRF2 treatment compared to the BBF treatment,but the differences between the reduced-N treatments RBBF and RCRF2 were not significant.Photosynthetic rates under the CRF1 and CRF2treatments were significantly higher than under the other treatments,and they had significantly greater RuBPCase,RuBisCO,glutamate synthase(GOGAT)and glutamine synthetase(GS)enzyme activities.Additionally,the soil NH_(4)^(+)-N and NO_(3)^(–)-N contents under the CRBBF treatments were significantly higher at the late growth stage of rice,which was more in-line with the fertilizer requirements of rice throughout the reproductive period.CRBBF also led to some improvement in rice quality.Compared with the BBF and RBBF treatments,the protein contents under the CRBBF treatments were reduced but the milling,appearance,eating and cooking qualities of the rice were improved.These results showed that the application of CRBBF can improve the NRE,photosynthetic rate and endogenous enzyme activities of rice,ensuring sufficient N nutrition and photosynthetic material production during rice growth and thereby achieving improved rice yield and quality.
基金funded by the National Key R&D Program of China(2017YFD0801300,2017YFD0801103)the National Natural Science Foundation of China(32001014).
文摘Compared with conventional fertilizers,nano fertilizer has many advantages such as controlled release,controlled or slow release of nutrients,high efficiency of nutrition use,cheap,and little polluting of the environment.The use of fertilizers with nanotechnology is a new field in agriculture,and it is a promising and cost-effective substitute for conventional fertilizers to improve the productivity of the world’s food supply.Photosynthesis is an essential biochemical reaction on Earth.Improving photosynthesis,the basic process for light’s transformation into chemical energy is one of the most important areas of research for improving agricultural output and tackling world food security.Nano fertilizers can promote plant photosynthesis,improve crop photosynthetic efficiency,increase plant biomass,improve plant stress resistance,improve nutrient uptake efficiency,and encourage plant growth and development due to their tunable surface properties,special electronic,magnetic,and optical properties,and other characteristics.It can be seen that nano fertilizers and improving photosynthetic efficiency in plants are a hot topic of concern.Therefore,an overview of the effects of nano fertilizers on plant photosynthesis is given in this paper.These effects include the ability to increase biomass,pigment and gas openness,photosynthetic efficiency,and plant resistance to stress.On the other hand,improper use of nano fertilizers can have the opposite effect,inhibiting plant photosynthesis.
基金Supported by Earmarked Fund for China Agriculture Research System(CARS-26)Project of High-quality Development in Hundred Counties,Thousands Towns and Ten Thousand Villages.
文摘[Objectives]To investigate the effects of 15 distinct citrus rootstock-scion combinations on tree growth,fruit quality,and photosynthetic characteristics under red loam soil conditions and provide a theoretical foundation for the selection of appropriate citrus rootstock-scion combinations in the Zhaoqing region.[Methods]A total of 15 citrus rootstock-scion combinations were utilized as test materials for a comprehensive analysis of their phenological periods(budding,flowering,and fruiting),tree growth indicators(tree height,crown diameter,and growth),and fruit quality(appearance quality and intrinsic quality).The photosynthetic characteristics of the test materials,including the net photosynthetic rate(Pn),transpiration rate(Tr),water use efficiency(WUE),apparent quantum yield(AQY),and carboxylation efficiency(CE),were analyzed to determine their significance.Additionally,the leaf photosynthetic physiological indicators,such as soluble protein,specific leaf weight,chlorophyll,and carotenoids,were evaluated.[Results]There were notable differences observed in the phenological period,growth potential of trees,fruit quality,and photosynthetic characteristics among various citrus rootstock-scion combinations.The phenological periods exhibited variation contingent on the grafting varieties.In terms of tree growth potential,the Citrus tangerina Tanaka‘Hongju’and C.haniana Hort.‘Suanju’rootstocks demonstrated greater tree height,crown growth,and overall tree strength;however,they were also prone to excessive growth.Conversely,the C.limonia Osbeck‘Hongningmeng’and C.sinensis×P.trifoliata‘Zhicheng’rootstocks displayed medium growth potential,while the Poncirus trifoliate(L)Raf.‘Zhike’rootstock resulted in shorter trees.In terms of fruit quality,the single fruit weight of C.flamea Hort.‘Shatangju’ranged from 33 to 50 g,exhibiting a flat and round shape.The total soluble solids and titratable acid content of‘Shatangju’grafted onto the‘Zhike’rootstock were notably high.In contrast,the single fruit weight of C.haniana Hort.‘Chuntianju’varied between 65 and 81 g,characterized by a high flat round shape.The‘Suanju’rootstock demonstrated a higher sugar and acid content compared to other rootstocks.Additionally,the single fruit weight of C.nobilis Lour.‘Gonggan’ranged from 62 to 145 g,with the fruit shape being either round or oval.The soluble sugar and total soluble solids content associated with the‘Zhike’rootstock was also elevated.In relation to photosynthetic characteristics,the photosynthetic performance of the‘Shatangju’variety was superior when grafted onto the‘Zhike’and‘Hongju’rootstocks.Similarly,the‘Chuntianju’variety exhibited enhanced photosynthetic performance on the‘Zhike’,‘Zhicheng’,and‘Hongju’rootstocks.Furthermore,the‘Gonggan’variety demonstrated improved photosynthetic performance when grafted onto the‘Zhike’and‘Suanju’rootstocks.[Conclusions]Based on the characteristics of the red loam soil in the Zhaoqing region,the rootstocks‘Zhike’and‘Hongju’are conducive to the cultivation of the‘Shatangju’variety.Additionally,the rootstocks‘Zhike’,‘Zhicheng’,and‘Hongju’are optimal for the growth of the‘Chuntianju’variety,while the rootstocks‘Zhike’and‘Suanju’are appropriate for the growth of the‘Gonggan’variety.
文摘Preserving microbial diversity has become a strategic undertaking. Thus, ex situ microalgal culture conservation results in strategic and functional resource in both biodiversity protection and application domains. Cryopreservation of microalgae has been practiced since the 1960s and is now considered the optimal preservation strategy. Furthermore, the overall monitoring during growth of cultures after freezing/thawing protocols was hardly investigated and there is poor evaluation related to preserve especially the photosystem apparatus. The present study focuses on Stichococcus bacillaris as case study for short-term cryopreservation at −80 °C storage. Various freezing pretreatments using cryoprotective agents, and two thawing methods were compared introducing a novel variable to evaluate viability recovery and assessing growth kinetics of cultures immediately after thawing and after a series batch cultivation. Photosynthetic rate and pigments assessment were proposed to evaluate hidden metabolic cell damage. Results underline cryoprotective agents can increase the kinetic recovery of preserved cells in terms of reduction of lag phase during batch cultivation tests: the use of dimethyl sulfoxide and glycerol granted a growth comparable to unpreserved cells when sudden thawing occurs after 24 hours of storage, but recovery after preservation is less sensitive to cryoprotective agents when gradual thawing and 1 month of storage is considered. However, cells are always able to restore their physiological pathways even without agents, so their kinetic effect has been proved and quantified. Interestingly, both the photosynthetic efficiency and the ratio between total chlorophyll and carotenoids are comparable (0.75 F<sub>v</sub>/F<sub>m</sub>, 2.2 ± 0.25 g/g) to unpreserved cells and they are unsensitive to chosen agents, but the ratio between chlorophyll a and chlorophyll b was clearly altered (up to 10 times), suggesting that photoactive pigments relative proportions can result in similar growth kinetic performances. Long-term studies will be carried out to assess whether the differences found could cause chronic damage to photosystem efficiency of S. bacillaris cultures.
文摘It is well known that plants have functional equilibrium between their above-ground parts (shoots) and below-ground parts (roots), but whether the above-ground parts of plants have functional equilibrium between their photosynthetic structures (leaves) and non-photosynthetic structures (branches and stem) is unknown. The purpose of this study is to test the hypotheses that: (1) the above-ground parts of plants have functional equilibriums between their photosynthetic structures and non-photosynthetic structures; (2) the maintenance of the equilibriums is guaranteed by the alteration of biomass partitioning to photosynthetic and non-photosynthetic structures. To test these hypotheses, a pruning experiment with four pruning intensities (0%, 20%, 50%, and 70%) were carried out with three subtropical Chinese tree species ( Ficus microcarpa, Ficus virens, Cinnamomum camphora). Pruning treatments were conducted in two successive years. The results were in conformity with the hypothesis, i.e. above-ground parts of trees had functional equilibriums between photosynthetic and non-photosynthetic structures. Pruning decreased instantaneously the mass ratios of photosynthetic structures to non-photosynthetic structures (P/NP) of all three tree species, the reduction in P/NP was strengthened with pruning intensity. However, one year after pruning, the P/NP of all pruned trees increased and were not smaller than those of unpruned trees. In agreement with the expectation, the biomass partitioning of pruned trees was altered, more newly produced above-ground biomass was partitioned to leaf growth and less to branch and stem growth, thus enabled the damaged trees to restore their functional equilibrium between photosynthetic and non-photosynthetic structures. It is clear that the maintenance of functional equilibrium between photosynthetic and non-photosynthetic structures guaranteed by the alteration of biomass partitioning provides plants a good strategy to resist external disturbance and damage.
基金The State Key Basic Research and Development Plan(G1998010100)The Innovative Foundation of Laboratory of Photosynthesis Basic Research,Insitute of Botany,The Chinese Academy of Sciences
文摘The photosynthetic functions and the sensitivity to photoinhibition were compared between two superhigh_yield hybrid rice (Oryza sativa L.) Liangyoupeijiu and X07S/Zihui 100, the newly developed from two parental lines and traditional hybrid rice Shanyou 63 developed from three parental lines. The results showed that, as compared to Shanyou 63, the net photosynthetic rate of Liangyoupeijiu and X07S/Zihui 100 was 9.1% and 11.9% higher, the transpiration rate was 37.4% and 31.4% lower, and their water use efficiency was 74.2% and 63.5% higher respectively. After strong light (2 000 μmol photons·m -2 ·s -1 ) treatment for 2 h, the photochemical quantum yield and the photochemical quenching increased by 37.0% and 18.0% respectively in Liangyoupeijiu, 28.3% and 46.2% in X07S/Zihui 100, but decreased a little in Shanyou 63. The non_photochemical quenching decreased in Liangyoupeijiu and X07S/Zihui 100 (about 50%) but increased greatly in Shanyou 63 (about 50%). Better photosynthetic functions, higher water use efficiency and stronger resistance to photoinhibition, may be the physiological basis for the super high_yield of the two hybrid rice under study.
