Ongoing climate change has a considerable influence on the seasonality,timing,and intensity of rainfall worldwide,and is also predicted to decrease snow cover in cold ecosystems.Larch is a widely distributed tree spec...Ongoing climate change has a considerable influence on the seasonality,timing,and intensity of rainfall worldwide,and is also predicted to decrease snow cover in cold ecosystems.Larch is a widely distributed tree species in boreal Eurasia,calling for a comprehensive understanding of how larch adapts to changes in both rainfall and snowfall by adjusting carbon-water physiology.Here,we conducted a short-term rainfall(−60% ambient rainfall;three-year)and snowfall(−73% ambient snowfall;two-year)exclusions experiment in Larix gmelinii forest in northeastern China,and aimed to explore the responses of hydraulic(leaf pressure-volume traits,leaf and branch hydraulic conductivity and embolism resistance),stomatal(stomatal closure point and stomatal safety margin),and economic(photosynthetic rate,nutrient and non-structural carbohydrates contents)traits to rainfall and snowfall reductions.Despite the weak alternation of leaf and branch hydraulic traits,both rainfall and snowfall reductions significantly led to early stomatal closure and increased stomatal safety margins(the difference between stomatal closure point and xylem embolism threshold,describing drought resistance by merging both hydraulic and stomatal strategies).Reductions in rainfall and snowfall induced water or/and low-temperature stress,resulting in more conservative leaf economic traits,including a reduced photosynthetic rate,lower leaf nitrogen concentration,and higher leaf density.In addition,larch responded to reductions in rainfall and snowfall by up-regulating non-structural carbohydrates in the xylem,which helps repair embolism or lower the freezing point acting as osmolytes.Overall,our findings reveal that larch could adapt to the drought and snowpack reduction by strict stomatal regulation and investing non-structural carbohydrates in embolism repairing,at the cost of carbon assimilation.展开更多
Secondary salinization is a major environmental factor that causes a stress response and growth inhibition in plants in protected agriculture.The positive effect of a low red to far-red light ratio(R:FR)in salt tolera...Secondary salinization is a major environmental factor that causes a stress response and growth inhibition in plants in protected agriculture.The positive effect of a low red to far-red light ratio(R:FR)in salt tolerance through antioxidant defense has been reported,while the underlying model remains obscure.In this study,we used physiological and genetic approaches to investigate the relationship between H_(2)O_(2) signaling and low R:FR-induced salt tolerance and antioxidant capacity in tomato seedlings.This study found that low R:FR treatment with calcium nitrate stress(SL treatment)enhanced the growth of plants and increased the net photosynthetic rate 5 days after stress compared with a higher R:FR ratio and calcium nitrate stress(S treatment).With transcriptomic analysis of tomato leaves at 5 d,compared with CK,most of glutaredoxin genes and antioxidant enzymes were upregulated by S treatment,which were upregulated further by SL treatment.Compared to the S treatment,within 5 days,the H_(2)O_(2) level was increased faster before 24 h and it was slowed down after 24 h by SL treatment,with less H_(2)O_(2) accumulation at 5 d than that of S treatment.The enhancement of gene expression of RBOH genes were also shown at 24 h under SL.It was found that stomatal conductance followed the dynamic change of H_(2)O_(2),with a rapid closure of stomata of a decrease at 3 h and an increase after 9 h in SL treatment compared to S treatment,respectively.There was same trend of stomata opening degrees of tomato leaves observed by optical microscope.However,the inhibitor of H_(2)O_(2) production(DPI pretreatment)weakened the positive effect of low R:FR on the regulation of stomatal movement.In addition,SL treatment increased the antioxidant enzyme activities and proline content and decreased the MDA content as compared to the S treatment,while the enhancement of ROS homeostasis was reduced by the DPI pretreatment.In conclusion,low R:FR improved redox homeostasis and stomatal status under calcium nitrate stress through H_(2)O_(2)signaling,improving the adaptation of tomato seedlings to soil salinization stress.展开更多
Heat stress hinders the growth and productivity of sweetpotato plants,predominantly through oxidative damage to cellular membranes.Therefore,the development of efficient approaches for mitigating heat-related impairme...Heat stress hinders the growth and productivity of sweetpotato plants,predominantly through oxidative damage to cellular membranes.Therefore,the development of efficient approaches for mitigating heat-related impairments is essential for the long-term production of sweetpotatoes.Melatonin has been recognised for its capacity to assist plants in dealing with abiotic stress conditions.This research aimed to investigate how different doses of exogenous melatonin influence heat damage in sweetpotato plants.Heat stress drastically affected shoot and root fresh weight by 31.8 and 44.5%,respectively.This reduction resulted in oxidative stress characterised by increased formation of hydrogen peroxide(H_(2)O_(2))by 804.4%,superoxide ion(O_(2)^(·-))by 211.5%and malondialdehyde(MDA)by 234.2%.Heat stress also reduced chlorophyll concentration,photosystemⅡefficiency(F_v/F_m)by 15.3%and gaseous exchange.However,pre-treatment with 100μmol L^(-1)melatonin increased growth and reduced oxidative damage to sweetpotato plants under heat stress.In particular,melatonin decreased H_(2)O_(2),O_(2)^(·-)and MDA by 64.8%,42.7%and 38.2%,respectively.Melatonin also mitigated the decline in chlorophyll levels and improved stomatal traits,gaseous exchange and F_(v)/F_(m)(13%).Results suggested that the favorable outcomes of melatonin treatment can be associated with elevated antioxidant enzyme activity and an increase in non-enzymatic antioxidants and osmo-protectants.Overall,these findings indicate that exogenous melatonin can improve heat stress tolerance in sweetpotatoes.This stu dy will assist re searchers in further investigating how melatonin makes sweetpotatoes more resistant to heat stress.展开更多
5-Aminolevulinic acid(ALA)is a novel plant growth regulator that has shown outstanding capability to promote stomatal opening.Starch degradation,catalyzed byβ-amylase(EC3.2.1.2,BAM),plays an important role in stomata...5-Aminolevulinic acid(ALA)is a novel plant growth regulator that has shown outstanding capability to promote stomatal opening.Starch degradation,catalyzed byβ-amylase(EC3.2.1.2,BAM),plays an important role in stomatal opening.However,whether the starch breakdown is involved in ALA-regulating stomatal movement is unclear.In the current study,we found that exogenous ALA effectively stimulated the starch breakdown in guard cells,increasedβ-amylase activity and promoted stomatal opening in leaves of apple(Malus×domestica).Based on genome-wide identification,we identified a total of 119 members of BAM gene family in ten commonly Rosaceae crops.Analyses of gene structure,motif identification,and gene pair collinearity revealed relative conservation among members within the same group or subgroup.Among these genes,MdBAM17 and other 12 genes were identified as the orthologous genes of AtBAM1,which is responsible for starch degradation to modulate the stomatal movement in Arabidopsis.qRT-PCR analysis revealed a positive correlation between the expressions of MdBAM17 and stomatal aperture,as well asβ-amylase activity,whereas a negative correlation was observed with the starch content.Subcellular localization analysis confirmed that MdBAM17 is a chloroplast protein,consistent with the AtBAM1.MdBAM17 was mainly expressed in guard cells and responsive to exogenous ALA.Overexpressing MdBAM17 increasedβ-amylase activity and promoted starch breakdown,leading to stomatal opening,which was further strengthened by ALA.RNA-interfering MdBAM17 decreasedβ-amylase activity,resulting in starch accumulation,and impairing the stomatal opening by ALA.However,modulation of MdBAM17 expression did not affect the levels of flavonols and H_(2)O_(2)in guard cells,suggesting that MdBAM17-promoted starch degradation may function at downstream of ROS signaling in the ALAregulated stomatal opening.Our findings provide new insights into the mechanisms of ALA-regulated stomatal movement.展开更多
Recurrent aphthous stomatitis(RAS)is a very frequent condition in developed countries whose basic symptom is a lesion referred to as an aphthous ulcer.High levels of interleukin(IL)-1 and IL-6 and low salivary levels ...Recurrent aphthous stomatitis(RAS)is a very frequent condition in developed countries whose basic symptom is a lesion referred to as an aphthous ulcer.High levels of interleukin(IL)-1 and IL-6 and low salivary levels of IL-10 are the basis of RAS pathogenesis.Sublingual supplements based on IL-10 can be very useful in reducing the phenomenon of aphthous recurrence in patients with RAS.An observational clinical experience with a group of 5 patients with RAS receiving a commercially available IL-10-based supplement was reported by the authors.The findings revealed a subsequent reduction in the incidence of mouth ulcers.展开更多
While biochar amendment enhances plant productivity and water-use efficiency(WUE),particularly under waterlimited conditions,the specific mechanisms driving these benefits remain unclear.Thus,the present study aims to...While biochar amendment enhances plant productivity and water-use efficiency(WUE),particularly under waterlimited conditions,the specific mechanisms driving these benefits remain unclear.Thus,the present study aims to elucidate the synergistic effects of biochar and reduced irrigation on maize(Zea mays L.)plants,focusing on xylem composition,root-to-shoot signaling,stomatal behavior,and WUE.Maize plants were cultivated in splitroot pots filled with clay loam soil,amended by either wheat-straw biochar(WSB)or softwood biochar(SWB)at 2%(w/w).Plants received full irrigation(FI),deficit irrigation(DI),or partial root-zone drying rrigation(PRD)from the 4-leaf to the grain-filling stage.Our results revealed that the WSB amendment significantly enhanced plant water status,biomass accumulation,and WUE under reduced irrigation,particularly when combined with PRD.Although reduced irrigation inhibited photosynthesis,it enhanced WUE by modulating stomatal morphology and conductance.Biochar amendment combined with reduced rrigation significantly increased xylem K^(+),Ca^(2+),Mg^(2+),NO_(3)^(-),Cl^(-),PO_(4)^(3-),and SO_(4)^(2-)-but decreased Na+,which in turn lowered xylem pH.Moreover,biochar amendment and especially WSB amendment further increased abscisic acid(ABA)contents in both leaf and xylem sap under reduced irrigation conditions due to changes in xylem ionic constituents and pH.The synergistic interactions between xylem components and ABA led to refined adjustments in stomatal size and density,thereby affecting stomatal conductance and ultimately improving the WUE of maize plants at different scales.The combined application of WSB and PRD can,therefore,emerge as a promising approach for improving the overall plant performance of maize plants with increased stomatal adaptations and WUE,especially under water-limited conditions.展开更多
Soil water content(SWC)and meteorological conditions,as key environmental variables influencing tree water use,vary highly within the growing season,hindering a better understanding of environmental control mechanisms...Soil water content(SWC)and meteorological conditions,as key environmental variables influencing tree water use,vary highly within the growing season,hindering a better understanding of environmental control mechanisms on canopy transpiration(Ec).Disentangling the effects of these variables on Ec across growing-season stages is crucial for Ec estimation and forest management.In this study,43-year-old Pinus tabuliformis Carr.and 31-yearold Platycladus orientalis(L.)Franco plantations in the semiarid Chinese Loess Plateau were monitored for Ec during the growing season of 2015-2020.The contributions of environmental factors to Ec were assessed using the boosted regression tree(BRT)model.Results showed that the contributions of SWC to Ec were greater at the early(May-June)and late(September)stages,while the contributions of vapor pressure deficit(VPD)and total solar radiation(Rs)to Ec increased at the middle(July-August)stage due to high soil water availability.Overall,Ec in both plantations was dominated by SWC(20.4%≤contributions≤48.8%)and Rs(22.7%≤contributions≤35.8%).Both species exhibited strong stomatal regulation of Ec.Specifically,stomatal opening was significantly inhibited by VPD at the early stage and strongly affected by SWC at the late stage.This study highlights that soil water conditions in artificial forests should be adjusted according to changes in influencing factors on Ec.Particularly during the early and late stages,measures(e.g.,land preparation,thinning,and pruning)can be implemented to improve soil moisture in such dryland forests.展开更多
The low efficiency of phytoextraction of lead(Pb)from agricultural fields poses a significant agricultural challenge.Organic chelating agents can influence Pb bioavailability in soil,affecting its uptake,transport,and...The low efficiency of phytoextraction of lead(Pb)from agricultural fields poses a significant agricultural challenge.Organic chelating agents can influence Pb bioavailability in soil,affecting its uptake,transport,and toxicity in plants.This study aimed to assess the impact of citric acid(CA)and diethylenetriaminepentaacetic acid(DTPA)on chelate-assisted phytoextraction of Pb and its effect on growth and physiology of two cultivars(07001;07002)of mung bean(Vigna radiata).The cultivars of mung bean were exposed to 60 lead chloride(PbCl_(2))solution,mg⋅L-1with or without the addition of 300 CA or 500 DTPA,until maturity.The exposure of plants to Pb mg⋅L^(-1) mg⋅L^(-1) stress increased the accumulation of Pb in roots(49%of control),stems(58%of control),leaves(67%of control),and seeds(61%of control).Maximum accumulation of Pb was observed in roots and the least accumulation was found in seeds of both mung bean cultivars.The extent of Pb accumulation in different plant parts correlated positively with Pb toxicity and reduced growth of both mung bean cultivars(33%to 40%).The cultivar cv 07001 was more susceptible to Pb stress.The addition of CA and DTPA increased the accumulation of Pb in plant parts of mung bean cultivars-phytoextraction(10.8%to 21.5%).However,the addition of CA partitioned Pb in vegetative parts,i.e.,root,stem thus mitigated the toxic effects of Pb on the growth of mung bean cultivars(6.25%–10.5%).In contrast,the addition of DTPA had adverse effects on the growth of mung bean cultivars.The addition of CA facilitated a greater uptake and accumulation of nitrogen,phosphorous,and potassium in the roots and leaves of mung bean cultivars.In addition,CA also improved the photosynthetic pigments(11%–14%)and photosynthetic rate(5%–12%)under both control and Pb stress conditions.The ameliorative effect of CA on the photosynthetic capacity of mung bean cultivars was likely associated with photosynthetic metabolic factors rather than stomatal factors.Furthermore,cv 07002 was found to be more tolerant to Pb stress and showed better performance in CA application.Overall,the application of CA demonstrated significant potential as a chelating agent for remediating Pb-contaminated soil.展开更多
Thalidomide,an immunomodulatory drug,is widely recommended for the treatment of recurrent aphthous stomatitis(RAS).This review aimed to assess the reliability of thalidomide for managing RAS,oro-genital ulcers associa...Thalidomide,an immunomodulatory drug,is widely recommended for the treatment of recurrent aphthous stomatitis(RAS).This review aimed to assess the reliability of thalidomide for managing RAS,oro-genital ulcers associated with Behçet’s disease(BD),and RAS in individuals with HIV infection.A systematic review was conducted following PICOS(Patient,Intervention,Control,Outcome,Study design)principles.Given the heterogeneity across studies,a qualitative analysis was performed in place of a meta-analysis.Eight randomized controlled trials(RCTs)were deemed eligible for inclusion.In three RCTs focused on RAS,a dosage of thalidomide at 100 mg/d demonstrated efficacy,while a lower dose of 25 mg/d helped prolong the recurrence interval of RAS.For oro-genital ulcers of BD,two RCTs indicated that both 300 mg/d for 24 weeks and 200 mg/d for 28 d,preceded by an initial dose of 400 mg/d for 5 d,were effective.In three RCTs investigating RAS in HIV-infected patients,thalidomide at 200 mg/d for either 4 or 7 weeks,with an initial dose of 400 mg/d for the first week,proved effective.However,a regimen of 100 mg three times per week failed to prevent the recurrence of oral ulcers.Adverse reactions to thalidomide were generally tolerable within the dosage ranges used in these studies.Overall,thalidomide showed promising efficacy for treating RAS,oro-genital ulcers in BD,and RAS in HIV-infected individuals.However,the variability in trial designs,dosages,and treatment durations makes it challenging to recommend an optimal dose and course of therapy.Further high-quality RCTs are necessary to establish more definitive guidelines.展开更多
Cupressus sempervirens is a relevant species in the Mediterranean for its cultural,economic and landscape value.This species is threatened by Seiridium cardinale,the causal agent of the cypress canker disease(CCD).The...Cupressus sempervirens is a relevant species in the Mediterranean for its cultural,economic and landscape value.This species is threatened by Seiridium cardinale,the causal agent of the cypress canker disease(CCD).The effects of biotic stressors on O_(3)risk assessment are unknown and a comprehensive O_(3)risk assessment in C.sempervirens is missing.To fill these gaps,two clones of C.sempervirens,one resistant(Clone R)and one susceptible to CCD(Clone S),were subjected to three levels of O_(3)(Ambient Air-AA;1.5×AA;2.0×AA)for two consecutive years in an O_(3)-free-air controlled exposure facility and artificially inoculated with S.cardinale.Both the exposure-(AOT40)and flux-based(PODy)indices were tested.We found that PODy performed better than AOT40 to assess O_(3)effects on biomass and the critical level for a 4%biomass loss was 2.51 mmol/m^(2)POD2.However,significant O_(3)dose-response relationships were not found for the inoculated cypresses because the combination of middle level O_(3)(1.5×AA)and inoculation stimulated a biomass growth in Clone S as hormetic response.Moreover,we found a different inter-clonal response to both stressors with a statistically significant reduction of total and belowground biomass following O_(3),and lower root biomass in Clone S than in Clone R following pathogen infection.In summary,Clone R was more resistant to O_(3),and inoculation altered O_(3)risk via an hormetic effect on biomass.These results warrant further studies on how biotic stressors affect O_(3)responses and risk assessment.展开更多
Rhododendron micranthum Turcz.is a shrub esteemed for its ornamental and medicinal attributes within the Changbai Mountain range of China.We selected 3-year saplings and subjected them to four distinct light condi-tio...Rhododendron micranthum Turcz.is a shrub esteemed for its ornamental and medicinal attributes within the Changbai Mountain range of China.We selected 3-year saplings and subjected them to four distinct light condi-tions:full light(CK),70%light(L1),50%light(L2),and 30%light(L3)to investigate variations in morphology,photosynthetic responses,stomatal ultrastructure as well as the mechanisms through which these saplings adapt to differing lighting environments.The results indicate that L2 leaves exhibit significantly greater length,width,and petiole development compared to other treatments across varying intensities.Over time,chlorophyll content and PSII levels in L2-treated saplings surpass those observed in other treatments;Proline(PRO),malondialdehyde(MDA),and soluble protein(SP)contents are markedly lower under L2 treatment.Catalase(CAT)and superoxide dismutase(SOD)demonstrate significant correlations across various light con-ditions but respond differently among treatments,indicat-ing distinct species sensitivities to light intensity while both contribute to environmental stress resistance mechanisms.Findings reveal that R.micranthum saplings at 50%light intensity benefit from enhanced protection via antioxidant enzymes,and shading reduces osmotic adjustment sub-stances yet increases chlorophyll content.Stomatal length/width along with conductance rates and net photosynthesis rates for L2 exceed those of CK,suggesting an improved photosynthetic structure conducive to efficient photosynthe-sis under this condition.Thus,moderate shading represents optimal growth at 50%illumination,a critical factor promot-ing sapling development.This research elucidates the ideal environment for R.micranthum adaptation to varying light conditions supporting future conservation initiatives.展开更多
【Objective】Jatropha curcas is a potential source of biodiesel plant grown on waste and unattended lands,and parts of the areas are often suffered from flooding.The present study was conducted to develop a model to c...【Objective】Jatropha curcas is a potential source of biodiesel plant grown on waste and unattended lands,and parts of the areas are often suffered from flooding.The present study was conducted to develop a model to calculate the net CO_(2)assimilation rate,transpiration rate and stomatal conductance with respect to leaf position,which affect the J.curcas productivity under soil flooding.【Method】The process of developing mathematical models for physiological responses associated with parameterization,optimization and validation.The concept was applied for the calculation of net CO 2 assimilation rate from transpiration rate and stomatal conductance,transpiration rate from net CO_(2)assimilation rate and stomatal conductance,and stomatal conductance from net CO_(2)assimilation rate and transpiration rate in different leaf positions of J.curcas.The models were tested under soil flooding and normal conditions to suffice its wider applicability.A model was proposed to calculate net CO 2 assimilation rate,transpiration rate and stomatal conductance responses from a known set of response function data by calculating a transformation characteristic constant between any two possible paired response functions.【Result】The mean deviations and root mean square errors(RMSE)of calculated physiological responses were low,which validated the proposed hypothesis and statistical models.The approach was applied for modeling physiological responses successfully in J.curcas.RMSE ranged from1.69%to 11.17%when transpiration rate and stomatal conductance were transformed to net CO_(2)assimilation rate,and from 1.70%to 11.61%in case net CO_(2)assimilation rate and stomatal conductance were transformed to transpiration rate,and from 3.87%to 13.21%if net CO_(2)assimilation rate and transpiration rate were transformed to stomatal conductance,respectively.【Conclusion】The model can be useful for calculating cumulative responses under different conditions from a basic known set of data.The key to successful physiological models is finding the better options that are realistic,easy to understand,interpretative and practical between adherence to reality,comprehensibility,interpretative value,and practical usefulness on sustainable agriculture in years to come.展开更多
Shanlan upland rice is an important landrace resource with high drought stress(DS)tolerance.Despite its importance,genes responsible for yield in Shanlan upland rice have yet to be discovered.Our previous study identi...Shanlan upland rice is an important landrace resource with high drought stress(DS)tolerance.Despite its importance,genes responsible for yield in Shanlan upland rice have yet to be discovered.Our previous study identified a drought-responsive zinc finger protein,ZOS7,as highly expressed in Shanlandao upland rice.However,the function of this gene in controlling drought tolerance remains largely unexplored.In this study,we found that overexpressing ZOS7,a drought-responsive zinc finger protein,in rice increased biomass and yield under drought stress.Co-overexpressing ZOS7 and MYB60,encoding a protein with which ZOS7 interacted,intensified the yield increase.ZOS7 and MYB60 appear to form a module that confers drought tolerance by regulating stomatal density and wax biosynthesis.The ZOS7-MYB60module could be used in molecular breeding for drought tolerance in rice.展开更多
The Ebola virus(EBOV)is a member of the Orthoebolavirus genus,Filoviridae family,which causes severe hemorrhagic diseases in humans and non-human primates(NHPs),with a case fatality rate of up to 90%.The development o...The Ebola virus(EBOV)is a member of the Orthoebolavirus genus,Filoviridae family,which causes severe hemorrhagic diseases in humans and non-human primates(NHPs),with a case fatality rate of up to 90%.The development of countermeasures against EBOV has been hindered by the lack of ideal animal models,as EBOV requires handling in biosafety level(BSL)-4 facilities.Therefore,accessible and convenient animal models are urgently needed to promote prophylactic and therapeutic approaches against EBOV.In this study,a recombinant vesicular stomatitis virus expressing Ebola virus glycoprotein(VSV-EBOV/GP)was constructed and applied as a surrogate virus,establishing a lethal infection in hamsters.Following infection with VSV-EBOV/GP,3-week-old female Syrian hamsters exhibited disease signs such as weight loss,multi-organ failure,severe uveitis,high viral loads,and developed severe systemic diseases similar to those observed in human EBOV patients.All animals succumbed at 2–3 days post-infection(dpi).Histopathological changes indicated that VSV-EBOV/GP targeted liver cells,suggesting that the tissue tropism of VSV-EBOV/GP was comparable to wild-type EBOV(WT EBOV).Notably,the pathogenicity of the VSV-EBOV/GP was found to be species-specific,age-related,gender-associated,and challenge route-dependent.Subsequently,equine anti-EBOV immunoglobulins and a subunit vaccine were validated using this model.Overall,this surrogate model represents a safe,effective,and economical tool for rapid preclinical evaluation of medical countermeasures against EBOV under BSL-2 conditions,which would accelerate technological advances and breakthroughs in confronting Ebola virus disease.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
Stomata play critical roles in gas exchange and immunity to pathogens.While many genes regulating early stomatal development up to the production of young guard cells(GCs)have been identified in Arabidopsis,much less ...Stomata play critical roles in gas exchange and immunity to pathogens.While many genes regulating early stomatal development up to the production of young guard cells(GCs)have been identified in Arabidopsis,much less is known about how young GCs develop into mature functional stomata.Here we perform a maturomics study on stomata,with“maturomics”defined as omics analysis of the maturation process of a tissue or organ.We develop an integrative scheme to analyze three public stomata-related single-cell RNAseq datasets and identify a list of 586 genes that are specifically up-regulated in all three datasets during stomatal maturation and function formation.The list,termed sc_586,is enriched with known regulators of stomatal maturation and functions.To validate the reliability of the dataset,we selected two candidate G2-like transcription factor genes,MYS1 and MYS2,to investigate their roles in stomata.These two genes redundantly regulate the size and hoop rigidity of mature GCs,and the mys1 mys2 double mutants cause mature GCs with severe defects in regulating their stomatal apertures.Taken together,our results provide a valuable list of genes for studying GC maturation and function formation.展开更多
Transplanting rice varieties grown in different seasons can lead to different yields due to different dry matterproduction. Early-season rice varieties transplanted in the late season can obtain high yields with short...Transplanting rice varieties grown in different seasons can lead to different yields due to different dry matterproduction. Early-season rice varieties transplanted in the late season can obtain high yields with short-growthduration and higher yields driven by higher dry matter production. To make clear the variations in dry matterproduction across seasons, four early-season rice varieties were chosen for late-season transplantation. The grainyield, dry matter accumulation, leaf photosynthetic, and leaf stomatal properties were studied. It was observedthat the average yields of these four varieties in the late season were 33% greater, despite a reduced growth periodof 13 days in comparison with the early season. Furthermore, there was a notable increase in both total and postheadingdry matter production during the late season. The leaf net photosynthetic rate, stomatal area, stomatalwidth, and stomatal length were higher in the late season. Despite no significant difference in stomatal densitybetween seasons, strong positive linear relationships were observed between net photosynthetic rate and stomatalconductance, and between stomatal conductance and area. These relationships demonstrate that the increase ofthe stomatal width and length of the leaves in the late season leads to an increase in the stomatal area, therebyincreasing the stomatal conductance and enhancing the photosynthesis of the leaves. Consequently, this leads togreater dry matter production and a higher yield compared to the early season. Therefore, when breeding newhigh-yielding and short-growing varieties, the large stomatal area can be used as a reference index.展开更多
Atmospheric CO_(2)concentration is elevated globally,which has“CO_(2)fertilization effects”and potentially improves plant photosynthesis,yield,and productivity.Despite the beneficial effect of CO_(2)fertilization be...Atmospheric CO_(2)concentration is elevated globally,which has“CO_(2)fertilization effects”and potentially improves plant photosynthesis,yield,and productivity.Despite the beneficial effect of CO_(2)fertilization being modulated by vapor pressure deficit(VPD),the underlying mechanism is highly uncertain.In the present study,the potential roles of hormones in determining CO_(2)fertilization effects under contrasting high and low VPD conditions were investigated by integrated physiological and transcriptomic analyses.Beneficial CO_(2)fertilization effects were offset under high VPD conditions and were constrained by plant water stress and photosynthetic CO_(2)utilization.High VPD induced a large passive water driving force,which disrupted the water balance and consequently caused plant water deficit.Leaf water potential,turgor pressure,and hydraulic conductance declined under high VPD stress.The physiological evidence combined with transcriptomic analyses demonstrated that abscisic acid(ABA)and jasmonic acid(JA)potentially acted as drought-signaling molecules in response to high VPD stress.Increased foliar ABA and JA content triggered stomatal closure to prevent excessive water loss under high VPD stress,which simultaneously increased the diffusion resistance for CO_(2)uptake from atmosphere to leaf intercellular space.High VPD also significantly increased mesophyll resistance for CO_(2)transport from stomatal cavity to fixation site inside chloroplast.The chloroplast“sink”CO_(2)availability was constrained by stomatal and mesophyll resistance under high VPD stress,despite the atmospheric“source”CO_(2)concentration being elevated.Thus,ABA-and JA-mediated drought-resistant mechanisms potentially modified the beneficial effect of CO_(2)fertilization on photosynthesis,plant growth,and yield productivity.This study provides valuable information for improving the utilization efficiency of CO_(2)fertilization and a better understanding of the physiological processes.展开更多
The 15-carbon terpenoid abscisic acid(ABA)acts in vascular plants as a versatile hormone playing essential roles in reproductive development,vegetative development and growth,stress-development interactions,and physio...The 15-carbon terpenoid abscisic acid(ABA)acts in vascular plants as a versatile hormone playing essential roles in reproductive development,vegetative development and growth,stress-development interactions,and physio-logical responses to abiotic and biotic stresses.Over the past 60 years,ABA dynamics,regulation,and responses have been progressively characterized:synthesis,transport and translocation,conjugation and deconjugation,metabolism,sensing,signal transduction,and downstream responses.In this context,the discovery of ABA expor-ters and importers has added novel dimensions to the understanding of ABA regulation.Moreover,since the initi-al discovery of the adenosine triphosphate-binding cassette(ABC)AtABCG25 exporter and AtABCG40 importer,several transporters of ABA have been characterized.As ABA is synthesized within cells,efflux transport of ABA to extracellular spaces is an important controlling step before ABA movements from cell to cell and from source to target.Until now,structural and functional mechanistic interactions between ABA and its transporters have remained poorly understood.Recent structure-function studies have unveiled key features of the mechanisms and functional dynamics of ABA-transporter interactions in the case of the ABCG25 exporter.ABCG25 has been established as a bonafide ABA efflux transporter involved in signal transmission leading to stomatal closure.It has also been shown to transport ABA-glucosyl ester(ABA-GE)conjugated form,thus implying involvement in conjugation and deconjugation dynamics.All of these mechanisms are essential for distribution throughout source tissues,source-to-target transmission,distribution throughout target tissues,and signal shape kinetics in target cells.This opinion piece emphasizes the pivotal role of transport discoveries in the history of ABA research,and how recent studies on ABA and ABA-GE transporters yield a more integrative vision of ABA reg-ulation and adaptive responses,open new avenues of research on signaling crosstalks,and constitute opportu-nities as well as challenges for crop improvement strategies.展开更多
Stomatal regulation is critical for mangroves to survive in the hyper-saline intertidal zone where water stress is severe and water availability is highly fluctuant.However,very little is known about the stomatal sens...Stomatal regulation is critical for mangroves to survive in the hyper-saline intertidal zone where water stress is severe and water availability is highly fluctuant.However,very little is known about the stomatal sensitivity to vapour pressure deficit(VPD)in mangroves,and its co-ordination with stomatal morphology and leaf hydraulic traits.We measured the stomatal response to a step increase in VPD in situ,stomatal anatomy,leaf hydraulic vulnerability and pressure-volume traits in nine true mangrove species of five families and collected the data of genome size.We aimed to answer two questions:(1)Does stomatal morphology influence stomatal dynamics in response to a high VPD in mangroves?with a consideration of possible influence of genome size on stomatal morphology;and(2)do leaf hydraulic traits influence stomatal sensitivity to VPD in mangroves?We found that the stomata of mangrove plants were highly sensitive to a step rise in VPD and the stomatal responses were directly affected by stomatal anatomy and hydraulic traits.Smaller,denser stomata was correlated with faster stomatal closure at high VPD across the species of Rhizophoraceae,and stomata size negatively and vein density positively correlated with genome size.Less negative leaf osmotic pressure at the full turgor(πo)was related to higher operating steady-state stomatal conductance(gs);and a higher leaf capacitance(Cleaf)and more embolism resistant leaf xylem were associated with slower stomatal responses to an increase in VPD.In addition,stomatal responsiveness to VPD was indirectly affected by leaf morphological traits,which were affected by site salinity and consequently leaf water status.Our results demonstrate that mangroves display a unique relationship between genome size,stomatal size and vein packing,and that stomatal responsiveness to VPD is regulated by leaf hydraulic traits and stomatal morphology.Our work provides a quantitative framework to better understand of stomatal regulation in mangroves in an environment with high salinity and dynamic water availability.展开更多
基金supported by the National Key R&D Program of China(2022YFE0127900,2021YFD2200401)the National Natural Science Foundation of China(31901278).
文摘Ongoing climate change has a considerable influence on the seasonality,timing,and intensity of rainfall worldwide,and is also predicted to decrease snow cover in cold ecosystems.Larch is a widely distributed tree species in boreal Eurasia,calling for a comprehensive understanding of how larch adapts to changes in both rainfall and snowfall by adjusting carbon-water physiology.Here,we conducted a short-term rainfall(−60% ambient rainfall;three-year)and snowfall(−73% ambient snowfall;two-year)exclusions experiment in Larix gmelinii forest in northeastern China,and aimed to explore the responses of hydraulic(leaf pressure-volume traits,leaf and branch hydraulic conductivity and embolism resistance),stomatal(stomatal closure point and stomatal safety margin),and economic(photosynthetic rate,nutrient and non-structural carbohydrates contents)traits to rainfall and snowfall reductions.Despite the weak alternation of leaf and branch hydraulic traits,both rainfall and snowfall reductions significantly led to early stomatal closure and increased stomatal safety margins(the difference between stomatal closure point and xylem embolism threshold,describing drought resistance by merging both hydraulic and stomatal strategies).Reductions in rainfall and snowfall induced water or/and low-temperature stress,resulting in more conservative leaf economic traits,including a reduced photosynthetic rate,lower leaf nitrogen concentration,and higher leaf density.In addition,larch responded to reductions in rainfall and snowfall by up-regulating non-structural carbohydrates in the xylem,which helps repair embolism or lower the freezing point acting as osmolytes.Overall,our findings reveal that larch could adapt to the drought and snowpack reduction by strict stomatal regulation and investing non-structural carbohydrates in embolism repairing,at the cost of carbon assimilation.
基金support from the Study on Vegetable Science of Farmland System in Qinghai-Tibet Plateau(Grant No.2019QZKK0303)funded by the Sichuan International Science and Technology Innovation Cooperation/Hong Kong Macao Taiwan Science and Technology Innovation Cooperation Project(Grant No.2022YFH0071)。
文摘Secondary salinization is a major environmental factor that causes a stress response and growth inhibition in plants in protected agriculture.The positive effect of a low red to far-red light ratio(R:FR)in salt tolerance through antioxidant defense has been reported,while the underlying model remains obscure.In this study,we used physiological and genetic approaches to investigate the relationship between H_(2)O_(2) signaling and low R:FR-induced salt tolerance and antioxidant capacity in tomato seedlings.This study found that low R:FR treatment with calcium nitrate stress(SL treatment)enhanced the growth of plants and increased the net photosynthetic rate 5 days after stress compared with a higher R:FR ratio and calcium nitrate stress(S treatment).With transcriptomic analysis of tomato leaves at 5 d,compared with CK,most of glutaredoxin genes and antioxidant enzymes were upregulated by S treatment,which were upregulated further by SL treatment.Compared to the S treatment,within 5 days,the H_(2)O_(2) level was increased faster before 24 h and it was slowed down after 24 h by SL treatment,with less H_(2)O_(2) accumulation at 5 d than that of S treatment.The enhancement of gene expression of RBOH genes were also shown at 24 h under SL.It was found that stomatal conductance followed the dynamic change of H_(2)O_(2),with a rapid closure of stomata of a decrease at 3 h and an increase after 9 h in SL treatment compared to S treatment,respectively.There was same trend of stomata opening degrees of tomato leaves observed by optical microscope.However,the inhibitor of H_(2)O_(2) production(DPI pretreatment)weakened the positive effect of low R:FR on the regulation of stomatal movement.In addition,SL treatment increased the antioxidant enzyme activities and proline content and decreased the MDA content as compared to the S treatment,while the enhancement of ROS homeostasis was reduced by the DPI pretreatment.In conclusion,low R:FR improved redox homeostasis and stomatal status under calcium nitrate stress through H_(2)O_(2)signaling,improving the adaptation of tomato seedlings to soil salinization stress.
基金supported jointly by the earmarked fund for CARS-10-GW2the key research and development program of Hainan Province(Grant No.ZDYF2020226)+1 种基金Collaborative innovation center of Nanfan and high-efficiency tropical agriculture,Hainan University(Grant No.XTCX2022NYC21)funding of Hainan University[Grant No.KYQD(ZR)22123]。
文摘Heat stress hinders the growth and productivity of sweetpotato plants,predominantly through oxidative damage to cellular membranes.Therefore,the development of efficient approaches for mitigating heat-related impairments is essential for the long-term production of sweetpotatoes.Melatonin has been recognised for its capacity to assist plants in dealing with abiotic stress conditions.This research aimed to investigate how different doses of exogenous melatonin influence heat damage in sweetpotato plants.Heat stress drastically affected shoot and root fresh weight by 31.8 and 44.5%,respectively.This reduction resulted in oxidative stress characterised by increased formation of hydrogen peroxide(H_(2)O_(2))by 804.4%,superoxide ion(O_(2)^(·-))by 211.5%and malondialdehyde(MDA)by 234.2%.Heat stress also reduced chlorophyll concentration,photosystemⅡefficiency(F_v/F_m)by 15.3%and gaseous exchange.However,pre-treatment with 100μmol L^(-1)melatonin increased growth and reduced oxidative damage to sweetpotato plants under heat stress.In particular,melatonin decreased H_(2)O_(2),O_(2)^(·-)and MDA by 64.8%,42.7%and 38.2%,respectively.Melatonin also mitigated the decline in chlorophyll levels and improved stomatal traits,gaseous exchange and F_(v)/F_(m)(13%).Results suggested that the favorable outcomes of melatonin treatment can be associated with elevated antioxidant enzyme activity and an increase in non-enzymatic antioxidants and osmo-protectants.Overall,these findings indicate that exogenous melatonin can improve heat stress tolerance in sweetpotatoes.This stu dy will assist re searchers in further investigating how melatonin makes sweetpotatoes more resistant to heat stress.
基金supported by the Natural Science Foundation of China(Grant No.32172512)the Jiangsu Special Fund for Frontier Foundation Research of Carbon Peaking and Carbon Neutralization(Grant No.BK20220005)a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions。
文摘5-Aminolevulinic acid(ALA)is a novel plant growth regulator that has shown outstanding capability to promote stomatal opening.Starch degradation,catalyzed byβ-amylase(EC3.2.1.2,BAM),plays an important role in stomatal opening.However,whether the starch breakdown is involved in ALA-regulating stomatal movement is unclear.In the current study,we found that exogenous ALA effectively stimulated the starch breakdown in guard cells,increasedβ-amylase activity and promoted stomatal opening in leaves of apple(Malus×domestica).Based on genome-wide identification,we identified a total of 119 members of BAM gene family in ten commonly Rosaceae crops.Analyses of gene structure,motif identification,and gene pair collinearity revealed relative conservation among members within the same group or subgroup.Among these genes,MdBAM17 and other 12 genes were identified as the orthologous genes of AtBAM1,which is responsible for starch degradation to modulate the stomatal movement in Arabidopsis.qRT-PCR analysis revealed a positive correlation between the expressions of MdBAM17 and stomatal aperture,as well asβ-amylase activity,whereas a negative correlation was observed with the starch content.Subcellular localization analysis confirmed that MdBAM17 is a chloroplast protein,consistent with the AtBAM1.MdBAM17 was mainly expressed in guard cells and responsive to exogenous ALA.Overexpressing MdBAM17 increasedβ-amylase activity and promoted starch breakdown,leading to stomatal opening,which was further strengthened by ALA.RNA-interfering MdBAM17 decreasedβ-amylase activity,resulting in starch accumulation,and impairing the stomatal opening by ALA.However,modulation of MdBAM17 expression did not affect the levels of flavonols and H_(2)O_(2)in guard cells,suggesting that MdBAM17-promoted starch degradation may function at downstream of ROS signaling in the ALAregulated stomatal opening.Our findings provide new insights into the mechanisms of ALA-regulated stomatal movement.
文摘Recurrent aphthous stomatitis(RAS)is a very frequent condition in developed countries whose basic symptom is a lesion referred to as an aphthous ulcer.High levels of interleukin(IL)-1 and IL-6 and low salivary levels of IL-10 are the basis of RAS pathogenesis.Sublingual supplements based on IL-10 can be very useful in reducing the phenomenon of aphthous recurrence in patients with RAS.An observational clinical experience with a group of 5 patients with RAS receiving a commercially available IL-10-based supplement was reported by the authors.The findings revealed a subsequent reduction in the incidence of mouth ulcers.
基金supported by the Natural Science Basic Research Program of Shaanxi Province,China(2024JCYBQN-0491)Heng Wan would like to thank the Chinese Scholarship Council(CsC)(202206300064)。
文摘While biochar amendment enhances plant productivity and water-use efficiency(WUE),particularly under waterlimited conditions,the specific mechanisms driving these benefits remain unclear.Thus,the present study aims to elucidate the synergistic effects of biochar and reduced irrigation on maize(Zea mays L.)plants,focusing on xylem composition,root-to-shoot signaling,stomatal behavior,and WUE.Maize plants were cultivated in splitroot pots filled with clay loam soil,amended by either wheat-straw biochar(WSB)or softwood biochar(SWB)at 2%(w/w).Plants received full irrigation(FI),deficit irrigation(DI),or partial root-zone drying rrigation(PRD)from the 4-leaf to the grain-filling stage.Our results revealed that the WSB amendment significantly enhanced plant water status,biomass accumulation,and WUE under reduced irrigation,particularly when combined with PRD.Although reduced irrigation inhibited photosynthesis,it enhanced WUE by modulating stomatal morphology and conductance.Biochar amendment combined with reduced rrigation significantly increased xylem K^(+),Ca^(2+),Mg^(2+),NO_(3)^(-),Cl^(-),PO_(4)^(3-),and SO_(4)^(2-)-but decreased Na+,which in turn lowered xylem pH.Moreover,biochar amendment and especially WSB amendment further increased abscisic acid(ABA)contents in both leaf and xylem sap under reduced irrigation conditions due to changes in xylem ionic constituents and pH.The synergistic interactions between xylem components and ABA led to refined adjustments in stomatal size and density,thereby affecting stomatal conductance and ultimately improving the WUE of maize plants at different scales.The combined application of WSB and PRD can,therefore,emerge as a promising approach for improving the overall plant performance of maize plants with increased stomatal adaptations and WUE,especially under water-limited conditions.
基金supported by the National Key Research&Development Project of China(No.2022YFF1300403)the National Natural Science Foundation of China(Nos.U21A2011,41971129,and 32401663)the Open Fund of the State Key Laboratory of Loess Science(No.SKLLQG2423).
文摘Soil water content(SWC)and meteorological conditions,as key environmental variables influencing tree water use,vary highly within the growing season,hindering a better understanding of environmental control mechanisms on canopy transpiration(Ec).Disentangling the effects of these variables on Ec across growing-season stages is crucial for Ec estimation and forest management.In this study,43-year-old Pinus tabuliformis Carr.and 31-yearold Platycladus orientalis(L.)Franco plantations in the semiarid Chinese Loess Plateau were monitored for Ec during the growing season of 2015-2020.The contributions of environmental factors to Ec were assessed using the boosted regression tree(BRT)model.Results showed that the contributions of SWC to Ec were greater at the early(May-June)and late(September)stages,while the contributions of vapor pressure deficit(VPD)and total solar radiation(Rs)to Ec increased at the middle(July-August)stage due to high soil water availability.Overall,Ec in both plantations was dominated by SWC(20.4%≤contributions≤48.8%)and Rs(22.7%≤contributions≤35.8%).Both species exhibited strong stomatal regulation of Ec.Specifically,stomatal opening was significantly inhibited by VPD at the early stage and strongly affected by SWC at the late stage.This study highlights that soil water conditions in artificial forests should be adjusted according to changes in influencing factors on Ec.Particularly during the early and late stages,measures(e.g.,land preparation,thinning,and pruning)can be implemented to improve soil moisture in such dryland forests.
基金funding from the Ongoing Research Funding program,ORF-2025-298,King Saud University,Riyadh,Saudi Arabia.
文摘The low efficiency of phytoextraction of lead(Pb)from agricultural fields poses a significant agricultural challenge.Organic chelating agents can influence Pb bioavailability in soil,affecting its uptake,transport,and toxicity in plants.This study aimed to assess the impact of citric acid(CA)and diethylenetriaminepentaacetic acid(DTPA)on chelate-assisted phytoextraction of Pb and its effect on growth and physiology of two cultivars(07001;07002)of mung bean(Vigna radiata).The cultivars of mung bean were exposed to 60 lead chloride(PbCl_(2))solution,mg⋅L-1with or without the addition of 300 CA or 500 DTPA,until maturity.The exposure of plants to Pb mg⋅L^(-1) mg⋅L^(-1) stress increased the accumulation of Pb in roots(49%of control),stems(58%of control),leaves(67%of control),and seeds(61%of control).Maximum accumulation of Pb was observed in roots and the least accumulation was found in seeds of both mung bean cultivars.The extent of Pb accumulation in different plant parts correlated positively with Pb toxicity and reduced growth of both mung bean cultivars(33%to 40%).The cultivar cv 07001 was more susceptible to Pb stress.The addition of CA and DTPA increased the accumulation of Pb in plant parts of mung bean cultivars-phytoextraction(10.8%to 21.5%).However,the addition of CA partitioned Pb in vegetative parts,i.e.,root,stem thus mitigated the toxic effects of Pb on the growth of mung bean cultivars(6.25%–10.5%).In contrast,the addition of DTPA had adverse effects on the growth of mung bean cultivars.The addition of CA facilitated a greater uptake and accumulation of nitrogen,phosphorous,and potassium in the roots and leaves of mung bean cultivars.In addition,CA also improved the photosynthetic pigments(11%–14%)and photosynthetic rate(5%–12%)under both control and Pb stress conditions.The ameliorative effect of CA on the photosynthetic capacity of mung bean cultivars was likely associated with photosynthetic metabolic factors rather than stomatal factors.Furthermore,cv 07002 was found to be more tolerant to Pb stress and showed better performance in CA application.Overall,the application of CA demonstrated significant potential as a chelating agent for remediating Pb-contaminated soil.
文摘Thalidomide,an immunomodulatory drug,is widely recommended for the treatment of recurrent aphthous stomatitis(RAS).This review aimed to assess the reliability of thalidomide for managing RAS,oro-genital ulcers associated with Behçet’s disease(BD),and RAS in individuals with HIV infection.A systematic review was conducted following PICOS(Patient,Intervention,Control,Outcome,Study design)principles.Given the heterogeneity across studies,a qualitative analysis was performed in place of a meta-analysis.Eight randomized controlled trials(RCTs)were deemed eligible for inclusion.In three RCTs focused on RAS,a dosage of thalidomide at 100 mg/d demonstrated efficacy,while a lower dose of 25 mg/d helped prolong the recurrence interval of RAS.For oro-genital ulcers of BD,two RCTs indicated that both 300 mg/d for 24 weeks and 200 mg/d for 28 d,preceded by an initial dose of 400 mg/d for 5 d,were effective.In three RCTs investigating RAS in HIV-infected patients,thalidomide at 200 mg/d for either 4 or 7 weeks,with an initial dose of 400 mg/d for the first week,proved effective.However,a regimen of 100 mg three times per week failed to prevent the recurrence of oral ulcers.Adverse reactions to thalidomide were generally tolerable within the dosage ranges used in these studies.Overall,thalidomide showed promising efficacy for treating RAS,oro-genital ulcers in BD,and RAS in HIV-infected individuals.However,the variability in trial designs,dosages,and treatment durations makes it challenging to recommend an optimal dose and course of therapy.Further high-quality RCTs are necessary to establish more definitive guidelines.
基金supported by the Italian Integrated Environmental Research Infrastructures Systems(ITINERIS)(Nos.IR0000032 and CUP B53C22002150006).
文摘Cupressus sempervirens is a relevant species in the Mediterranean for its cultural,economic and landscape value.This species is threatened by Seiridium cardinale,the causal agent of the cypress canker disease(CCD).The effects of biotic stressors on O_(3)risk assessment are unknown and a comprehensive O_(3)risk assessment in C.sempervirens is missing.To fill these gaps,two clones of C.sempervirens,one resistant(Clone R)and one susceptible to CCD(Clone S),were subjected to three levels of O_(3)(Ambient Air-AA;1.5×AA;2.0×AA)for two consecutive years in an O_(3)-free-air controlled exposure facility and artificially inoculated with S.cardinale.Both the exposure-(AOT40)and flux-based(PODy)indices were tested.We found that PODy performed better than AOT40 to assess O_(3)effects on biomass and the critical level for a 4%biomass loss was 2.51 mmol/m^(2)POD2.However,significant O_(3)dose-response relationships were not found for the inoculated cypresses because the combination of middle level O_(3)(1.5×AA)and inoculation stimulated a biomass growth in Clone S as hormetic response.Moreover,we found a different inter-clonal response to both stressors with a statistically significant reduction of total and belowground biomass following O_(3),and lower root biomass in Clone S than in Clone R following pathogen infection.In summary,Clone R was more resistant to O_(3),and inoculation altered O_(3)risk via an hormetic effect on biomass.These results warrant further studies on how biotic stressors affect O_(3)responses and risk assessment.
基金funded by the National Natural Science Foundation of China(No.32171770)Natural Science Foundation Program of Jilin Provincial Department of Education(No.JJKH20230074KJ).
文摘Rhododendron micranthum Turcz.is a shrub esteemed for its ornamental and medicinal attributes within the Changbai Mountain range of China.We selected 3-year saplings and subjected them to four distinct light condi-tions:full light(CK),70%light(L1),50%light(L2),and 30%light(L3)to investigate variations in morphology,photosynthetic responses,stomatal ultrastructure as well as the mechanisms through which these saplings adapt to differing lighting environments.The results indicate that L2 leaves exhibit significantly greater length,width,and petiole development compared to other treatments across varying intensities.Over time,chlorophyll content and PSII levels in L2-treated saplings surpass those observed in other treatments;Proline(PRO),malondialdehyde(MDA),and soluble protein(SP)contents are markedly lower under L2 treatment.Catalase(CAT)and superoxide dismutase(SOD)demonstrate significant correlations across various light con-ditions but respond differently among treatments,indicat-ing distinct species sensitivities to light intensity while both contribute to environmental stress resistance mechanisms.Findings reveal that R.micranthum saplings at 50%light intensity benefit from enhanced protection via antioxidant enzymes,and shading reduces osmotic adjustment sub-stances yet increases chlorophyll content.Stomatal length/width along with conductance rates and net photosynthesis rates for L2 exceed those of CK,suggesting an improved photosynthetic structure conducive to efficient photosynthe-sis under this condition.Thus,moderate shading represents optimal growth at 50%illumination,a critical factor promot-ing sapling development.This research elucidates the ideal environment for R.micranthum adaptation to varying light conditions supporting future conservation initiatives.
文摘【Objective】Jatropha curcas is a potential source of biodiesel plant grown on waste and unattended lands,and parts of the areas are often suffered from flooding.The present study was conducted to develop a model to calculate the net CO_(2)assimilation rate,transpiration rate and stomatal conductance with respect to leaf position,which affect the J.curcas productivity under soil flooding.【Method】The process of developing mathematical models for physiological responses associated with parameterization,optimization and validation.The concept was applied for the calculation of net CO 2 assimilation rate from transpiration rate and stomatal conductance,transpiration rate from net CO_(2)assimilation rate and stomatal conductance,and stomatal conductance from net CO_(2)assimilation rate and transpiration rate in different leaf positions of J.curcas.The models were tested under soil flooding and normal conditions to suffice its wider applicability.A model was proposed to calculate net CO 2 assimilation rate,transpiration rate and stomatal conductance responses from a known set of response function data by calculating a transformation characteristic constant between any two possible paired response functions.【Result】The mean deviations and root mean square errors(RMSE)of calculated physiological responses were low,which validated the proposed hypothesis and statistical models.The approach was applied for modeling physiological responses successfully in J.curcas.RMSE ranged from1.69%to 11.17%when transpiration rate and stomatal conductance were transformed to net CO_(2)assimilation rate,and from 1.70%to 11.61%in case net CO_(2)assimilation rate and stomatal conductance were transformed to transpiration rate,and from 3.87%to 13.21%if net CO_(2)assimilation rate and transpiration rate were transformed to stomatal conductance,respectively.【Conclusion】The model can be useful for calculating cumulative responses under different conditions from a basic known set of data.The key to successful physiological models is finding the better options that are realistic,easy to understand,interpretative and practical between adherence to reality,comprehensibility,interpretative value,and practical usefulness on sustainable agriculture in years to come.
基金supported by the Finance Science and Technology Project of Hainan Province(ZDYF2021XDNY167)the National Natural Science Foundation of China(32170245,32260447)+1 种基金the Project of Sanya Yazhou Bay Science and Technology City(SCKJJYRC-2022-04)Scientific Research Foundation of Hainan Tropical Ocean University(RHDRC202342)。
文摘Shanlan upland rice is an important landrace resource with high drought stress(DS)tolerance.Despite its importance,genes responsible for yield in Shanlan upland rice have yet to be discovered.Our previous study identified a drought-responsive zinc finger protein,ZOS7,as highly expressed in Shanlandao upland rice.However,the function of this gene in controlling drought tolerance remains largely unexplored.In this study,we found that overexpressing ZOS7,a drought-responsive zinc finger protein,in rice increased biomass and yield under drought stress.Co-overexpressing ZOS7 and MYB60,encoding a protein with which ZOS7 interacted,intensified the yield increase.ZOS7 and MYB60 appear to form a module that confers drought tolerance by regulating stomatal density and wax biosynthesis.The ZOS7-MYB60module could be used in molecular breeding for drought tolerance in rice.
基金supported by National Key R&D Program of China(grant number 2023YFC2605500)Jilin Province Youth Talent Support Project(grant number QT202208)+1 种基金the Ministry of Science and Technology of the People's Republic of China(grant number 2022YFC0867900)Nation Key Research and Development Program of China,New technology of rapid of pathogens in laboratory animals(grant number 2021YFF07033600).
文摘The Ebola virus(EBOV)is a member of the Orthoebolavirus genus,Filoviridae family,which causes severe hemorrhagic diseases in humans and non-human primates(NHPs),with a case fatality rate of up to 90%.The development of countermeasures against EBOV has been hindered by the lack of ideal animal models,as EBOV requires handling in biosafety level(BSL)-4 facilities.Therefore,accessible and convenient animal models are urgently needed to promote prophylactic and therapeutic approaches against EBOV.In this study,a recombinant vesicular stomatitis virus expressing Ebola virus glycoprotein(VSV-EBOV/GP)was constructed and applied as a surrogate virus,establishing a lethal infection in hamsters.Following infection with VSV-EBOV/GP,3-week-old female Syrian hamsters exhibited disease signs such as weight loss,multi-organ failure,severe uveitis,high viral loads,and developed severe systemic diseases similar to those observed in human EBOV patients.All animals succumbed at 2–3 days post-infection(dpi).Histopathological changes indicated that VSV-EBOV/GP targeted liver cells,suggesting that the tissue tropism of VSV-EBOV/GP was comparable to wild-type EBOV(WT EBOV).Notably,the pathogenicity of the VSV-EBOV/GP was found to be species-specific,age-related,gender-associated,and challenge route-dependent.Subsequently,equine anti-EBOV immunoglobulins and a subunit vaccine were validated using this model.Overall,this surrogate model represents a safe,effective,and economical tool for rapid preclinical evaluation of medical countermeasures against EBOV under BSL-2 conditions,which would accelerate technological advances and breakthroughs in confronting Ebola virus disease.
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supported by grants from the Strategic Priority Research Program of the Chinese Academy of Science(XDA24010303)the National Natural Science Foundation of China(31770268)+1 种基金the Fundamental Research Funds for the Central Universities(WK2070000091)the University of Science and Technology of China(Start-up fund to S.M.)。
文摘Stomata play critical roles in gas exchange and immunity to pathogens.While many genes regulating early stomatal development up to the production of young guard cells(GCs)have been identified in Arabidopsis,much less is known about how young GCs develop into mature functional stomata.Here we perform a maturomics study on stomata,with“maturomics”defined as omics analysis of the maturation process of a tissue or organ.We develop an integrative scheme to analyze three public stomata-related single-cell RNAseq datasets and identify a list of 586 genes that are specifically up-regulated in all three datasets during stomatal maturation and function formation.The list,termed sc_586,is enriched with known regulators of stomatal maturation and functions.To validate the reliability of the dataset,we selected two candidate G2-like transcription factor genes,MYS1 and MYS2,to investigate their roles in stomata.These two genes redundantly regulate the size and hoop rigidity of mature GCs,and the mys1 mys2 double mutants cause mature GCs with severe defects in regulating their stomatal apertures.Taken together,our results provide a valuable list of genes for studying GC maturation and function formation.
基金the Science and Technology Innovation Program of Hunan Province(Grant No.2021RC3088)the Hunan Provincial Natural Science Foundation of China(Grant No.2023JJ40309)the National Natural Science Foundation of China(Grant No.32001470).
文摘Transplanting rice varieties grown in different seasons can lead to different yields due to different dry matterproduction. Early-season rice varieties transplanted in the late season can obtain high yields with short-growthduration and higher yields driven by higher dry matter production. To make clear the variations in dry matterproduction across seasons, four early-season rice varieties were chosen for late-season transplantation. The grainyield, dry matter accumulation, leaf photosynthetic, and leaf stomatal properties were studied. It was observedthat the average yields of these four varieties in the late season were 33% greater, despite a reduced growth periodof 13 days in comparison with the early season. Furthermore, there was a notable increase in both total and postheadingdry matter production during the late season. The leaf net photosynthetic rate, stomatal area, stomatalwidth, and stomatal length were higher in the late season. Despite no significant difference in stomatal densitybetween seasons, strong positive linear relationships were observed between net photosynthetic rate and stomatalconductance, and between stomatal conductance and area. These relationships demonstrate that the increase ofthe stomatal width and length of the leaves in the late season leads to an increase in the stomatal area, therebyincreasing the stomatal conductance and enhancing the photosynthesis of the leaves. Consequently, this leads togreater dry matter production and a higher yield compared to the early season. Therefore, when breeding newhigh-yielding and short-growing varieties, the large stomatal area can be used as a reference index.
基金y the National Natural Science Foundation of China(Grant No.32102466)the Major Scientific Innovation Project of Shandong Province(Grant No.2022CXGC020708).
文摘Atmospheric CO_(2)concentration is elevated globally,which has“CO_(2)fertilization effects”and potentially improves plant photosynthesis,yield,and productivity.Despite the beneficial effect of CO_(2)fertilization being modulated by vapor pressure deficit(VPD),the underlying mechanism is highly uncertain.In the present study,the potential roles of hormones in determining CO_(2)fertilization effects under contrasting high and low VPD conditions were investigated by integrated physiological and transcriptomic analyses.Beneficial CO_(2)fertilization effects were offset under high VPD conditions and were constrained by plant water stress and photosynthetic CO_(2)utilization.High VPD induced a large passive water driving force,which disrupted the water balance and consequently caused plant water deficit.Leaf water potential,turgor pressure,and hydraulic conductance declined under high VPD stress.The physiological evidence combined with transcriptomic analyses demonstrated that abscisic acid(ABA)and jasmonic acid(JA)potentially acted as drought-signaling molecules in response to high VPD stress.Increased foliar ABA and JA content triggered stomatal closure to prevent excessive water loss under high VPD stress,which simultaneously increased the diffusion resistance for CO_(2)uptake from atmosphere to leaf intercellular space.High VPD also significantly increased mesophyll resistance for CO_(2)transport from stomatal cavity to fixation site inside chloroplast.The chloroplast“sink”CO_(2)availability was constrained by stomatal and mesophyll resistance under high VPD stress,despite the atmospheric“source”CO_(2)concentration being elevated.Thus,ABA-and JA-mediated drought-resistant mechanisms potentially modified the beneficial effect of CO_(2)fertilization on photosynthesis,plant growth,and yield productivity.This study provides valuable information for improving the utilization efficiency of CO_(2)fertilization and a better understanding of the physiological processes.
文摘The 15-carbon terpenoid abscisic acid(ABA)acts in vascular plants as a versatile hormone playing essential roles in reproductive development,vegetative development and growth,stress-development interactions,and physio-logical responses to abiotic and biotic stresses.Over the past 60 years,ABA dynamics,regulation,and responses have been progressively characterized:synthesis,transport and translocation,conjugation and deconjugation,metabolism,sensing,signal transduction,and downstream responses.In this context,the discovery of ABA expor-ters and importers has added novel dimensions to the understanding of ABA regulation.Moreover,since the initi-al discovery of the adenosine triphosphate-binding cassette(ABC)AtABCG25 exporter and AtABCG40 importer,several transporters of ABA have been characterized.As ABA is synthesized within cells,efflux transport of ABA to extracellular spaces is an important controlling step before ABA movements from cell to cell and from source to target.Until now,structural and functional mechanistic interactions between ABA and its transporters have remained poorly understood.Recent structure-function studies have unveiled key features of the mechanisms and functional dynamics of ABA-transporter interactions in the case of the ABCG25 exporter.ABCG25 has been established as a bonafide ABA efflux transporter involved in signal transmission leading to stomatal closure.It has also been shown to transport ABA-glucosyl ester(ABA-GE)conjugated form,thus implying involvement in conjugation and deconjugation dynamics.All of these mechanisms are essential for distribution throughout source tissues,source-to-target transmission,distribution throughout target tissues,and signal shape kinetics in target cells.This opinion piece emphasizes the pivotal role of transport discoveries in the history of ABA research,and how recent studies on ABA and ABA-GE transporters yield a more integrative vision of ABA reg-ulation and adaptive responses,open new avenues of research on signaling crosstalks,and constitute opportu-nities as well as challenges for crop improvement strategies.
基金financially supported by a grant of the National Natural Science Foundation of China(31670406)the Bagui Fellow scholarship(C33600992001)of Guangxi Zhuang Autonomous Region to KFC.
文摘Stomatal regulation is critical for mangroves to survive in the hyper-saline intertidal zone where water stress is severe and water availability is highly fluctuant.However,very little is known about the stomatal sensitivity to vapour pressure deficit(VPD)in mangroves,and its co-ordination with stomatal morphology and leaf hydraulic traits.We measured the stomatal response to a step increase in VPD in situ,stomatal anatomy,leaf hydraulic vulnerability and pressure-volume traits in nine true mangrove species of five families and collected the data of genome size.We aimed to answer two questions:(1)Does stomatal morphology influence stomatal dynamics in response to a high VPD in mangroves?with a consideration of possible influence of genome size on stomatal morphology;and(2)do leaf hydraulic traits influence stomatal sensitivity to VPD in mangroves?We found that the stomata of mangrove plants were highly sensitive to a step rise in VPD and the stomatal responses were directly affected by stomatal anatomy and hydraulic traits.Smaller,denser stomata was correlated with faster stomatal closure at high VPD across the species of Rhizophoraceae,and stomata size negatively and vein density positively correlated with genome size.Less negative leaf osmotic pressure at the full turgor(πo)was related to higher operating steady-state stomatal conductance(gs);and a higher leaf capacitance(Cleaf)and more embolism resistant leaf xylem were associated with slower stomatal responses to an increase in VPD.In addition,stomatal responsiveness to VPD was indirectly affected by leaf morphological traits,which were affected by site salinity and consequently leaf water status.Our results demonstrate that mangroves display a unique relationship between genome size,stomatal size and vein packing,and that stomatal responsiveness to VPD is regulated by leaf hydraulic traits and stomatal morphology.Our work provides a quantitative framework to better understand of stomatal regulation in mangroves in an environment with high salinity and dynamic water availability.
