The responses of drip-irrigated rice physiological traits to water and fertilizers have been widely studied.However,the responses of yield,root traits and their plasticity to the nitrogen environment in different nitr...The responses of drip-irrigated rice physiological traits to water and fertilizers have been widely studied.However,the responses of yield,root traits and their plasticity to the nitrogen environment in different nitrogen-efficient cultivars are not fully understood.An experiment was conducted from 2020-2022 with a high nitrogen use efficiency(high-NUE)cultivar(T-43)and a low-NUE cultivar(LX-3),and four nitrogen levels(0,150,300,and 450 kg ha^(-1))under drip irrigation in large fields.The aim was to study the relationships between root morphology,conformation,biomass,and endogenous hormone contents,yield and NUE.The results showed three main points:1)Under the same N application rate,compared with LX-3,the yield,N partial factor productivity(PFP),fine root length density(FRLD),shoot dry weight(SDW),root indole-3-acetic acid(IAA),and root zeatin and zeatin riboside(Z+ZR)of T-43 were significantly greater by11.4-18.9,11.3-13.5,11.6-15.7,9.9-31.1,6.1-48.1,and 22.8-73.6%,respectively,while the root-shoot ratio(RSR)and root abscisic acid(ABA)were significantly lower(P<0.05);2)nitrogen treatment significantly increased the rice root morphological indexes and endogenous hormone contents(P<0.05).Compared to N0,the yield,RLD,surface area density(SAD),root volume density(RVD),and root endogenous hormones(IAA,Z+ZR)were significantly increased in both cultivars under N2 by 61.6-71.6,64.2-74.0,69.9-105.6,6.67-9.91,54.0-67.8,and 51.4-58.9%,respectively.Compared with N3,the PFP and N agronomic efficiency(NAE)of nitrogen fertilizer under N2 increased by 52.3-62.4 and39.2-63.0%,respectively;3)the responses of root trait plasticity to the N environment significantly differed between the cultivars(P<0.05).Compared with LX-3,T-43 showed a longer root length and larger specific surface area,which is a strategy for adapting to changes in the nutrient environment.For the rice cultivar with high-NUE,the RSR was optimized by increasing the FRLD,root distribution in upper soil layers,and root endogenous hormones(IAA,Z+ZR)under suitable nitrogen conditions(N2).An efficient nutrient acquisition strategy can occur through root plasticity,leading to greater yield and NUE.展开更多
Plant nitrogen assimilation and use efficiency in the seedling's root system are beneficial for adult plants in field condition for yield enhancement.Identification of the genetic basis between root traits and N u...Plant nitrogen assimilation and use efficiency in the seedling's root system are beneficial for adult plants in field condition for yield enhancement.Identification of the genetic basis between root traits and N uptake plays a crucial role in wheat breeding.In the present study,198 doubled haploid lines from the cross of Yangmai 16/Zhongmai 895 were used to identify quantitative trait loci(QTLs)underpinning four seedling biomass traits and five root system architecture(RSA)related traits.The plants were grown under hydroponic conditions with control,low and high N treatments(Ca(NO_(3))_(2)·4H_(2)O at 0,0.05 and 2.0 mmol L^(-1),respectively).Significant variations among the treatments and genotypes,and positive correlations between seedling biomass and RSA traits(r=0.20 to 0.98)were observed.Inclusive composite interval mapping based on a high-density map from the Wheat 660 K single nucleotide polymorphisms(SNP)array identified 51 QTLs from the three N treatments.Twelve new QTLs detected on chromosomes 1 AL(1)in the control,1 DS(2)in high N treatment,4 BL(5)in low and high N treatments,and 7 DS(3)and 7 DL(1)in low N treatments,are first reported in influencing the root and biomass related traits for N uptake.The most stable QTLs(RRS.caas-4 DS)on chromosome 4 DS,which were related to ratio of root to shoot dry weight trait,was in close proximity of the Rht-D1 gene,and it showed high phenotypic effects,explaining 13.1%of the phenotypic variance.Twenty-eight QTLs were clustered in 12 genetic regions.SNP markers tightly linked to two important QTLs clusters C10 and C11 on chromosomes 6 BL and 7 BL were converted to kompetitive allele-specific PCR(KASP)assays that underpin important traits in root development,including root dry weight,root surface area and shoot dry weight.These QTLs,clusters and KASP assays can greatly improve the efficiency of selection for root traits in wheat breeding programmes.展开更多
Synthetic hexaploid wheat(SHW),possesses numerous genes for drought that can help breeding for drought-tolerant wheat varieties.We evaluated 10 root traits at seedling stage in 111 F9 recombinant inbred lines derived ...Synthetic hexaploid wheat(SHW),possesses numerous genes for drought that can help breeding for drought-tolerant wheat varieties.We evaluated 10 root traits at seedling stage in 111 F9 recombinant inbred lines derived from a F2 population of a SHW line(SHW-L1)and a common wheat line,under normal(NC)and polyethylene glycol-simulated drought stress conditions(DC).We mapped quantitative trait loci(QTLs)for root traits using an enriched high-density genetic map containing 120370 single nucleotide polymorphisms(SNPs),733 diversity arrays technology markers(DArT)and 119 simple sequence repeats(SSRs).With four replicates per treatment,we identified 19 QTLs for root traits under NC and DC,and 12 of them could be consistently detected with three or four replicates.Two novel QTLs for root fresh weight and root diameter under NC explained 9 and 15.7%of the phenotypic variation respectively,and six novel QTLs for root fresh weight,the ratio of root water loss,total root surface area,number of root tips,and number of root forks under DC explained 8.5–14%of the phenotypic variation.Here seven of eight novel QTLs could be consistently detected with more than three replicates.Results provide essential information for fine-mapping QTLs related to drought tolerance that will facilitate breeding drought-tolerant wheat cultivars.展开更多
C3 plant Reaumuria soongorica and C4 plant Salsola passerina are super xerophytes and coexist in a mixed community in either isolated or associated growth, and interspecific facilitation occurs in associated growth. I...C3 plant Reaumuria soongorica and C4 plant Salsola passerina are super xerophytes and coexist in a mixed community in either isolated or associated growth, and interspecific facilitation occurs in associated growth. In the present study, the root traits including root distribution, root length（RL）, root surface area（RSA）, root weight（RW） and specific root length（SRL） of both species in two growth forms were investigated to clarify their response to facilitation in associated growth. Six isolated plants of each species, as well as six associated plants similar in size and development were selected during the plant growing season, and their roots were excavated at 0–10, 10–20, 20–30, 30–40 and 40–50 cm soil depths at the end of the growing season. All the roots of each plant were separated into the two categories of fine roots（2 mm diameter） and coarse roots（≥2 mm diameter）. Root traits such as RL and RSA in the fine and coarse roots were obtained by the root analyzing system WinRHIZO. Most of the coarse roots in R. soongorica and S. passerina were distributed in the top 10 cm of the soil in both growth forms, whereas the fine roots of the two plant species were found mainly in the 10–20 and 20–30 cm soil depths in isolated growth, respectively. However, the fine roots of both species were mostly overlapped in 10–20 cm soil depth in associated growth. The root/canopy ratios of both species reduced, whereas the ratios of their fine roots to coarse roots in RL increased, and both species had an increased SRL in the fine roots in associated growth. In addition, there was the increase in RL of fine roots and content of root N for S. passerina in associated growth. Taken together, the root growth of S. passerina was facilitated for water and nutrient exploration under the interaction of the overlapped roots in both species in associated growth, and higher SRL allowed both species to more effectively adapt to the infertile soil in the desert ecosystem.展开更多
Cotton(Gossypium spp.) is an important fiber and oil crop grown worldwide. Water and nutrient stresses are major issues affecting cotton production globally. Root traits are critical in improving water and nutrient up...Cotton(Gossypium spp.) is an important fiber and oil crop grown worldwide. Water and nutrient stresses are major issues affecting cotton production globally. Root traits are critical in improving water and nutrient uptake and maintaining plant productivity under optimal as well as drought conditions.However, root traits have rarely been utilized in cotton breeding programs, a major reason being the lack of information regarding genetic variability for root traits. The objective of this research was to evaluate ten selected cotton genotypes for root traits and water use efficiency. The tested genotypes included germplasm lines(PD 1 and PD 695) and cultivars that are currently grown in the southeastern USA(PHY 499 WRF, PHY 444 WRF, PHY 430 W3 FE, DP 1646 B2 XF, DP 1538 B2 XF, DP 1851 B3 XF, NG5007 B2 XF, and ST 5020 GLT). Experiments were conducted under controlled environmental conditions in 2018 and 2019. A hardpan treatment was included in the second year to evaluate the effect of a soil hardpan on root traits and water use efficiency. Genotype PHY 499 WRF ranked at the top and NG5007 B2 XF ranked at the bottom for root morphological traits(total and fine root length, surface area,and volume) and root weight. PHY 499 WRF was also one of the best biomass producers and had high water use efficiency. PHY 444 WRF, PHY 430 W3 FE, and PD-1 were the other best genotypes in terms of root traits and water use efficiency. All genotypes had higher values for root traits and water use efficiency under hardpan conditions. This trend indicates a horizontal proliferation of root systems when they incur a stress imposed by a hardpan. The genotypic differences identified in this research for root traits and water use efficiency would be valuable for selecting genotypes for cotton breeding programs.展开更多
Soil salinization is the main factor that threatens the growth and development of plants and limits the increase of yield.It is of great significance to study the key soil environmental factors affecting plant root tr...Soil salinization is the main factor that threatens the growth and development of plants and limits the increase of yield.It is of great significance to study the key soil environmental factors affecting plant root traits to reveal the adaptation strategies of plants to saline-alkaline-stressed soil environments.In this study,the root biomass,root morphological parameters and root mineral nutrient content of two alfalfa cultivars with different sensitivities to alkaline stress were analyzed with black soil as the control group and the mixed saline-alkaline soil with a ratio of 7:3 between black soil and saline-alkaline soil as the saline-alkaline treatment group.At the same time,the correlation analysis of soil salinity indexes,soil nutrient indexes and the activities of key enzymes involved in soil carbon,nitrogen and phosphorus cycles was carried out.The results showed that compared with the control group,the pH,EC,and urease(URE)of the soil surrounding the roots of two alfalfa cultivars were significantly increased,while soil total nitrogen(TN),total phosphorus(TP),organic carbon(SOC),andα-glucosidase activity(AGC)were significantly decreased under saline-alkaline stress.There was no significant difference in root biomass and root morphological parameters of saline-alkaline tolerant cultivar GN under saline-alkaline stress.The number of root tips(RT),root surface area(RS)and root volume(RV)of AG were reduced by 61.16%,44.54%,and 45.31%,respectively,compared with control group.The ratios of K^(+)/Na^(+),Ca^(2+)/Na^(+)and Mg^(2+)/Na^(+)of GN were significantly higher than those of AG(p<0.05).The root fresh weight(RFW)and dry weight(RDW),root length(RL),RV and RT of alfalfa were positively regulated by soil SOC and TN,but negatively regulated by soil pH,EC,and URE(p<0.01).Root Ca^(2+)/Na+ratio was significantly positively correlated with soil TN,TP and SOC(p<0.01).The absorption of Mg and Ca ions in roots is significantly negatively regulated by soilβ-glucosidase activity(BGC)and acid phosphatase activity(APC)(p<0.05).This study improved knowledge of the relationship between root traits and soil environmental factors and offered a theoretical framework for elucidating how plant roots adapt to saline-alkaline stressed soil environments.展开更多
Mechanical hill wet-seeded rice machine is beneficial for establishing and growing uniform rows of seedlings.However,there is limited knowledge regarding the effects of the establishment of furrows on growth,lodging a...Mechanical hill wet-seeded rice machine is beneficial for establishing and growing uniform rows of seedlings.However,there is limited knowledge regarding the effects of the establishment of furrows on growth,lodging and yield,and their relationships with root traits.In this study,field experiments were conducted during 2012 and 2013 using two super rice varieties(hybrid rice Peizataifeng and inbred rice Yuxiangyouzhan)under three furrow establishment treatments(T1,both water and seed furrows were established by the machine;T2,only seed furrows were established by the machine;and T3,neither water nor seed furrows were established by the machine).Lodging index,lodging-related traits,grain yield,above-ground dry weight and root traits were measured.The results showed that the lodging index was significantly affected by the treatments with furrows(T1 and T2).The strongest lodging resistance was detected in the mechanical hill wet-seeded rice with furrow treatment(T1)in both 2012 and 2013.Lodging resistance was strongly related to the breaking resistance.No significant difference was found in grain yield or dry weight of the mechanical hill wet-seeded rice.Therefore,the mechanical hill wet-seeded rice with furrow treatment increased rice lodging resistance,which was related to root traits.展开更多
In natural ecosystems, nutrition available for plants shows great spatial heterogeneity. Much is known about plant root responses to the spatial heterogeneity of nutrition, but little is known about carbon usage in ro...In natural ecosystems, nutrition available for plants shows great spatial heterogeneity. Much is known about plant root responses to the spatial heterogeneity of nutrition, but little is known about carbon usage in roots in nutrition-deficient patches and its effect on root longevity. In this study, split-room boxes were used for culture of Cercis chinensis seedlings, and the small rooms were supplied with different nutrition levels. The number of the first-order roots in the rooms with nutrition supply was significantly higher than that in the rooms with deficient nutrition. Specific root length （SRL） of the first-order roots in the rooms with deficient nutrition reached its peak at day 64 after nutrition treatment. There was no significant SRL differences between the two order roots during the experiment. Biomass of the first-order roots in the rooms without nutrition supply was significantly less than that of the first-order roots in the rooms with nutrition supply from day 64 to 96. The total biomass of the lateral roots in the rooms without nutrition supply decreased from day 64 to 96. The activities of the enzymes in roots in the rooms without nutrition supply increased and the activities of alkaline invertases in roots in the two sides of split box did not change significantly. The activities of the enzymes in roots in the rooms without nutrition supply increased gradually. These results suggest that nutrition spatial heterogeneity induced the changes in root traits and plants actively controlled carbon usage in roots in nutrition-deficient patches by regulating the activities of invertases and sucrose synthases, resulting in the reduction in carbon usage in the roots in nutrition-deficient patches.展开更多
Root anatomical traits play an important role in understanding the link between root physiological function and ecological process. To determine how plants change root anatomical traits to adapt to distinct environmen...Root anatomical traits play an important role in understanding the link between root physiological function and ecological process. To determine how plants change root anatomical traits to adapt to distinct environments, we measured four key root anatomical traits-stele diameter(SD), cortex thickness(CT), root diameter(RD), and the stele to root diameter ratio(SDRD)-of first-order roots of 82species collected from different vegetation zones along a 2000 m altitudinal gradient on the northern slope of Taibai Mountain. Compared with other altitudes, plants located in temperate birch and fir forests had thinner SD, CT, RD, and SDRD. We found that elevational variation in root anatomical traits could largely be explained by phylogenetic taxonomy(clade). In addition, changes in SD were driven by soil bulk density, whereas variations in CT and RD were influenced by soil available nitrogen. When phylogenetic factors were removed from our analysis, allometric relationships between RD and root anatomical traits(SD and CT) were observed across different altitudes. Our study reveals the influence of phylogeny and environment on the elevational variation in root anatomical traits and further supports the allometric relationship between root anatomical traits(SD and CT) and RD. These findings enhance our understanding of the evolutionary and adaptive mechanisms of root anatomical structures, providing a basis for predicting how root anatomical traits respond to global changes.展开更多
Phosphorous （P） deficiency is a major restraint factor for crop production and plants have developed several mechanisms to adapt to low P stress. In this study, a set of 271 introgression lines （ILs） were used to ...Phosphorous （P） deficiency is a major restraint factor for crop production and plants have developed several mechanisms to adapt to low P stress. In this study, a set of 271 introgression lines （ILs） were used to characterize the responses of seedlings to low P availability and to identify QTLs for root traits, biomass, and plant height under P-deficiency and P-sufficiency conditions. Plant height, total dry weight, shoot dry weight, and root number were inhibited under P-deficiency, whereas maximum root length （MRL） and root-shoot ratio （RS） were induced by P-deficiency stress. Relative MRL （RMRL, the ratio of MRL under P-deficiency to MRL under P-sufficiency con- dition） and relative RS （RRS） were used to evaluate P-deficiency tolerance at the seedling stage. A total of 24 additive QTLs and 29 pairs of epistatic QTLs were detected, but only qRN4 was detected in both conditions. This suggested that different mechanisms may exist in both P supply levels. QTLs for adaptive traits （RMRL, RRS, RRV, and RRDW） and qRN4 consistently expressed to increase trait stability may contribute to P-deficiency tolerance. Twelve intervals were cluster regions of QTLs for P-deficiency tolerance, and one QTL （qRRSS） showed pleiotropic effects on P-deficiency tolerance and drought tolerance. These interesting QTLs can be used in marker-assisted breeding through the target ILs.展开更多
Aims Competition,temperature and nutrient are the most important determinants of tree growth in the cold climate on the eastern Tibetan Plateau.Although many studies have reported their individual effects on tree grow...Aims Competition,temperature and nutrient are the most important determinants of tree growth in the cold climate on the eastern Tibetan Plateau.Although many studies have reported their individual effects on tree growth,little is known about how the interactions of competition with fertilization and temperature affect root growth.We aim to test whether climate warming and fertilization promote competition and to explore the functional strategies of Picea asperata in response to the interactions of these factors.Methods We conducted a paired experiment including competition and non-competition treatments under elevated temperature(ET)and fertilization.We measured root traits,including the root tip number over the root surface(RTRS),the root branching events over the root surface(RBRS),the specific root length(SRL),the specific root area(SRA),the total fine root length and area(RL and RA),the root tips(RTs)and root branching(RB)events.These root traits are considered to be indicators of plant resource uptake capacity and root growth.The root biomass and the nutrient concentrations in the roots were also determined.Important Findings The results indicated that ET,fertilization and competition individually enhanced the nitrogen(N)and potassium(K)concentrations in fine roots,but they did not affect fine root biomass or root traits,including RL,RT,RA and RB.However,both temperature and fertilizationz as well as their interaction,interacting with competition increased RL,RA,RT,RB and nutrient uptake.In addition,the SRL,SRA,RTRS and RBRS decreased un der fertilization,the interaction between temperature and competition decreased SRL and SRA,while the other parameters were not affected by temperature or competition.These results indicate that P.asperata maintains a conservative nutrient strategy in response to competition,climate warming,fertilization and their interactions.Our results improve our understanding of the physiological and ecological adaptability of trees to global change.展开更多
The relationships between plant organs and root hydrological traits are not well known and the question arises whether elevated CO2 changes these relationships. This study attempted to answer this question. A pseudo-r...The relationships between plant organs and root hydrological traits are not well known and the question arises whether elevated CO2 changes these relationships. This study attempted to answer this question. A pseudo-replicated experiment was conducted with two times 24 American elm （Ulmus americana L.） and 23 and 24 red oak （Quercus rubra L.） seedlings growing in ambient CO2 （around 360 μmol.L^-1） and 540 ± 7.95 μmol.L^-1 CO2 in a greenhouse. After 71 days of treatment for American elm and 77 days for red oak, 14 American elm and 12 red oak seedlings from each of the two CO2 levels were randomly selected in order to examine the flow rate of root xylem sap, root hydraulic conductance, total root hydraulic conductivity, fine root and coarse root hydraulic conductivity. All seedlings were harvested to investigate total plant biomass, stem biomass and leaf biomass, leaf area, height, basal diameter, total root biomass, coarse root biomass and fine root biomass. The following conclusions are reached： 1） plant organs respond to the elevated CO2 level earlier than hydraulic traits of roots and may gradually lead to changes in hydraulic traits; 2） plant organs have different relationships with hydraulic traits of roots and elevated CO2 changes these relationships; the changes may be of importance for plants as means to acclimatize to changing environments; 3） biomass of coarse roots increased rather more than that of fine roots; 4） Lorentzian and Caussian models are better in estimating the biomass of seedlings than single-variable models. Key words American elm, biomass, elevated CO2, modeling, red oak, root hydraulic traits展开更多
How sex-related root traits and soil microbes and their interactions respond to drought remains unclear.Here,we investigated how fine root traits and the composition of rhizosphere microbial communities in Populus eup...How sex-related root traits and soil microbes and their interactions respond to drought remains unclear.Here,we investigated how fine root traits and the composition of rhizosphere microbial communities in Populus euphratica females and males respond to drought in concert in 17-year-old plantations.Females increased specific root length(SRL)in response to drought.However,males showed no changes in their roots but significant increases in arbuscular mycorrhizal hyphal biomass and population of Gram-negative bacteria in the rhizosphere.Also,fungal symbiotroph communities associated with root systems in males differed from those in females under drought.We further demonstrated that the Gram-positive to Gram-negative bacteria ratios positively correlated with the SRL,while fungi to bacteria ratios were negatively correlated.Meanwhile,the relative abundance of symbiotrophs was negatively correlated with the SRL,while saprotroph abundance was positively correlated.Nevertheless,the relative abundance of symbiotrophs was positively correlated with the root carbon content(RCC).These findings indicate that microbial responses to drought depend highly upon the sex of the plant and microbial group and are related to root trait adjustments to drought.This discovery also highlights the role of plant-microbial interactions in the ecosystems of P.euphratica forest plantations.展开更多
Research on root morphological traits of dry-raised seedlings (D-RS) at different growth stages of rice have so far attracted less attention. In this study, using mid-season indica hy-
Phosphorus use efficiency(PUE)can be improved through cultivation techniques and breeding.However,little is known about rice(Oryza sativa L.)agronomic and physiological traits associated with high PUE.We characterized...Phosphorus use efficiency(PUE)can be improved through cultivation techniques and breeding.However,little is known about rice(Oryza sativa L.)agronomic and physiological traits associated with high PUE.We characterized the agronomic and physiological traits of rice varieties with different tolerances to low phosphorus in nutrient solution.Two varieties with strong tolerance to low phosphorus(STVs)and two with weak tolerance(WTVs)were grown at normal(NP,control)and low phosphorus(LP,1/20 of NP)concentrations.Plants grown at LP produced significantly lower grain yield than those grown at NP.WTVs yields were lower than STVs yields.Compared to NP,LP significantly increased phosphorus translocation efficiency(PTE),internal phosphorus efficiency(IPE)and phosphorus harvest index(PHI).Under the LP condition,PTE and IPE were higher for STVs than for WTVs.LP also reduced tiller number,shoot biomass,leaf area index(LAI),leaf photosynthetic rate,and mean root diameter of both kinds of varieties at the main growth stages,but to a lower extent in STVs.LP significantly increased the number of productive tillers,root biomass,root-shoot ratio,root bleeding rate,and root acid phosphatase(RAP)activity.Total root length,root oxidation activity(ROA),and root total and active absorbing surface areas for STVs were significantly increased under LP,whereas the opposite responses were observed for WTVs.Total root length,ROA,root bleeding rate,root active absorbing surface area,and RAP activity were positively and significantly correlated with grain yield,PTE,and IPE.These results suggest that the tolerance of rice varieties to a low-phosphorus growth condition is closely associated with root growth with higher biomass and activity.展开更多
Artificial vegetation restoration is the main measure for vegetation restoration and soil and water conservation in alpine mine dumps on the Qinghai-Tibet Plateau,China.However,there are few reports on the dynamic cha...Artificial vegetation restoration is the main measure for vegetation restoration and soil and water conservation in alpine mine dumps on the Qinghai-Tibet Plateau,China.However,there are few reports on the dynamic changes and the influencing factors of the soil reinforcement effect of plant species after artificial vegetation restoration under different recovery periods.We selected dump areas of the Delni Copper Mine in Qinghai Province,China to study the relationship between the shear strength and the peak displacement of the root-soil composite on the slope during the recovery period,and the influence of the root traits and soil physical properties on the shear resistance characteristics of the root-soil composite via in situ direct shear tests.The results indicate that the shear strength and peak displacement of the rooted soil initially decreased and then increased with the increase of the recovery period.The shear strength of the rooted soil and the recovery period exhibited a quadratic function relationship.There is no significant function relationship between the peak displacement and the recovery period.Significant positive correlations(P<0.05)exists between the shear strength of the root-soil composite and the root biomass density,root volume density,and root area ratio,and they show significant linear correlations(P<0.05).There are no significant correlations(P>0.05)between the shear strength of the root-soil composite and the root length density,and the root volume ratio of the coarse roots to the fine roots.A significant negative linear correlation(P<0.05)exists between the peak displacement of the rooted soil and the coarse-grain content,but no significant correlations(P>0.05)with the root traits,other soil physical property indices(the moisture content and dry density of the soil),and slope gradient.The coarse-grain content is the main factor controlling the peak displacement of the rooted soil.展开更多
The presented work is based on laboratory testing of seed germination speed, emergence and seedling growth under different stress conditions simulated by subnormal water revel, extreme high and low temperatures. It al...The presented work is based on laboratory testing of seed germination speed, emergence and seedling growth under different stress conditions simulated by subnormal water revel, extreme high and low temperatures. It allows one to eliminate the plant materials （initial breeding materials and cultivars） which do not tolerate extreme temperatures and temperature changes during germination, have low water use efficiency and is intolerant to abiotic stressors all right at the seed level. It was confirmed that these genotypes also have poor t^eld emergence and initial root growth implications for further vegetation periods, mainly for over wintering and spring regeneration which has significant influence on the yield. The method also represents the tool for screening genetic resources with the resistance to the abiotic stressors and this technology process is also acceptable for other crops. The results confirm the importance of the seed and root characteristics for crop production. The deteriorating quality of soil in recent years, increasing variability of weather and long periods of drought directly support the need to intensify activities in this research. Obtained results also show the influence of seed quality characteristics on roots and above ground parts of the plant. A relationship exists also vice versa.展开更多
In this study, 14 wheat cultivars with contrasting yield and N use efficiency （NUE） were used to investigate the agronomic and NUE-related traits, and the N assimilation-associated enzyme activities under low and hi...In this study, 14 wheat cultivars with contrasting yield and N use efficiency （NUE） were used to investigate the agronomic and NUE-related traits, and the N assimilation-associated enzyme activities under low and high N conditions. Under deficient-N, the cultivars with high N uptake efficiency （UpE） and high N utilization efficiency （UtE） exhibited higher plant biomass, yields, and N contents than those with medium and low NUEs. The high UpE cultivars accumulated more N than other NUE type cultivars. Under sufficient-N, the tested cultivars showed similar patterns in biomass, yield, and N content to those under deficient-N, but the varietal variations in above traits were smaller. In addition, the high UpE cultivars displayed much more of root biomass and larger of root length, surface area, and volume than other NUE type cultivars, indicating that the root morphological traits under N deprivation are closely associated with the plant biomass through its improvement of the N acquisition. The high UtE cultivars showed higher activities of nitrate reductase （NR）, nitrite reductase （NIR）, and gluta- mine synthetase （GS） at stages of seediling, heading and filling than other NUE type cultivars under both low and high N conditions. Moreover, the high UpE and UtE cultivars also displayed higher photosynthetic rate under deficient-N than the medium and low NUE cultivars. Together, our results indicated that the tested wheat cultivars possess dramatically genetic variations in biomass, yield, and NUE. The root morphological traits and the N assimilation enzymatic acitivities play critical roles in regulating N accumulation and internal N translocation under the N-starvation stress, respectively. They can be used as morphological and biochemical references for evaluation of UpE and UtE in wheat.展开更多
The use of nitrogen(N)-efficient rice(Oryza sativa L.) varieties could reduce excessive N input without sacrificing yields. However, the plant traits associated with N-efficient rice varieties have not been fully defi...The use of nitrogen(N)-efficient rice(Oryza sativa L.) varieties could reduce excessive N input without sacrificing yields. However, the plant traits associated with N-efficient rice varieties have not been fully defined or comprehensively explored. Here, three japonica N-efficient varieties(NEVs) and three japonica N-inefficient varieties(NIVs) of rice were grown in a paddy field under N omission(0 N, 0 kg N ha^(-1)) and normal N(NN, 180 or 200 kg N ha^(-1)) treatments. Results showed that NEVs exhibited higher grain yield and nitrogen use efficiency(NUE) than NIVs under both treatments, due to improved sink size and filled-grains percentage in the former which had higher root oxidation activity and greater root dry weight, root length and root diameter at panicle initiation(PI), as well as higher spikelet-leaf ratio and more productive tillers during the grain-filling stage. Compared with NIVs, NEVs also exhibited enhanced N translocation and dry matter accumulation after heading and improved flag leaf morpho-physiological traits, including greater leaf thickness and specific leaf weight and higher contents of ribulose^(-1),5-bisphosphate carboxylase/oxygenase, chlorophyll, nitrogen, and soluble sugars, leading to better photosynthetic performance. Additionally, NEVs had a better canopy structure, as reflected by a higher ratio of the extinction coefficient for effective leaf N to the light extinction coefficient, leading to enhanced canopy photosynthesis and dry matter accumulation. These improved agronomic and physiological traits were positively and significantly correlated with grain yield and internal NUE, which could be used to select and breed N-efficient rice varieties.展开更多
Aims: Plant roots show various functional strategies in soil phosphorus(P) acquisition. Under limited soil phosphatase activity, P deficiency is the main concern, and roots either invest carbon(C) to produce higher le...Aims: Plant roots show various functional strategies in soil phosphorus(P) acquisition. Under limited soil phosphatase activity, P deficiency is the main concern, and roots either invest carbon(C) to produce higher levels of phosphatase or establish more symbioses with mycorrhizal fungi. However, these strategies and their interactions are not clear. Furthermore, few studies have investigated trade-offs of functional traits in woody species associated with different types of mycorrhizal partners.Methods: Here we examined the abilities to release acid phosphatase(AP) and the colonization ratio by arbuscular and ectomycorrhizal fungi for fine roots of 15 woody species growing in a tropical common garden in Xishuangbanna, China. We also measured acid phosphatase activities of bulk soils under the canopy of target trees.Results: Soil and root AP activities exhibited a positive correlation, indicating that roots actively produced AP to acquire P even bulk soil AP was increasing. We found a significantly negative correlation(P=0.02) between mycorrhizal colonization ratio and root-released AP activity across target species, reflecting a trade-off between these two P acquisition strategies.Conclusions: Our findings suggest a trade-off of resource allocation between these two strategies at both species and individual levels, and provide information on the overall mechanism of P acquisition by fine roots that they either ‘do it by themselves’ or ‘rely on mycorrhizal partners’. These two strategies might be integrated into the collaboration gradient of the root economics space.展开更多
基金supported by the National Natural Science Foundation of China(31860345 and 31460541)the Youth Innovative Top Talents Project of Shihezi University,China(CXBJ202003)the Third Division of Xinjiang Production and Construction Corps Scientific and Technological Achievements Transfer and Transformation Project,China(KJ2023CG03)。
文摘The responses of drip-irrigated rice physiological traits to water and fertilizers have been widely studied.However,the responses of yield,root traits and their plasticity to the nitrogen environment in different nitrogen-efficient cultivars are not fully understood.An experiment was conducted from 2020-2022 with a high nitrogen use efficiency(high-NUE)cultivar(T-43)and a low-NUE cultivar(LX-3),and four nitrogen levels(0,150,300,and 450 kg ha^(-1))under drip irrigation in large fields.The aim was to study the relationships between root morphology,conformation,biomass,and endogenous hormone contents,yield and NUE.The results showed three main points:1)Under the same N application rate,compared with LX-3,the yield,N partial factor productivity(PFP),fine root length density(FRLD),shoot dry weight(SDW),root indole-3-acetic acid(IAA),and root zeatin and zeatin riboside(Z+ZR)of T-43 were significantly greater by11.4-18.9,11.3-13.5,11.6-15.7,9.9-31.1,6.1-48.1,and 22.8-73.6%,respectively,while the root-shoot ratio(RSR)and root abscisic acid(ABA)were significantly lower(P<0.05);2)nitrogen treatment significantly increased the rice root morphological indexes and endogenous hormone contents(P<0.05).Compared to N0,the yield,RLD,surface area density(SAD),root volume density(RVD),and root endogenous hormones(IAA,Z+ZR)were significantly increased in both cultivars under N2 by 61.6-71.6,64.2-74.0,69.9-105.6,6.67-9.91,54.0-67.8,and 51.4-58.9%,respectively.Compared with N3,the PFP and N agronomic efficiency(NAE)of nitrogen fertilizer under N2 increased by 52.3-62.4 and39.2-63.0%,respectively;3)the responses of root trait plasticity to the N environment significantly differed between the cultivars(P<0.05).Compared with LX-3,T-43 showed a longer root length and larger specific surface area,which is a strategy for adapting to changes in the nutrient environment.For the rice cultivar with high-NUE,the RSR was optimized by increasing the FRLD,root distribution in upper soil layers,and root endogenous hormones(IAA,Z+ZR)under suitable nitrogen conditions(N2).An efficient nutrient acquisition strategy can occur through root plasticity,leading to greater yield and NUE.
基金the National Key R&D Program of China(2016YFD0101804-6)the National Natural Science Foundation of China(31671691)the International Science&Technology Cooperation Program of China(2016YFE0108600)。
文摘Plant nitrogen assimilation and use efficiency in the seedling's root system are beneficial for adult plants in field condition for yield enhancement.Identification of the genetic basis between root traits and N uptake plays a crucial role in wheat breeding.In the present study,198 doubled haploid lines from the cross of Yangmai 16/Zhongmai 895 were used to identify quantitative trait loci(QTLs)underpinning four seedling biomass traits and five root system architecture(RSA)related traits.The plants were grown under hydroponic conditions with control,low and high N treatments(Ca(NO_(3))_(2)·4H_(2)O at 0,0.05 and 2.0 mmol L^(-1),respectively).Significant variations among the treatments and genotypes,and positive correlations between seedling biomass and RSA traits(r=0.20 to 0.98)were observed.Inclusive composite interval mapping based on a high-density map from the Wheat 660 K single nucleotide polymorphisms(SNP)array identified 51 QTLs from the three N treatments.Twelve new QTLs detected on chromosomes 1 AL(1)in the control,1 DS(2)in high N treatment,4 BL(5)in low and high N treatments,and 7 DS(3)and 7 DL(1)in low N treatments,are first reported in influencing the root and biomass related traits for N uptake.The most stable QTLs(RRS.caas-4 DS)on chromosome 4 DS,which were related to ratio of root to shoot dry weight trait,was in close proximity of the Rht-D1 gene,and it showed high phenotypic effects,explaining 13.1%of the phenotypic variance.Twenty-eight QTLs were clustered in 12 genetic regions.SNP markers tightly linked to two important QTLs clusters C10 and C11 on chromosomes 6 BL and 7 BL were converted to kompetitive allele-specific PCR(KASP)assays that underpin important traits in root development,including root dry weight,root surface area and shoot dry weight.These QTLs,clusters and KASP assays can greatly improve the efficiency of selection for root traits in wheat breeding programmes.
基金supported by the National Natural Science Foundation of China(31771794,91731305 and 31560388)the outstanding Youth Foundation of the Department of Science and Technology of Sichuan Province,China(2016JQ0040)+1 种基金the Key Technology Research and Development Program of the Department of Science and Technology of Sichuan Province,China(2016NZ0057)the International Science&Technology Cooperation Program of the Bureau of Science and Technology of Chengdu,China(2015DFA306002015-GH03-00008-HZ)。
文摘Synthetic hexaploid wheat(SHW),possesses numerous genes for drought that can help breeding for drought-tolerant wheat varieties.We evaluated 10 root traits at seedling stage in 111 F9 recombinant inbred lines derived from a F2 population of a SHW line(SHW-L1)and a common wheat line,under normal(NC)and polyethylene glycol-simulated drought stress conditions(DC).We mapped quantitative trait loci(QTLs)for root traits using an enriched high-density genetic map containing 120370 single nucleotide polymorphisms(SNPs),733 diversity arrays technology markers(DArT)and 119 simple sequence repeats(SSRs).With four replicates per treatment,we identified 19 QTLs for root traits under NC and DC,and 12 of them could be consistently detected with three or four replicates.Two novel QTLs for root fresh weight and root diameter under NC explained 9 and 15.7%of the phenotypic variation respectively,and six novel QTLs for root fresh weight,the ratio of root water loss,total root surface area,number of root tips,and number of root forks under DC explained 8.5–14%of the phenotypic variation.Here seven of eight novel QTLs could be consistently detected with more than three replicates.Results provide essential information for fine-mapping QTLs related to drought tolerance that will facilitate breeding drought-tolerant wheat cultivars.
基金support by the National Natural Science Foundation of China (91025026, 31070359)the National Basic Research Program of China (Y31JA61001)
文摘C3 plant Reaumuria soongorica and C4 plant Salsola passerina are super xerophytes and coexist in a mixed community in either isolated or associated growth, and interspecific facilitation occurs in associated growth. In the present study, the root traits including root distribution, root length（RL）, root surface area（RSA）, root weight（RW） and specific root length（SRL） of both species in two growth forms were investigated to clarify their response to facilitation in associated growth. Six isolated plants of each species, as well as six associated plants similar in size and development were selected during the plant growing season, and their roots were excavated at 0–10, 10–20, 20–30, 30–40 and 40–50 cm soil depths at the end of the growing season. All the roots of each plant were separated into the two categories of fine roots（2 mm diameter） and coarse roots（≥2 mm diameter）. Root traits such as RL and RSA in the fine and coarse roots were obtained by the root analyzing system WinRHIZO. Most of the coarse roots in R. soongorica and S. passerina were distributed in the top 10 cm of the soil in both growth forms, whereas the fine roots of the two plant species were found mainly in the 10–20 and 20–30 cm soil depths in isolated growth, respectively. However, the fine roots of both species were mostly overlapped in 10–20 cm soil depth in associated growth. The root/canopy ratios of both species reduced, whereas the ratios of their fine roots to coarse roots in RL increased, and both species had an increased SRL in the fine roots in associated growth. In addition, there was the increase in RL of fine roots and content of root N for S. passerina in associated growth. Taken together, the root growth of S. passerina was facilitated for water and nutrient exploration under the interaction of the overlapped roots in both species in associated growth, and higher SRL allowed both species to more effectively adapt to the infertile soil in the desert ecosystem.
基金the South Carolina Cotton Board and Cotton Incorporated for funding this project。
文摘Cotton(Gossypium spp.) is an important fiber and oil crop grown worldwide. Water and nutrient stresses are major issues affecting cotton production globally. Root traits are critical in improving water and nutrient uptake and maintaining plant productivity under optimal as well as drought conditions.However, root traits have rarely been utilized in cotton breeding programs, a major reason being the lack of information regarding genetic variability for root traits. The objective of this research was to evaluate ten selected cotton genotypes for root traits and water use efficiency. The tested genotypes included germplasm lines(PD 1 and PD 695) and cultivars that are currently grown in the southeastern USA(PHY 499 WRF, PHY 444 WRF, PHY 430 W3 FE, DP 1646 B2 XF, DP 1538 B2 XF, DP 1851 B3 XF, NG5007 B2 XF, and ST 5020 GLT). Experiments were conducted under controlled environmental conditions in 2018 and 2019. A hardpan treatment was included in the second year to evaluate the effect of a soil hardpan on root traits and water use efficiency. Genotype PHY 499 WRF ranked at the top and NG5007 B2 XF ranked at the bottom for root morphological traits(total and fine root length, surface area,and volume) and root weight. PHY 499 WRF was also one of the best biomass producers and had high water use efficiency. PHY 444 WRF, PHY 430 W3 FE, and PD-1 were the other best genotypes in terms of root traits and water use efficiency. All genotypes had higher values for root traits and water use efficiency under hardpan conditions. This trend indicates a horizontal proliferation of root systems when they incur a stress imposed by a hardpan. The genotypic differences identified in this research for root traits and water use efficiency would be valuable for selecting genotypes for cotton breeding programs.
基金the Agricultural Science and Technology Innovation Project of Jilin Province(Postdoctoral Fund Project)(CXGC2021RCB007)Agricultural Science and Technology Innovation Project of Jilin Province(Introduction of Doctor and High-Level Talents Project)(CXGC2022RCG008)+1 种基金Jilin Province Science and Technology Development Project(20200403014SF)Agricultural Science and Technology Innovation Project of Jilin Province(CXGC2021ZY036).
文摘Soil salinization is the main factor that threatens the growth and development of plants and limits the increase of yield.It is of great significance to study the key soil environmental factors affecting plant root traits to reveal the adaptation strategies of plants to saline-alkaline-stressed soil environments.In this study,the root biomass,root morphological parameters and root mineral nutrient content of two alfalfa cultivars with different sensitivities to alkaline stress were analyzed with black soil as the control group and the mixed saline-alkaline soil with a ratio of 7:3 between black soil and saline-alkaline soil as the saline-alkaline treatment group.At the same time,the correlation analysis of soil salinity indexes,soil nutrient indexes and the activities of key enzymes involved in soil carbon,nitrogen and phosphorus cycles was carried out.The results showed that compared with the control group,the pH,EC,and urease(URE)of the soil surrounding the roots of two alfalfa cultivars were significantly increased,while soil total nitrogen(TN),total phosphorus(TP),organic carbon(SOC),andα-glucosidase activity(AGC)were significantly decreased under saline-alkaline stress.There was no significant difference in root biomass and root morphological parameters of saline-alkaline tolerant cultivar GN under saline-alkaline stress.The number of root tips(RT),root surface area(RS)and root volume(RV)of AG were reduced by 61.16%,44.54%,and 45.31%,respectively,compared with control group.The ratios of K^(+)/Na^(+),Ca^(2+)/Na^(+)and Mg^(2+)/Na^(+)of GN were significantly higher than those of AG(p<0.05).The root fresh weight(RFW)and dry weight(RDW),root length(RL),RV and RT of alfalfa were positively regulated by soil SOC and TN,but negatively regulated by soil pH,EC,and URE(p<0.01).Root Ca^(2+)/Na+ratio was significantly positively correlated with soil TN,TP and SOC(p<0.01).The absorption of Mg and Ca ions in roots is significantly negatively regulated by soilβ-glucosidase activity(BGC)and acid phosphatase activity(APC)(p<0.05).This study improved knowledge of the relationship between root traits and soil environmental factors and offered a theoretical framework for elucidating how plant roots adapt to saline-alkaline stressed soil environments.
基金the Guangdong Basic and Applied Basic Research Foundation(Grant No.2020B1515020034)the National Postdoctoral Program for Innovative Talents(Grant No.BX201700083)+3 种基金the Commonweal Project(Grant No.201203059)the Key Research and Development Program of Guangdong(Grant No.2019B020221003)the National Key Research and Development Program of China(Grant No.2018YFD0100800)as well as the China Agriculture Research System(Grant No.CARS-01-41).
文摘Mechanical hill wet-seeded rice machine is beneficial for establishing and growing uniform rows of seedlings.However,there is limited knowledge regarding the effects of the establishment of furrows on growth,lodging and yield,and their relationships with root traits.In this study,field experiments were conducted during 2012 and 2013 using two super rice varieties(hybrid rice Peizataifeng and inbred rice Yuxiangyouzhan)under three furrow establishment treatments(T1,both water and seed furrows were established by the machine;T2,only seed furrows were established by the machine;and T3,neither water nor seed furrows were established by the machine).Lodging index,lodging-related traits,grain yield,above-ground dry weight and root traits were measured.The results showed that the lodging index was significantly affected by the treatments with furrows(T1 and T2).The strongest lodging resistance was detected in the mechanical hill wet-seeded rice with furrow treatment(T1)in both 2012 and 2013.Lodging resistance was strongly related to the breaking resistance.No significant difference was found in grain yield or dry weight of the mechanical hill wet-seeded rice.Therefore,the mechanical hill wet-seeded rice with furrow treatment increased rice lodging resistance,which was related to root traits.
基金supported by the National Natural Science Foundation of China (Grant No. 30500064)Postdoctoral Science Funds of China (No. 2003033385)
文摘In natural ecosystems, nutrition available for plants shows great spatial heterogeneity. Much is known about plant root responses to the spatial heterogeneity of nutrition, but little is known about carbon usage in roots in nutrition-deficient patches and its effect on root longevity. In this study, split-room boxes were used for culture of Cercis chinensis seedlings, and the small rooms were supplied with different nutrition levels. The number of the first-order roots in the rooms with nutrition supply was significantly higher than that in the rooms with deficient nutrition. Specific root length （SRL） of the first-order roots in the rooms with deficient nutrition reached its peak at day 64 after nutrition treatment. There was no significant SRL differences between the two order roots during the experiment. Biomass of the first-order roots in the rooms without nutrition supply was significantly less than that of the first-order roots in the rooms with nutrition supply from day 64 to 96. The total biomass of the lateral roots in the rooms without nutrition supply decreased from day 64 to 96. The activities of the enzymes in roots in the rooms without nutrition supply increased and the activities of alkaline invertases in roots in the two sides of split box did not change significantly. The activities of the enzymes in roots in the rooms without nutrition supply increased gradually. These results suggest that nutrition spatial heterogeneity induced the changes in root traits and plants actively controlled carbon usage in roots in nutrition-deficient patches by regulating the activities of invertases and sucrose synthases, resulting in the reduction in carbon usage in the roots in nutrition-deficient patches.
基金supported by the National Natural Science Foundation of China(No.32271611)Functional traits of plant communities at different elevation gradients in the Taibai Mountain of Qinling Mountains financed by the Ministry of Science and Technology of China(No.2016YFC0500202)245 Qinling National Forest Ecosystem Research Station in 2022 financed by Ministry of Education of China.
文摘Root anatomical traits play an important role in understanding the link between root physiological function and ecological process. To determine how plants change root anatomical traits to adapt to distinct environments, we measured four key root anatomical traits-stele diameter(SD), cortex thickness(CT), root diameter(RD), and the stele to root diameter ratio(SDRD)-of first-order roots of 82species collected from different vegetation zones along a 2000 m altitudinal gradient on the northern slope of Taibai Mountain. Compared with other altitudes, plants located in temperate birch and fir forests had thinner SD, CT, RD, and SDRD. We found that elevational variation in root anatomical traits could largely be explained by phylogenetic taxonomy(clade). In addition, changes in SD were driven by soil bulk density, whereas variations in CT and RD were influenced by soil available nitrogen. When phylogenetic factors were removed from our analysis, allometric relationships between RD and root anatomical traits(SD and CT) were observed across different altitudes. Our study reveals the influence of phylogeny and environment on the elevational variation in root anatomical traits and further supports the allometric relationship between root anatomical traits(SD and CT) and RD. These findings enhance our understanding of the evolutionary and adaptive mechanisms of root anatomical structures, providing a basis for predicting how root anatomical traits respond to global changes.
基金supported by the Hi-Tech Research and Development Program of China (No. 2006AA10Z158 and No. 2006AA100101)the "948" Project (No. 2006-G1)+1 种基金China National Key Technologies R & D Program (No. 2006BAD13B01-6)the Program for Chang Jiang Scholars and Innovative Research Team in University, Program of Introducing Talents of Discipline to Universi-ties in China (111-2-03).
文摘Phosphorous （P） deficiency is a major restraint factor for crop production and plants have developed several mechanisms to adapt to low P stress. In this study, a set of 271 introgression lines （ILs） were used to characterize the responses of seedlings to low P availability and to identify QTLs for root traits, biomass, and plant height under P-deficiency and P-sufficiency conditions. Plant height, total dry weight, shoot dry weight, and root number were inhibited under P-deficiency, whereas maximum root length （MRL） and root-shoot ratio （RS） were induced by P-deficiency stress. Relative MRL （RMRL, the ratio of MRL under P-deficiency to MRL under P-sufficiency con- dition） and relative RS （RRS） were used to evaluate P-deficiency tolerance at the seedling stage. A total of 24 additive QTLs and 29 pairs of epistatic QTLs were detected, but only qRN4 was detected in both conditions. This suggested that different mechanisms may exist in both P supply levels. QTLs for adaptive traits （RMRL, RRS, RRV, and RRDW） and qRN4 consistently expressed to increase trait stability may contribute to P-deficiency tolerance. Twelve intervals were cluster regions of QTLs for P-deficiency tolerance, and one QTL （qRRSS） showed pleiotropic effects on P-deficiency tolerance and drought tolerance. These interesting QTLs can be used in marker-assisted breeding through the target ILs.
基金supported by National Key Research and Development Project of China(2017YFC0505002)National Natural Science Foundation of China(31400424,31570477).
文摘Aims Competition,temperature and nutrient are the most important determinants of tree growth in the cold climate on the eastern Tibetan Plateau.Although many studies have reported their individual effects on tree growth,little is known about how the interactions of competition with fertilization and temperature affect root growth.We aim to test whether climate warming and fertilization promote competition and to explore the functional strategies of Picea asperata in response to the interactions of these factors.Methods We conducted a paired experiment including competition and non-competition treatments under elevated temperature(ET)and fertilization.We measured root traits,including the root tip number over the root surface(RTRS),the root branching events over the root surface(RBRS),the specific root length(SRL),the specific root area(SRA),the total fine root length and area(RL and RA),the root tips(RTs)and root branching(RB)events.These root traits are considered to be indicators of plant resource uptake capacity and root growth.The root biomass and the nutrient concentrations in the roots were also determined.Important Findings The results indicated that ET,fertilization and competition individually enhanced the nitrogen(N)and potassium(K)concentrations in fine roots,but they did not affect fine root biomass or root traits,including RL,RT,RA and RB.However,both temperature and fertilizationz as well as their interaction,interacting with competition increased RL,RA,RT,RB and nutrient uptake.In addition,the SRL,SRA,RTRS and RBRS decreased un der fertilization,the interaction between temperature and competition decreased SRL and SRA,while the other parameters were not affected by temperature or competition.These results indicate that P.asperata maintains a conservative nutrient strategy in response to competition,climate warming,fertilization and their interactions.Our results improve our understanding of the physiological and ecological adaptability of trees to global change.
基金supported by the National Natural Science Foundation of China (Grant No. 30872000) and the K. C. Wong Education Foundation, Hong Kong.
文摘The relationships between plant organs and root hydrological traits are not well known and the question arises whether elevated CO2 changes these relationships. This study attempted to answer this question. A pseudo-replicated experiment was conducted with two times 24 American elm （Ulmus americana L.） and 23 and 24 red oak （Quercus rubra L.） seedlings growing in ambient CO2 （around 360 μmol.L^-1） and 540 ± 7.95 μmol.L^-1 CO2 in a greenhouse. After 71 days of treatment for American elm and 77 days for red oak, 14 American elm and 12 red oak seedlings from each of the two CO2 levels were randomly selected in order to examine the flow rate of root xylem sap, root hydraulic conductance, total root hydraulic conductivity, fine root and coarse root hydraulic conductivity. All seedlings were harvested to investigate total plant biomass, stem biomass and leaf biomass, leaf area, height, basal diameter, total root biomass, coarse root biomass and fine root biomass. The following conclusions are reached： 1） plant organs respond to the elevated CO2 level earlier than hydraulic traits of roots and may gradually lead to changes in hydraulic traits; 2） plant organs have different relationships with hydraulic traits of roots and elevated CO2 changes these relationships; the changes may be of importance for plants as means to acclimatize to changing environments; 3） biomass of coarse roots increased rather more than that of fine roots; 4） Lorentzian and Caussian models are better in estimating the biomass of seedlings than single-variable models. Key words American elm, biomass, elevated CO2, modeling, red oak, root hydraulic traits
基金supported by the National Natural Science Foundation of China(Grant No.U1803231).
文摘How sex-related root traits and soil microbes and their interactions respond to drought remains unclear.Here,we investigated how fine root traits and the composition of rhizosphere microbial communities in Populus euphratica females and males respond to drought in concert in 17-year-old plantations.Females increased specific root length(SRL)in response to drought.However,males showed no changes in their roots but significant increases in arbuscular mycorrhizal hyphal biomass and population of Gram-negative bacteria in the rhizosphere.Also,fungal symbiotroph communities associated with root systems in males differed from those in females under drought.We further demonstrated that the Gram-positive to Gram-negative bacteria ratios positively correlated with the SRL,while fungi to bacteria ratios were negatively correlated.Meanwhile,the relative abundance of symbiotrophs was negatively correlated with the SRL,while saprotroph abundance was positively correlated.Nevertheless,the relative abundance of symbiotrophs was positively correlated with the root carbon content(RCC).These findings indicate that microbial responses to drought depend highly upon the sex of the plant and microbial group and are related to root trait adjustments to drought.This discovery also highlights the role of plant-microbial interactions in the ecosystems of P.euphratica forest plantations.
文摘Research on root morphological traits of dry-raised seedlings (D-RS) at different growth stages of rice have so far attracted less attention. In this study, using mid-season indica hy-
基金supported by the National Key Research and Development Program(2016YFD0300206-4,2018YFD0300800)the National Natural Science Foundation of China(31461143015,31771710,31871559)+4 种基金Young Elite Scientists Sponsorship Program by CAST(2016QNRC001)Six Talent Peaks Project in Jiangsu Province(SWYY-151)the Jiangsu Provincial Key Research and Development Program(Modern Agriculture)(BE2015320)the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutionsthe Top Talent Supporting Program of Yangzhou University(2015-01)。
文摘Phosphorus use efficiency(PUE)can be improved through cultivation techniques and breeding.However,little is known about rice(Oryza sativa L.)agronomic and physiological traits associated with high PUE.We characterized the agronomic and physiological traits of rice varieties with different tolerances to low phosphorus in nutrient solution.Two varieties with strong tolerance to low phosphorus(STVs)and two with weak tolerance(WTVs)were grown at normal(NP,control)and low phosphorus(LP,1/20 of NP)concentrations.Plants grown at LP produced significantly lower grain yield than those grown at NP.WTVs yields were lower than STVs yields.Compared to NP,LP significantly increased phosphorus translocation efficiency(PTE),internal phosphorus efficiency(IPE)and phosphorus harvest index(PHI).Under the LP condition,PTE and IPE were higher for STVs than for WTVs.LP also reduced tiller number,shoot biomass,leaf area index(LAI),leaf photosynthetic rate,and mean root diameter of both kinds of varieties at the main growth stages,but to a lower extent in STVs.LP significantly increased the number of productive tillers,root biomass,root-shoot ratio,root bleeding rate,and root acid phosphatase(RAP)activity.Total root length,root oxidation activity(ROA),and root total and active absorbing surface areas for STVs were significantly increased under LP,whereas the opposite responses were observed for WTVs.Total root length,ROA,root bleeding rate,root active absorbing surface area,and RAP activity were positively and significantly correlated with grain yield,PTE,and IPE.These results suggest that the tolerance of rice varieties to a low-phosphorus growth condition is closely associated with root growth with higher biomass and activity.
基金supported by the Project of Qinghai Science&Technology Department(Grant No.2021-ZJ-956Q).
文摘Artificial vegetation restoration is the main measure for vegetation restoration and soil and water conservation in alpine mine dumps on the Qinghai-Tibet Plateau,China.However,there are few reports on the dynamic changes and the influencing factors of the soil reinforcement effect of plant species after artificial vegetation restoration under different recovery periods.We selected dump areas of the Delni Copper Mine in Qinghai Province,China to study the relationship between the shear strength and the peak displacement of the root-soil composite on the slope during the recovery period,and the influence of the root traits and soil physical properties on the shear resistance characteristics of the root-soil composite via in situ direct shear tests.The results indicate that the shear strength and peak displacement of the rooted soil initially decreased and then increased with the increase of the recovery period.The shear strength of the rooted soil and the recovery period exhibited a quadratic function relationship.There is no significant function relationship between the peak displacement and the recovery period.Significant positive correlations(P<0.05)exists between the shear strength of the root-soil composite and the root biomass density,root volume density,and root area ratio,and they show significant linear correlations(P<0.05).There are no significant correlations(P>0.05)between the shear strength of the root-soil composite and the root length density,and the root volume ratio of the coarse roots to the fine roots.A significant negative linear correlation(P<0.05)exists between the peak displacement of the rooted soil and the coarse-grain content,but no significant correlations(P>0.05)with the root traits,other soil physical property indices(the moisture content and dry density of the soil),and slope gradient.The coarse-grain content is the main factor controlling the peak displacement of the rooted soil.
文摘The presented work is based on laboratory testing of seed germination speed, emergence and seedling growth under different stress conditions simulated by subnormal water revel, extreme high and low temperatures. It allows one to eliminate the plant materials （initial breeding materials and cultivars） which do not tolerate extreme temperatures and temperature changes during germination, have low water use efficiency and is intolerant to abiotic stressors all right at the seed level. It was confirmed that these genotypes also have poor t^eld emergence and initial root growth implications for further vegetation periods, mainly for over wintering and spring regeneration which has significant influence on the yield. The method also represents the tool for screening genetic resources with the resistance to the abiotic stressors and this technology process is also acceptable for other crops. The results confirm the importance of the seed and root characteristics for crop production. The deteriorating quality of soil in recent years, increasing variability of weather and long periods of drought directly support the need to intensify activities in this research. Obtained results also show the influence of seed quality characteristics on roots and above ground parts of the plant. A relationship exists also vice versa.
基金supported by the Chinese National Programs of Science and Technology for High Yielding Crop Production (2011BAD16B08, 2012BAD04B06, and 2013BAD07B05)the Key Laboratory of Crop Growth Regulation of Hebei Province, China
文摘In this study, 14 wheat cultivars with contrasting yield and N use efficiency （NUE） were used to investigate the agronomic and NUE-related traits, and the N assimilation-associated enzyme activities under low and high N conditions. Under deficient-N, the cultivars with high N uptake efficiency （UpE） and high N utilization efficiency （UtE） exhibited higher plant biomass, yields, and N contents than those with medium and low NUEs. The high UpE cultivars accumulated more N than other NUE type cultivars. Under sufficient-N, the tested cultivars showed similar patterns in biomass, yield, and N content to those under deficient-N, but the varietal variations in above traits were smaller. In addition, the high UpE cultivars displayed much more of root biomass and larger of root length, surface area, and volume than other NUE type cultivars, indicating that the root morphological traits under N deprivation are closely associated with the plant biomass through its improvement of the N acquisition. The high UtE cultivars showed higher activities of nitrate reductase （NR）, nitrite reductase （NIR）, and gluta- mine synthetase （GS） at stages of seediling, heading and filling than other NUE type cultivars under both low and high N conditions. Moreover, the high UpE and UtE cultivars also displayed higher photosynthetic rate under deficient-N than the medium and low NUE cultivars. Together, our results indicated that the tested wheat cultivars possess dramatically genetic variations in biomass, yield, and NUE. The root morphological traits and the N assimilation enzymatic acitivities play critical roles in regulating N accumulation and internal N translocation under the N-starvation stress, respectively. They can be used as morphological and biochemical references for evaluation of UpE and UtE in wheat.
基金supported by the grants from the National Natural Science Foundation of China(32071843,31901444 and 31901445)the National Key Research and Development Program of China(2016YFD0300206-4 and 2018YFD0300800)+3 种基金the Priority Academic Program Development of Jiangsu Higher Education Institutions,China(PAPD)the Top Talent Supporting Program of Yangzhou University,China(2015-01)the Natural Science Foundation of Jiangsu Province,China(BK20190880)the Natural Science Foundation of Jiangsu Higher Education Institutions,China(19KJB210019)。
文摘The use of nitrogen(N)-efficient rice(Oryza sativa L.) varieties could reduce excessive N input without sacrificing yields. However, the plant traits associated with N-efficient rice varieties have not been fully defined or comprehensively explored. Here, three japonica N-efficient varieties(NEVs) and three japonica N-inefficient varieties(NIVs) of rice were grown in a paddy field under N omission(0 N, 0 kg N ha^(-1)) and normal N(NN, 180 or 200 kg N ha^(-1)) treatments. Results showed that NEVs exhibited higher grain yield and nitrogen use efficiency(NUE) than NIVs under both treatments, due to improved sink size and filled-grains percentage in the former which had higher root oxidation activity and greater root dry weight, root length and root diameter at panicle initiation(PI), as well as higher spikelet-leaf ratio and more productive tillers during the grain-filling stage. Compared with NIVs, NEVs also exhibited enhanced N translocation and dry matter accumulation after heading and improved flag leaf morpho-physiological traits, including greater leaf thickness and specific leaf weight and higher contents of ribulose^(-1),5-bisphosphate carboxylase/oxygenase, chlorophyll, nitrogen, and soluble sugars, leading to better photosynthetic performance. Additionally, NEVs had a better canopy structure, as reflected by a higher ratio of the extinction coefficient for effective leaf N to the light extinction coefficient, leading to enhanced canopy photosynthesis and dry matter accumulation. These improved agronomic and physiological traits were positively and significantly correlated with grain yield and internal NUE, which could be used to select and breed N-efficient rice varieties.
基金supported by funding from the National Natural Science Foundation of China(Nos.32001218,42141006 and 31988102).
文摘Aims: Plant roots show various functional strategies in soil phosphorus(P) acquisition. Under limited soil phosphatase activity, P deficiency is the main concern, and roots either invest carbon(C) to produce higher levels of phosphatase or establish more symbioses with mycorrhizal fungi. However, these strategies and their interactions are not clear. Furthermore, few studies have investigated trade-offs of functional traits in woody species associated with different types of mycorrhizal partners.Methods: Here we examined the abilities to release acid phosphatase(AP) and the colonization ratio by arbuscular and ectomycorrhizal fungi for fine roots of 15 woody species growing in a tropical common garden in Xishuangbanna, China. We also measured acid phosphatase activities of bulk soils under the canopy of target trees.Results: Soil and root AP activities exhibited a positive correlation, indicating that roots actively produced AP to acquire P even bulk soil AP was increasing. We found a significantly negative correlation(P=0.02) between mycorrhizal colonization ratio and root-released AP activity across target species, reflecting a trade-off between these two P acquisition strategies.Conclusions: Our findings suggest a trade-off of resource allocation between these two strategies at both species and individual levels, and provide information on the overall mechanism of P acquisition by fine roots that they either ‘do it by themselves’ or ‘rely on mycorrhizal partners’. These two strategies might be integrated into the collaboration gradient of the root economics space.
