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
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
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
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
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
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
Growth traits of root system of 13 autumn-sowing alfalfa cultivars were analyzed. The results indicated that there were significant difference in growth pa- rameters of root system among alfalfa cultivars （ P 〈 0.05...Growth traits of root system of 13 autumn-sowing alfalfa cultivars were analyzed. The results indicated that there were significant difference in growth pa- rameters of root system among alfalfa cultivars （ P 〈 0.05 ）. The cultivars, Prime and WI323, showed the highest root biomass （ higher than 32 g） ; cuhivar WI323 had the largest lateral root number （17.8 branches）. Cultivars Prime, WI323, Super7 and L90 had better root traits than other cultivars based on comprehensive evaluation. Among three times of mowing within a year, root growth and development of alfalfa had mutual promotion with the first and second time growth of abovegraund part, but had competition with the third time growth. Overwintering alfalfa root restricted the grass yield in the following year, especially the third-cut yield in the next year.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
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
[ Objective ] The paper was to study the effects of anti-nematode preparations with different mechanisms on changes of enzyme systems and membrane permeability of tomato leaves, so as to provide reference basis for ef...[ Objective ] The paper was to study the effects of anti-nematode preparations with different mechanisms on changes of enzyme systems and membrane permeability of tomato leaves, so as to provide reference basis for effective control of soil root-knot nematode in greenhouse. [ Method] With tomato seedlings af- fected by root-knot nematode as material, changes of superoxide dismutase（SOD）, peroxidase（ POD）, relative conductivity and malondialdehyde （MDA） in toma- toes were tested after the seedling soil was treated by preparations of Wuxianmei, Hailvsu, Duxiandna and Avermectin. [ Result] After treated by different prepara- tions, SOD and POD activity of tomato leaves were higher than control, and that treated by Wuxianmei was the highest. In addition to Duxiandna, the relative con- ductivity and MDA content of other treatments were significantly lower than control. When tomatoes were planted for 70 d, the effect of Avermectin against reot-knot nematode Was the best of 66.3%. [ Conclusion] After tomatoes were infected by root-knot nematode, different preparation treatments all had certain control effect, which made the physical indicators of tomato have obvious change. Integrated control of multiple preparations in greenhouse was beneficial to control soil root-knot nematode.展开更多
A Double Haploid (DH) population, 116 plants, derived from the cross between Japonica upland rice IRAT109 and paddy rice Yuefu, planted in PVC pipe under upland ecosystem in 2001 and 2002, was used in this study. Seve...A Double Haploid (DH) population, 116 plants, derived from the cross between Japonica upland rice IRAT109 and paddy rice Yuefu, planted in PVC pipe under upland ecosystem in 2001 and 2002, was used in this study. Seven root traits, including basal root thickness (BRT), total root number (RN), maximum root length (MRL), root fresh weight (RFW), root dry weight (RDW), ratio of root fresh weight to shoot fresh weight (RFW/SFW) and ratio of root dry weight to shoot dry weight (RDW/SDW), were studied. Using index of drought resistance (IDR), the ratio of yield under upland ecosystem to yield under lowland ecosystem of DH lines, as the criteria of drought resistance, and correla-tion analysis between root traits and IDR, showed that BRT, MRL and RN were significantly correlated with IDR. High IDR lines had thicker BRT, longer MRL and less RN than low IDR lines. A molecular linkage map with 94 RFLP markers and 71 SSR markers covering 1535.1 cM was pro-duced. QTLs and G譋 interactions for BRT, RN, MRL, RFW, RDW, RFW/SFW and RDW/SDW were obtained based on the constructed molecular linkage map and soft-ware QTLmapper version 1.0. A total of 18 additive QTLs and 18 pairs of epistatic QTLs associated with root traits were detected. There were nine additive QTLs and two pairs of epistatic QTLs performed significant interactions with environment. Some QTLs with high general contribution and no G譋 interaction were obtained. Two pairs of epistatic QTLs mrl3 and mrl8, brt3 and brt11a controlling MRL and BRT had high general contributions of 21.51% and 13.03% respectively. An additive QTL and a pair of epistatic QTLs controlling RFW and RDW had high general contributions of 13.50% and 25.64% respectively. Marker assisted selec-tion (MAS) for rice drought resistance based on QTL with high general contribution, low G譋 interaction and tightly linkage with IDR were also discussed.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
Development of fine roots and formation of symbiosis with arbuscular mycorrhizal(AM) fungi represent two strategies for plants to acquire nutrient and water from soil. Here, we elucidated how fine root development and...Development of fine roots and formation of symbiosis with arbuscular mycorrhizal(AM) fungi represent two strategies for plants to acquire nutrient and water from soil. Here, we elucidated how fine root development and symbolized mycorrhizal fungi with Stipa purpurea responded to the precipitation change in Tibetan alpine steppe ecosystem across a precipitation gradient from 50 mm to 400 mm. As precipitation increased, the proportion of thinner fine roots(diameter < 0.4 mm) in total roots increased significantly; while the mycorrhizal colonization percentage, either associated with thinner or thicker roots, decreased. This phenomenon indicated that fine root development and symbolized mycorrhizal fungi are likely alternative, and plant preferred to develop fine root rather than build a symbiotic relationship with mycorrhizal fungi in more benign niches with higher precipitation. Also, root diameter was negatively correlated with specific root length(SRL), but positively correlated with AM fungal colonization percentage, indicating thicker-root species rely more on mycorrhizal fungi in alpine steppe. The complementarity between fine root and mycorrhizal fungi of S. purpurea is mediated by precipitation in Tibetan alpine steppe.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-
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 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 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 Fundamental Special Project of the Ministry of Science and Technology"Special Investigation of Northeast Grassland Plant Resources"(2014FY210300)Special Investigation of Grassland Plant Resources in Liaoning Province
文摘Growth traits of root system of 13 autumn-sowing alfalfa cultivars were analyzed. The results indicated that there were significant difference in growth pa- rameters of root system among alfalfa cultivars （ P 〈 0.05 ）. The cultivars, Prime and WI323, showed the highest root biomass （ higher than 32 g） ; cuhivar WI323 had the largest lateral root number （17.8 branches）. Cultivars Prime, WI323, Super7 and L90 had better root traits than other cultivars based on comprehensive evaluation. Among three times of mowing within a year, root growth and development of alfalfa had mutual promotion with the first and second time growth of abovegraund part, but had competition with the third time growth. Overwintering alfalfa root restricted the grass yield in the following year, especially the third-cut yield in the next year.
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 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.
基金Supported by Transformation and Promotion Projects of Agriculture Science and Technology Achievements of Tianjin City"Integration and Demonstration of Integrated Control Technology of Greenhouse Vegetable Fields with Continuous Cropping Obstacles"(0804140)Basic Application and Cutting-edge Technology Research Projects of Tianjin City"Risk Assessment and Regulation Research of Nitrogen and Phosphorus Non-point Source Pollution in Facility Agriculture"(09JCYBJC08600)~~
文摘[ Objective ] The paper was to study the effects of anti-nematode preparations with different mechanisms on changes of enzyme systems and membrane permeability of tomato leaves, so as to provide reference basis for effective control of soil root-knot nematode in greenhouse. [ Method] With tomato seedlings af- fected by root-knot nematode as material, changes of superoxide dismutase（SOD）, peroxidase（ POD）, relative conductivity and malondialdehyde （MDA） in toma- toes were tested after the seedling soil was treated by preparations of Wuxianmei, Hailvsu, Duxiandna and Avermectin. [ Result] After treated by different prepara- tions, SOD and POD activity of tomato leaves were higher than control, and that treated by Wuxianmei was the highest. In addition to Duxiandna, the relative con- ductivity and MDA content of other treatments were significantly lower than control. When tomatoes were planted for 70 d, the effect of Avermectin against reot-knot nematode Was the best of 66.3%. [ Conclusion] After tomatoes were infected by root-knot nematode, different preparation treatments all had certain control effect, which made the physical indicators of tomato have obvious change. Integrated control of multiple preparations in greenhouse was beneficial to control soil root-knot nematode.
基金supported by the Hi-Tech Research and Development Program of China(Grant No.2001AA211091)the National Natural Science Foundation of China(Grant No.30070464)+1 种基金China National Key Technologies R&D Program(Grant No.02-04)“948"project(Grant No.2001-204)of Ministry of the Agriculture of China.
文摘A Double Haploid (DH) population, 116 plants, derived from the cross between Japonica upland rice IRAT109 and paddy rice Yuefu, planted in PVC pipe under upland ecosystem in 2001 and 2002, was used in this study. Seven root traits, including basal root thickness (BRT), total root number (RN), maximum root length (MRL), root fresh weight (RFW), root dry weight (RDW), ratio of root fresh weight to shoot fresh weight (RFW/SFW) and ratio of root dry weight to shoot dry weight (RDW/SDW), were studied. Using index of drought resistance (IDR), the ratio of yield under upland ecosystem to yield under lowland ecosystem of DH lines, as the criteria of drought resistance, and correla-tion analysis between root traits and IDR, showed that BRT, MRL and RN were significantly correlated with IDR. High IDR lines had thicker BRT, longer MRL and less RN than low IDR lines. A molecular linkage map with 94 RFLP markers and 71 SSR markers covering 1535.1 cM was pro-duced. QTLs and G譋 interactions for BRT, RN, MRL, RFW, RDW, RFW/SFW and RDW/SDW were obtained based on the constructed molecular linkage map and soft-ware QTLmapper version 1.0. A total of 18 additive QTLs and 18 pairs of epistatic QTLs associated with root traits were detected. There were nine additive QTLs and two pairs of epistatic QTLs performed significant interactions with environment. Some QTLs with high general contribution and no G譋 interaction were obtained. Two pairs of epistatic QTLs mrl3 and mrl8, brt3 and brt11a controlling MRL and BRT had high general contributions of 21.51% and 13.03% respectively. An additive QTL and a pair of epistatic QTLs controlling RFW and RDW had high general contributions of 13.50% and 25.64% respectively. Marker assisted selec-tion (MAS) for rice drought resistance based on QTL with high general contribution, low G譋 interaction and tightly linkage with IDR were also discussed.
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funded by the The National Key Research and Development Program of China (2016YFC0501802)the Key Projects in the National Basic Research Programs (2013CB956000)Strategic Priority Research Program (B) of the Chinese Academy of Sciences (XDB15010201) of China
文摘Development of fine roots and formation of symbiosis with arbuscular mycorrhizal(AM) fungi represent two strategies for plants to acquire nutrient and water from soil. Here, we elucidated how fine root development and symbolized mycorrhizal fungi with Stipa purpurea responded to the precipitation change in Tibetan alpine steppe ecosystem across a precipitation gradient from 50 mm to 400 mm. As precipitation increased, the proportion of thinner fine roots(diameter < 0.4 mm) in total roots increased significantly; while the mycorrhizal colonization percentage, either associated with thinner or thicker roots, decreased. This phenomenon indicated that fine root development and symbolized mycorrhizal fungi are likely alternative, and plant preferred to develop fine root rather than build a symbiotic relationship with mycorrhizal fungi in more benign niches with higher precipitation. Also, root diameter was negatively correlated with specific root length(SRL), but positively correlated with AM fungal colonization percentage, indicating thicker-root species rely more on mycorrhizal fungi in alpine steppe. The complementarity between fine root and mycorrhizal fungi of S. purpurea is mediated by precipitation in Tibetan alpine steppe.
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-
