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1.
PI471938是从美国引进的大豆耐萎蔫抗旱种质资源。为更好了解和利用该材料,分别在灌水和干旱胁迫条件下比较PI471938与普通大豆品种Dare、丰收黄根系及地上部性状的差异,并配制杂交组合,构建分离群体,利用主基因-多基因混合遗传模型分析杂交后代根系性状的遗传规律。结果表明,在正常灌水和干旱处理条件下,PI471938的根干重、根体积、主根长均显著高于Dare和丰收黄(P<0.01),说明根系发达是PI471938耐萎蔫的重要原因。供试亲本和各世代材料的株高、地上部干重均与根干重及根体积显著正相关,可作为对根系性状进行间接选择的指标。在Dare×PI471938杂交组合的F2代,不论在灌水还是干旱条件下,根干重均以微效多基因控制为主,主基因遗传率较低;根体积在灌水条件下表现多基因遗传,而在干旱条件下则由2对加性-显性-上位性主基因+加性-显性多基因控制,主基因遗传率为54.63%。在干旱条件下,丰收黄 × PI471938组合的根干重、根体积均以多基因控制为主。以在干旱条件下种植的Dare×PI471938组合的F2代群体为材料,采用SSR标记对大豆根系及地上部性状进行QTL定位,检测到位于3个不同连锁群的5个主效QTL,表型贡献率在16.07%~38.44%之间。  相似文献   

2.
Drought cycling and soil re-watering trends due to intermittent rainfall patterns are key stress factors that influence rice growth and yield under upland cultivation conditions. However, upland rice adaptation responses to fluctuating soil moisture conditions remain poorly understood. This study investigated root and shoot responses of upland New Rice for Africa (NERICA) varieties to episodic drought and re-watering during growth. We examined root and shoot growth of NERICA 1 and NERICA 4 compared with those of IR72, an improved lowland variety, and Dular, a traditional drought-tolerant variety, in terms of soil moisture fluctuations with different levels of nitrogen fertilization under field conditions that impeded deep root development. During soil moisture fluctuation, all varieties reduced shoot dry weight compared with well-watered plants, regardless of nitrogen fertilization levels. However, total root length for the three upland varieties was enhanced by soil moisture fluctuations at moderate and high nitrogen fertilization, while that of the lowland variety was reduced. Comparing root development during water fluctuations revealed that NERICA 1 had a greater root system than NERICA 4, which was attributed to lateral root development. Furthermore, we found that NERICA varieties increase lateral root mass during soil desiccation under adequate nitrogen fertilization, while Dular and IR72 reduced their root growth rate during drought and increased it after re-watering. Both root growth patterns developed, from around maximum tillering to heading. The analysis of regression between root elongation and shoot growth with fluctuating soil moisture indicated that an enhanced root system during drought, on adequate nitrogen fertilization, can contribute to shoot growth when sufficient water becomes available, specifically around the maximum tillering to the heading growth stage of rice.  相似文献   

3.
Drought is a major abiotic constraint for rice production worldwide. The quantitative trait loci (QTLs) for drought tolerance traits identified in earlier studies have large confidence intervals due to low density linkage maps. Further, these studies largely focused on the above ground traits. Therefore, this study aims to identify QTLs for root and shoot traits at the vegetative growth stage using a genotyping by sequencing (GBS) based saturated SNP linkage map. A recombinant inbred line (RIL) population from a cross between Cocodrie and N-22 was evaluated for eight morphological traits under drought stress. Drought was imposed to plants grown in 75 cm long plastic pots at the vegetative growth stage. Using a saturated SNP linkage map, 14 additive QTLs were identified for root length, shoot length, fresh root mass, fresh shoot mass, number of tillers, dry root mass, dry shoot mass, and root-shoot ratio. Majority of the drought responsive QTLs were located on chromosome 1. The expression of QTLs varied under stress and irrigated condition. Shoot length QTLs qSL1.38 and qSL1.11 were congruent to dry shoot mass QTL qDSM1.38 and dry root mass QTL qDRM1.11, respectively. Analysis of genes present within QTL confidence intervals revealed many potential candidate genes such as laccase, Calvin cycle protein, serine threonine protein kinase, heat shock protein, and WRKY protein. Another important gene, Brevis radix, present in the root length QTL region, was known to modulate root growth through cell proliferation and elongation. The candidate genes and the QTL information will be helpful for marker-assisted pyramiding to improve drought tolerance in rice.  相似文献   

4.
Drought stress may affect sucrose accumulation of sugar beet by restricting leaf development and storage root growth. The objective of this study was to identify changes occurring in the storage root of Beta beets in growth characteristics and ions and compatible solutes accumulation under drought with regard to sucrose accumulation. Two pot experiments were conducted: (1) sugar beet well supplied with water (100 % water capacity), under continuous moderate (50 %) and severe drought stress (30 %), (2) sugar beet and fodder beet well supplied with water (100 %) and under continuous severe drought stress (30 %). Under drought stress, the ratio of storage root to leaf dry matter of sugar beet decreased indicating a different partitioning of the assimilates. The sucrose concentration of the storage root was reduced. In the root, the number of cambium rings was only slightly affected, although drought stress was implemented already 6 weeks after sowing. In contrast, the distance between adjacent rings and the cell size was considerably restricted, which points to a reduced expansion of existing sink tissues. The daily rate of sucrose accumulation in the root showed a maximum between 16 and 20 weeks after sowing in well‐watered plants, but it was considerably reduced under drought stress. The concentration of compatible solutes (K, Na, amino acids, glycine betaine, glucose and fructose) decreased during growth, while it was enhanced because of drought. However, when sucrose concentration was added, a constant sum of all examined solutes was found throughout the vegetation period. It was similar in sugar beet and in fodder beet despite different concentrations of single solutes, and the total sum was not affected by water supply. A close negative relationship between the concentration of compatible solutes and sucrose occurred. It is therefore concluded that the accumulation of compatible solutes in the storage root of Beta beets under drought might be a physiological constraint limiting sucrose accumulation.  相似文献   

5.
Plant genotypes with higher drought tolerance through improved root characteristics are poorly studied in orchardgrass. In the current research, 30 orchardgrass genotypes were polycrossed and the resulting half‐sib families evaluated under both normal and water stress environments. Under water stress conditions, values for most root traits decreased at 0–30 cm soil depth, while at 30–60 cm depths, the root length (RL), root area (RA), root volume, percentage of root dry weight (RDW) and the ratio of root to shoot were increased. We identified drought‐tolerant genotypes with a high combining ability for root characteristics and a high yield potential. High estimates of heritability as well as genetic variation for root traits indicated that phenotypic selection would be successful in order to achieve genetic progress. Indirect selection to improve dry matter yield was most efficient when selecting for RL and RDW under water stress conditions. Significant associations between a drought tolerance index and RL, RA and root volume confirmed the importance of these traits in conferring drought tolerance of orchardgrass.  相似文献   

6.
为探讨玉米（Zea mays L.）苗期对水分亏缺的响应机制,以抗旱性具有显著差异的2个玉米品种为材料,使用PEG-6000溶液模拟不同强度的干旱胁迫,对逆境中玉米苗期的形态及生理生化特性进行分析。结果表明：干旱胁迫后抗旱性强的成单30的株高、叶面积、根长及根重呈上升趋势,抗旱性弱的金玉306呈下降趋势;干旱胁迫使成单30的地上部干重、根重和干物重等生物产量增加,而金玉306的各生物产量逐渐下降;干旱胁迫导致玉米的丙二醛含量升高,细胞膜稳定性下降,成单30的变化幅度比金玉306小;干旱胁迫使玉米的叶绿素a/b比值及叶绿素含量下降,类胡萝卜素含量增加;成单30的可溶性糖及可溶性蛋白含量在干旱胁迫后变化不显著,而金玉306在后期才出现显著变化;干旱胁迫后,成单30与金玉306的脯氨酸含量均极显著增加;干旱胁迫使玉米的超氧化物歧化酶、过氧化物酶及过氧化氢酶活性提高。这些结果说明不同抗旱性玉米品种的抗旱机制存在一定差异。  相似文献   

7.
We investigated the leaf : stem partitioning of winter wheat (Triticum aestivum L. varieties ‘Dekan’ and ‘Batis’) with and without drought influence. Irrigated and drought‐stressed winter wheat, grown in a rainout shelter in 2009/10 and 2013/14, were sampled during shoot elongation phase at the experimental Farm Hohenschulen located in Northern Germany. The data set contains leaf (DML) and stem dry masses (DMS), as well as measured water contents for several soil layers. A reduced relative dry matter allocation to leaves was observed under drought stress. Our results clearly show that, if simulated leaf : stem partitioning is not sensitive to drought, this will cause a positive bias in simulated leaf and a negative bias in simulated stem dry matter under water‐limited conditions. This is in accordance with previous studies which revealed that crop simulators often overestimate the impact of drought on light‐use efficiency, whereas the consequences on leaf area development are underestimated. However, the drought stress‐induced shift in leaf : stem partitioning is yet not considered by most common wheat crop simulators. Our aim was to fill the gap in simulation of drought stress implications on leaf area development. A simple allometric model for leaf : stem partitioning () was parameterized. Starting from the allometric leaf : stem relationship observed under optimum water supply, a correction term was introduced, which allows to adapt the partitioning to drought stress conditions. The lg‐transformed root‐weighted soil water potential in the rooting zone (lgψroot, lg(hPa)), calculated as a function of measured water contents and simulated root distribution, was used as a drought stress indicator. The linear correction term assumes an increase of the stem fraction, proportional to the difference between lgψroot and a drought stress threshold (pFcrit, lg(hPa)). The analysis revealed that the shift in allometric partitioning towards stem fraction starts with lgψroot greater than 1.92 [lg(hPa)]. The slope of the relative increase of dry matter allocated to the stem fraction was determined with 0.26 [lg(hPa)?1]. Both parameters of the correction term were found to be highly significant. Implications for crop modelling are discussed.  相似文献   

8.
甘蓝型油菜DH群体苗期抗旱性的评价   总被引：2，自引：0，他引：2  
李真  梅淑芳  梅忠  刘芳  周广生  吴江生 《作物学报》2012,38(11):2108-2114
中国油菜主产区常常受到秋冬旱和春旱危害而影响产量及品质。本文通过盆栽试验,以株高(PH)、根长(RL)、地上部干重(SDW)、根干重(RDW)、根冠比(R/S)、总干重(TDW) 6个性状的抗旱系数作为抗旱性评价指标,对甘蓝型油菜DH(doubled haploid)群体的118个株系及其亲本进行苗期抗旱性评价,筛选极端抗旱DH系。结果表明,与对照相比,干旱严重抑制了甘蓝型油菜苗期的生长,6个评价指标均表现出显著差异,其中根干重的变异系数最大;在对照和干旱条件下,群体各株系各性状均表现出超亲连续分离,大部分呈正态分布,抗旱条件下的分离更为明显;相关性分析表明,地上部干重、根干重和总干重抗旱系数可作为甘蓝型油菜苗期抗旱性的主要评价指标;  相似文献   

9.
The growth behaviour of Dekama (drought tolerant) and Kufri Jyoti (drought susceptible) was studied using potted plants maintained at well watered condition and water deficit condition respectively. Periodic harvestings were done starting from 50 days after planting till maturity. Recordings of plant height, leaf area, dry weights of different plant parts, the proportion of thinner and thicker roots, stomatal conductance and water saturation deficit were obtained. The plant height, leaf area and dry weight of shoot decreased to nearly the same extent in both the cultivars under stress. The stomatal conductance decreased by 61.7 % in Dekama and by 64 % in Kufri Jyoti due to water stress. Water saturation deficit increased by about 80 % in both the cultivars. The ratios of root to shoot and that of thinner to thicker root increased due to stress in both cultivars and this increase was 85 % and 71 % in Dekama and 64 % and 19 % in Kufri Jyoti respectively. The distribution of dry matter to leaf, stem, root were more at the expense of tuber under stress conditions in both cultivars. However, the tolerant cultivar Dekama got adjusted to the stress condition, with more dry matter partitioned to tubers in the last two samplings. The study points out the factors responsible for better drought tolerance of Dekama compared to Kufri Jyoti and the possible physiological traits useful for selecting drought tolerant cultivars.  相似文献   

10.
To study the effects of different levels of drought stress on root yield and some morpho-physiological traits of sugar beet genotypes, a study was conducted in the research farm of Islamic Azad University of Birjand, Iran in 2013 as strip-split plot experiments based on randomized complete block design. Different levels of drought stress were considered as vertical factor in three levels including normal irrigation, moderate stress, and severe stress. Horizontal factor was assigned to five varieties of sugar beet. Drought stress had a significant effect on root dry weight, total dry weight, root yield, and leaf temperature at 1% probability level and on leaf dry weight, crown dry weight, and harvest index at 5% probability level. Drought stress had an adverse effect on root yield of investigated genotypes of sugar beet. Under normal conditions, the mean of root yield was higher than middle and severe drought stress. Different investigated genotypes of sugar beet responded to drought stress based on their yield potential. The highest positive correlation of root yield was observed with root dry weight (r=0.977**). Stepwise regression analysis and path coefficient analysis showed that root dry weight and petiole dry weight are the most important traits that can affect root yield of sugar beet under drought stress and can used as selection criteria in investigated cultivars of sugar beet. Finally, 7221 genotypes can be considered as tolerant genotypes in the next studies. In comparison, Jolgeh cultivar (as susceptible control) yielded well in areas with normal irrigation, but under moderate and severely stresses its root yield was reduced.  相似文献   

11.
SPACSYS, a model of C and N cycling in the soil–plant–atmosphere continuum that incorporates a detailed three-dimensional root growth sub-model, was tested for its ability to predict the growth and root length density (RLD) distribution of winter wheat. The root growth sub-model was parameterized using published or unpublished data for wheat and barley, and validated against an independent data-set from field experiments on wheat in the UK published in 1978. The model reproduced the experimental results well, accurately simulating total above-ground (r = 0.98) and root (r = 0.96) biomass. There was a slight tendency to over estimate root biomass before the start of stem extension and the rate of root loss after anthesis, suggesting that the partitioning coefficient for dry matter between shoot and root system overwinter and the rate of root mortality and the root decay constant after anthesis may require some adjustment. Simulations of rooting depth and RLD distribution over the season were also acceptable. Further simulation work investigated the sensitivity of root length and relative distribution in the soil profile to changes in specific root morphological traits. The total length of the root system was sensitive to changes in traits regulating the number of lateral branches a given root order can produce (the inter-branch distance, the maximum length of root and its apical non-branching distance) and the elongation rate of main axes. The distribution of the root system was most sensitive to the maximum elongation rate of main axes and their initial growth trajectory. The model will have applications in guiding the design of root system ideotypes for improved water and nutrient use efficiency and for investigating their effectiveness under a range of soil conditions and crop management regimes.  相似文献   

12.
萌发期的干旱胁迫是限制高粱生产的主要障碍因子，种子引发是提高作物抗逆性的一个重要技术。为了明确不同引发处理对干旱胁迫下高粱萌发及生理特性的影响，以晋杂22和晋早5564为研究材料，分别进行聚乙二醇（PEG）、KCl、CaCl2、水杨酸（SA）引发和未引发（NP）5个处理，研究在正常情况和干旱胁迫下种子发芽情况及生理特性变化。结果表明，干旱胁迫显著降低高粱种子发芽率，抑制胚芽和胚根伸长。干旱胁迫下PEG、KCl、CaCl2和SA引发后，晋杂22的萌发率比NP处理分别提高了18.18%、12.72%、35.45%和31.82%，晋早5564的萌发率比NP处理分别提高了20.18%、10.76%、26.91%和30.04%。干旱胁迫下，引发处理促进了胚根和胚芽的伸长，CaCl2和SA处理在晋杂22抗旱效果最佳，芽长分别比NP处理增加了267.07%和271.95%，根长分别比NP处理增加了231.94%和355.56%。CaCl2处理在晋早5564效果最好，芽长和根长分别比NP处理增加了195.96%和206.60%。种子引发提高了胚芽内抗氧化酶活性，减轻了膜脂过氧化对胚芽的损伤；同时种子引发促进了糖代谢，提高了脯氨酸含量，缓解了干旱胁迫对种子萌发的抑制效应。  相似文献   

13.
Plants are often subjected to periods of water stress. There are little data examining the effect of water stress on the forage species Plantago lanceolata and Cichorium intybus. In two pot experiments with P. lanceolata and C. intybus, morphological responses under optimum, dry, and very‐dry water treatments with weekly, fortnightly and 3‐weekly defoliation intervals and physiological responses under optimum and very‐dry water treatments were measured. A third experiment compared the rooting depths of P. lanceolata and C. intybus under field conditions. These findings suggest that both P. lanceolata and C. intybus can survive and continue to grow under water stress conditions with the main differences between the two species being attributable to morphological characteristics (root mass, taproot diameter and shoot mass fraction) rather than differences at a physiological level. Overall, the results suggest plantain may be more productive under moderate drought due to its greater shoot mass fraction, whereas chicory may be more productive and persistent under severe drought due to its greater root mass, taproot diameter and root depth under field conditions.  相似文献   

14.
Polyethylene glycol and cell membrane stability (CMS) assay were used to evaluate drought and heat tolerance, respectively, among 14 wheat lines based on seedling traits and molecular analysis. Significant variation was evidenced for all the investigated seedling traits. Different levels of heritability and genetic advance were found among the tested traits, indicating whether the trait is controlled by additive or non-additive gene action. Drought caused a significant reduction in root and shoot lengths. However, root/shoot ratio under drought stress was increased. Root length showed a highly significant negative correlation with drought susceptibility index (DSI) under drought conditions. Cluster analysis based on seedling traits separated lines mainly by DSI and CMS. Some lines showed drought and heat tolerance by exhibiting a low DSI with high CMS. Sequence-related amplified polymorphism (SRAP) generated a total of 135 bands, with a level of polymorphism ranging from 30 to 86% among the tested lines. SRAP showed its efficiency in discriminating wheat genotypes by gathering all high-DSIlines in one sub-cluster and generating 10 and 3 unique and specific bands for high-DSI-lines and low-DSI-lines, respectively. These bands could be used for further work as SRAP markers associated with drought tolerance in wheat.  相似文献   

15.
Experiments were performed to evaluate seed germination and seedling growth in simulated drought as screening techniques for drought tolerance raring. Several laboratory screening tests were evaluated for ability to estimate drought resistance in 18 cultivars of legume plants (field bean, soybean, field pea, lupine). Drought was simulated by a water solution of mannitol of chemical water potential ψ= -0.3 and -0.6 MPa. Both solutions significantly affected seed germination (final germination and promptness index) and seedling growth parameters (seedling height, dry matter of shoot and root as well as leaf injury by drought and high temperature). The tested cultivars could be grouped as drought resistant and drought susceptible plants. Drought tolerance ratings of legume plants in the laboratory tests were, on the whole, consistent with the ratings based on estimation of direct effects of soil drought on seed yield in field experiments. Measurements of electroconductivity of leaf diffusate to evaluate invisible injury caused by drought or high temperature were found to be an adequate criterion for drought tolerance rating. It is concluded that tolerance to drought stress in growing seedlings can be screened for by using mannitol containing nutrient solution. According to the results collected in this research, varieties differences in seed germination, seedling growth and leaf injury affected by drought or heat temperature were evident, however, not all treatments appeared to be equally useful for screening of legume species cultivars.  相似文献   

16.
Fine roots (roots with a diameter of less than 2 mm) and root hairs are the primary absorbers of water and nutrients; however, the morphology of cotton fine roots and root hairs in response to drought stress has not yet been defined. To solve this problem, this study characterized a self-made in situ root observation device (RhizoPot) with a scanner with a resolution of up to 4,800 DPI was used to observe the roots of cotton plants grown indoors under both well-watered and drought stress conditions. RhizoPot provided healthy growth conditions for cotton, and fine roots as well as root hairs were successfully observed. Root length density increased significantly under drought stress, whereas the average root diameter decreased gradually with the extension of treatment time. Drought stress accelerated fine root death, and the diameter of the fine roots was positively correlated with root lifespan. Additionally, the root hair lifespan was negatively regulated by soil drought stress and was associated with the growth stage. This result suggests that cotton developed more slender fine roots and longer root hairs under drought stress, which accelerated the death process of both, in order to develop new fine roots. This process helps cotton absorb as much water as possible under drought stress.  相似文献   

17.
Water deficit is a major factor responsible for soybean yield gap in Southern Brazil and tends to increase under climate change. An alternative to reduce such gap is to identify soybean cultivars with traits associated to drought tolerance. Thus, the aim of this study was to assess soybean adaptive traits to water deficit that can improve yield under current and future climates, providing guidelines for soybean cultivar breeding in Southern Brazil. The following soybean traits were manipulated in the CSM-CROPGRO-Soybean crop model: deeper root depth in the soil profile; maximum fraction of shoot dry matter diverted to root growth under water stress; early reduction of transpiration under mild stress; transpiration limited as a function of vapor pressure deficit; N2 fixation drought tolerance; and sensitivity of grain filling period to water deficit. The yields were predicted for standard and altered traits using climate data for the current (1961–2014) and future (middle-century) scenarios. The traits with greater improvement in soybean yield were deeper rooting profile, with yield gains of ≈300 kg ha−1, followed by transpiration limited as a function of vapor pressure deficit and less drought-induced shortening of the grain filling period. The maximum fraction of shoot dry matter diverted to root and N2 fixation drought tolerance increased yield by less than 75 kg ha−1, while early reduction of transpiration resulted in a small area of country showing gains. When these traits were combined, the simulations resulted in higher yield gains than using any single trait. These results show that traits associated with deeper and greater root profile in the soil, reducing transpiration under water deficit more than photosynthesis, creating tolerance of nitrogen fixation to drought, and reducing sensitivity of grain filling period to water deficit should be included in new soybean cultivars to improve soybean drought tolerance in Southern Brazil.  相似文献   

18.
Drought is the most important limitation to summer mungbean production in the tropics and subtropics dependent on usually insufficient summer rainfall. As increased irrigation is not a viable answer to the problem, an economically and environmentally desirable solution is new varieties with drought tolerance. However, there is little genotypic information on drought tolerance in summer mungbean. The objectives of this study were to assess the genotypic differences in physiological traits and dry matter partitioning in mungbean and to measure the association of these traits with crop performance under drought conditions. Six mungbean genotypes were tested in drought micro plots at CCS Haryana Agricultural University, Hisar, India. A split plot design was used; two irrigation treatments (watered and droughted) in the main plots and six mungbean genotypes in the subplots with three replicate micro plots. Drought decreased leaf water status, rates of photosynthesis (Pn) and altered dry matter partitioning in different plant parts. Our results showed that Pn did not limit yield, but it was partitioning of dry matter governed by leaf water content (RWC) which influenced the final yield. RWC was positively correlated to the number of pods per plant and seed yield, genotypes maintaining high RWC produced higher seed yield. Therefore, the drought tolerance of summer mungbean was related to the maintenance of high RWC, which can be used as a physiological marker to identify and develop superior genotypes suited to drought-prone environments.  相似文献   

19.
Drought stress is a major abiotic constraint limiting crop production worldwide. Screening for drought tolerance and the traits that enhance drought tolerance is not straightforward in large mapping populations. In this study, we investigated the possibility of screening a mapping population in vitro for PEG-induced water deficit stress and recovery potential. We have measured several shoot and root growth parameters or traits in the C × E diploid potato mapping population. Significant variation was observed for genotype-specific responses to water deficit and recovery potential. Genetic variation and heritability estimates were high to very high for the measured traits depending on growth conditions. In order to identify potato QTLs for drought tolerance and recovery potential an SNP marker-rich integrated linkage map was used. A total of 23 QTLs were detected under control, stress and recovery treatments explaining 10.3–22.4% of the variance for each phenotypic trait. Among these, 10 QTLs were located on chromosome 2. Three QTLs involved in the important trait root to shoot ratio were identified on linkage groups 2, 3 and 8. These loci explained together 41.1% of the variance for this trait, and may be breeding targets for stress tolerance and yield in the field as well. The SNP markers derived from EST sequences underlying these QTLs led to the identification of putative candidate genes for further study in potato. This study constitutes the first knowledge of in vitro screening of a mapping population for drought tolerance in potato.  相似文献   

20.
Drought stress is a major limiting factor for crop production in the arid and semi‐arid regions. Here, we screened eighty barley (Hordeum vulgare L.) genotypes collected from different geographical locations contrasting in drought stress tolerance and quantified a range of physiological and agronomical indices in glasshouse trails. The experiment was conducted in large soil tanks subjected to drought treatment of eighty barley genotypes at three‐leaf stage and gradually brought to severe drought by withholding irrigation for 30 days under glasshouse conditions. Also, root length of the same genotypes was measured from stress‐affected plants growing hydroponically. Drought tolerance was scored 30 days after the drought stress commenced based on the degree of the leaf wilting, fresh and dry biomass and relative water content. These characteristics were related to stomatal conductance, stomatal density, residual transpiration and leaf sap Na, K, Cl contents measured in control (irrigated) plants. Responses to drought stress differed significantly among the genotypes. The overall drought tolerance was significantly correlated with relative water content, stomatal conductance and leaf Na+ and K+ contents. No significant correlations between drought tolerance and root length of 6‐day‐old seedling, stomatal density, residual transpiration and leaf sap Cl? content were found. Taking together, these results suggest that drought‐tolerant genotypes have lower stomatal conductance, and lower water content, Na+, K+ and Cl? contents in their tissue under control conditions than the drought‐sensitive ones. These traits make them more resilient to the forthcoming drought stress.  相似文献   

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