Soil Drought Applied During the Vegetative Growth of Triticale Modifies the Physiological and Biochemical Adaptation to Drought During the Generative Development

It could be taken into account that under natural conditions of plant growth, the spring drought after‐effects can stimulate or inhibit the adaptation to drought during the generative growth phase of the triticale. It is expected that the response to drought during the generative growth of plants (heading and/or flowering) can be modified by the exposure to drought during the vegetative stage (tillering). Therefore, the aim of this study was to investigate whether drought occurring during the vegetative phase can modify the physiological/biochemical adaptation to drought during the generative one. The measurements of the osmotic potential, relative water content, chlorophyll fluorescence and blue fluorescence were performed. Moreover, the analysis of the total pool of phenolic compounds and cell‐wall bound ferulic acid were performed. Genotypes subjected to drought during the tillering phase, maintained the osmotic regulation (high osmotic potential) during drought applied at the heading phase and, consequently, were able to maintain better leaf hydration and the functioning of the photosynthetic apparatus. The increase in the content of cell‐wall bound ferulic acid, observed as an after‐effect of drought applied at the tillering phase, was noticeable for the majority of genotypes. Ferulic acid bound through covalent bonds with carbohydrates of the cell wall can inhibit an increment of leaf surface. It can be linked to adaptation mechanisms, acting during drought, which can involve the inhibition of the utilization of carbohydrates in the growth processes of leaves and to maintain high osmotic potential of the cell sap.     

Effect of Water Stress on Physiological Attributes and their Relationship with Growth and Yield of Wheat Cultivars at Different Stages

The effects of water stress on physiological attributes of drought‐sensitive (Kalyansona) and drought‐tolerant (C‐306) wheat cultivars were studied in a pot experiment. Water stress was imposed by withholding irrigation at boot and anthesis stages. Leaf water potential, leaf osmotic potential and leaf turgor potential (measured with pressure chamber and osmometer), as well as leaf diffusive resistance, leaf transpiration rate and leaf‐to‐air transpiration gradient (measured with a steady‐state porometer) were measured diurnally. Growth and yield parameters were recorded after harvesting of the crop. Triplicate data were analysed using a completely randomized design and correlations amongst these parameters were computed. Water stress was found to reduce diurnal leaf water potential and leaf osmotic potential in both the genotypes but leaf osmotic potential was significantly higher in the drought‐tolerant cultivar C‐306 than in the drought‐sensitive cultivar Kalyansona. Positive turgor was recorded in both the genotypes under water stress and non‐stress conditions. Water‐stressed plants showed significantly lower turgor potential than control plants. In diurnal observations, water‐stressed plants exhibited significantly higher leaf diffusive resistance in both genotypes at both stages. The diffusive resistance of C‐306 was predominantly higher than that of Kalyansona. Water stress decreased leaf transpiration rate at both stages but the reduction was higher at the anthesis stage. The leaf‐to‐air temperature gradient was much higher in C‐306 than in Kalyansona at the boot stage but at the anthesis stage genotypic variation was non‐significant. The capacity to maintain cooler foliage was lower at the anthesis stage than at the boot stage in both the cultivars. Shoot dry weight, number of grains, test weight, grain yield, biological yield and harvest index decreased to a greater extent when water stress was imposed at the anthesis stage, while imposition of water stress at the boot stage caused a greater reduction in plant height and number of tillers. Similarly, water stress caused a smaller reduction in growth, yield and yield attributes in C‐306 than in Kalyansona. In general, the correlation coefficient of grain and biological yield with water potential and its components was positive and highly significant. Similarly, turgor potential was also correlated positively and significantly with grain yield at both the stages, but with biological yield it was significant only at the anthesis stage. A negative and significant correlation was obtained for diffusive resistance and leaf‐to‐air temperature gradient with grain yield at the boot and anthesis stages. The rate of transpiration was also positively and significantly correlated to grain and biological yields at both the stages. Amongst the yield attributes, number of leaves and number of tillers were positively correlated at the anthesis stage, whereas leaf area and shoot dry weight were significantly correlated with grain and biological yields at both the stages.     

Induction of Drought Tolerance in Maize (Zea mays L.) due to Exogenous Application of Trehalose: Growth,Photosynthesis, Water Relations and Oxidative Defence Mechanism

The present investigation was conducted to assess the ameliorative effects of foliar‐applied trehalose on growth, photosynthetic attributes, water relation parameters and oxidative defence mechanism in two maize cultivars under field water deficit conditions. Various components of the experiment comprised two maize cultivars (EV‐1098 and Agaiti‐2002), two water‐stress levels (irrigation after 2 weeks and irrigation after 3 weeks during the entire period of growth), and two levels of trehalose (0 and 30 mm ) and four replicates of each treatment. Water stress significantly reduced the plant biomass production, photosynthetic attributes and water relation parameters in both maize cultivars. In contrast, water stress considerably increased the leaf malondialdehyde (MDA) contents, the activities of antioxidant enzymes such as peroxidase (POD), superoxide dismutase (SOD) and catalase (CAT), and the levels of non‐enzymatic compounds such as ascorbic acid and tocopherols. In contrast, water stress caused a marked reduction in leaf phenolic contents. Foliar‐applied trehalose significantly increased plant biomass production, and improved some key photosynthetic attributes and plant–water relation parameters. The ameliorative effect of exogenously applied trehalose was also observed on the activities of some key antioxidant enzymes (POD and CAT) and non‐enzymatic compounds (tocopherols and phenolics). Overall, exogenously applied trehalose considerably improved drought tolerance of maize plants by up‐regulating photosynthetic and water relation attributes as well as antioxidant defence mechanism.     

用于玉米品种抗旱性鉴定的生理生化指标

通过对67个玉米品种幼苗叶片的水势、抗坏血酸、脯氨酸、电解质渗漏率和萎蔫分数在大田干旱条件下及室内水分胁迫条件下的测定证明,各指标对干旱反应的灵敏度顺序为:抗坏血酸>电解质渗漏率>脯氨酸>萎蔫分数。室内结果可代替大田结果。室内幼苗上述各指标测定结果可用于玉米品种抗旱性鉴定,但是可否用于分级有待进一步研究。     

Responses of Canopy Photosynthesis,Spectral Indices and Solar-Induced Chlorophyll Fluorescence in Cotton under Drought Stress

[Objective] Study canopy photosynthesis, spectral indices and solar-induced chlorophyll fluorescence in cotton under drought stress. [Method] Using transgenic cotton cultivar Nongda 601 as material, a two-year experiment was conducted with four irrigation regimes (CK, light drought, moderate drought and severe drought) under a field mobile shed to measure the following indices and parameters at canopy level: canopy photosynthetic rate (CAP), spectral indices (normalized difference vegetation index (NDVI), photochemical reflectance index (PRI) and water index (WI)) and solar-induced fluorescence at 761 nm (F761), as well as plant leaf water content (LWC) and leaf area index (LAI). [Result] The results indicated that LWC, LAI, CAP, NDVI, PRI and F761showed a downward trend along with the prolonging of the drought stress, while WI showed an increasing trend. Extremely significant differences (P＜0.01) were found among drought treatments and CK for all parameters. NDVI, PRI and WI were significantly correlated with LAI and LWC (P＜0.01). The absolute values of correlation coefficient for NDVI, PRI, WI, F761with LAI (|r|>0.6) were lower than those with LWC (|r|>0.8). F761 was better correlated with leaf water content and LAI than other spectral indices. [Conclusion] It was concluded that CAP, PRI, NDVI, WI and F761 are good indicators in cotton leaves during drought stress. Solar-induced fluorescence seems more sensitive to leaf water status than other spectral indices at canopy level in cotton.     

不同抗旱性甘薯品种叶片生理性状差异及抗旱指标筛选

在人工控水条件下,以15个甘薯品种为试验材料,设置正常灌水和干旱胁迫2个土壤水分处理,研究了干旱胁迫条件下不同甘薯品种叶片生理特性的差异。结果表明,干旱胁迫条件下,叶面积系数均不同程度下降,反映了品种抗旱性的差异。通过抗旱系数聚类分析,将15个甘薯品种分为3个抗旱类型,抗旱品种:济薯21、济薯25、济徐23、济薯15、烟薯25;中等抗旱品种:徐薯18、济薯26、北京553、济紫薯2号、济薯18;不抗旱品种:郑薯20、济紫薯3号、济薯22、济紫薯1号、凌紫。叶面积系数与抗旱系数的相关性分析表明,干旱胁迫条件下抗旱性强的甘薯品种可维持较高的叶面积系数;而正常灌水条件下的叶面积系数不能反映甘薯品种抗旱性。干旱胁迫导致功能叶叶绿素含量和相对含水量下降,叶片相对电导率升高。干旱胁迫条件下,功能叶叶绿素含量和相对含水量与甘薯品种的抗旱性呈显著正相关关系,而功能叶相对电导率则与甘薯品种抗旱性呈显著的负相关关系。因此,叶面积系数以及功能叶叶绿素含量、相对含水量和相对电导率等指标可作为甘薯品种抗旱性鉴定的评价指标。     

Use of image analysis to estimate anthocyanin and UV-excited fluorescent phenolic compound levels in strawberry fruit

Strawberry is rich in anthocyanins, which are responsible for the red color, and contains several colorless phenolic compounds. Among the colorless phenolic compounds, some, such as hydroxycinammic acid derivatives, emit blue-green fluorescence when excited with ultraviolet (UV) light. Here, we investigated the effectiveness of image analyses for estimating the levels of anthocyanins and UV-excited fluorescent phenolic compounds in fruit. The fruit skin and cut surface of 12 cultivars were photographed under visible and UV light conditions; colors were evaluated based on the color components of images. The levels of anthocyanins and UV-excited fluorescent compounds in each fruit were also evaluated by spectrophotometric and high performance liquid chromatography (HPLC) analyses, respectively and relationships between these levels and the image data were investigated. Red depth of the fruits differed greatly among the cultivars and anthocyanin content was well estimated based on the color values of the cut surface images. Strong UV-excited fluorescence was observed on the cut surfaces of several cultivars, and the grayscale values of the UV-excited fluorescence images were markedly correlated with the levels of those fluorescent compounds as evaluated by HPLC analysis. These results indicate that image analyses can select promising genotypes rich in anthocyanins and fluorescent phenolic compounds.     

Evaluation of chlorophyll fluorescence as a tool for the identification of drought tolerance in upland cotton

Chlorophyll fluorescence (CF) is one tool used by researchers to quantify plant water status during periods of limited water availability. The research reported herein was designed to evaluate a CF-based protocol as a tool for use in cotton, Gossypium spp. breeding programs for the identification of drought tolerant genotypes. Twenty genotypes were selected to represent diverse and distinct US germplasm pools. Replicated tests were performed in Lubbock and College Station, TX in 2006 and 2007. Dryland and irrigated treatments, as main plots, were applied in a randomized complete block design, split to genotypes. CF measurements were taken at mid-bloom and late bloom growth stages. Source leaf tissue was harvested at predawn and subjected to high temperature incubation with CF measurements subsequently taken hourly for 5 h. Drought stressed plants had not mobilized their carbohydrate reserves from their source leaves overnight and thus maintained cell viability and therefore higher CF values throughout the incubation and measurement period with the opposite being true for non-stressed plants. Fiber lint yield and fiber properties were measured for comparison with the CF data. Genotype × treatment effects complicated the classification of genotypic response to drought. Few and inconsistent correlations were found among CF values and lint yield or fiber properties. Data suggested that this procedure provides little potential in selecting plants for drought tolerance when plants are grown under field culture.     

Characterization of Drought‐Tolerance Traits in Nodulated Soya Beans: The Importance of Maintaining Photosynthesis and Shoot Biomass Under Drought‐Induced Limitations on Nitrogen Metabolism

Drought is the single most important factor limiting soya bean (Glycine max L. Merr.) yields in the field. The following study was therefore undertaken to identify phenotypic markers for enhanced drought tolerance in nodulated soya beans. Leaf and nodule parameters were compared in three genotypes: Prima 2000, glyphosate‐resistant A5409RG and Jackson, which had similar shoot biomass and photosynthesis rates at the third trifoliate leaf stage under water‐replete conditions. When water was withheld at the third trifoliate leaf stage, photosynthesis, nodule numbers, nodule biomass and symbiotic nitrogen fixation (SNF) were greatly decreased. Significant cultivar–drought interactions were observed with respect to photosynthesis, which also showed a strong positive correlation with nodule SNF, particularly under drought conditions. Prima leaves had high water‐use efficiencies, and they also maintained high photosynthetic electron transport efficiencies under long‐term drought. Moreover, Prima had the highest shoot biomass under both water‐replete and drought conditions. A‐5409RG was the most drought‐sensitive genotype showing early closure of stomata and rapid inhibition of photosynthesis in response to drought. In addition to classifying the genotypes in relation to drought tolerance, the results demonstrate that the ability to sustain shoot biomass under nitrogen limitation is an important parameter, which can be easily applied in germplasm screening for drought tolerance in soya bean.     

不同灌溉条件下冠菌素对大豆光合特性与产量的调控效应

干旱是限制大豆丰产稳产的重要因素之一,利用生物调节剂提高大豆耐旱性是生产中一种新型的生物节水管理模式。本研究在常规灌溉与无灌溉条件下,采用生物调节剂冠菌素(COR)于大豆初花期进行叶面喷施处理,研究COR对植株农艺性状、叶片水势和光合特征、产量及其构成因素的调控效应。试验结果表明:在正常灌溉条件下, COR处理对大豆叶片水势、叶绿素含量、光合速率、叶绿素荧光参数、RuBP羧化酶和SPS活性等影响较小,与对照相比其产量和生物量差异不显著。但在生长季无灌溉的雨养条件下,COR处理会显著提高大豆开花后叶片水势、叶绿素含量、光合速率和叶绿素荧光参数,增加叶片RuBP羧化酶和SPS活性,改善大豆产量构成因素,最终导致籽粒产量增加。总之,在雨养条件下, COR对大豆光合特征和产量形成具有积极的调控效应。     

Genetic Variation for Maize Epicuticular Wax Response to Drought Stress at Flowering

Drought stress is thought to promote epicuticular wax accumulation on maize leaves, which reduces plant water loss. We evaluated 62 maize inbred lines and their hybrid testcross progeny for epicuticular wax accumulation on flag leaves at flowering under full and limited irrigation regimes. Extracted wax was measured as a percentage of wax weight to leaf weight (WLW) and leaf area (WLA). Eleven genotypes had above average WLW as both inbred lines and hybrid testcrosses. Thirteen genotypes had above average WLA as either inbred lines or hybrid testcrosses. The drought treatment did not significantly alter WLW or WLA. Heritability of WLW was 0.17 (inbred lines) and 0.58 (hybrid testcrosses). Heritability of WLA was 0.41 (inbred lines) and 0.59 (hybrid testcrosses), suggesting it is a better trait than WLW for epicuticular wax screening. Correlations (r) between inbred lines and their testcross progeny were 0.44 and 0.18, for WLW and WLA, respectively. Heritability of grain weight per ear and plot yield was highest in hybrid testcrosses, with no correlation between inbred and hybrid germplasm. It is not warranted to evaluate epicuticular wax accumulation as the sole drought tolerance mechanism. However, it may be a good secondary trait to observe in relation to grain yield production in hybrids tested under water‐limiting conditions.     

Relationships between leaf morpho‐anatomy,water status and cell membrane stability in leaves of wheat seedlings subjected to severe soil drought

The impact of the genotype‐specific leaf morphological and anatomical characteristics on the ability of wheat plants to preserve leaf water balance and cell membranes stability under drought stress was investigated. Seedlings of six modern semi‐dwarf (carriers of Rht, Reduced height genes) and six old tall bread wheat varieties were subjected to soil drought by withholding watering for 6 days. Morpho‐anatomical traits (leaf area, perimeter, thickness, stomata and trichome density) of daily watered (control) plants were characterized by light microscopy, scanning and image analyses. The leaf water status in both control and stressed plants was determined by measuring the relative water content (RWC). The leaf cell membranes stability in stressed plants was estimated by conductometric determination of the membranes injury index. On average, the modern semi‐dwarf varieties had less leaf area and leaf perimeter, and less dissection index, a parameter characterizing the leaf shape. Under drought stress, the modern genotypes maintained better water balance evidenced by significantly higher leaf RWC and better‐preserved the cell membranes stability supported by significantly lower Injury index. The correlations between morpho‐anatomical traits in control plants and drought tolerance‐related traits showed that the higher the leaf dissection index (i.e. more oblong leaves), the greater the water loss and the leaf membrane damages after desiccation were. The effect of shape of the evaporating surface on the water loss was modelled using wet filter paper. Similar to plant leaves, the evaporation and, respectively, water loss from paper pieces of more oblong shape (i.e. higher dissection index) was more intensive. The elucidation of the impact of the leaf shape on transpiration might contribute to better understanding of the mechanisms used by plants to maintain water reserves during drought stress and could be a basis for developing of simple and fast screening methods aiding the selection of drought tolerant genotypes.     

水分胁迫对玉米叶绿素荧光特性的影响

以吉单261和京单28两个玉米品种为试验材料,研究水分胁迫对玉米叶片光合特性及叶绿素荧光参数的影响.结果表明:水分胁迫下玉米叶片的最大净光合速率、光补偿点、光饱和点和表观量子效率均显著下降;基础荧光显著增加,最大荧光、可变荧光和PSⅡ光化学效率显著降低;随着光强增加,水分胁迫条件下的光化学猝灭系数和实际光化学效率下降幅度明显加剧;非光化学猝灭系数和表观电子传递速率增加幅度则明显减缓.表明水分胁迫使玉米叶片光合性能减弱,PsⅡ反应中心开放部分的比例减少,光合电子传递能力下降,PSⅡ潜在活性受到抑制,过多的光能多是以非光化学猝灭等其他形式耗散掉,从而保护光合机构免受伤害.     

Genotypic Variability in Drought Performance and Recovery in Cowpea under Controlled Environment

Mid‐season drought is a factor frequently limiting crop production in the moist to dry savannah zones of the tropical and subtropical regions of the world. Ten cowpea genotypes were subjected to a cycle of drought at flowering followed by re‐watering to study variation in drought performance and recovery. Drought caused a reduction in leaf assimilation rate, transpiration rate and stomatal conductance with genotypic variances of 75.4, 57.9, and 83.3 %, respectively. Only genotypic variance in stomatal conductance increased appreciably under drought. Reductions in leaf water potential as a consequence of drought positively correlated with a decline in assimilation rate, which was associated with stomatal closure. One week after re‐watering, the three gas exchange parameters of stressed plants recovered fully and attained values 10–30 % higher than the well‐watered plants with increased genotypic variability. Reductions in the total dry matter during the drought interval varied from 11 to 50 % among genotypes, but were of minor importance for the total dry matter at maturity. After stress, the gain in dry matter varied considerably among the stressed genotypes, with stressed plants showing higher gain than the unstressed plants during this interval. This was associated with increased availability of assimilates due to enhanced green leaf area duration after stress release. Variability in drought recovery among genotypes was found, and appears to be more important for final yield than responses during drought.     

Understanding physiological and morphological traits contributing to drought tolerance in barley

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.     

Functional mechanisms of drought tolerance in maize through phenotyping and genotyping under well watered and water stressed conditions

Developing tolerant genotypes is crucial for stabilizing maize productivity under drought stress conditions as it is one of the most important abiotic stresses affecting crop yields. Twenty seven genotypes of maize (Zea mays L.) were evaluated for drought tolerance for three seasons under well watered and water stressed conditions to identify interactions amongst various tolerance traits and grain yield as well as their association with SSR markers. The study revealed considerable genetic diversity and significant variations for genotypes, environment and genotype × environment interactions for all the traits. The ranking of genotypes based on drought susceptibility index for morpho-physiological traits was similar to that based on grain yield and principal component analysis. Analysis of trait – trait and trait – yield associations indicated significant positive correlations amongst the water relations traits of relative water content (RWC), leaf water potential and osmotic potential as well as of RWC with grain yield under water stressed condition. Molecular analysis using 40 SSRs revealed 32 as polymorphic and 62 unique alleles were detected across 27 genotypes. Cluster analysis resulted in categorization of the genotypes into five distinct groups which was similar to that using principal component analysis. Based on overall performance across seasons tolerant and susceptible genotypes were identified for eventual utilization in breeding programs as well as for QTL identification. The marker-trait association analysis revealed significant associations between few SSR markers with water relations as well as yield contributing traits under water stressed conditions. These associations highlight the importance of functional mechanisms of intrinsic tolerance and cumulative traits for drought tolerance in maize.     

Root pulling resistance in rice: Inheritance and association with drought tolerance

Summary Avoidance of drought stress is commonly associated with root system characteristics and root development. The inheritance of root pulling resistance in rice (Oryza sativa L.) was investigated and its relationship with visual field scores for drought tolerance was studied. Transgressive segregation for high root pulling resistance was observed in 3 crosses (high x high, low x high, and intermediate x intermediate). Both dominant and additive genes control the variation. F₁ superiority for high root pulling resistance was observed and could be exploited in an F₁ hybrid breeding program. F₂ distribution curves indicated that plants highly resistant to root pulling can be obtained not only from low x high and high x high crosses, but also from intermediate x intermediate crosses. Root pulling resistance in rice has a low heritability (39 to 47%). Thus, breeding for a high root pulling resistance may best be accomplished by selection based on line means rather than individual plant selection. Field screening showed significant differences in leaf water potential among random F₃ lines. F₃ lines with higher leaf water potential had better visual scores for drought tolerance. Visual drought tolerance scores were correlated with root pulling resistance. Plants with high root pulling resistance had the ability to maintain higher leaf water potentials under severe drought stress. The usefulness of the root pulling technique in selecting drought tolerant genotypes was confirmed.     

Drought tolerance screening for potato improvement

Six potato genotypes including ‘Desiree’ and five breeding clones (2/14, 95C, 125B, 3589, 4056) were grown in the field under well-watered and stress conditions. The stress response of leaf tissue was assessed 8 and 12 weeks after plant emergence (WAE) by measuring canopy temperature and chlorophyll α fluorescence induction kinetics in detached leaves. Under drought-stress conditions, chlorophyll α fluorescence dropped in clones 2/14 and 4056, remained constant in 95C and 125B and increased in clone 3589. The canopy temperature exhibited little difference between drought and irrigated treatments in clones 95C and 125B, and significant effects in the other genotypes. This performance was interpreted in terms of tolerance to drought stress, and the potential use of canopy temperature and chlorophyll fluorescence as tools for drought screening of potato germplasm and segregant generations is discussed. The physiological properties of 95C and 125B highlighted by this study need further investigation and, if confirmed, they could be recombined with other useful agronomic characters by crossing in a breeding programme.     

Maize Genotypes Differing in Salt Resistance Vary in Jasmonic Acid Accumulation During the First Phase of Salt Stress

Plant hormones are considered to play an important role in plant adaptation to drought and salt stress. The objective of the study was to investigate the changes in endogenous jasmonic acid (JA) in relation to differences in the salt resistance of maize genotypes. Two maize genotypes (SR 03 and Across 8023) were compared for changes in water relations, growth and tissue JA levels in response to 100 mm NaCl. Salt stress significantly reduced the shoot growth of both genotypes; however, SR 03 exhibited significantly less reduction in relative shoot fresh weight than Across 8023. Both genotypes showed an identical response to salt stress regarding plant water relations; therefore, genotypic differences in the salt resistance could not be attributed to changes in shoot turgor and these results were further confirmed by the response of both genotypes under equiosmotic stress (?0.49 MPa) of either 100 mm NaCl or PEG‐6000. GC‐MS/MS analysis showed that salt stress did not alter shoot JA levels of both genotypes, however significantly increased the root JA levels of Across 8023. In contrast, root JA levels of salt‐resistant SR 03 did not change by salt stress. Increase in root JA levels in response to stress treatments does not coincide with the growth inhibition of shoot in Across 8023. In contrast, both PEG and NaCl did not change the JA concentrations in both root and shoot tissues of SR 03. Growth assays with maize seedlings showed that JA supply in root medium inhibits shoot extension growth and both maize genotypes were sensitive to the inhibitory effects of JA. These results suggest that maize genotypes differ in JA accumulation during the first phase of salt stress and JA may indirectly be involved in leaf growth inhibition of the salt‐sensitive genotype. In addition, our results also showed that treatment of salt‐stressed plants with exogenous JA improved the Na⁺ exclusion by decreasing the Na⁺ uptake at the root surface.