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1.
Summary As a result of the analysis of 31 fenugreek (Trigonella foenum-graecum L.) genotypes we demonstrated that subsp. indica surpass significantly subsp. foenum-graecum in fresh weight, seed yield, nodulation ability, resistance to coot rot and the duration of the interstage and growing periods. There was no difference between the subspecies for leafiness and biochemical composition of seeds (concentrations of diosgenin and steroid glucosides, nitrogen, fat, inhibitors of tripsin and hemotripsin). The most promising genotypes (as compared with the standard cv. Nakhichevanskaya Shambala) yield 1650–1938 g/m2 of fresh weight, 98.2–116.1 g/m2 of seeds and accumulate 1.45–1.64% of diosgenin in seeds. High positive correlations (r=+0.53 ... +0.84; Po<0.01) were found between fresh weight, seed yield, plant leafiness and height. Inoculation of the cv. Nakhichevanskaya Shambala with Rhizobium meliloti strains 851 and 852 increased its fresh weight by 94.5% and 93.6% and seed yield by 83.1% and 60.5%, respectively. Significant correlations of the nodule number with the fresh weight and seed yield (r=+0.70 and +0.77; Po<0.01) allow us to assume that selection for increased symbiotic activity may be useful for improving the fenugreek productivity. The intersubspecies hybrids (four genotypes) surpass the subsp. indica (six genotypes) for the sizes of calli formed in presence of 2.4-D and kinetin. The sizes of calli formed by ten analysed genotypes in presence of BAP and kinetin (or 2.4-D) were negatively correlated with the nodule number (or fresh weight).  相似文献   

2.
Field experiments were conducted using two sweet potato cultivars (Jishu 21, a drought-tolerant cultivar, and Jizishu 1, a drought-sensitive cultivar) with four water treatments to investigate the effects of drought treatments at different growth stages on growth and the activity of osmotic adjustment in sweet potato [Ipomoea batatas (L.) Lam.], including well-watered treatment during the whole growth period (WW, control), drought stress during the establishment stage (DS1), drought stress during the storage root initial stage (DS2), and drought stress during the storage root bulking stage (DS3). Drought stress resulted in significant decrease of fresh weight of storage roots in sweet potato. Compared with drought stress in different periods, drought stress during the establishment stage (DS1) decreased the fresh weight most. Compared between cultivars, drought-sensitive cultivar decreased the fresh weight most. The average in three years, compared with the control, the fresh weight of drought-tolerant cultivar (Jishu 21) and drought-sensitive cultivar (Jizishu 1) decreased 28.59% and 38.77% in DS1 treatment, respectively, while 25.20% and 33.50% in DS2 treatment, respectively and 14.55% and 19.56% in DS3 treatment, respectively. Drought stress resulted in significant decrease of biomass of storage roots in sweet potato. One hundred days after planting, compared with the control, the biomass of aboveground part of Jishu 21 in DS1, DS2, and DS3 decreased 32.68%, 20.79%, and 11.72%, respectively, while Jizishu 1 decreased 46.45%, 31.89%, and 18.43%, respectively. The biomass of underground part of Jishu 21 in DS1, DS2, and DS3 decreased 37.69%, 25.86%, and 10.67%, respectively, while Jizishu 1 decreased 54.34%, 33.48%, and 14.20%, respectively. Under drought stress, the relative water content of functional leaves decreased, and the content of soluble sugar, soluble protein, free amino acid and proline in functional leaves, fibrous roots and storage roots increased. The earlier the application of drought stress, the greater the decrease or increase. The effects of drought stress applied at early stages on osmotic adjustment could not be effectively recovered after re-watering, while the osmotic adjustment could be recovered to the control level after re-watering when drought stress was applied at later stage.  相似文献   

3.
NaCl胁迫对胡卢巴幼苗抗氧化酶活性和丙二醛含量的影响   总被引:1,自引:0,他引:1  
以胡卢巴幼苗为试验材料,研究NaCl胁迫下胡卢巴幼苗叶和根中抗氧化酶SOD、POD、CAT活性及丙二醛(MDA)含量的变化。结果表明:随着NaCl处理浓度的升高,SOD、POD、CAT活性总体呈现先上升后下降的趋势,MDA含量则呈上升趋势。叶片中抗氧化酶活性在NaCl浓度为1.0%时达到峰值,根中抗氧化酶活性在NaCl浓度为0.5%时达到峰值。在0.5%的NaCl浓度处理下,随着处理时间的延长,3种抗氧化酶协同作用,使MDA含量减少并控制在较稳定的阶段。可见,盐胁迫下胡卢幼苗可通过提高抗氧化酶活性,降低膜质过氧化水平,减缓盐胁迫对植株的伤害,从而增强其耐盐性。  相似文献   

4.
Integrating soil amendment biochar to legume‐based intercropping systems may amplify the intercropping benefits and lead to more sustainable production due to its positive effects on the soil physicochemical and biological environment. Fenugreek (Trigonella foenum‐graecum) is a legume used in an intercropping system in several countries in Southern Europe, the Middle East, and Asia. A barley cultivar and an Iranian fenugreek ecotype were studied in two replacement series experiments to find the best combination of the two species as well as the effect of adding biochar to the soil. Fenugreek and barley were grown in 4‐L pots in five density combinations (20:0, 15:5, 10:10, 5:15, 0:20) with and without application of biochar in sandy loam soil. The biomass, nitrogen (N) and carbon (C) amount of the two crops were measured fifty days after sowing, and the Relative Yield Total (RYT) was estimated. Our results showed that biochar application resulted in a higher total biomass, N and C amount in all combinations of fenugreek and barley. Total biomass was increased by biochar 19.2% when fenugreek was grown alone and 8.1 and 12.9% in series with 25 and 50% barley when biochar was added, respectively. Biochar increased dry matter, N and C accumulation in both crop species in the mixtures. An exception was the C amount of barley which was not influenced by biochar in intercropping. RYT values were largest for biomass, C and N amount in mixtures with 15 fenugreek plants per pot and 5 barley plants per pot corresponding to approximately 400 fenugreek plants per m mixed with 130 barley plants per m2. Biochar application increased RYT of the total dry weight by 2.7 and 5.5% in mixtures of 25 and 50% barley plants, RYT of the total nitrogen by 0.8% in mixtures with 25% barley plants, and RYT of the total carbon by 2.7 and 6.6% in mixtures with 25 and 50% barley plants. The RYT values declined with increasing number of barley plants as a result of a less competitive ability of fenugreek when growing in high barley densities. The yield was highest with intercropping but monoculture of barley also resulted in high yields. The total highest yield was found when approximately 130 fenugreek plants per m2 were mixed with 400 barley plants per m2. Mixtures with 75% fenugreek and 25% barley obtained RYT values larger than 1 for biomass, carbon and nitrogen percentages.  相似文献   

5.
The growth and production of sweet sorghum [Sorghum bicolor (L.) Moench] crops under semi-arid conditions in the Mediterranean environment of southern Italy are constrained by water stress. The effects of temporary water stress on growth and productivity of sweet sorghum were studied during three seasons at Rutigliano (Bari, Italy). The aim of this research was to evaluate the sensitivity of phenological stages subjected to the same water deficit. In a preliminary study it was observed that stomata closed when pre-dawn leaf water potential (Ψb) became lower than −0.4 MPa. This criterion was used in monitoring plant water status in three different plots: one never stressed and two stressed at different phenological stages (‘leaf’ and ‘stem’) when mainly leaves or stems were growing, respectively. An evaluation of the sensitivity of phenological stages subjected to identical water stress was obtained by comparing the above-ground biomass and WUE of drought crops with those of the well-irrigated crop (up to 32.5 t ha−1 of dry matter and 5.7 g kg−1). The sensitivity was greatest at the early stage (‘leaf’), when a temporary soil water stress reduced the biomass production by up to 30% with respect to the control and WUE was 4.8 g kg−1 (average of three seasons). These results help quantify the effects of water constraints on sweet sorghum productivity. An irrigation strategy based on phenological stage sensitivity is suggested.  相似文献   

6.
Brazil is the world's largest producer of common beans (Phaseolus vulgaris L.). Drought stress harms the morphological and agronomic traits of beans. This study evaluates the reaction to water deficit in five genotypes of black beans. The experiment was conducted in the IDR-IAPAR-EMATER in Londrina-PR, Brazil. A split-plot design was used, with three replications. The genotypes were included in the subplots and the treatments with or without water deficit in the plots. Water deficit was induced on the pre-flowering stage and maintained for 20 days in the plots submitted to drought stress. For the growth analysis, plants were collected at 35, 54 and 70 days after emergence. At the stage of physiological ripeness, several morphological and yield traits were evaluated. The genotypes IPR Uirapuru and BRS Esplendor can be considered tolerant and used as a tolerant source to water deficit in common bean germplasm banks. The line LP 08-90 has morphological and agronomic adaptations efficient to overcome water deficit's effects, presenting a higher grain yield in both crop conditions, which indicates the success of black beans breeding to deal with water deficit.  相似文献   

7.
亚洲棉石系亚1号耐旱相关基因SSH文库的构建及其分析   总被引:2,自引:0,他引:2  
通过抑制消减杂交技术成功地构建了亚洲棉石系亚1号耐旱相关基因cDNA文库。通过蓝白斑筛选、菌落PCR及生物信息学等分子生物学手段分析和检验了库的质量,最终筛选出阳性克隆392个。通过EST测序得到265个单一序列,其中41个为重叠群,224个为单拷贝。生物信息学分析结果表明,该文库含有大量与耐旱相关的基因,并且涉及植物生理中多种代谢途径。  相似文献   

8.
Improved adaptation of potato to limited water availability is needed for stable yields under drought. The maintenance of the cell water status and protection of cellular components against dehydration are important for drought tolerance, and the N status of plants affects the regulation of various respective metabolic processes. A 2‐year pot trial with 17 potato cultivars was conducted under a rain‐out shelter including two water regimes and two N‐levels to investigate genotypic differences concerning osmotic adjustment (OA) and relevant biochemical traits in relation to nitrogen (N) supply. Drought stress resulted in a rapid decrease in the leaf osmotic potential. The N, protein and proline contents increased under drought, while the N protein/NKjeldahl ratio decreased. Initially, total soluble sugars increased at both N‐levels but dropped back to the control level at high N‐availability under prolonged drought while remaining high in N‐deficient plants. Results indicate that potatoes have only a limited capacity of active OA and that increasing sugar and proline concentrations are rather associated with the protection of cellular components. High N supply promoted the N protein/NKjeldahl ratio at short‐term drought and enhanced proline accumulation. Significant genotypic differences were observed for all investigated traits.  相似文献   

9.
屋顶绿化木本植物的抗旱性研究   总被引:1,自引:0,他引:1  
为了筛选出适宜屋顶绿化需要的节水抗旱木本植物,在2010年4-6月,以石家庄市的气候条件为基础,测定自然干旱胁迫条件下16种屋顶绿化木本植物的叶片面积、相对含水量、质膜相对透性、可溶性糖含量等指标,综合分析16种木本植物树种的抗旱性。结果表明,柳树、小叶杨、白榆、杠柳抗旱性最强,推荐用于屋顶绿化;金叶女贞、桑树、紫叶小檗、棣棠、红瑞木、珍珠梅、金银木、臭椿、大叶黄杨的抗旱性中等,通过精细管理也可用于屋顶绿化;金叶榆、构树、火炬的抗旱性弱,建议选用时应加强灌溉措施。  相似文献   

10.
蓝藻堆积对水环境和沉水植物生长的影响   总被引:1,自引:0,他引:1  
湖泊富营养化是世界面临的重大环境问题,针对湖泊富营养化引起的蓝藻(Cyanobacteria)爆发等问题的研究具有重要实践意义,湖泊富营养化常导致蓝藻生物量的增加,水质恶化。本实验于2012年8月12日至9月3日研究添加蓝藻的围隔和对照植被区的水体中总氮(TN)、总磷(TP)、铵氮(NH4 -N)、叶绿素a浓度以及植物生长的区别,并采用自然状态下的水体,研究了蓝藻堆积对水环境和沉水植物生长的影响。研究表明:添加蓝藻的围隔中TN、TP以及叶绿素a含量均显著高于对照区域;蓝藻堆积的围隔中,沉水植物群落总生物量下降,而对照区沉水植物生物量则大量增加;金鱼藻(Ceratophyllum demersum L)、马来眼子菜(Potamogeton wrightii Morong)、伊乐藻和微齿眼子菜(Potamogeton maackianus A. Bennett)等沉水植物的生物量下降,但狐尾藻(Myriophyllum verticillatum)的生物量略有增加。由此得出,蓝藻堆积导致水环境营养盐含量增加,藻类密度增加,沉水植物群落受到抑制,大部分沉水植物的生长受到抑制,但对狐尾藻的影响不大。  相似文献   

11.
Drought stress is one of the major environmental factors limiting peanut (Arachis hypogea L.) productivity. Peanut response to drought varies depending on genotypic characteristics, crop growth stages, and environmental conditions. The objective of this study was to evaluate the effects of drought stress and rehydration on symbiotic nitrogen fixation and carbon isotope discrimination in peanut genotypes with varying drought tolerance. Experiments were conducted for 2 years in rainout shelters under three irrigation regimes: irrigated control, middle-season drought with rehydration, and late-season drought with rehydration. Reduction in percentages of shoot N derived from the atmosphere (%Ndfa) occurred under both drought treatments in both years; a greater reduction occurred under middle-season drought than under late-season drought. Middle-season drought negatively affected carbon isotope discrimination in both years, although there were no significant differences under late-season drought. Variabilities in %Ndfa and carbon isotope discrimination were found among different genotypes. Under middle-season drought, both %Ndfa and carbon isotope discrimination were higher in drought-tolerant lines than drought-susceptible lines. The most drought-tolerant lines had the highest N-fixing capacity under both drought treatments. Additionally, there was a positive correlation between %Ndfa and carbon isotope discrimination under both drought treatments. In most genotypes, %Ndfa remained unchanged after rehydration; only a few genotypes showed a slight increase in %Ndfa after rehydration following both drought treatments. Our data suggested that symbiotic nitrogen fixation in many peanut genotypes was negatively affected by drought and may not recover from the damage caused by drought upon rehydration.  相似文献   

12.
In this study, we examined responses of maize hybrids differing in susceptibility to soil compaction and drought in the case of their separate or combined action. We ran field and greenhouse experiments and determined effects on grain yield, biomass, weight of 1000 grains, shoot and roots dry matter (DM), shoot-to-roots ratio, harvest index, plant height, emergence index, leaf area and greening and root number and length. Individual and combined effects of both stresses were observed in the field and greenhouse. Compared with plants growing in loose soil and optimal irrigation (LI), the resistant hybrids in treatments HI, LD and HD showed a smaller reduction in GY, BY, S, R, RN and RL than the sensitive. In both groups, stress influence on HA, W-1000, LA and SPAD was smaller and the differences were insignificant. Compared with LI treatment, the roots of LD, HI and HD increased their DM, number and length in the upper level of the soil profile and the number of roots developed at 0–30° and 30–60° in relation to the root main axis. Analysis of those traits in the hybrids resistant and sensitive to both stress factors enabled to explain a defence response. Our study demonstrated that soil compaction and soil drought, which usually occurs simultaneously, caused significant changes in components of plant yield and showed plant plasticity in response to environmental factors under natural conditions.  相似文献   

13.
Soybean plants were subjected, during their growing seasons, to well-watered and water-stressed conditions, and three levels of ozone concentration (zero, low and high) in open top chambers (OTCs). At the end of the soybean growing season accumulated AOT40 values were zero, 3400 and 9000 ppb h for the filtered (control), low and high levels of ozone concentration, respectively.

In well-watered conditions, an increase in ozone concentration led to a reduction in leaf area, dry matter and reproductive organs. Whereas, an increase in ozone had no effect on plants in water-stressed conditions. At a high level of ozone concentration, there was a 47% reduction in yield and a 25% reduction in WUE in comparison with the control treatment. The reduction in yield was due to a lower number of pods per plant and 1000-grain weight. Despite changes in the grain yield, the yield quality was not altered by ozone.

During the 3-year study, AOT40 was significantly correlated with the leaf area and the final above-ground dry matter. The latter was less sensitive to ozone than leaf area. These results were reliable and would be useful in soybean yield-prediction models.

Finally, the conclusion highlights the reliability of the approach adopted, which was to make observations on various time scales (hourly, daily and entire crop cycle).  相似文献   


14.
The allelopathic water extracts (AWEs) may help improve the tolerance of crop plants against abiotic stresses owing to the presence of the secondary metabolites (i.e., allelochemicals). We conducted four independent experiments to evaluate the influence of exogenous application of AWEs (applied through seed priming or foliage spray) in improving the terminal heat and drought tolerance in bread wheat. In all the experiments, two wheat cultivars, viz. Mairaj‐2008 (drought and heat tolerant) and Faisalabad‐2008 (drought and heat sensitive), were raised in pots. Both wheat cultivars were raised under ambient conditions in the wire house till leaf boot stage (booting) by maintaining the pots at 75% water‐holding capacity (WHC). Then, managed drought and heat stresses were imposed by maintaining the pots at 35% WHC, or shifting the pots inside the glass canopies (at 75% WHC), at booting, anthesis and the grain filling stages. Drought stress reduced the grain yield of wheat by 39%–49%. Foliar application of AWEs improved the grain yield of wheat by 26%–31%, while seed priming with AWEs improved the grain yield by 18%–26%, respectively, than drought stress. Terminal heat stress reduced the grain yield of wheat by 38%. Seed priming with AWEs improved the grain yield by 21%–27%; while foliar application of AWEs improved the grain yield by 25%–29% than the heat stress treatment. In conclusion, the exogenous application of AWEs improved the stay green, accumulation of proline, soluble phenolics and glycine betaine, which helped to stabilize the biological membranes and improved the tolerance against terminal drought and heat stresses.  相似文献   

15.
水分胁迫对花生幼苗叶片内源激素含量的影响   总被引:4,自引:1,他引:4  
研究了水分胁迫对花生幼苗叶片内源激素含量的影响。结果表明,GA3含量先升后降,出现了两个高峰值,ABA含量则逐渐升高,IAA和ZR先降低后升高。随着胁迫时间的延长,叶片中ABA/IAA的值先升后降,ABA/ZR逐渐升高。  相似文献   

16.
The objective of this work was to investigate the effects of nutrient solution pH, nitrogen form (NO3, NH4NO3), bicarbonate and different Fe concentrations in the nutrient solution on the Fe concentration in roots and on the development of Fe deficiency symptoms in sunflower plants (Helianthus annuus L.). High pH in the nutrient solution induced by nitrate supply or by a pH-stat device led to increased Fe concentrations in roots and low leaf Fe concentrations associated with a significant decrease in leaf chlorophyll concentration manifested by yellow leaves. Plants of the nitrate fed treatments with 1 μM Fe in the nutrient solution were also characterized by reduced leaf growth and by the suppression of new leaf formation. The reduced leaf growth and the suppression of new leaves only occurred with nitrate and not with NH4NO3 in all treatments with 1 μM Fe in the nutrient solution. All symptoms were removed by a high Fe concentration in the nutrient solution (100 μM) at low external pH proving that suppression of leaf formation, reduced leaf growth and low chlorophyll concentration were caused by Fe deficiency. In the nitrate treatment with a low Fe supply (1 μM Fe) and pH 4 in the nutrient solution leaf chlorophyll concentrations similar to the controls were found. In comparison to control plants (NH4NO3, 1 μM Fe), leaf growth was still significantly reduced, and new leaf formation was suppressed. The chlorophyll concentration and CO2 assimilation rate did not differ from those of the control plants. These results show that Fe deficiency is also characterized by small green leaves and the suppression of leaf formation. At the onset of leaf development, leaf growth and new leaf formation may respond more sensitively to poor Fe efficiency than chlorophyll concentration. In experiments with NO3 plus HCO3, simulating soil solution conditions prevailing in calcareous soils, the Fe efficiency of the youngest leaves was poor, showing retarded leaf growth and low chlorophyll concentration.  相似文献   

17.
Wheat (Triticum aestivum L.)/maize (Zea mays L.) strip intercropping is widely practiced in arid regions of northwestern China because of its high land use efficiency. However, its sustainability has been questioned because it consumes much more water than sole cropped wheat or maize. The present study was conducted to investigate the effects of water limitation on the yield advantage and water use of this system. Three field experiments were conducted in the Hetao Irrigation District in Inner Mongolia during the growing seasons of 2012–2014. Each experiment comprised two water applications, in which one was full irrigation and the other was a period of water limitation during the co-growth period of intercropping.The interspecific competition in wheat/maize intercropping was intensified by water stress. For water limitation applied during the wheat booting/maize V5 stage (Exp. I, second irrigation was not applied), the yield advantage of intercropped wheat (IW) over sole wheat was enhanced, whereas that of intercropped maize (IM) over sole maize was reduced compared with full irrigated treatments; for water limitation applied during the wheat jointing/maize V2 stage (Exp. II, first irrigation was not applied), the yield advantages of both IW and IM were greatly reduced; for water limitation applied during the wheat grain filling/maize V9 stage (Exp. III, third irrigation was not applied), the yield advantage of IW was slightly improved, whereas that of IM was reduced. The yield advantage of intercropping under limited irrigation was 25%, 3%, and 18% in Exps. I–III, respectively, whereas that under full irrigation ranged between 22 and 24%.Under well-watered conditions, wheat/maize intercropping used 24–29% more water than the weighted means of sole crops with the water use efficiency equivalent to sole crops. After the application of water limitation, 60 mm irrigation water was saved by intercropping every year, whereas the reduction of water use ranged from 25.1 to 70.8 mm; the changes in water use of intercropping relative to sole crops was reduced to 18–24%; the changes in water use efficiency stayed at nearly zero in Exps. I and III but decreased to a value of −13% in Exp. II. These results indicated that water limitation could be applied during wheat booting or filling stage in wheat/maize intercropping to save irrigation water in our study area.  相似文献   

18.
Drought stress is one of the most important abiotic factors which adversely affect growth, metabolism and yield of crops worldwide. The objective of this study was to determine the effects of drought stress on photosynthesis in barley and examine the differential responses of photosynthetic apparatus in relatively tolerant (Yousof) and susceptible (Morocco) barley genotypes. Plants were subjected to different levels of soil water availability including control, mild and severe drought stress. In both genotypes, drought stress led to decrease in chlorophylls, β‐carotene and stomatal conductance accompanied by decrease in CO2 assimilation rate. Significant increase in αtochoperol content was only observed in Yousof cultivar under drought stress. Initial slope and plateau phase of CO2 response curve of drought‐stressed plants as well as polyphasic chlorophyll a fluorescence transient curve (OJIP test) and fast fluorescence induction kinetics were influenced by drought stress. These parameters were more affected in Morocco cultivar by drought stress compare with Yousof. Drought stress also resulted in reduction of D1 protein content in both genotypes and accelerated photoinhibition process. Based on our results, stomatal conductance is the main factor limiting photosynthesis in Yousof genotype under mild drought stress. However, in Morocco, in addition to stomatal limitation, damage to photosystem II (PSII), reduced electron transport and carboxylation efficiencies were important parts of limitation in photosynthesis. Severe drought stress resulted in structural and biochemical impairment of light‐dependent reactions as well as carboxylation process of photosynthesis in both genotypes. Alpha‐tocopherol showed an important protective role against drought stress in Yousof cultivar as a relatively drought‐tolerant cultivar.  相似文献   

19.
合理的种植方式可以在不增加灌溉耗水量的前提下,利用植物个体间的正相互作用关系和群体适应特点来达到提高作物产量和水分利用效率的目的。通过田间试验,研究了河西走廊黑河中游边缘绿洲区1穴1株、1穴2株和1穴3株种植方式对青贮玉米产量及水肥利用效率的影响。结果表明,1穴2株和1穴3株的地上生物产量均高于1穴1株,1穴2株最高,鲜重为102.9 t/hm~2,比1穴1株提高了29.4%;1穴2株与1穴1株之间存在显著差异(P0.05),1穴3株与1穴1株之间差异不显著(P0.05)。同样,1穴2株和1穴3株的地上生物产量水肥利用效率也均高于1穴1株,1穴2株的水分和氮肥利用效率也均最高,分别为9.3 kg/m~3和342.9 kg/kg;1穴2株与1穴1株之间存在显著差异(P0.05),1穴3株与1穴1株之间差异不显著(P0.05)。在河西走廊边缘绿洲区,采用1穴2株的种植方式能显著提高青贮玉米的地上生物产量和水肥利用效率,可在生产中推广应用。  相似文献   

20.
Plant responses to soil drying and the metabolic basis of drought-induced limitations in stomatal opening are still being discussed. In this study, we investigate the roles of root-born chemical and hydraulic signals on stomatal regulation in wheat genotypes as affected by soil drought and vapour pressure deficit. Twelve consecutive pot experiments were carried out in a glasshouse. Two bread wheat cultivars (Gönen and Basribey) were subjected to drought under high and low vapour pressure deficit (VPD) in a growth chamber. Total dry matter, specific leaf area, xylem ABA content, xylem osmotic potential, xylem pH, root water potential (RWP), stomatal conductance, leaf ABA content and photosynthetic activity were determined daily during 6 days after the onset of treatments (DAT). In the first phase of drought stress, soil drying induced an increase in the xylem ABA with a peak 3 DAT while RWP drastically decreased during the same period. Then the osmotic potential of leaves decreased and leaf ABA content increased 4 DAT. A similar peak was observed for stomatal conductance during the early stress phase, and it became stable and significantly higher than in well-watered conditions especially in high vapour deficit conditions (H-VPD). Furthermore, xylem pH and xylem osmotic potential appeared to be mostly associated with atmospheric moisture content than soil water availability. The results are discussed regarding possible drought adaptation of wheat under different atmospheric humidity.  相似文献   

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