Awasthi Rashmi, Kaushal Neeru, Vadez Vincent, Turner Neil C, Berger Jens, Siddique Kadambot H M, Nayyar Harsh
Department of Botany, Panjab University, Chandigarh, 160014, India.
International Crops Research Institute for Semiarid Tropics, Patancheru, 502 324 Andra Pradesh, India.
Funct Plant Biol. 2014 Oct;41(11):1148-1167. doi: 10.1071/FP13340.
High temperatures and decreased rainfall are detrimental to yield in chickpea (Cicer arietinum L.), particularly during grain filling. This study aimed to (i) assess the individual and combined effects of drought and heat stress on biochemical seed-filling processes, (ii) determine genotypic differences in heat and drought tolerance, and (iii) determine any cross-tolerance. Plants were grown outdoors in the normal growing season when temperatures during seed filling were <32-20°C or were planted late (temperatures >32-20°C; heat stress). Half of the pots were kept adequately watered throughout, but water was withheld from the others from the initiation of seed filling until the relative leaf water content reached 50% of the irrigated plants (drought stress); all plants were rewatered thereafter until seed maturit. Water was withheld for 13 days (normal sowing) and 7 days (late sowing), so soil moisture decreased by 54-57%. Tests on leaves and seeds were performed after the stress. Individual and combined stress damaged membranes, and decreased cellular oxidising ability, stomatal conductance, PSII function and leaf chlorophyll content; damage was greater under combined stress. Leaf Rubisco activity increased with heat stress, decreased with drought stress and decreased severely with combined stress. Sucrose and starch concentrations decreased in all seeds through reductions in biosynthetic enzymes; reductions were greater under combined stress. These effects were more severe in heat- and drought-sensitive genotypes compared with drought-tolerant genotypes. Drought stress had a greater effect than heat stress on yield and the biochemical seed-filling mechanisms. Drought- and heat-tolerant genotypes showed partial cross-tolerance.
高温和降雨减少对鹰嘴豆（Cicer arietinum L.）的产量不利，尤其是在灌浆期。本研究旨在：（i）评估干旱和热胁迫对种子生化灌浆过程的单独和综合影响；（ii）确定耐热性和耐旱性的基因型差异；（iii）确定是否存在交叉耐受性。在正常生长季节，当种子灌浆期温度<32 - 20°C时，植株在户外种植，或晚播（温度>32 - 20°C；热胁迫）。一半的花盆始终保持充分浇水，但另一半从种子灌浆开始到相对叶水含量达到灌溉植株的50%时停止浇水（干旱胁迫）；此后所有植株重新浇水直至种子成熟。正常播种时停水13天，晚播时停水7天，土壤湿度降低了54 - 57%。胁迫处理后对叶片和种子进行检测。单独胁迫和复合胁迫均损害了细胞膜，降低了细胞氧化能力、气孔导度、PSII功能和叶片叶绿素含量；复合胁迫下的损害更大。叶片核酮糖-1,5-二磷酸羧化酶（Rubisco）活性随热胁迫增加，随干旱胁迫降低，在复合胁迫下严重降低。由于生物合成酶减少，所有种子中的蔗糖和淀粉浓度均降低；复合胁迫下的降低幅度更大。与耐旱基因型相比，这些影响在热敏感和干旱敏感基因型中更为严重。干旱胁迫对产量和种子生化灌浆机制的影响大于热胁迫。耐旱和耐热基因型表现出部分交叉耐受性。
