Combined drought and heat stress impact during flowering and grain filling in contrasting rice cultivars grown under field conditions
Combined drought and heat stress impact during flowering and grain filling in contrasting rice cultivars grown under field conditions
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DOI：
10.1016/j.fcr.2018.09.009
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发表时间：
2018-12-01
影响因子：
5.8
通讯作者：
Krishna Jagadishi, S. V.
中科院分区：
文献类型：
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作者：
Lawas, Lovely Mae F.;Shi, Wanju;Krishna Jagadishi, S. V.
旱热联合胁迫是田间条件下最常见的非生物胁迫，对水稻产量产生负面影响。对水稻品种在田间条件下对这种复合胁迫的反应还没有进行系统的评估。为了填补这一主要知识空白，三个水稻品种(N22、Dular、Anjali)在开花和灌浆早期利用避雨和自然夏季条件于2013、2014和2015年暴露于干旱和高温联合胁迫下。通过采用交错播种，在两个时期和品种之间同时施加胁迫，这有助于在不受其他气候条件干扰的情况下捕捉土壤和冠层气温和土壤水势。在整个实验中，干旱下的土壤水势在开花和灌浆期间分别高达-61和-57千帕，导致冠层-空气温度分别高出1.75摄氏度和1.17摄氏度。在不同年份和品种中，在开花和灌浆期间，在复合胁迫下，穗电导率降低50.0%和74.5%，导致穗组织温度分别升高3.94摄氏度和3.27摄氏度。开花期和灌浆期的复合胁迫减产幅度相似(约20-80%)，但品种间存在明显差异。在开花期间，Dular的减产幅度最大(73.2%)，而在灌浆期间，N22的减产幅度类似(77.6%)。在两个发育阶段施加胁迫时，与籽粒品质相关的参数也记录到了相似的品种差异反应。我们的发现证明了利用现有的避雨设施系统地描述水稻和其他作物在大田条件下对干旱和高温的联合影响的潜力，并寻找新的耐多胁迫供体来支持非生物胁迫育种计划。
Combined drought and heat stress is the most common abiotic stress occurring under field conditions that negatively affects rice productivity. Systematic evaluation of the response of rice cultivars to this combined stress under field conditions has not been attempted. To fill this major knowledge gap, three rice cultivars (N22, Dular, Anjali) were exposed to combined drought and heat stress during flowering and early grain-filling stages, using rainout shelters and natural summer conditions in 2013, 2014 and 2015. By employing staggered sowing, stress was imposed at the same time across both stages and between cultivars, which helped capture temporal soil and canopy-air temperature and soil water potential without being confounded by other climatic conditions. Across experiments, soil water potential under drought reached up to -61 and -57 kPa during flowering and grain filling, resulting in up to 1.75 degrees C and 1.17 degrees C higher canopy-air temperature, respectively. Across years and cultivars, 50.0% and 74.5% lower panicle conductance under combined stress during flowering and grain filling led to an increase in panicle tissue temperature by up to 3.94 degrees C and 3.27 degrees C, respectively. The range in combined stressinduced yield reduction between flowering and grain filling was similar (approximately 20-80%), while there were clear differences among cultivars. Dular had the highest reduction in yield (73.2%) with stress exposure during flowering, while N22 recorded a similar reduction (77.6%) during grain filling. A similar differential cultivar response in parameters related to grain quality was recorded with stress imposed at both developmental stages. Our findings demonstrate the potential of using existing rainout shelters to systematically characterize rice and other crops for combined drought and heat stress impact under field conditions, and to identify novel multistress-tolerant donors to support abiotic stress breeding programs.