Jagadish S V K, Murty M V R, Quick W P
International Rice Research Institute, Metro Manila, DAPO BOX, 7777, Philippines.
Animal and Plant Sciences, University of Sheffield, Sheffield, S10 2TN, UK.
Plant Cell Environ. 2015 Sep;38(9):1686-98. doi: 10.1111/pce.12430. Epub 2014 Oct 9.
Phenotypic plasticity in overcoming heat stress-induced damage across hot tropical rice-growing regions is predominantly governed by relative humidity. Expression of transpiration cooling, an effective heat-avoiding mechanism, will diminish with the transition from fully flooded paddies to water-saving technologies, such as direct-seeded and aerobic rice cultivation, thus further aggravating stress damage. This change can potentially introduce greater sensitivity to previously unaffected developmental stages such as floral meristem (panicle) initiation and spikelet differentiation, and further intensify vulnerability at the known sensitive gametogenesis and flowering stages. More than the mean temperature rise, increased variability and a more rapid increase in nighttime temperature compared with the daytime maximum present a greater challenge. This review addresses (1) the importance of vapour pressure deficit under fully flooded paddies and increased vulnerability of rice production to heat stress or intermittent occurrence of combined heat and drought stress under emerging water-saving rice technologies; (2) the major disconnect with high night temperature response between field and controlled environments in terms of spikelet sterility; (3) highlights the most important mechanisms that affect key grain quality parameters, such as chalk formation under heat stress; and finally (4), we model and estimate heat stress-induced spikelet sterility taking South Asia as a case study.
在热带炎热水稻种植区，克服热应激诱导损伤的表型可塑性主要受相对湿度的控制。蒸腾降温作为一种有效的避热机制，其表达会随着从完全淹水的稻田向节水技术（如直播稻和旱作水稻栽培）的转变而减弱，从而进一步加重胁迫损伤。这种变化可能会使水稻对以前未受影响的发育阶段（如花分生组织（穗）起始和小穗分化）产生更大的敏感性，并在已知的敏感配子发生和开花阶段进一步加剧脆弱性。与白天最高温度相比，夜间温度的变异性增加和更快上升，比平均温度上升带来的挑战更大。本综述探讨了以下内容：（1）完全淹水稻田下蒸汽压亏缺的重要性，以及在新兴的节水水稻技术下，水稻生产对热应激或热旱复合胁迫间歇性发生的脆弱性增加；（2）在小穗不育方面，田间环境与控制环境中对高夜温响应的主要脱节；（3）强调影响关键谷物品质参数的最重要机制，如热应激下垩白的形成；最后（4），我们以南亚为例，对热应激诱导的小穗不育进行建模和估计。
