Under currently projected global warming, heat waves are expected to become more frequent, and crops will be exposed to more extreme heat events during both day and night periods. It is well known that high daytime temperatures during flowering induce spikelet sterility in rice plants and directly reduce yields. However, the effects of short-term heat stress at night have not been well documented. Here, we investigated the effects of 1- to 3-night high nighttime temperatures at anthesis on rice spikelet fertility. We found that a single night high temperature of ∼32 °C just before anthesis induced spikelet sterility even in the absence of high daytime temperature. Fertile grain number was significantly decreased by a 3-night exposure to high temperatures of ≥30 °C, much lower than the reported threshold of 35 °C for heat-induced sterility during the daytime. Moreover, high nighttime temperature substantially exacerbated the sterility induced by high daytime temperature. These results indicate that short periods of high nighttime temperatures, which may be experienced during heat waves, will increase the risk of heat damage to rice yield and increase the uncertainty in predictions of future rice production. Sensitivity to high nighttime temperature differed among cultivars but was positively correlated with their sensitivity to high daytime temperatures. This suggests that concurrent improvement of tolerance to daytime and nighttime high temperatures may be possible through breeding.

根据目前预测的全球变暖，预计热浪会变得更加频繁，农作物在白天和夜间都会受到更多极端高温事件的影响。众所周知，开花期间白天的高温会导致水稻小穗不育并直接降低产量。然而，夜间短期热应激的影响尚未得到充分记录。在这里，我们研究了开花期 1 到 3 晚夜间高温对水稻小穗生育力的影响。我们发现，即使在白天没有高温的情况下，开花前一晚约 32 °C 的高温也会导致小穗不育。在≥30°C的高温下暴露3晚，可育粒数显着减少，远低于报告的白天热诱导不育的 35°C 阈值。此外，夜间高温度大大加剧了白天高温度引起的不育。这些结果表明，热浪期间可能出现的夜间短时高温将增加水稻产量受热损害的风险，并增加对未来水稻产量预测的不确定性。不同品种对夜间高温度的敏感性不同，但与它们对白天高温度的敏感性呈正相关。这表明通过繁殖可能同时提高对白天和夜间高温的耐受性。这些结果表明，热浪期间可能出现的夜间短时高温将增加水稻产量受热损害的风险，并增加对未来水稻产量预测的不确定性。不同品种对夜间高温度的敏感性不同，但与它们对白天高温度的敏感性呈正相关。这表明通过繁殖可能同时提高对白天和夜间高温的耐受性。这些结果表明，热浪期间可能出现的夜间短时高温将增加水稻产量受热损害的风险，并增加对未来水稻产量预测的不确定性。不同品种对夜间高温度的敏感性不同，但与它们对白天高温度的敏感性呈正相关。这表明通过繁殖可能同时提高对白天和夜间高温的耐受性。不同品种对夜间高温度的敏感性不同，但与它们对白天高温度的敏感性呈正相关。这表明通过繁殖可能同时提高对白天和夜间高温的耐受性。不同品种对夜间高温度的敏感性不同，但与它们对白天高温度的敏感性呈正相关。这表明通过繁殖可能同时提高对白天和夜间高温的耐受性。