To evaluate soybean performance in response to high night temperature (HNT), a soybean cultivar, Fukuyutaka, was grown in two years under different night temperatures on a mini field in a temperature gradient chamber (TGC) at Kyoto, Japan. The average night temperature ranged from 21.7°C to 23.9°C and from 20.3°C to 22.8°C in 2017 and 2018, respectively. An additional experiment was conducted using a phytotron observing the same cv. under NT as high as 28°C (extreme HNT) and the control at 22°C from a R1 to R6.5 period. In the TGC yield tended to decline by 4.6% per °C when the results from the two years were combined. The responses of yield components tended to offset and the harvest index did not respond to varying NT. And thus the decrease in yield by HNT resulted from the change in biomass. The reduction of biomass was attributable more to branch growth than to main stem and more to leaf growth thant to other organs. Leaf area and leaf weight showed responses to NT as convex curves, suggesting that HNT may inhibit leaf growth. Reduction of biomass was more evident by extreme HNT in the phytotron. P_n was not significantly affected by HNT in TGC. The estimated maintenance respiration (R_m) increased with HNT but it seemed to explain the biomass response to HNT only partially. The results suggested that the growth and yield of soybean are potentially affected by increased NT through a negative impact on biomass production caused by multiple factors.

为了评估大豆对高夜间温度（HNT）的响应性能，在日本京都的温度梯度箱（TGC）中的微型田地上，在不同的夜间温度下，于两年内种植了一个大豆品种Fukuyutaka。2017年和2018年的平均夜间温度分别为21.7°C至23.9°C和20.3°C至22.8°C。使用观察到相同简历的光电子进行了另外的实验。在NT高达28°C（极端HNT）的条件下，在R1至R6.5期间将温度控制在22°C。当合并两年的结果时，TGC中的产率倾向于每℃下降4.6％。产量构成要素的响应趋于抵消，收获指数对变化的氮素无响应。因此，HNT的产量下降是由于生物量的变化所致。生物量的减少更多地归因于分支生长而不是主要茎，而更多地归因于叶片生长而不是其他器官。叶面积和叶重显示出对NT的凸曲线响应，表明HNT可能抑制叶片生长。光电子反应器中的极端HNT可以更明显地减少生物量。P在TGC中，_n不受HNT的显着影响。估计的维持呼吸（R _m）随着HNT的增加而增加，但似乎只能部分解释生物量对HNT的响应。结果表明，由于多种因素对生物量生产的负面影响，NT的增加可能会影响大豆的生长和产量。