ABSTRACT

To evaluate soybean performance in response to high night temperature (HNT), a soybean cultivar, Fukuyutaka, was grown in 2 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 2 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.

摘要

为了评估大豆在高夜间温度 (HNT) 下的表现，在日本京都的温度梯度室 (TGC) 中的小型田间，在不同夜间温度下种植了大豆品种 Fukuyutaka 2 年。2017年和2018年的夜间平均温度分别为21.7°C至23.9°C和20.3°C至22.8°C。使用 phytotron 进行了额外的实验，观察相同的 cv。在高达 28°C（极端 HNT）的 NT 和从 R1 到 R6.5 的 22°C 控制下。当将 2 年的结果结合起来时，TGC 产率倾向于每°C 下降 4.6%。产量成分的反应趋于抵消，收获指数对变化的 NT 没有反应。因此，HNT 产量的下降是由于生物量的变化造成的。生物量的减少更多地归因于分支生长而不是主茎，更多地归因于叶生长而不是其他器官。叶面积和叶重对 NT 的响应表现为凸曲线，表明 HNT 可能抑制叶生长。植物加速器中的极端 HNT 对生物量的减少更为明显。磷_n在 TGC 中不受 HNT 的显着影响。估计的维持呼吸 (R _m ) 随 HNT 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，通过多种因素对生物量生产的负面影响，NT 增加可能会影响大豆的生长和产量。