With the expected increase of abiotic stress under global climate change, significant research has been devoted to how abiotic stress will affect crop production. To date, there has been little research on the stage sensitivity of short‐term heat stress to crop lodging and yield determination in canola. This research was conducted in a controlled growth facility and aimed to examine root morphology, pod fertility, seed yield and crop lodging of two contrasting canola genotypes subjected to a short‐term heat stress (27.0/24.3°C, light/dark), imposed respectively at three growth stages, rosette vegetative stage (RVHT), early flowering stage (EFHT) and late flowering stage (LFHT), in comparison with non‐stressed control (CK) (23/17°C). The results demonstrate that heat stress imposed at RVHT and LFHT was less detrimental to seed yield and lodging resistance. However, EFHT showed significant adverse effects on both, which was further confirmed by redundancy analysis (RDA) and structural equation modelling (SEM). Compared with the CK, EFHT resulted in a yield loss of 43%, which was mainly due to poor pod fertility, less number of filled pods (−28%), decreased pollen viability (−38%) and a lower success ratio of filled pods (−29%). The taproot was found to be relatively tolerant to heat stress, but lateral roots were sensitive to heat stress at EFHT and LFHT. Root capacitance could be used as a non‐destructive method for evaluating lateral root morphology. Compared with the CK, EFHT displayed a high risk of stem lodging, as indicated by a 27% lower safety factor. This was mainly attributed to the reduced stem bending strength that was caused by the deterioration of stem mechanical properties under EFHT, as illustrated by SEM. Root lodging resistance was not altered by any stages of short‐term heat stress, as the taproot remained stable.

中文翻译：

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油菜（Brassica napus L.）短期热胁迫对抗倒伏性状的阶段敏感性和产量测定

随着全球气候变化下非生物胁迫的预期增加，非生物胁迫将如何影响作物生产已进行了大量研究。迄今为止，关于油菜中短期热胁迫对作物倒伏和产量确定的阶段敏感性的研究很少。这项研究是在受控生长设施中进行的，旨在检查施加短期热胁迫（27.0 / 24.3°C，明/暗）的两种不同油菜基因型的根系形态，豆荚育性，种子产量和农作物倒伏与无压力对照（CK）（23/17°C）相比，莲座营养期（RVHT），开花早期（EFHT）和开花后期（LFHT）分别处于三个生长阶段。结果表明，施加于RVHT和LFHT的热胁迫对种子产量和抗倒伏性的危害较小。但是，EFHT对两者均显示出明显的不利影响，这一点已通过冗余分析（RDA）和结构方程模型进一步证实（SEM）。与CK相比，EFHT导致产量损失43％，这主要是由于荚果育性差，填充荚果数量较少（-28％），花粉活力降低（-38％）和填充成功率较低豆荚（-29％）。发现主根对热胁迫具有相对的耐受性，但是在EFHT和LFHT下侧根对热胁迫敏感。根电容可以用作评估侧根形态的一种非破坏性方法。与CK相比，EFHT显示出高的茎倒伏风险，安全系数降低了27％。如SEM所示，这主要归因于EFHT下杆的机械性能下降，导致杆的弯曲强度降低。。由于主根保持稳定，因此短期热胁迫的任何阶段都不会改变耐根性。