In a semi-arid climate, heat and drought stress can significantly reduce photosynthesis during grain filling hence, the remobilization of stored carbon reserves from stems becomes important to wheat (Triticum aestivum L.) yield. A 2-year field study was conducted to better understand the contributions of different internodes to grain yield. We measured remobilization of stored carbon reserves in eight wheat genotypes under irrigated and dryland conditions. For each genotype, plant samples consisting of ten culms were collected between anthesis and physiological maturity. There was no difference in single stem weight loss between two water levels, but the stem loss contribution to yield was higher in dryland wheat (54.4%) than that in irrigated wheat (38.5%). Among the genotypes, the stem loss contribution to yield ranged 38.9%–58.1% in the relatively wet season of 2017 and 36.5%–62.5% in the dry season of 2018. The amount of stem loss showed a strong relationship with grain yield, especially under the dryland condition. At each sampling date, length as well as the dry weight of peduncle (first internode from the top) was greater than the other internodes; however, more stem loss (in weight and percentage weight) occurred in the third internode, followed by second and fourth internodes. Results suggest that the stem loss contribution to yield is greater under dryland than irrigated condition and occurs mainly in the middle portion of the culm.

中文翻译：

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小麦秆的中部将更多的碳储备重新调动到干旱下的谷物中

在半干旱气候中，高温和干旱胁迫会显着降低灌浆过程中的光合作用，因此，重新利用茎中储存的碳储备对小麦（Triticum aestivumL.) 产量。进行了为期 2 年的实地研究，以更好地了解不同节间对粮食产量的贡献。我们测量了灌溉和旱地条件下八种小麦基因型中储存的碳储备的再动员。对于每种基因型，在开花和生理成熟之间收集由十个秆组成的植物样品。两个水位之间单茎重量损失没有差异，但旱地小麦的茎损失对产量的贡献（54.4%）高于灌溉小麦（38.5%）。各基因型中，2017 年相对丰水季节茎秆损失对产量的贡献范围为 38.9%~58.1%，2018 年旱季为 36.5%~62.5%。在旱地条件下。在每个采样日期，花序梗的长度和干重（从顶部开始的第一个节间）大于其他节间；然而，更多的茎损失（重量和百分比重量）发生在第三节间，其次是第二和第四节间。结果表明，旱地比灌溉条件下的茎损失对产量的贡献更大，并且主要发生在秆的中部。