Shading and drought stresses during the flowering stage of maize ( Zea mays L.) production cause seed losses, making them two of the major limitations to yield output. The mechanisms by which the two stresses reduce seed numbers are still unclear. Here, different durations of shading and different degrees of drought were applied, accompanied by synchronous pollination, and the early development of fertilized apical kernels was suppressed, with decreases in sucrose and hexose levels and the promotion of ethylene emission. Consequently, the two distinct stresses led to a common consequence: up to 20–30% of the fertilized kernels were aborted at maturity, which accounted for the yield losses under both scenarios. Notably, by removing the shading net or the preventing pollination of the basal kernels, the apical kernels, were partial or fully restored from abortion, with an increased sugar status and suppressed ethylene emission, even under stress conditions. We found that dry matter accumulation within the early stage was positively correlated with sucrose and hexose contents but negatively correlated with ethylene emission. By altering the sugar status within developing kernels, we verified the antagonistic relationships between endogenous ethylene emission and soluble sugars, including sucrose and hexoses. Collectively, these findings suggest that the equilibrium between sugars and ethylene may determine the development or abortion of early developing kernels exposed to environmental stresses.

中文翻译：

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糖和乙烯之间的平衡与遮荫和干旱引起的玉米籽粒流产有关

玉米 (Zea mays L.) 生产开花阶段的遮荫和干旱胁迫会导致种子损失，使其成为产量的两个主要限制因素。两种胁迫减少种子数量的机制仍不清楚。在这里，不同遮荫时间和不同程度的干旱，伴随着同步授粉，受精的顶端籽粒的早期发育受到抑制，蔗糖和己糖水平降低，乙烯排放量增加。因此，这两种不同的压力导致了一个共同的后果：高达 20-30% 的受精谷粒在成熟时中止，这导致了两种情况下的产量损失。值得注意的是，通过去除遮光网或阻止基部籽粒、顶端籽粒的授粉，部分或完全从流产中恢复，糖状态增加并抑制乙烯排放，即使在压力条件下也是如此。我们发现早期干物质积累与蔗糖和己糖含量呈正相关，与乙烯排放呈负相关。通过改变发育中的籽粒中的糖状态，我们验证了内源性乙烯排放与可溶性糖（包括蔗糖和己糖）之间的拮抗关系。总的来说，这些发现表明糖和乙烯之间的平衡可能决定暴露于环境压力的早期发育谷粒的发育或流产。我们发现早期干物质积累与蔗糖和己糖含量呈正相关，与乙烯排放呈负相关。通过改变发育中的籽粒中的糖状态，我们验证了内源性乙烯排放与可溶性糖（包括蔗糖和己糖）之间的拮抗关系。总的来说，这些发现表明糖和乙烯之间的平衡可能决定暴露于环境压力的早期发育谷粒的发育或流产。我们发现早期干物质积累与蔗糖和己糖含量呈正相关，与乙烯排放呈负相关。通过改变发育中的籽粒中的糖状态，我们验证了内源性乙烯排放与可溶性糖（包括蔗糖和己糖）之间的拮抗关系。总的来说，这些发现表明糖和乙烯之间的平衡可能决定暴露于环境压力的早期发育谷粒的发育或流产。