Wet direct‐seeded rice (WDSR) is considered as a practicable substitute to transplanted‐flooded rice (TFR) because it copes with labor and water shortages, and reduces greenhouse gas emissions. However, the differences between WDSR and TFR in leaf senescence after flowering and the associated mechanisms have rarely been identified. In this study, the growth dynamics, SPAD value of flag leaf, dry matter accumulation and translocation, and the contents of plant hormones (ABA, CTKs, and GA₃) in WDSR and TFR rice flag leaves after flowering were compared during the rice‐growing seasons of 2013, 2014, and 2018. The results showed that leaf senescence after flowering in WDSR was faster in comparison with TFR. The amount of dry matter acquired after flowering (ΔW) in WDSR was significantly lower and might be related to the faster leaf senescence after flowering in WDSR compared with TFR. The CTK content in flag leaves after flowering was lower in WDSR than in TFR, and CTK content declined earlier than SPAD value, which implied that decrease in CTK content could be a possible reason for the early leaf senescence in WDSR. In conclusion, faster leaf senescence after flowering in WDSR was mainly attributed to the decline in leaf CTK content.

中文翻译：

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与移栽水稻相比，湿润直播水稻开花后叶片衰老更快主要受到细胞分裂素含量下降的调节。

湿式直接播种稻米（WDSR）被认为是可替代人工移植的稻米（TFR）的可行替代品，因为它可以解决劳动力和水资源短缺问题，并减少温室气体排放。然而，很少发现开花后叶片衰老中WDSR和TFR之间的差异及其相关机理。本研究研究了剑叶的生长动力学，SPAD值，干物质的积累和转运以及植物激素（ABA，CTK和GA _3）的含量。）比较了2013年，2014年和2018年水稻生长季节在WDSR和TFR水稻中的旗叶。结果表明，与TFR相比，WDSR开花后的叶片衰老更快。与TFR相比，WDSR开花后获得的干物质量（ΔW）明显较低，并且可能与WDSR开花后叶片衰老更快有关。WDSR花后旗叶中的CTK含量低于TFR，且CTK含量下降早于SPAD值，这表明CTK含量降低可能是WDSR叶片早衰的可能原因。总之，WDSR开花后叶片衰老更快的主要原因是叶片CTK含量下降。