Plastic-film mulch significantly improves maize (Zea mays L.) productivity in hydrothermally limited areas, but there is a lack of understanding of how mulch affects the partitioning of dry matter and nutrients to grain. This study was conducted to investigate the effects of plastic-film mulch on the remobilization of biomass and nutrients accumulated in the presilking stage to grain during the grain-filling period. A 2-yr field experiment was conducted with five maize hybrids in a cold semiarid environment. The vegetative biomass in all cultivars at maturity was generally greater than that at silking regardless of whether the soil was mulched or not, indicating that there was no translocation of presilking assimilates to the grain. The increased grain yield in plastic-film mulched plots compared with those that were nonmulched was ascribed to their enhanced partitioning of postsilking assimilates to grain. Conversely, increased accumulation of nitrogen and phosphorus in grain at maturity under mulch relative to no mulch mainly was due to increased remobilization from presilking vegetative organs. The benefit of plastic-film mulch in increasing the partitioning of postsilking assimilates and the remobilization of nutrients from presilking vegetative organs was greater in a drier than in a wetter year. The results of this study strongly support the conclusion that in hydrothermally limited environments, maize generally does not remobilize presilking assimilates but does remobilize presilking nitrogen and phosphorus in vegetative organs to the grain during grain filling. Further, plastic-film mulched, relative to nonmulched, maize increases the translocation to the grain of postsilking assimilates and presilking nitrogen and phosphorus accumulated in vegetative organs.

中文翻译：

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地膜覆盖影响玉米生物量和养分在谷物中的分配

地膜覆盖显着改善玉米（Zea maysL.) 热液受限地区的生产力，但对覆盖物如何影响干物质和养分在谷物中的分配缺乏了解。本研究旨在探讨地膜覆盖对灌浆期预丝期积累的生物质和养分再迁移至粮食的影响。在寒冷的半干旱环境中对五个玉米杂交种进行了为期 2 年的田间试验。无论土壤是否覆盖，所有品种在成熟时的营养生物量普遍大于吐丝时的营养生物量，这表明没有预丝绸同化物向籽粒转移。与未覆盖的地块相比，覆盖塑料薄膜的地块增加的谷物产量归因于它们增强的丝后同化物与谷物的分配。相反，相对于没有覆盖，覆盖下成熟时谷粒中氮和磷的积累增加主要是由于来自预丝化营养器官的再活化增加。塑料薄膜覆盖物在增加丝后同化物的分配和从丝前营养器官中重新释放养分方面的益处在干燥年份比潮湿年份更大。这项研究的结果有力地支持了这样的结论，即在热液受限的环境中，玉米通常不会重新激活预丝化同化物，但会在灌浆过程中将营养器官中的预丝化氮和磷重新转移到谷物中。