Southern Regional Collaborative Innovation Center for Grain and Oil Crops (CICGO), Hunan Agricultural University, Changsha, 410128, China.
Hunan Rice Research Institute, Hunan Academy of Agricultural Sciences, Changsha, 410125, China.
Sci Rep. 2020 Sep 16;10(1):15197. doi: 10.1038/s41598-020-71983-y.
Topdressing at panicle differentiation (PF) according to soil fertility and regularity of rice nutrient absorption is an important agronomic practice used in cultivation of rice cultivars with a long growth duration. We studied the impacts of timing of nitrogen fertilizer application during PF on photosynthesis and yield-related agronomic traits in 'Y-Liang-You 900' and 'Y-Liang-You 6', which are representative rice cultivars with a long growth duration. Data for two years showed that timing of topdressing application during PF affected panicles per unit area, percentage grain set, spikelets per panicle, and leaf photosynthetic traits during the grain-filling period. Topdressing at the initial stage of flag-leaf extension resulted in higher grain yield (typically by 10.55-19.95%) than in plants without topdressing. Grain yield was significantly correlated with flag leaf photosynthetic rate and leaf SPAD value (r = 0.5640 and r = 0.5589, respectively; p < 0.01) at an advanced grain-filling stage (30 days after heading). Surprisingly, grain yield was not correlated with carbohydrate remobilization from the stem and sheath. For rice cultivars with a long growth duration, nitrogen-fertilizer topdressing must be applied at the initial stage of flag-leaf extension to delay leaf senescence during the grain-filling stage and realize the enhanced yield potential.
在颖花分化期（PF）根据土壤肥力和水稻养分吸收规律进行追肥是一种重要的农业实践，适用于生育期较长的水稻品种的栽培。我们研究了在 PF 期氮肥施用时间对生育期较长的代表性水稻品种 'Y-Liang-You 900' 和 'Y-Liang-You 6' 的光合作用和与产量相关的农艺性状的影响。两年的数据表明，PF 期追肥时间影响单位面积穗数、结实率、穗粒数和灌浆期叶片光合特性。在旗叶伸长期初期追肥比不追肥的产量更高（通常高 10.55-19.95%）。产量与灌浆后期（抽穗后 30 天）的旗叶光合速率和叶片 SPAD 值呈显著正相关（r=0.5640 和 r=0.5589，均 p<0.01）。令人惊讶的是，产量与茎鞘中碳水化合物的再运转无关。对于生育期较长的水稻品种，必须在旗叶伸长期初期进行氮肥追肥，以延缓灌浆期叶片衰老，实现增产潜力。
