籽粒蛋白质含量不同的转基因水稻株系产量形成特点

水稻籽粒蛋白质含量与产量的关系仍不十分清楚。本试验以日本晴和以其为亲本通过转基因方式获得的5个籽粒蛋白质含量有明显差异的水稻株系为材料，在大田栽培条件下研究上述株系产量的形成特点。结果表明，在相同施氮量条件下，蛋白质含量高的水稻株系，其产量水平相对较低，结实率与籽粒蛋白质含量呈显著负相关。随着施氮水平的提高，各株系籽粒蛋白质含量和产量明显增加，产量增加的主要原因是单位面积穗数和每穗粒数的增加。抽穗前积累的干物质少，抽穗后叶片功能期相对较短，光合速率低，灌浆结实期茎秆中的干物质和非结构性碳水化合物向籽粒转运率低，引起结实率下降，是导致籽粒蛋白质含量高的水稻株系产量降低的重要生理原因。

Yield Formation Characteristics of Transgenic Rice Strains with Different Protein Contents in Grains

Relationship between protein content (PC) in grains and grain yield in rice has not been clearly understood. Nipponbare and its five transgenic strains with different PCs in grains were used in the study to investigate their yield formation characteristics under the condition of field cultivation. There were two main results: (1) Under the same nitrogen amount, grain yields were lower in strains with higher PC in grains. Filled grain rate was very significantly and negatively correlated with PC in grains. With an increase in N fertilizer, PC in grains and grain yield significantly increased and the increase in yield was mainly dependent on the increase in panicle number and grains per panicle. (2) Under the same nitrogen amount, the strains with higher PC had less dry matter accumulation before heading stage, shorter functional period and lower photosynthetic rate of flag leaves after heading stage and lower apparent translocation amounts of dry matter and non-structure carbohydrates (NSC) from stems to grains during grain filling stage, leading to lower filled grain rate, which is the possible physiological reason for lower yield in those strains.