不同播期对直播早稻干物质积累的影响

为明确播期对直播早稻个体和群体干物质积累的影响。以常规籼稻中早35和中早39为材料,利用大田分期播种试验,分析不同播期直播早稻干物质积累及转运的差异。结果表明,随播期推迟,全生育期积温逐渐减少,抽穗后积温逐渐增加。成苗率随分蘖前日平均温度升高而增加,成苗率与单株干物质积累量呈系数为0.83以上的极显著负相关关系,与单位面积干物质积累量呈系数为0.72以上的显著正相关关系。随播期推迟,茎叶干物质向子粒输出转化逐渐减少,单株和单位面积茎叶干物质输出转化与抽穗后积温呈负相关关系,单株抽穗后光合产物积累量随积温增加而减少,单位面积抽穗后光合产物积累量随积温增加而增加。在水稻直播生产过程中,提前播种,保证一定基本苗,协调好个体和群体干物质积累和转化,能获得较高产量。

Effects of Different Sowing Dates on Dry Matter Accumulation of Direct-Seeded Early Rice

In order to reveal the impacts of sowing date on dry matter accumulation of individual and population in direct sowed early rice, an interval sowing experiment was conducted with indica rice Zhongzao 35 and Zhongzao 39 as experiment materials, to analyzing the difference of dry matter accumulation and transport in direct seeded early rice. The results showed that the accumulated temperature gradually decreased during the whole growth period and increased after heading with the delay of sowed date. The seedling rate increased with the increase of daily mean temperature before tillering, the correlation between seedling rate and the dry matter accumulation per plant reached 0.83, the correlation between seedling rate and the dry matter accumulation per unit area reached 0.72. With the delay of sowed date, the dry matter transferred from stem and leaf to panicle decreased gradually, the dry matter transfered from stem and leaf per plant, per unit area were negatively correlated with the accumulated temperature after heading. The photosynthetic product per plant decreased and the photosynthetic product per unit area increased with the increase of accumulated temperature after heading. So early sowing could ensure certain basic seedlings to coordinate the relationship of accumulation and transformation of dry matter of individuals and groups to obtain high yields.