不同播期冬小麦氮素出籽效率与氮素利用及转运的相关性

为探讨不同播期冬小麦氮素出籽效率与氮素利用及转运的关系,在2014—2016年2个生长季,比较了不同播期(S₁:9月24日;S₂:10月1日;S₃:10月8日;S₄:10月15日;S₅:10月22日)冬小麦氮素出籽效率、氮素利用和转运的差异及相互间的关系.结果表明: 籽粒产量和单位面积粒数在不同播期处理间未发生显著差异.推迟播期降低了地上部氮素积累量和穗部氮素积累量,从而降低了氮素吸收效率,但明显提高了氮素利用效率和氮素出籽效率.氮素出籽效率与氮素利用效率呈正相关,而与氮素吸收效率呈负相关,与氮素利用率无显著相关关系.氮素营养指数随播期推迟趋于最佳状态,与氮素出籽效率的改善展现出同步性.推迟播期显著降低了花前营养器官氮素转移量和花后氮素积累量,但明显改善了花前营养器官氮素转运效率.氮素出籽效率与氮素转运效率之间存在正相关关系,说明氮素转运效率的改善一定程度上有利于穗部氮素生产籽粒能力的提升.综合来看,适当推迟播期减少了氮素吸收,但提高了氮素利用效率和氮素出籽效率,改善了氮素供应状态.研究结果为本地区冬小麦生产中氮素减施增效的实施提供了理论依据.

Correlation between nitrogen fruiting efficiency and nitrogen utilization and remobilization in winter wheat at different sowing dates

To understand the correlation between nitrogen fruiting efficiency and nitrogen utilization and remobilization in winter wheat, the differences and mutual relationships of nitrogen fruiting efficiency, nitrogen utilization and remobilization of winter wheat at different sowing dates (S₁:24 September, S₂:1 October, S₃:8 October, S₄:15 October and S₅:22 October) were analyzed in two growing seasons from 2014 to 2016. The results showed that there was no significant difference in grain yield and grain number per unit area among different sowing dates. Delayed sowing date decreased nitrogen accumulation in both shoots and spikes, and then reduced nitrogen uptake efficiency and increased nitrogen utilization efficiency and nitrogen fruiting efficiency. Nitrogen fruiting efficiency was positively correlated with nitrogen utilization efficiency, negatively correlated with nitrogen uptake efficiency, but not significantly correlated with nitrogen use efficiency. Nitrogen nutrition index tended to be optimum with delayed sowing dates, showed synchronicity with the improvement of nitrogen fruiting efficiency. Pre-anthesis nitrogen remobilization amount in vegetative organs and post-anthesis nitrogen accumulation amount significantly decreased with postpone of sowing dates, but pre-anthesis nitrogen remobilization efficiency remarkably rise. There was a positive correlation between nitrogen fruiting efficiency and nitrogen remobilization efficiency, indicating that the improvement in nitrogen remobilization efficiency facilitated the increment in nitrogen frui-ting efficiency. Taken together, properly delayed sowing date reduced nitrogen uptake, but increased nitrogen utilization efficiency and nitrogen fruiting efficiency and improved nitrogen supply status, which provided a theoretical basis for the implementation of reducing input and improving nitrogen utilization efficiency in wheat production in this region.