不同生育期遮荫对番茄氮素分配的影响

EFFECTS OF SHADING ON NITROGEN IN TOMATO PLANTS AT DIFFERENT GROWTH STAGES

以番茄为材料 ,研究了不同生长阶段 (开花早期、盛花期和开花后期 )夏季午间不同光照强度 (不遮荫 ,4 0 %遮荫和 75 %遮荫 )对氮素在番茄各器官中分配的影响 .结果显示 ,遮荫不影响开花早期和盛花期叶片氮的含量及其分配效应 ,但 4 0 %遮荫使开花后期叶片中氮的含量增加 ,叶、茎、茬中氮的分配指数高于开花早期和盛花期 .这表明 ,在开花后期适度遮荫有利于氮优先分配给叶组织 ,改善番茄氮素状况 ,增加开花后期番茄的经济产量 ,在设施栽培中具有一定实际意义 .图 3表 1参 2

The effects of three levels of shading (0%,40% and 75% shading) on the nitrogen allocation in tomato plants were investigated at three growth stages 〔early flowering (EF), peak flowering (PF) and late flowering (LF) stages〕. The results showed that shading had no effect on the leaf N contents and N allocation index (NAI) at the EF and PF stages, while the leaf N contents and the NAI of leaf, stem and stubble tissues at the LF stage were higher than those at the EF and PF stages under 40% shading conditions. It is suggested that moderate shading at the LF stage could increase nitrogen content in tomato plants, help nitrogen enter into the leaf tissue preferentially and improve nitrogen nutrition status of tomato plant. Finally, the 40% shading treatment at the LF stage significantly enhanced the fruit yield, showing that tomato could grow well and a better yield could be obtained if some moderate shading (i.e. 40% shading) was applied at the LF stage in the summer midday time. Fig 3, Tab 1, Ref 21