施氮对冬水田杂交中稻本田生长期叶片叶绿素含量的影响

Effects of Nitrogen Application on Leaf Chlorophyll Content in Post-transplanting Growing Stages of Medium Hybrid Rice in Winter Water Logged Fields

以18个杂交中稻组合为材料,通过施氮与不施氮(CK)处理,研究了四川冬水田区杂交水稻本田生长期间叶片叶绿素含量(SPAD值)受氮肥影响的敏感时期及主要生育时期的敏感叶位。结果表明,本田叶片叶绿素含量(SPAD值)受氮肥影响的敏感时期有分蘖期、最高苗期、拔节—抽穗期和籽粒灌浆结实中后期,施氮处理与CK叶片SPAD值的差值表现为分蘖初期和籽粒灌浆结实中后期较大,其余时期较小,其中移栽后第9～11天秧苗叶绿素含量受氮肥的影响最大,可作为测苗确定蘖肥施氮量的最佳时期;各叶位叶片的叶绿素含量受氮肥影响的程度以下部叶片较大,顶4叶是反应植株氮素状况最好的指示叶。

Using 18 medium hybrid rice varieties as the materials, the sensitive stages and leaf positions of leaf chlorophyll content to nitrogen application were studied in growing stages after transplanting of medium hybrid rice in winter water logged fields in Sichuan. In the experimental design, the nitrogen fertilizer containing 150 kg/hm^2 of pure nitrogen was applied before transplanting for the treatment of nitrogen application （ AN）, while no nitrogen fertilizer was applied for the control （NN）. The results showed that the leaf chlorophyll contents （SPAD） of AN were significantly higher than those of NN in the periods from the 7^th to 28S days after transplanting（DAT） （ tille- ring stage）, from the 63^rd to 77^th DAT （jointing to heading stages） and from 98^th to 112^th DAT（mid to late grain filling stage）, indicating these stages were sensitive to nitrogen application. In these periods, the difference of leaf chlorophyll content between AN and NN had a highest value from 9^th to I 1 ^th DAT, indicating that it is the optimum time to determine the amount of nitrogen to be applied by measuring seedlings. Moreover, the lower leaves had a bigger difference between AN and NN in chlorophyll content than the higher leaves. The 4^th leaf from the top had the highest difference value between AN and NN, so it can be the best marker leaf for the nitrogen nutrition of rice plants.