为探明不同阶段涝渍胁迫解除后棉花叶片生理特性的恢复,采取池栽试验,分别在盛蕾期（6月24日~7月3日）和花铃期（7月24日~8月2日）对泗棉3号进行渍水处理,比较定型功能期叶片（T1）、迅速伸长期叶片（T2）和平展期叶片（T3）3类在渍水停止时和渍水停止后10 d叶绿素含量和硝酸还原酶活性的变化,以及在渍水停止后20d内净光合速率和整株叶片的氮素含量、可溶性糖含量和叶面积的变化特征。结果表明：盛蕾期渍水停止后5~10d 3类叶片的净光合速率逐渐达到或超过对照（正常灌水处理）,花铃期渍水停止后10~15 d 3类叶片的净光合速率达到对照水平;盛蕾期和花铃期渍水停止后10 d 3类叶片的硝酸还原酶（NR）活性均得到恢复;定型功能期叶片（T1）的叶绿素含量未得到恢复,而迅速伸长期叶片（T2）和平展期叶片（T3）的叶绿素含量则呈现明显的增长趋势;盛蕾期胁迫解除后整株叶片的含氮量得到恢复,而花铃期仍低于对照;盛蕾期和花铃期胁迫解除后叶片的可溶性糖均高于对照,但是盛蕾期在渍水停止后20 d已低于对照,花铃期叶片可溶性糖含量仍高于对照;棉花植株叶面积在渍水停止时明显降低,胁迫解除后有所增长,但达不到对照植株叶片水平。说明新生叶片在渍水处理后较容易恢复,而定型功能叶恢复难度较大,盛蕾期涝渍胁迫解除后各叶片的恢复能力较花铃期涝渍胁迫解除后各叶片的恢复能力强。
[Objective] This study aimed to investigate the effects of waterlogging in different growth stages on nitrogen （N） uptake, distribution, and utilization of cotton. [Method] A pool-culture experiment in field was conducted to investigate the effects of wateriogging through comparing WL1 （waterlogging at peak squaring stage） and WL2 （waterlogging at flowering and boll-forming stage） treatments with their controls respectively. [Result] The results showed that the effect of WL1 on N uptake of cotton root was stronger than WL2. At 20 days （d） after WL1 treatment, the root biomass （RB）, N uptake （NU）, and N uptake rate （NUR） significantly decreased by 38.1%, 48.6%, and 53.0% respectively. At 20 d after WL2 treatment, the RB, NU, and NUR significantly decreased by 27.3%, 46.0%, and 44.8% respectively. More N was distributed to root and leaf after WL1 treatment, and to square, flower, and boll after WL2 treatment. N physiological use efficiency increased by 11.4% and 44.4% after WL1 and WL2 treatments respectively. Further analysis showed that the effects of WL1 on yield and its components of cotton were stronger than WL2. The boll number, boll weight, and lint yield per plant significantly reduced by 40.5%, 12.4%, and 49.5% after WL1 treatment, and significantly decreased by 23.1%, 6.9%, and 29.9% after WL2 treatment, respectively. [Conclusion] The negative effects of water- logging at peak squaring stage on N nutrition and yield of cotton were stronger than waterlogging at flowering and boll-forming stage, indicating that more attention should be paid to waterlogging at peak squaring stage and sound N management can improve cotton regrowth and reduce yield loss after waterlogging.
