施氮量对花铃期短期渍水棉花叶片抗氧化酶活性和内源激素含量的影响

Effects of nitrogen application rate on cotton leaf antioxidant enzyme activities and endogenous hormone contents under short-term waterlogging at flowering and boll-forming stage

于2005—2006年在江苏南京(32°02′N,118°50′E)南京农业大学卫岗试验站进行盆栽试验,设置正常灌水和棉花花铃期短期渍水处理(渍水8d,恢复15d),每个水分处理设置3个施氮水平(0、240、480kgN.hm-2),研究施氮量对渍水棉花叶片抗氧化酶活性和内源激素含量的影响.结果表明:在渍水结束时,与正常灌水相比,渍水棉花叶片可溶性蛋白含量、超氧化物歧化酶和过氧化氢酶活性降低,过氧化物酶活性升高,丙二醛(MDA)含量升高;与此同时,内源激素含量发生变化,脱落酸(ABA)含量升高,玉米素核苷(ZR)、赤霉素(GA)、生长素(IAA)含量及ZR/ABA、GA/ABA、IAA/ABA降低;其中以240kgN.hm-2渍水棉花MDA和ABA含量最低,而ZR、GA和IAA含量及ZR/ABA、GA/ABA和IAA/ABA最高,净光合速率最高.到停止渍水15d时,渍水棉花叶片的抗氧化酶活性、MDA含量、内源激素含量与正常灌水处理的差异较小;施氮可提高渍水处理棉花叶片抗氧化酶活性,降低MDA含量,使ABA水平降低,ZR、GA、IAA水平及ZR/ABA、GA/ABA、IAA/ABA升高.本试验中,渍水条件下以240kgN.hm-2处理的效果最好,生物量和籽棉产量最高.

A pot experiment was conducted to study the effects of applying 0,240,and 480 kg N·hm-2 on the cotton leaf antioxidant enzyme activities and endogenous hormone contents under eight days waterlogging at flowering and boll-forming stage.Under this short-term waterlogging,the leaf soluble protein content and SOD and CAT activities decreased while the MDA content and POD activity increased,and in the meantime,the leaf ABA content increased while the ZR,GA,and IAA contents as well as the ZR/ABA,IAA/ABA,and GA/ABA ratios decreased,compared with those under normal watering.Treatment 240 kg N·hm-2 had the lowest contents of leaf MDA and ABA,but the highest contents of leaf ZR,GA,and IAA,highest ratios of ZR/ABA,GA/ABA,and IAA/ABA,and highest net photosynthetic rate.At the 15th day after terminating waterlogging,no significant differences in the leaf antioxidant enzyme activities,MDA content,and endogenous hormone contents were observed between the short-term waterlogged and well-watered cotton.N application promoted the cotton leaf antioxidant enzyme activities,decreased the MDA and ABA contents,and increased the ZR,GA,and IAA contents as well as the ZR/ABA,IAA/ABA,and GA/ABA ratios,with the highest cotton biomass and yield in treatment 240 kg N·hm^-2.