摘要： 以易衰型品种33B和延衰型品种丰抗6为材料，研究了不同氮素水平对棉花光合和衰老特性的影响。研究表明，各测定时期，丰抗6的Pn在不同氮素水平下均较33B明显增加。随着处理时间延长，不同氮素处理下33B和丰抗6的叶绿素a含量、叶绿素b含量、类胡萝卜素含量和可溶蛋白含量均不断下降，其中，在低氮下，处理中后期丰抗6的上述参数高于33B。可溶性糖含量的表现规律与上述参数相反。低氮处理下，与33B相比，丰抗6处理中后期具有较高的SOD活性。不同氮素处理中，各测定时期丰抗6的丙二醛(MDA)含量均低于33B，而单株干质量和单株叶面积则均高于33B。较低的细胞膜质过氧化程度可能是延衰型品种丰抗6不同氮素水平下衰老缓慢的重要生理基础。生产中，适期适量增施氮肥，通过减轻细胞的膜质过氧化程度、降低植株体内的碳/氮比值，在延缓棉花衰老、改善叶片光合特性和增加产品的生产能力中具有较重要的作用。

关键词: 棉花, 氮素水平, 衰老, 光合特性, 细胞保护酶活性

Abstract: Using the cultivar 33B with senescing property and Fengkang6 with non-senescing property to be the experimental materials,the effects of nitrogen application levels on photosynthetic characteristics and activities of cellular protection enzymes were studied.The results indicated that the photosynthetic rates(Pn)in Fengkang6 were all higher than in 33B at two measurement points under two nitrogen levels.With the delaying of treatments,the contents of chlorophyll a,chlorophyll b,carotenoid and soluble protein of 33B and Fengkang6 were all decreased in CK and low-N treatment.But under low-N condition,there were relative high values of above parameters in Fengkang6 compared to those in 33B during late-phase of treatment.The soluble sugar contents in tested cultivars showed an adverse tendency with the soluble protein contents.Under low-N condition,Fengkang6 had higher SOD activities than 33B during late-phase of treatment.Under CK and low-N condition,the MDA contents in Fengkang6 at all assays were lower,and the dry weight per plant and leaf area per plant were higher than those in 33b.Thus,the relative low over-oxidation degree of the cytoplasm membrane was the important physiological basis for Fengkang6 to be senescence delay under different nitrogen application levels.In cotton production,application of nitrogen with suitable amount and at suitable time will be have an important role in delaying senescence,improving photosynthesis and increasing yield by alleviating the cytoplasm over-oxidation and decreasing the ratio of carbon assimilates to nitrogen compounds.

Key words: Cotton, Nitrogen level, Senescence, Photosynthetic characteristics, Activities of cellular protection enzymes

中图分类号: 

• S562.01