中文摘要：

以小麦顺序衰老（正置茎）和非顺序衰老（倒置茎）茎为材料，比较研究了自然天气和干旱条件下小麦正置茎和倒置茎叶片绿叶面积、光合速率、蔗糖磷酸转运酶活性以及地上器官同化物积累和转运特性，旨为进一步研究小麦叶片非顺序衰老的生理生化机制提供思路和理论指导。试验表明：无论是自然天气条件还是干旱条件，温麦19、豫麦19和兰考矮早8倒置茎倒二叶的绿叶面积、光合速率和叶片干重均明显高于旗叶，表现出旗叶早于倒二叶衰老的特征；倒置茎花后同化物转运量、转运率和对籽粒的贡献率、穗重以及叶片蔗糖磷酸合成酶活性均明显高于正置茎。表明小麦叶片的非顺序衰老与花后同化物的快速转运有关，这种衰老方式对小麦籽粒的后期充实是有利的，并且对干旱条件有较强的适应能力。

英文摘要：

Under natural weather and drought conditions ,green leaf area ,photosynthetic rate and sucrose-phosphate synthase activity of top three leaves ,assimilate accumulation and transport characteristics in wheat leaf sequential and non-sequential senescence were measured in order to provide insights into the physiological and biochemical mechanisms of wheat leaf non-sequential senescence .The results show that ,for natural weather and drought condition ,the top 2nd leaf green area ,photosynthetic rate and dry matter of inverted stems of Wenmai19 ,Yumai19 and Lankaoaizao8 are higher than those of flag leaf ,indicating earlier senesce of flag leaf than that of top 2nd leaf .Assimilation transportation ,trans-porting rate and contribution rate to grain after anthesis ,and leaf sucrose-phosphate synthase activity of inverted stems in two treatments were greater than that of conventional stems ,suggesting that wheat leaf non-sequential senescence is asso-ciated with the rapid transport of assimilation .Leaf non-sequential senescence is beneficial to grain filling ,rendering strong adaptation to drought stress .