苜蓿轮作玉米后不同种植年限玉米生育后期叶片衰老特性

The Characteristics of Leaf Senescence of Different Cultivation Years Maize of Alfalfa-maize Rotation at Late-growth

为探讨苜蓿轮作玉米后不同种植年限玉米生育后期叶片衰老特性,以金山27为试材,紫花苜蓿地为前茬,连续4年采用同一高产栽培方案种植玉米,吐丝期开始,每10 d 1次,测定不同层位叶片叶绿素、丙二醛(MDA)含量和超氧化物歧化酶(SOD)、过氧化物酶(POD)活性。结果表明:苜蓿轮作玉米后,玉米产量随玉米种植年限的增加而降低,与种植玉米第一年相比,第二、三、四年产量分别下降了9.7%,13.6%和19.1%。苜蓿轮作玉米后,不同种植年限玉米吐丝后叶片衰老速率随玉米种植年限的增加而增加,且随生育进程差异增加。不同生育时期和层位春玉米叶片叶绿素含量随玉米种植年限增加而下降,吐丝后20 d到叶丝后40 d差异达显著水平,尤以穗位叶为甚。不同生育时期和层位叶片SOD和POD活性随玉米种植年限的递增均呈下降趋势,不同年限间SOD、POD活性随生育进程差异逐渐增加。不同生育时期和层位玉米叶片MDA含量随玉米种植年限增加而增加,且随生育进程差异增大,穗位叶最为明显。苜蓿轮作玉米后,随玉米种植年限的增加,玉米产量下降,生育后期叶片SOD、POD活性降低,MDA含量升高,叶片衰老速率增大,尤以穗位叶为甚。

To inquire the characteristics of leaf senescence of different cultivation years maize of alfalfa-maize rotation. The Jinshan 27 was grown under 4-year high-yielding cultivation maize in preceding of 7-growth-year alfalfa. After silking,content of chlorophyll,MDA content,SOD and POD activity were measured every 10 days. The yield of maize of alfalfa-maize rotation was decreased with tillage years prolonged,compared with the first year,the yield of second,third and fourth felled 9. 7%,13. 6% and 19. 1%,respectively. Leaf senescence rate of maize of different cultivation years were increased with tillage years prolonged,and the difference was decreased with tillage years prolonged. The content of chlorophyll of leaf of maize of different cultivation years was significant different at different stage and different leaf position from 20 days to 40 days after the silking,and were decreased with tillage years prolonged,and three-ear leaves was more obvious. The SOD and POD activity of leaf maize of different cultivation years were decreased with tillage years prolonged,and the difference of SOD and POD activity of leaf were increased with the growing process. The MDA content of maize of different cultivation years was increased with tillage years prolonged,and different of maize of different cultivation years were increased with the growing process,and three-ear leaves were more obvious. The yield of maize of alfalfa-maize rotation was decreased with tillage years prolonged,the SOD and POD activity of leaf were decreased,and the MDA content was increased at late-growth,andthree-ear leaves were more obvious.