连作对马铃薯根系生物学特征和叶片抗逆生理的影响

Effect of continuous cropping on morphology and physiological characteristics of potato root and leaf

针对连作导致马铃薯生长发育受阻和产量下降等问题,在甘肃省景泰县条山农场设置了不同连作年限的大田试验,从植株自身形态和生理响应方面初探马铃薯连作障碍的可能机制。结果表明:连作明显降低了马铃薯地上和地下部生物量,增加了总根长、根表面积、根尖数和根冠比,且随着连作年限的延长,生物量下降越大,而总根长、根表面积、根尖数和根冠比增加越大,连作5年的总根长、根表面积、根尖数和根冠比比轮作分别增加了39.35%、26.60%、31.67%和70.90%;连作明显增加了块茎膨大期叶片MDA活性,叶片SOD、POD和CAT的活性随连作年限表现为先上升后下降,从连作3 a开始,叶片MDA活性急剧增加,而叶片SOD、POD和CAT的活性急剧下降;连作1 a和2 a地块的块茎产量差异不显著,但连作3 a后块茎产量较轮作下降了45%以上。由此可见,在当地生态环境和栽培及品种条件下连作的阈值年限可能为2 a,根系生长增加是马铃薯应对连作逆境的主动性适应机制。

This study aims to investigate the effect of continuous cropping on growth and yield of potato,employing field experiment conducted at Tiao Shan farm,Jing Tai country in 2010. The results showed that dry weight of root and shoot significantly reduced with the increasing years of continuous cropping. However,total root length,root surface area,root numbers and root-to-shoot ratio significantly increased. Compared with rotation cropping,total root length,root surface area,root numbers and root-to-shoot ratio increased by 39. 35%,26. 60%,31. 67%,and 70. 90% after five years of continuous cropping,respectively. The activity of leave MDA significantly increased,while those of SOD,POD and CAT increased at first for the early year but decreased sharply at later years of continuous cropping. After three years of continuous cropping,the activity of leave MDA significantly increased,while the activity of SOD,POD and CAT decreased sharply. Tuber yield had no significant difference between one year or two years of continuous cropping,while it decreased more than 45% after three years of continuous cropping. The result shows that the threshold of potato continuous cropping may be at least two years,when the positive effect of promoting root growth begins to emerge.