外源水杨酸对连作马铃薯生长发育及抗性生理的影响

摘要

The experiment was conducted to investigate the influences of exogenous salicylic acid (SA ) on seedling growth ,resistance to continuous cropping obstacles ,oxidation resistance and tuber nutrition of both continuous and dis-continuous cropping potato . The results indicated that 5 years of continuous cropping induced significant decrease in chlorophyll content ,net photosynthetic rate ,cell membrane stability index ,osmoregulation substance content ,antioxi-dant content ,antioxidant enzyme activities ,tuber yield ,tuber hardness ,and the contents of starch ,Vc and soluble pro-tein in tubers ,significant increase in the contents of MDA and reactive oxygen species in leaves ,and significant inhibi-tion in plant growth of potato . However , after being treated by exogenous SA , the relative water content of potato seedlings were increased ,the chlorophyll content ,net photosynthetic rate ,root activity and cell membrane stability index were enhanced ,the growth of plants was promoted ,the osmoregulation substance content ,antioxidant content and antiox-idative enzyme activities in leaves were improved ,the tuber yield ,tuber hardness and the contents of starch ,Vc and sol-uble protein were raised ,while the contents of MDA and reactive oxygen species were decreased significantly .As for the treatments of exogenous SA ,the concentrations of 20μmol·L-1 and 30μmol·L-1 were better than other concentrations in promoting the growth of potato seedlings and resistance to continuous cropping obstacles .For potato with 5 years continu-ous cropping ,the treatment of 30 μmol·L-1 exogenous SA increased the tuber yield by 64 .4% and net photosynthetic rate in leaves by 287 .0% compared with the control .It is concluded that proper concentration of exogenous SA can relief the damage caused by continuous cropping obstacles ,promote the growth and development of potato plants ,raise the tu-ber yield ,and improve the nutrition and quality of tubers .%探讨了不同浓度外源水杨酸处理对连作马铃薯幼苗生长发育、耐连作障碍、抗氧化能力以及块茎营养的影响。结果表明：5年连作导致马铃薯幼苗叶片中叶绿素含量、净光合速率、细胞膜稳定指数、渗透调节物质含量、抗氧化剂含量、抗氧化酶活性显著下降，块茎产量和硬度降低，块茎淀粉、Vc、可溶性蛋白含量下降，叶片MDA含量、活性氧水平显著增加，植株生长发育受到显著抑制；在施用外源水杨酸处理后，马铃薯幼苗的相对含水量增高，叶绿素含量、净光合速率、根系活力和细胞膜稳定指数增强，生长得到促进，植物叶片内渗透调节物质含量、抗氧化剂含量、抗氧化酶活性提高，块茎产量、硬度以及块茎淀粉、Vc、可溶性蛋白含量增高，叶片MDA含量、活性氧水平显著降低；比较不同浓度的外源水杨酸处理，以20μmol·L-1和30μmol·L-1对促进马铃薯连作幼苗生长发育及缓解连作伤害效果最佳，其中对于连作5年的马铃薯，30μmol·L-1外源水杨酸处理相比于对照块茎产量相对增加64．4％，而叶片净光合速率相对增加287．0％。可见，适宜浓度的外源水杨酸处理显著减轻了连作障碍造成的伤害，促进了马铃薯植株的生长发育，提高了马铃薯块茎的产量，并改善了块茎的营养与品质。