锰处理下棉花幼苗根部对镉胁迫的生理响应

Physiological Response of Two Cotton Seedlings to Cadmium Stress Treated with Different Concentrations of Manganese

探讨Mn处理下棉花幼苗根部对Cd胁迫生理响应及Cd累积的影响。以湘C178和湘FZ001为试验材料,研究不同浓度Mn离子处理(0,5,10,50μmol/L)后,Cd胁迫下棉花幼苗根部超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、丙二醛(MDA)、游离脯氨酸(Pro)、Cd含量、干物质质量及主根长度的变化。10μmol/L Cd胁迫对棉花根部生长有明显影响,棉花幼苗通过构建物理性屏障和抗氧化防卫机制来减轻Cd对根部细胞的损害,导致SOD活性降低,CAT活性、MDA含量和Pro含量增加。同时,Mn处理会影响棉花幼苗根部对Cd胁迫的生理响应。低浓度Mn处理会导致棉花幼苗根部Cd含量降低,SOD活性和Pro含量提升、CAT活性和MDA含量降低,有效预防Cd胁迫对棉花幼苗根部生长的抑制作用;较高浓度Mn处理会导致棉花幼苗根部Cd含量增加,SOD活性提升、CAT活性和MDA含量提升、Pro含量降低,影响棉花幼苗根部生长。在利用棉花修复Cd污染耕地时可用小于10μmol/L的Mn离子处理来提高棉花耐Cd幼苗能力,保障棉花植株正常生长。

To investigate the effects of Mn treatment on the growth,development and cadmium adsorption capacity of cotton under Cd stress.Different concentrations of Mn treatment(0,5,10,50μmol/L)were applied to exploit changes of superoxide dismutase(SOD),catalase(CAT),malondialdehyde(MDA),free proline(Pro),Cd content,dry matter quality,and main root length of roots of cotton seedlings of Xiang C178 and Xiang FZ001 under Cd stress.The stress of 10μmol/L Cd had a significant effect on the growth of cotton root.The physical barrier and antioxidant defense mechanism were constructed to reduce the damage of Cd to root cells,resulting in a decrease in SOD activity and an increase in CAT activity,MDA content and Pro content.And,adding Mn was observed to effect the physiological response to cadmium of cotton seedling roots.Low concentration of Mn treatment resulted in the decrease of Cd content,the increase in SOD activity and Pro content,the decrease in CAT activity and MDA content in the root of cotton seedlings,which effectively prevented the inhibition of Cd stress on the root growth of cotton seedlings.High concentrations of Mn could increase Cd content and SOD activity in cotton seedling roots,which affected the root growth of cotton seedlings.When using cotton to repair Cd-contaminated farmland,it can be less than 10μmol/L Mn ion treatment is used to improve the Cd tolerance of cotton seedlings and ensure the normal growth of cotton plants.