水杨酸对镉、锌复合胁迫下小麦幼苗生长及生理特性的影响

在水培条件下,以辽春10号小麦品种为供试材料,研究了10-4mol.L-1、10-5mol.L-1、10-6mol.L-13种不同浓度的水杨酸(SA)对1mmol.L-1Cd2+、5mmol.L-1Zn2+复合胁迫下小麦幼苗生长及生理特性的影响。结果表明:与对照组(未加SA处理的Cd2+、Zn2+复合污染)相比,经SA处理Cd2+、Zn2+复合胁迫下小麦幼苗地上及地下生物量都有明显增高,特别是10-4mol.L-1SA处理组分别增加23.78%和24.7%;10-4mol.L-1SA处理组小麦幼苗根系活力提高6.74%。在试验第6 d、11 d根系和叶片中超氧化物歧化酶(SOD)、过氧化物酶(POD)分别达到峰值且以10-4mol.L-1SA处理组最高;在整个试验期间3个SA处理组过氧化氢酶(CAT)活性始终高于对照,其中10-4mol.L-1SA处理组为对照组的146.6%;SA处理使丙二醛(MDA)含量降低,在试验第11 d,10-4mol.L-1SA处理组叶片和根系中丙二醛含量分别为对照组的85.5%和87.6%。但是在试验第14 d各组小麦幼苗叶片和根系中丙二醛含量全部有所回升。综合来看,不同浓度的SA处理均能提高小麦幼苗的抗氧化酶活性且高浓度SA(10-4mol.L-1)处理效果最明显。这表明,水杨酸能够通过促进保护酶活性的升高,抑制活性氧含量的增加,从而有效缓解Cd2+、Zn2+复合胁迫对小麦的毒害。

Effects of salicylic acid on the growth and biophysical characteristics of wheat seedlings under the stress of cadmium and zinc

The present paper is engaged in the study of the effects of different concentrations of salicylic acid(SA) on the wheat growth and some bio-physical characteristics of wheat seedling development under the stress of cadmium(1 mmol·L-1) and zinc(5 mmol·L-1) through hydroponic experiments by using wheat as our case study material.The results of our experiments show that,as compared with the CK group(under the stress of cadmium and zinc with no effects of SA),and with the effect of SA,the biomass(dry weight) under and above the ground surface were let to grow by 23.78% and 19.92% respectively,with particular attention paid to the increased concentrations of salicylic acid(10-4 mol·L-1) groups.As is found,under the effect of 10-4 mol·L-1 SA,the root activities of wheat seedling tend to increase by 6.74%;On the 6th day of the experiment,the superoxide dismutase(SOD),peroxicase(POD) in the roots and leaves were found to reach the highest stage of activities whereas the 10-4 mol·L-1 SA treated group was found among the highest ones.During the entire period of experiment,the activities of catalase(CAT) of the three SA treatment groups were noticed higher than the CK group continuously.Among them,the 10-4 mol·L-1 SA treatment group was detected to increase to 146.6% of the CK group.However,under the treatment of SA,the content of malondiadehyde(MDA) was found decreased.On the 11th day of the experiment,the content of MDA in the leaves and roots of the 10-4 mol·L-1 SA treatment group turned to decrease to 85.5% and 87.6% of the CK groups,respectively.But on 14th day of the experiment,the content of MDA in the leaves and roots of all groups were found increased.From the above results,it can be concluded that different concentrations of SA can promote the activities of antioxidase and the high concentrations of salicylic acid(10-4 mol·L-1) may have obvious effects on the seedling growth.Thus,it can be concluded that SA treatment tends to alleviate the stress of cadmium and zinc through increasing the antioxidase activities and decrease of the content of the reactive oxygen.