柽柳组培苗抗氧化酶及渗透调节物质对NaCl胁迫的响应

Changes in Antioxidase Activity and Osmotic Adjusting Substance of Tamarix chinensis Seedlings under NaCl Stress

以柽柳种子为材料,利用组培方法建立其无菌离体培养体系而获得组培苗。向培养基(MS+1.0 mg/L6-BA+0.1mg/L NAA)中添加不同浓度NaCl(0、50、80、100、120、150和200mmol/L)建立胁迫条件,测定各浓度NaCl胁迫下柽柳组培苗抗氧化酶活性、渗透调节物质含量、质膜透性及超氧阴离子(O-·2)生成速率等的变化,探讨柽柳组培苗应对NaCl胁迫的生理机制。结果显示:(1)随着NaCl胁迫浓度的增加,柽柳组培苗超氧化物歧化酶(SOD)和过氧化物酶(POD)活性表现出先增加后降低的趋势,并均在100mmol/L NaCl的胁迫下达到最大值,而抗坏血酸过氧化物酶(APX)活性则表现出逐渐下降的趋势;(2)随着NaCl胁迫浓度的增加,组培苗体内有机渗透调节物质游离脯氨酸(Pro)、可溶性蛋白(Pr)和可溶性糖的含量逐渐升高且显著高于同期对照,在200mmol/L浓度下分别比对照显著增加53.77%、47.38%和67.65%;(3)组培苗过氧化氢(H2O2)、超氧阴离子(O-·2)生成速率、丙二醛(MDA)含量以及细胞质膜透性也随着NaCl胁迫浓度的增加均表现出逐渐增加的趋势且显著高于同期对照,在200mmol/L浓度下分别比对照显著增加36.42%、58.71%、82.60%和42.54%。研究表明,柽柳组培苗抗氧化酶系统在低浓度NaCl(≤100mmol/L)胁迫下表现出良好的活性氧清除活性,而其体内渗透调节物质在各浓度胁迫下均发挥着积极的调节作用,从而使柽柳表现出较强的耐盐性。

To obtain tissue-cultured plant,We used Tamarix chinensis seeds as materials and established their sterile solated culture system by tissue culture method.A stress condition was formed through adding different concentrations of NaCl（0,50,80,100,120,150 and 200mmol/L）to the medium（MS＋1.0mg/L6-BA＋0.1mg/L NAA）.To explore the physiological mechanism of T.chinensis tissue-cultured plant response to NaCl-stress,We investigated the changes of activities of T.chinensis tissue-cultured plant antioxidases,contents of osmotica,plasma membrane permeability and production rate of super oxygen anion（O-·2）under different concentrations of NaCl-stress.The results indicated that：（1）The activities of superoxide dismutase（SOD）and peroxidase（POD）of T.chinensis tissue-cultured plant were rising and thengoing down as concentrations of NaCl-stress were increasing,and both at 100mmol/L NaCl-stress reached a maximum,whereas,the activity of ascorbic acid peroxidase（APX）was gradually declining.（2）The contents of osmotica such as free proline（Pro）,soluble protein（Pr）and soluble sugar of tissue-cultured plant were gradually rising and significantly higher than that of the concurrent control as concentrations of NaClstress were increasing,and at 200mmol/L concentration notably increased 53.77%,47.38% and 67.65%,respectively.（3）The production rates of hydrogen peroxide（H2O2）and super oxygen anion（O-·2）,content of malonic dialdehyde（MDA）and plasma membrane permeability of tissue-cultured plant were all gradually rising and significantly higher than that of the concurrent control as concentrations of NaCl-stress were increasing,and at 200mmol/L concentration notably increased 36.42%,58.71%,82.60%and 42.54%,respectively.The study confirmed that antioxidases system of T.chinensis tissue-cultured plant showed favorable active oxygen scavenging activity under a low concentration of NaCl-stress（≤100 mmol/L）and the osmotica played positively regulated functions under different concentrations of NaCl-stress.Accordingly,T.chinensis showed a strong salt tolerance.