杠柳幼苗对盐胁迫的生理响应及耐盐机理研究

Study on Physiological Response and Salt Tolerance Mechanism in Salt-Stress of Periploca sepium Seedlings

目的:探究盐胁迫对杠柳生长、生理指标及总黄酮含量的影响,初步了解杠柳的耐盐机制。方法:以培养30 d的杠柳实生苗为材料,分别用0.2%、0.5%、1.0%、2.0%的NaCl溶液进行盐胁迫处理,胁迫处理10 d后,测定植株地上及地下部分的性状指标、生理指标、总黄酮含量。结果:杠柳在中低盐浓度(0.2%和0.5%NaCl)下生长良好,不同浓度的高盐(1.0%和2.0%NaCl)环境下生长受到不同程度的抑制;幼苗根及茎中丙二醛含量随盐胁迫浓度的升高而持续升高,抗氧化酶类(SOD、POD和CAT)活性呈先上升后下降的趋势,游离脯氨酸、可溶性糖含量显著升高,可溶性蛋白含量则呈先上升后下降的趋势;地上和地下部分的次生代谢产物总黄酮在盐胁迫下均显著增加,且茎中总黄酮含量在胁迫前后均显著高于根中总黄酮的含量。结论:杠柳具有很强的耐盐性,可通过提高抗氧化酶系统活性,诱导渗透调节物质和非酶还原产物总黄酮的合成,以及生理落叶等方式提高其耐盐性。

Objective: To explore the effects of salt stress on the growth, physiological indexes and total flavonoids content of Periploca sepium,and to preliminarily understand its salt tolerance mechanism.Methods: The seedlings of Periploca sepium were cultured for 30 days and treated with NaCl at concentrations of 0.2%,0.5%,1.0%and 2.0%,respectively.The stress period was 10 days.After 10 days of stress treatment, the character indexes, physiological indexes and total flavonoids content of aboveground and underground parts were determined.Results: The growth of Periploca sepium was well under medium and low salt concentration(0.2%,0.5%NaCl),but the growth of Periploca sepium was inhibited under different contentration of high salt concentration(1.0%,2.0%NaCl).The content of malondialdehyde in roots and stems of seedlings increased with the increase of salt stress concentration, the activities of antioxidant enzymes SOD,POD,CAT increased first and then decreased, the contents of free proline and soluble sugar increased significantly, and the content of soluble protein increased first and then decreased.The total flavonoids of secondary metabolites in the aboveground and underground parts increased significantly under salt stress, and the total flavonoids content in stem was significantly higher than that in root before and after salt stress.Conclusion: Periploca sepium is very resistant to salt, its salt tolerance can be improved by increasing the activity of antioxidant enzyme system, inducing the synthesis of osmolyte and total flavonoids(a class of non-enzymatic reduction products),and physiological defoliation.