GA3对NaCl胁迫下‘泡桐1201'幼苗生理代谢及离子吸收的影响

Effects of GA3 on physiological metabolism and ion absorption of ‘Paulownia 1201' seedlings under NaCl stress

关键词:  ‘泡桐1201', NaCl胁迫, 赤霉素, 离子吸收, PCA分析

Key words:  ‘Paulownia 1201', NaCl stress, gibberellin, ion uptake, PCA analysis

摘要:

为探究赤霉素(GA₃)对NaCl胁迫下‘泡桐1201'幼苗生长的缓解效应及生理机制,该研究以‘泡桐1201'幼苗为材料,设置不同的NaCl、GA₃浓度,测定分析GA₃缓解NaCl胁迫下泡桐幼苗的生理指标、光合指标及离子转运能力。结果表明:(1)150 mmol·L^-1NaCl胁迫下泡桐幼苗的生长量显著下降(P<0.05),下降量超过50%; 适宜浓度的外源GA₃显著提高泡桐幼苗的株高、根长及生物量,400 mg·L^-1的GA₃处理干重较A0增加69.71%。(2)随着GA₃浓度的增加,3种抗氧化酶(SOD、POD、CAT)活性显著提高,MDA含量显著降低,叶绿素含量、气体交换参数(P_n、T_r、C_i、G_s)均增大,光合效率提高,各离子含量(K⁺、Ca²⁺、Mg²⁺)均呈先上升后下降的趋势; 400 mg·L^-1的GA₃处理组叶片及根系中的Na⁺含量比A0分别降低了23.59%和11.92%。(3)相关性分析及PCA分析显示,各项指标之间存在相关性,不同浓度GA₃处理幼苗的差异明显,当GA₃浓度为400 mg·L^-1时缓解效果最佳。综上认为,叶面喷施GA₃能增强盐胁迫下‘泡桐1201'幼苗的抗氧化能力,缓解因盐胁迫导致活性氧过多而引起的膜脂过氧化反应,促进植株光合作用和生物量的积累,减少植物对Na⁺的吸收促进营养离子的积累,以添加400 mg·L^-1GA₃更能提高‘泡桐1201'幼苗的抗性。该研究结果为深入了解泡桐耐盐机理提供理论基础,也为泡桐在盐渍地开发利用提供科学依据。

Abstract:

To explore the alleviation effect and physiological mechanism of gibberellin(GA₃)on the growth of ‘Paulownia 1201' seedlings under NaCl stress, this study took ‘Paulownia 1201' seedlings as materials, different NaCl and GA₃ concentrations were set to determine and analyze the physiological indexes, photosynthetic indexes and ion transport capacity of ‘Paulownia 1201' seedlings under NaCl stress alleviated by GA₃. The results were as follows:(1)Under 150 mmol·L^-1 NaCl stress, the growth of ‘Paulownia 1201' seedlings decreased significantly(P<0.05), which was more than 50%. The appropriate concentration of exogenous GA₃ significantly increased the plant height, root length and biomass of ‘Paulownia 1201' seedling. The dry weight of 400 mg·L^-1 GA₃ treatment increased by 69.71% compared with A0.(2)With the increase of GA₃ concentration, the activities of three antioxidant enzymes(SOD, POD, CAT)increased significantly; content of MDA decreased significantly; chlorophyll content and gas exchange parameters(P_n, T_r, C_i, G_s)were increased, and the photosynthetic efficiency increased; the contents of each ion(K⁺, Ca²⁺, Mg²⁺)increased first and then decreased. The Na⁺ contents in leaves and roots of 400 mg·L^-1 GA₃ treatment group decreased by 23.59% and 11.92% compared with A0.(3)Correlation analysis and PCA analysis showed that there was a correlation between each index, seedlings which treated with different concentrations of GA₃ had obvious differences, and the best alleviating effect was found when the concentration of GA₃ was 400 mg·L^-1. In summary, foliar spraying GA₃ can enhance the antioxidant capacity of ‘Paulownia 1201' seedlings under salt stress, alleviate the membrane lipid peroxidation reaction caused by the increase of reactive oxygen species under salt stress, promote the accumulation of photosynthesis and biomass of plants, reduce the absorption of Na⁺ by plants, promote the accumulation of nutrient ions, adding 400 mg·L^-1 GA₃ can improve the resistance of ‘Paulownia 1201' seedlings best. This study provides a basis for further understanding of Paulownia salt tolerance mechanism identification, and also provides a scientific reference for the development and utilization of Paulownia in saline land.