混合盐胁迫对二倍体刺槐和绒毛白蜡根系形态和抗氧化指标的影响

以二倍体刺槐和绒毛白蜡幼苗为材料,配制NaCl和Na2CO3混合盐梯度,比较2种植物根系生物量和形态差异,测定根系保护酶活性以及膜脂过氧化产物和可溶性蛋白含量,以探讨盐碱胁迫对植物根系生长和生理的影响。结果表明:1)低盐碱胁迫(80mmol·L^-1盐浓度)促进二倍体刺槐根系生物量、总长度、总表面积和总体积增加,而抑制绒毛白蜡根系生物量和形态指标;2)绒毛白蜡根系SOD活性对低混合盐浓度敏感,而二倍体刺槐根系SOD活性在高盐浓度下显著上升;2种植物根系POD活性在低盐浓度下最大,CAT活性在240~320mmol·L^-1盐浓度下达到峰值;3)二倍体刺槐根系中MDA含量高峰值出现在低盐浓度下,绒毛白蜡则出现在240mmol·L^-1浓度;随着混合盐浓度增加,二倍体刺槐根系可溶性蛋白含量逐渐降低,绒毛白蜡则先升高后降低;4)多因素方差分析表明,2种植物根系主要形态指标间存在物种间差异,混合盐胁迫对根系形态和抗氧化生理指标的影响不同。在盐碱胁迫下,二倍体刺槐和绒毛白蜡根系表现出适应性差异。

Responses of Root Morphology and Antioxidant Indexes of Diploid Robinia pseudoacacia and Fraxinus velutina to Mixed Salt Stress

Seedlings of diploid Robinia pseudoacacia and Fraxinus velutina were planted under the mixed salt stress with different concentrations of NaCl and Na 2CO 3.The biomass and morphological characteristics of the roots were compared and the activities of root protective enzymes and the contents of lipid peroxidation and soluble proteins were determined.The purposes were to explore the effects of mixed salt stress on the growth and physiology of plant roots,and to elucidate the salt tolerance strategies of two species.The results showed that 1) the root biomass,root length,total surface area and volume of diploid R.pseudoacacia increased under low saline-alkali stress (80 mmol·L^-1 salt concentration),while the biomass and morphology of F.velutina were suppressed.2) Root SOD activity of F.velutina was sensitive to low saline-alkali stress,while that of diploid R.pseudoacacia increased significantly in the 240 mmol·L^-1 salt concentration.The maximum root POD activity of two species was observed under low saline-alkali stress and root CAT activity reached the peak value under 240-320 mmol·L^-1 salt concentration.3) The maximum content of root MDA appeared under low salt concentration in diploid R.pseudoacacia and 240 mmol·L^-1 salt concentration in F.velutina .With the increase of saline-alkali stress,the root soluble protein content of diploid R.pseudoacacia decreased gradually,while that of F.velutina increased firstly and then decreased.4) By two-way ANOVA analysis,the significant differences were observed on the morphology characteristics with SOD activity and MDA contents between two species.It was suggested that the roots of diploid R.pseudoacacia and F.velutina adapted to saline-alkali stress differently.