摘要
为探讨外源2,4-表油菜素内酯(2,4-epibrassinolide,EBR)提高紫花苜蓿(Medicago sativa L.)耐盐性的生理调控机制,采用营养液水培法,以紫花苜蓿品种‘中苜3号’和‘陇中苜蓿’为材料,研究Na Cl胁迫下添加外源EBR对紫花苜蓿幼苗根系生长、渗透调节物质含量、抗氧化酶活性、非酶抗氧化物质、活性氧及MDA含量的影响。结果表明:150 mmol·L?1 Na Cl胁迫下,‘中苜3号’、‘陇中苜蓿’幼苗根系的生长显著受到抑制,根系干重和根系活力显著降低,幼苗根系中的可溶性蛋白含量和抗氧化酶活性显著降低,活性氧和MDA含量显著增加,根系脂质过氧化程度加剧,细胞质膜完整性受到破坏。添加0.1μmol·L?1外源EBR显著增加了2个品种苜蓿幼苗的主根长、根系总长度、根系总表面积、根体积、根尖数、根系干重和根系活力,幼苗根系中的可溶性蛋白含量、抗氧化酶(SOD、APX、GPX、CAT、GR)活性、非酶抗氧化物质(As A、GSH)含量均显著增加,超氧阴离子自由基(O2·?)产生速率、羟自由基(OH·)浓度、H2O2含量和膜脂过氧化产物MDA含量显著降低,有效缓解了根系脂质过氧化程度,提高了细胞质膜的完整性。说明外源EBR能够有效缓解Na Cl胁迫对紫花苜蓿幼苗根系生长的抑制作用,增强紫花苜蓿幼苗根系的渗透调节能力和抗氧化系统活性,降低活性氧的积累和膜脂过氧化水平,减小Na Cl胁迫对紫花苜蓿幼苗根系造成的氧化伤害,促进根系生长,增强苜蓿幼苗的抗盐性。
This study discussed physiological regulation mechanism of salt resistance improvement of Medicago sativa L. (‘Zhongmu 3’ and ‘Longzhong’) by exogenous 2,4-epibrassinolide (EBR) in hydroponic conditions. The study analyzed the effects of exogenous EBR on the root growth, contents of osmotic adjustment substances, content of malondialdehyde (MDA), activities of antioxidant enzymes, contents of non-enzymatic antioxidant and active oxygen of M. sativa seedlings under NaCl stress. The result showed that under 150 mmol·L^-1 NaCl stress, root growth of ‘Zhongmu 3’ and ‘Longzhong’ seedlings were restrained significantly. Also root dry weight and root activity significantly decreased along with soluble protein content and antioxidant enzyme activities decreased in seedling root. On the other hand, active oxygen and MDA contents increased significantly along with the enhanced root lipid peroxidation while plasma membrane integrity was damaged. After addition of 0.1 μmol·L^-1 exogenous EBR, main root length, total root length, total root surface area, root volume, root tip number, root dry weight and root activity of the two alfalfa varieties significantly increased. Also soluble protein content, antioxidant enzymes (SOD, APX, GPX, CAT, GR) activities and non-enzymatic antioxidants (AsA, GSH) contents of seedling roots increased significantly. Then the production rate of superoxide anion free radicals, concentration of hydroxyl free radicals and contents of H2O2 and MDA decreased dramatically. Peroxidation of root lipid was relieved and the integrity of plasma membrane was enhanced. The above results illustrated that apart from mitigating the suppression effect of NaCl stress on alfalfa seedling root growth and enhancement of osmotic adjustment and antioxidant system activity, exogenous EBR promoted root growth and salt resistance of alfalfa. It also reduced active oxygen accumulation, membrane lipid peroxidation and oxidative damage on seedling root induced by NaCl stress.
出处
《中国生态农业学报》
CAS
CSCD
北大核心
2015年第8期1010-1019,共10页
Chinese Journal of Eco-Agriculture
基金
国家现代牧草产业技术体系建设专项(CARA-35)
全国种质资源保种项目(NB2130135)资助