【摘要】 以"楚雄"金花菜(Medicago polymorpha cv. Chuxiong)为试材,通过PEG (聚乙二醇-6000)模拟干旱胁迫和Na Cl溶液模拟盐胁迫,研究干旱和盐胁迫对金花菜萌发以及幼苗抗氧化能力的影响。结果表明,低浓度的胁迫延迟了种子的萌发,而高浓度的Na Cl和PEG溶液最终降低了种子的萌发。在达到极限值(20%PEG和200mmol/L的Na Cl)之前其发芽势、发芽率一直维持较高水平,但发芽指数、活力指数以及平均萌发时间在轻度胁迫下就已经受到影响;不同程度的干旱胁迫抑制了胚芽的生长,但促进了根的生长。此外,低浓度的Na Cl溶液促进了幼苗胚芽和胚根的生长,而高浓度的Na Cl溶液却抑制了幼苗胚芽和胚根的生长,这说明金花菜对盐和干旱的响应不同;干旱和盐胁迫同样诱发了氧胁迫,使得超氧阴离子(O2-)和过氧化氢含量(H2O2)以及MDA含量增加。同时诱导超氧化物歧化酶(Superoxide dismutase,SOD)、过氧化氢酶(Catalase,CAT)、过氧化物酶(Peroxidase,POD)和抗坏血酸过氧化物酶(Ascorbate peroxidase,APX)活性不同程度的增加,来减缓胁迫引起的膜损伤和氧伤害。以上结果表明:在萌发期,金花菜具有一定的耐盐耐旱能力,能够维持较高的发芽率,且通过增加胚根长以及抗氧化能力来减轻胁迫损伤。更多还原

【Abstract】 In order to determine the effect of drought and salt stress on seed germination and oxidation resistance protection in Medicago polymorpha,seeds of cv. "Chuxiong"were incubated in various solutions of PEG-600 and Na Cl solution. These results showed low concentration stress intensities only delayed germination,whereas the highest conceatration of Na Cl and PEG reduced germination percentages. The germination vigor and germination rate maintained the high level before stress reaching the limit( 20%PEG and 20 mmol/LNa Cl),in contrast,germination index,vigor index and mean germination significantly affected by mild stress. Different water stress( 0% to 20%PEG) induced inhibit the growth of germ,but promote root growth. In addition,the low concentration of Na Cl solution induced inhibit the growth of,the germ and root of seedlings,while the high concentration of Na Cl solution inhibited the growth of seedlings and root,these results suggested the response of Medicago polymorpha to drought and salt was different. Drought and salt stress also induced oxidative stress along with the increase of superoxide anion( O2-),hydrogen peroxide( H2 O2) and MDA conten. At the same time,all stress improved antioxidant enzyme activity including SOD,POD,CAT and APX in different degrees leading to reduced effectively lipid injury and oxidative damage. In conclusion,the results indicated that medicago polymorpha has a better tolerance to drought and salt stress with a higher germination rate in the germination period,and can alleviated damage stress by increasing root length and oxidation resistance protection.更多还原