干旱预处理对盐胁迫下花生幼苗生理特性的影响

Effects of Drought Pretreatment on Physiological Characteristics of Peanut Seedlings under Salt Stress

为探究干旱预处理对盐胁迫下花生(Arachis hypogaea)幼苗生理特性的影响,以耐盐品种花育25和不耐盐品种花育22为试验材料,采用室内砂培试验通过干旱后复水再盐处理方法研究了干旱预处理对盐胁迫下花生幼苗叶片的相对含水量、叶片光合性能、根系活力、叶片保护酶活性以及叶片渗透调节物质含量的影响。结果表明:盐胁迫增加了两花生品种幼苗叶片丙二醛、脯氨酸、可溶性糖含量,降低了叶片相对含水量、叶绿素含量、最大光化学效率和光化学淬灭系数,且随着胁迫时间的推移,超氧化物歧化酶活性、过氧化物酶活性和根系活力呈先上升后下降趋势,最终小于对照;与未干旱预处理相比,干旱预处理提高了盐胁迫下两花生品种幼苗叶片相对含水量、叶片抗氧化酶活性、根系活力和叶片渗透调节物质含量,降低了丙二醛含量以及减弱了对叶绿素荧光参数的影响。盐胁迫下,干旱预处理可以有效提高不同抗盐性花生品种幼苗叶片相对含水量和光合速率,增强渗透调节作用,提高体内保护酶活性,降低细胞膜脂过氧化程度,保证细胞膜的完整性,维持正常的细胞代谢活动,从而有效减轻盐胁迫对花生幼苗的伤害。

In order to explore the effects of drought pretreatment on physiological characteristics of pea-nut （Arachis hypogaea）,the cultivars HY25 and HY22 with high and low salt resistance respectively were used as experimental materials.Indoor sand culture experiments were conducted to study the effects of drought pretreatment on the relative water content,photosynthetic performance,protective enzyme activity and osmotic adjustment substance contents of leaves and root activity under salt stress with pretreatment of rehydration after drought treatment.The results showed that salt stress increased the contents of malondialdehyde （MDA）,pro-line and soluble sugar in leaves of the two cultivars seedlings,reduced the relative water content,chlorophyll content,maximum photochemical efficiency and photochemical quenching coefficient.With the time of stress going on,the superoxide dismutase （SOD）activity,peroxidase （POD）activity and root activity increased firstly,then decreased and finally lower than those of control.Compared with no drought pretreatment, drought pretreatment increased the relative water content,antioxidant enzyme activity and osmotic regulation substance content of leaves and root activity,reduced the content of MDA and weakened the influences on chlorophyll fluorescence parameters of the two cultivars seedlings under salt stress.These results showed that drought pretreatment could improve the leaf relative water content and photosynthetic rate of peanut,enhance the role of osmotic adjustment,improve the activities of protective enzymes,decrease cell membrane lipid per-oxidation and ensure the integrity of cell membrane to maintain normal cell metabolism,thus effectively re-duced the damage of salt stress to peanut seedlings.