PEG模拟干旱胁迫对玉竹生理特性的影响

摘要

利用聚乙二醇6000( PEG6000)高渗溶液模拟干旱胁迫,研究了不同质量分数(10％、20％、30％)处理对玉竹(Polygoncatum odoratum)5个生理指标的影响,评价其抗旱能力.结果表明:质量分数为20％、30％的PEG分别胁迫42、35 h,玉竹观赏价值逐浙丧失.随着PEG质量分数的增加和胁迫时间的延长:叶片相对含水量持续下降,复水后各处理均有5％～ 10％幅度的上升；电导率与胁迫程度呈极显著正相关,复水后质量分数为30％的PEG处理的电导率不能恢复；胁迫14 h后玉竹叶绿素b质量分数下降,同时叶绿素a质量分数上升；PEG质量分数为10％、20％处理的超氧化物歧化酶(SOD)活性在胁迫21 h后显著上升,35 h达到峰值,说明玉竹保护酶系统有清除活性氧自由基以抵御干旱胁迫的能力.研究表明:玉竹通过自身调节能够适应质量分数为20％和30％的PEG胁迫28 ～35 h,有较强的抗旱能力.%An experiment was conducted to study the effects of drought stress on five physiological characteristics of Polygonatum odoratum treated with different mass concentrations (10% , 20% , and 30% ) of Polyethylene glycol 6000( PEC6000) hy-pertonic solution in order to evaluate its drought resistance. Results showed that the ornamental value of P. odoratum, disappeared gradually after 42 and 35 hours of stress by 20% and 30% PEG, respectively. With PEG concentration increasing and stress time prolonging, the leaf relative water content continued to decline, and then increased by 5% -10% after rewatering. There was a highly significant positive correlation between the electrical conductivity and the level of stress, and the electrical conductivity of P. odoratum stressed by 30% PEG could not resume after rewatering. Chlorophyll a content increased and chlorophyll b content declined after 14 hours of stress. Superoride dismutase (SOD) activity increased significantly after 21 hours of stress by 10% and 20% PEG, with a peak value at 35 h after stress. It shows that the protective enzyme system of P. odoratum can resist drought stress by scavenging reactive oxygen free radicals. P. odoratum has a strong ability to resist drought stress, and it is able to adapt to 28-35 hours of stress by 20% and 30% PEG through self-regulation.