Abstract: To study the drought-resistant ability of Sonchus brachyotus DC.,physiological indexes of Sonchus branchyotus DC.seedlings were measured in drought Stress under pot culture experiments simulating different soil water regimes.Results showed that under water stress,relative water content(RWC) of leaves gradually decreased,while the permeability of plasma membrane and malondialdehyde(MDA) content increased.There was no significant difference between treatments and control under the light drought stress(P<0.05).Catalase(CAT) activities were increased under drought stress.Activities of both superoxide dismutase(SOD) and peroxidase(POD) were initially increased but decreased slightly during drought stress.Both,however,were still higher than that of control.Free proline,soluble sugar and soluble protein contents continue to increase during drought stress.Proline content of treated seedlings was increased(11.06 times) compared with the control plants under severe drought stress.Results showed that Sonchus branchyotus DC.had high adaptability to drought stress.

Key words: Sonchus branchyotus DC., Drought stress, Relative water content, Plasma membrane permeability, Malondialdehyde, Antioxidative, Osmoregulation substance

摘要： 为探究野生苣荬菜(Sonchus brachyotus DC.)抗旱能力,用盆栽控制浇水模拟干旱的方法,研究了不同程度干旱胁迫下苣卖菜幼苗对干旱胁迫的响应。结果表明:随着干旱胁迫程度的加深,苣荬菜叶片相对含水量逐渐降低,质膜透性、丙二醛(MDA)含量升高,轻度干旱胁迫下以上3种指标与对照相比差异不显著(P<0.05)。超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性升高,SOD,POD活性在重度干旱条件下稍有下降,但仍高于对照。可溶性有机渗透调节物质脯氨酸、可溶性糖含量、可溶性蛋白含量持续上升,尤以脯氨酸上升幅度最大,重度干旱时达对照的11.06倍,表明苣荬菜有一定的抗旱能力。

关键词: 苣荬菜, 干旱胁迫, 相对含水量, 质膜透性, 丙二醛, 抗氧化酶, 渗透调节物质