Abstract: To reveal the physiological mechanisms of plant under grazing stress in degraded Seriphidium transiliense desert rangeland,the physiological characteristics of S.transiliense,Petrosimonia sibirica and Tulipa iliensis are analyzed in four different succession stages from non-degradation,medium-degradation,heavy-degradation to over-degradation in April,2007.Results show that physiological indexes fluctuate with the intensity of degradation.Soluble sugar(WSS) contents show a decreased trend,but photosynthetic pigment,soluble protein,praline(Pro) and malondiadehyde(MDA) content have tend to increase as a whole.Physiology/ecology adaptation of the three degraded stages are different from non-degraded stage.Three plants have different physiological mechanisms under grazing stress.The physiology adaptation of S.transiliense changed from strong to weak with intensity of degradation.P.sibirica has the strongest physiology adaptation among three plants.And the physiology adaptation of T.iliensis becomes weak with intensity of degradation.

Key words: Grassland, Degraded successional stage, Physiological characteristic, Change tendency

摘要： 为揭示退化伊犁绢蒿(Seriphidium transiliense)荒漠草地植物对放牧胁迫的抗逆生理机制,于2007年4月运用野外实地采样结合室内样品测定的方法,选取其3个层片的代表植物伊犁绢蒿、叉毛蓬(Petrosimonia sibirica)和伊犁郁金香(Tulipa iliensis),从未退化、中度退化、重度退化和极度退化4个演替阶段分别进行植物生理特性的研究。结果表明:随着草地演替的增强,3种植物叶片各指标呈现一定的波动性,可溶性糖含量(WSS)总体表现出下降趋势,光合色素、可溶性蛋白质、游离脯氨酸(Pro)和丙二醛(MDA)总体表现出上升趋势;生理生态适应性均表现为未退化阶段与其他各退化阶段存在显著差异。不同强度的放牧胁迫下,3种植物表现出不同的生理响应机制,随草地放牧压力增大,伊犁绢蒿生理调节能力先增强后减弱,极度退化阶段其生理适应能力严重削弱;叉毛蓬生理调节能力较强,表现为适应放牧胁迫;伊犁郁金香生理调节能力逐渐减弱。

关键词: 草地, 退化演替阶段, 生理特性, 变化趋势