入侵植物少花蒺藜草对干旱胁迫的生理响应及抗旱性评价

Physiological response and drought resistance evaluation of invasive plants Cenchrus pauciflorus to drought

摘要:

【目的】探究入侵植物少花蒺藜草（Cenchrus pauciflorus）及本地伴生种狗尾草（Setaria viri- dis）对干旱胁迫生理响应的差异。【方法】以 2 种植物幼苗为研究对象，采用聚乙二醇（PEG-6000）溶液模拟干旱胁迫环境，设置 4 个处理水平，对照、轻度、中度、重度胁迫，相对应的 PEG 浓度分别为 0%、 5%、10%、15%，测定 2 种植物的相对含水量（RWC）、叶绿素（Chl）含量以及保护酶活性、可溶性蛋白 （SP）含量等生理指标，利用隶属函数分析法进行抗旱性综合评价。【结果】1）随着胁迫程度的增强，2 种植物的游离氨基酸（FAA）、可溶性蛋白含量，过氧化物酶（POD）、过氧化氢酶（CAT）活性均呈先增加后降低的趋势，RWC 呈逐渐降低的趋势，丙二醛（MDA）和可溶性糖（SS）含量则持续增加，少花蒺藜草的 Chl 含量呈逐渐降低的趋势，狗尾草的 Chl 含量呈先降低后升高的趋势；2）少花蒺藜草的 POD 活性在中度干旱胁迫时活性最高 ，为 224. 867 μg/g，狗尾草在中度干旱胁迫时 CAT 活性最高 ，为 72. 667 μg/g；3）抗旱性综合评价表明，2 种植物幼苗的抗旱水平基本相同。【结论】2 种植物在干旱胁迫时表现出不同的生理特征变化以适应干旱生境，生理响应虽存在差异，但均具有较强的耐旱性。

Abstract:

【Objective】 In order to investigate the difference of physiological responses of invasive plant Cenchrus pauciflorus and its native associated species Setaria viridis to drought stress.【Method】 The seedlings of two plants were used as the research objectand PEG 6000 solution was used to simulate drought stress. Four treatment levels were set （CK，mild LD，moderate MD and severe SD）and PEG concentrations were 0%，5%，10% and 15%，re- spectively. The relative water content （RWC），chlorophyll （Ch l） content，protective enzyme，soluble protein（SP） and other physiological indexes of the two plants were determined. The comprehensive evaluation of drought resis- tance was carried out by membership function analysis.【Result】 The results showed that：1） with the increase of the degree of the drought stress，the contents of free amino acids （FAA），soluble protein （SP） and the activities of per- oxidase （POD） and catalase （CAT） increased firstly and then decreased，RWC content decreased gradually，malondi- aldehyde （MDA） and soluble sugar （SS） contents increased continuously，The Ch l content of Cenchrus pauciflorus showed a decreasing trend，and that of Setaria viridis showed a decreasing first and then increasing trend；2） POD ac- tivity of C. pauciflorus was the highest under moderate stress （224. 867 U/g），and CAT activity of S. viridis was the highest under moderate drought stress （72. 667 U/g）；3） The comprehensive evaluation of drought resistance showed that the drought resistance level of the seedlings of the two plants was basically the same.【Conclusion】 The two plants showed different physiological characteristics to adapt to the arid habitat under drought stress. Although there were differences in physiological response，both plants had strong drought tolerance.