沙漠腹地醉鱼草(Buddleja alternifolia)栽培苗对水盐胁迫的响应

Response of Buddleja alternifolia seedlings to salinity and water stress in desert hinterland

为了研究盐、旱及其交互胁迫下植物生长和生理特性的变化,了解沙漠腹地极端生境下互叶醉鱼草(Buddleja alternifolia)幼苗的适应性,确定合理的灌溉方式,为沙漠腹地醉鱼草的引种提供理论依据。通过大田控制实验,设计了3个水分梯度和4个盐分梯度随机结合实验,定位测量生长量和生化指标,最后基于隶属函数法综合评价醉鱼草的抗旱耐盐性。结果表明:(1)在干旱胁迫或低浓度盐胁迫下,醉鱼草的地径、新枝和冠幅生长量均呈上升趋势,而在高盐浓度胁迫下均降低;水盐交互胁迫下,不同的盐浓度与干旱交互胁迫效果不同,低盐浓度与干旱交互胁迫时(W1S1、W2S1),植物生长量均上升,高盐浓度与干旱交互胁迫时(W1S3、W2S3),植物生长量均降低。(2)无论是盐胁迫、干旱胁迫还是盐、旱交互胁迫,醉鱼草游离脯氨酸(Pro)含量随着胁迫程度的增加均呈显著上升的趋势。(3)醉鱼草的超氧化物歧化酶(SOD)活性和过氧化物酶(POD)活性变化相对复杂,除了在干旱胁迫时,SOD活性和POD活性都显著下降外,在盐胁迫和交互胁迫时它们各自的变化并不一致。醉鱼草在盐胁迫、交叉胁迫和干旱胁迫时,渗透调节物质和酶活性各自对应的发生了变化,没有明显的同步性,存在相互协调的可能,同时植物细胞的敏感性远远强于表型生长的变化,高盐浓度的伤害并没有表现在植物外部形态上,但酶活性及渗透调节物质却有显著变化。通过隶属函数分析显示,醉鱼草最佳的生长水盐条件是盐浓度为8 g·L^-1、灌水量为25 L·次^-1,对水盐胁迫的抗旱耐盐性为:干旱胁迫>交互胁迫>盐胁迫。

This paper provides a theoretical basis for the introduction of plant in the desert hinterland to study the changes of plant growth and physiological characteristics under salt,drought,and their interaction stress,to understand the adaptability of Buddleja alternifolia seedlings,and determine the reasonable irrigation method in the extreme habitat of the desert hinterland,Xinjiang,China.Experiments of random combinations of three field moisture gradients and four salt gradients were designed to control the growth and biochemical indicators.Finally,the drought resistance and salt tolerance of Buddleja alternifolia were evaluated based on the membership function method.The results showed as follows:(1)Under drought stress or low-salt stress,the growth of ground diameter,new shoots,and crown width of Buddleja alternifolia increased,but decreased under high salt stress;Under interaction stress,the salt concentration was different from the drought stress.With low salt concentration and drought interaction(W1S1,W2S1),the plant growth increased,while with high salt concentration and drought interaction(W1S3,W2S3),the plant growth decreased.(2)Regardless of the type of stress,the content of free proline(Pro)content of Buddleja alternifolia increased significantly with the increase of stress.(3)The changes of superoxide dismutase(SOD)and peroxidase(POD)activities were relatively complex.Except for the drought stress,the SOD activity and POD activity are significantly decreased.Inconsistent changes were observed under salt stress and salt-drought interaction stress.This indicated that under salt stress,cross stress,and drought stress,change in the corresponding osmotic adjustment substances and enzyme activities were observed,no obvious synchronization was found,a possibility of coordination exists,and the sensitivity of plant cells was found to be far stronger than the phenotypic growth.Changes in the phenotypic growth under high salt concentration damage did not appear in the external morphology of the plant.However,the enzyme activity and osmotic adjustment substances have significant changes.Finally,the analysis of the membership function showed that the most suitable water and salt conditions for the Buddleja alternifolia were:salt concentration of 8 g·L-1,irrigation amount of 25 L·times-1,and drought and salt tolerance to water and salt stress:drought stress>interaction stress>salt stress.