盐旱交叉胁迫对柽柳幼苗生长及生理生化特性的影响

以3年生柽柳为材料,采用盆栽实验测定分析不同盐旱交叉胁迫下柽柳的生长状况、光合色素含量、超氧化物歧化酶(SOD)活性、过氧化物酶(POD)活性及丙二醛(MDA)含量,以阐明盐旱交叉胁迫对柽柳幼苗生长及生理生化特性的影响。结果显示:(1)盐胁迫对柽柳生长影响大于干旱胁迫,茎叶对盐旱胁迫的敏感性高于根系部分;随着盐胁迫的加剧,柽柳株高、基径以及干物质量均降低。(2)随盐旱胁迫的加剧,柽柳幼苗叶片光合色素含量先升高后降低,主导影响因子由干旱胁迫转为盐胁迫;重度盐胁迫下,叶绿素a、b下降明显。(3)中度干旱胁迫下,SOD和POD活性随盐胁迫的增强先降低后升高;随盐旱胁迫的加剧,SOD和POD活性逐渐减弱。(4)适度的盐旱胁迫能降低幼苗MDA含量,但重度干旱、轻中度盐分胁迫下MDA含量较高。研究发现,柽柳能通过调整自身生长和生理生化特性来提高其对逆境适应能力,表现出较强的抗旱耐盐性;盐旱胁迫下柽柳表现出一定的交叉适应性,适度的干旱胁迫能增强柽柳的耐盐能力。

Growth,Physiological and Biochemical Characteristics of Tamarix chinensis Seedlings under Salt-drought Intercross Stress

The growth,photosynthetic pigment content,activities of SOD,POD,and MDA content of three years old Tamarix chinensis under different salt-drought intercross stress were studied in order to clarify the effect of salt and drought stresses on the growth and physio-biochemical characteristics of T.chinensis seedling.The results showed that:(1)The influence of salt stress on growth was greater than drought stress,and the sensitivity of stem and leaf to salt and drought stress was higher than that of root system.The plant height,stem base diameter and dry matter of T.chinensis were all reduced with the salt stress intensified.(2)With the salt and drought stresses intensified,photosynthetic pigment content increased and then decreased,the major factor transformed from drought to salt stress.Under severe salt stress,the contents of chlorophyll a and b decreased significantly.(3)Under moderate drought stress,the activities of POD and SOD firstly increased and then decreased with the salt stress intensified.The oxidation resistance of SOD and POD weakened gradually with salt and drought stresses intensified.(4)Appropriate salt and drought stresses can weaken the content of MDA.However,the content of MDA was higher under severe drought and mild and moderate salt stress.The study indicated that T.chinensis can improve its stress resistance by adjusted self-growth and physiological and biochemical characteristics,and exhibited stronger drought and salt resistance.T.chinensis had tolerance to intercross salt-drought stress,and appropriate drought stress could increase the resistance of T.chinensis to salt stress.