干旱胁迫下文冠果耐盐生理生化特性研究

Physiological and Biochemical Characteristics of Salt Tolerance in Xanthoceras sorbifolium Under Drought Stress

为探讨干旱对文冠果耐盐生理生化特性的影响,以2年生文冠果为材料,用15%聚乙二醇及不同浓度NaCl分别模拟旱盐环境,通过测定不同旱盐胁迫条件下文冠果叶片有机渗透调节系统、无机离子浓度和膜系统等方面的生理生化指标,研究干旱胁迫下文冠果耐盐生理生化特性。结果表明:在干旱胁迫、单盐胁迫下,文冠果叶片可溶性糖含量、可溶性蛋白、脯氨酸、钠离子含量、相对电导率、丙二醛含量等随胁迫程度加剧呈上升趋势;可溶性糖、可溶性蛋白含量随胁迫时间延长呈先上升后下降趋势外,其余指标均呈上升趋势;钾离子含量随胁迫程度加重和胁迫时间延长呈下降趋势。旱盐交叉胁迫下,文冠果叶片各生理生化指标随盐分浓度变化和随胁迫时间延长同干旱胁迫、单盐胁迫下总体变化趋势相同。在低盐浓度下,除钾离子含量外,经15%聚乙二醇处理的叶片其他指标均低于未经聚乙二醇处理的,当NaCl浓度达到0.45%时,结果与之相反。上述研究表明,在一定盐浓度范围内,文冠果可通过提高可溶性糖、脯氨酸、可溶性蛋白等来抵御逆境胁迫,而相对电导率、丙二醛、钠离子含量的升高以及钾离子含量的降低不利于其抵御逆境。当盐浓度超过苗木耐受范围或者对其盐胁迫时间过长,它的生理代谢将会失衡,从而引起可溶性糖、可溶性蛋白等物质含量的降低;在低盐浓度下,经15%聚乙二醇处理可提高文冠果对盐害的抵御能力。

In order to explore the effect of drought on salt tolerance physiological and biochemical characteristics of two-year-old Xanthoceras sorbifolium seedlings,the physiological and biochemical indicators of leaf organic osmotic adjustment system,inorganic ion concentration,and membrane system were studied under 15%concentrated PEG 6000 and different concentrations of salt(NaCl)stress treatment.The results showed that these indicators,such as the soluble sugar,proline,soluble protein,sodium ion(Na+)content,relative electrical conductivity,and malondialdehyde(MDA)content of seedling leaves,showed an upward trend with intensification of stress level under drought stress and single salt stress.The contents of soluble sugar and soluble protein increased first and then decreased with the extension of the stress time,the other indicators except potassium which decreased showed an upward trend.Under drought and salt cross stress,the change trend of physiological and biochemical indexes of X.sorbifolium leaves with salt concentration and with the extension of stress time were the same as the overall change trend under drought stress and single salt stress.Under low salt concentration,compared with single salt stress and drought and salt cross treatment,except for potassium ion content,all other indicators of leaves treated with 15%PEG 6000 were lower than those without PEG 6000.When the concentration of NaCl reached 0.45%,the result was the opposite.The above results showed that X.sorbifolium could resist the stress by increasing soluble sugar,proline and soluble protein in a certain salt concentration range,while the increase of relative conductivity,malondialdehyde,sodium ion and the decrease of potassium ion were not conducive to its resistance to the stress.When the salt concentration exceeded the tolerance range of the seedlings or the salt stress time was too long,its physiological metabolism would be unbalanced,which would cause the content of soluble sugar,soluble protein and other substances to decrease.At the low salt concentration,it was beneficial to the resistance of X.sorbifolium to salt damage that was treated by 15%PEG 6000.