干旱胁迫下不同品种杨树矿质离子含量变化

【目的】了解杨树在干旱胁迫下矿质离子分布及其动态变化。【方法】以吴屯杨、新疆杨和荷兰杨为实验材料,在中度和重度干旱条件下测定了根、茎、叶和质外体的K^+、Ca^2+、Na^+和Mg^2+等4种离子含量的变化。【结果】干旱胁迫使K^+、Ca^2+和Na^+离子含量上升,Mg^2+含量下降,其中K^+和Ca^2+含量自胁迫开始明显升高,Na^+含量则在中度胁迫之后明显增加。离子在各器官分布情况为:K^+主要分布于杨树的叶片,Ca^2+、Na^+和Mg^2+主要分布于杨树根部,且离子分布存在品种间差异,荷兰杨和新疆杨中K^+分布为:叶>根>茎,而吴屯杨体内K^+分布则为:叶>茎>根;3种杨树中Ca^2+分布均为:根>叶>茎;吴屯杨和荷兰杨中Na^+分布为:根>茎>叶,新疆杨则为:根>叶>茎;在Mg^2+的分布上吴屯杨和新疆杨较为类似即:根>叶>茎,而荷兰杨为叶>根>茎。【结论】干旱胁迫下杨树首选吸收的离子是K^+和Ca^2+,K^+主要分布在杨树的叶片中,其次是根部,Ca^2+主要分布在杨树的根部。重度干旱胁迫下,杨树开始吸收Na^+,储存在杨树的根部。不同品种杨树之间离子的分布和吸收都存在品种差异。质外体作为离子的运输通道,在各干旱条件下运输4种矿质离子至杨树的其他部位,Mg^2+存在滞留在质外体中的情况。本研究可为植物在干旱胁迫下矿质离子吸收和分布的研究提供理论依据。

Changes of mineral ion content of different varieties of poplar under drought stress

【Objective】In order to study the distribution and dynamic changes of mineral ions in poplar under drought stress,【Method】The roots,stems,leaves and apoplasts were determined under moderate and severe drought conditions using Populus wutunensis,Xinjiang Populus and Populus×euramericana as experimental materials.Changes in four ion contents such as K^+,Ca^2+,Na^+,and Mg^2+.【Result】The content of K^+,Ca^2+ and Na^+ ions increased and the content of Mg^2+ decreased under drought stress.The contents of K^+and Ca^2+ increased significantly from the stress and the Na^+ content increased significantly after moderate stress.The distribution of ions in various organs was as follows:K^+was mainly distributed in the leaves of poplar,Ca^2+,Na^+and Mg^2+were mainly distributed in the roots of poplar,and the ion distribution was different between varieties.The K^+distribution of Populus×euramericana and Populus bolleana Lauche was:leaf>root>stem,while K^+distribution in Populus wutunensis is:leaf>stem>root;Ca^2+ distribution in three poplars is:root>leaf>stem;Na^+distribution in Populus wutunensis and Populus×euramericana is:root>stem>leaf,Populus bolleana Lauche is:root>leaf>stem;in the distribution of Mg^2+,Populus wutunensis and Populus bolleana Lauche are similar:root>leaf>stem,while Populus×euramericana is leaf>root>stem.【Conclusion】The first ions that poplars absorb under drought stress are K^+ and Ca^2+.K^+ is mainly distributed in the leaves of poplars,followed by roots,and Ca^2+ is mainly distributed in the roots of poplars.Under severe drought stress,poplars began to absorb Na^+and stored in the roots of poplars.There are differences in the distribution and absorption of ions between different varieties of poplars.As a transport channel for ions,four kinds of mineral ions are transported to other parts of poplar under various drought conditions.Mg^2+is retained in the apoplast.This study provides a theoretical basis for the study of mineral ion absorption and distribution of plants under drought stress.