土壤盐胁迫对构树幼苗生理特性的影响

对盐胁迫下构树幼苗生理的研究有助于探明构树的耐盐机理为治理盐碱地和荒漠化的造林树种选育及栽培提供依据.以不同浓度的NaCl胁迫当年生构树幼苗,对胁迫后叶片细胞质膜的伤害程度,渗透调节物质进行研究.结果显示:幼苗经盐胁迫,其叶片相对电导率随着盐浓度的增加和时间的延长而升高;叶绿素在中盐和高盐胁迫下含量降低;胁迫第2 d,叶片中的脯氨酸便大量积累;盐胁迫前期对幼苗叶片中的可溶性蛋白没有影响,随后,蛋白质含量下降并且盐浓度越大含量越低;可溶性糖在盐胁迫前期逐渐升高但到中后期的变化无明显的规律.实验结果显示构树在一定的盐浓度范围和时间内能够主动调整其生理代谢,通过合成有机溶质以提高适应能力而忍受逆境.

Effects of Saltinity Stress on Characteristics of Seedling Physiology in Broussonetia papyrifera L.

The research on physiological characteristics of Broussonetia papyrifera L.seedling under salt stress would help ascertain the tree species' salt-tolerant mechanism so as to provide the basis for selecting and cultivating plants on saline land.The yearling seedlings of Broussonetia papyrifera L.were subjected to the salinity stress of soil with different NaCl concentrations.The injury degree of cell plasma membrane and the osmoregulation substance in the leaves of the seedlings were studied.The results showed that the leaves' relative conductivity went up as the NaCl concentration increased and the time extended.The content of chlorophyll decreased under medium and high salt tress.In two days of the salt stress,proline accumulated greatly.The salt stress made no difference to the soluble protein of leaves on the seedlings during the early stage.At a later time,the content of soluble protein decreased and the higher the concentration was,the lower of the content would be.During the early stage of the stress the content of soluble sugar increased gradually.But in the middle and late stages its content changed irregularly.The experiments indicated that Broussonetia papyrifera L.could avoid the iniury of salt stress for the tree by composing organic solutes improves the ability to fit stress circumstance.