干旱胁迫对北美红栎幼苗生理特性的影响

摘要

采用盆栽控水法设置5种干旱胁迫梯度，研究干旱胁迫对1年生北美红栎幼苗生理特性的影响。结果表明：在干旱胁迫下，北美红栎幼苗叶片的叶绿素a和叶绿素b质量分数呈下降趋势，而w（叶绿素a）∶w（叶绿素b）呈现上升趋势，说明叶绿素b比叶绿素a更容易受到破坏。可溶性糖质量分数也呈先升高再降低的趋势。随着干旱胁迫强度的增加及持续时间的延长，在土壤田间持水量15％（ W1）和土壤田间持水量30％（ W2）梯度下的细胞膜相对透性增大，相对电导率增大，膜脂过氧化产物丙二醛（ MDA）质量摩尔浓度增加。同时超氧化物歧化酶（ SOD）、过氧化物酶（ POD）的活性先升高后下降，而在土壤田间持水量60％（ W4）下的各生理生化指标变化趋势不明显。复水后，各指标均基本恢复至对照水平。%With five levels of drought stress , we investigated the effects of drought on physiological characteristics on one -year-old potted seedlings of Quercus rbu ra.The contents of chlorophyll a and b were downtrend , while the ratio of chlorophyll a and b was increasing trend .Chlorophyll b was easier to damage than chlorophyll a .The soluble sugar contents showed the trend of increasing firstly and then reducing again .With the increasing of drought stress intensity and duration extension , the relative permeability of cell membrane , relative conductivity and malondialdehyde ( MDA) of the membrane lipid per-oxidation product increased at W1 and W2 levels.While the superoxide dismutase (SOD) and peroxidase (POD) activity increased firstly and then decreased , but the variation tendency of every physiological and biochemical indicators was not obvious at W4 levels.Each index recovered to the control level after rewatering .