干旱胁迫对华北落叶松和油松幼苗叶绿素含量与根系活力的影响

Drought Stress on Chlorophyll Content and Root Activity in Seedlings of Larix principis-rupprechtii and Pinus tabuliformis

为研究干旱胁迫对针叶树种幼苗生长的影响,以华北落叶松和油松的2年生幼苗为材料进行大田干旱胁迫模拟试验,通过对比干旱胁迫下针叶中叶绿素a、叶绿素b、叶绿素a+b的含量、叶绿素a/b值以及根系活力的变化,探究不同干旱胁迫强度对华北落叶松和油松幼苗生长的影响。结果表明:(1)华北落叶松的叶绿素a、叶绿素b以及叶绿素a+b的含量在干旱胁迫下呈现出先增加后下降的趋势,叶绿素a/b的值在干旱胁迫下不断减小;而油松的叶绿素a、叶绿素b以及叶绿素a+b的含量呈现缓慢下降的趋势,叶绿素a/b的值在较小范围内波动。(2)华北落叶松和油松的根系含水率在干旱胁迫下不断下降,根系活力先增强后减弱。(3)在干旱胁迫下,华北落叶松的叶绿素a+b含量与其根系活力之间表现出极显著的正相关关系,而油松的叶绿素a+b含量随根系活力增大而呈现增加趋势,但并没有达到显著水平。经过综合分析并结合植物的抗旱性表现,得出华北落叶松幼苗对干旱胁迫的敏感程度远大于油松,其适应性和抗旱性相比于油松较弱。

To study the effect of drought stress on coniferous seedlings,2-year-old seedlings of Larix principisrupprechtii and Pinus tabuliformis were adopted as test materials,and drought stress experiments were conducted using a field simulating method,to analyze the changes of chlorophyll a,chlorophyll b,chlorophyll a＋b contents and the value of chlorophyll a/b as well as root activity.Results showed that：（1） the contents of chlorophyll a,chlorophyll b,chlorophyll a＋b rose first and then fall under the drought stress in L.principisrupprechtii,but in P.tabuliformis they all decreased,the value of chlorophyll a/b decreased continuously in L.principis-rupprechtii and fluctuated within a small range in P.tabuliformis;（2） the root water content declined continuously and the root activity increased firstly and then decreased in the two tested species under drought stress;（3） the chlorophyll a＋b content had a significantly positive correlation with root activity in L.principisrupprechtii,but there was no significant correlation in P.tabuliformis,only an increasing trend of chlorophyll a＋b content along with the increase of root activity.In conclusion,the seedling of L.principis-rupprechtii was more sensitive to drought stress than that of P.tabuliformis,and had lower adaptability and drought resistance.