干旱胁迫对榆树幼苗生物量分配的影响

干旱是主要的环境胁迫因子之一,严重影响植物的分布与生长发育。通过选取辽宁阜新章古台沙地1年生榆树幼苗为材料,采用盆栽控水方法,设置田间持水量80%、60%、40%和20%等4个水分处理梯度,研究干旱胁迫对榆树幼苗株高、基径及叶片、茎和根系生物量分配的影响。结果表明:随着干旱胁迫程度增加,幼苗茎和根系的生物量逐渐降低;但轻度干旱胁迫增加了株高和基径的生长,提高了叶片生物量,以抵御干旱胁迫的影响。中度干旱胁迫下,增加了根系生物量分配的比例,从而更利于获取水分资源适应干旱环境;重度干旱胁迫下幼苗无法存活。在科尔沁沙地,栽植榆树幼苗保证存活生长的最低田间持水量为40%。

Effects of Drought Stress on Biomass Allocation of Ulmus pumila Seedlings

Drought is the main environmental stress factor that affects plant growth,development and distribution. Taking one-year-old U.pumila seedlings in Zhanggutai sand land in Fuxin City of Liaoning Province as research ob-jects,adopting water-controlled in pot,four water gradient of field capacity (80%,60%,40% and 20%)were set;the effects of drought stress on tree height,basal diameter and biomass allocation of leaf,stem and root ofUlmus pumi-la seedlings were studied.Result shows that the biomass of stem and root declined with the increase of degree of drought stress.Mild drought stress increase the growth of tree height and basal diameter,increase leaf biomass un-der to prevent drought stress.The distribution proportion of root biomass increased under moderate drought stress to adapt drought environment.The seedlings were dead under severe drought stress.Therefore,the lowest field ca-pacity for survival and growth of U.pumila seedlings should be 40% in Horqin sand land.