干旱胁迫对紫叶紫薇容器苗生长及生理的影响

Effects of Drought Stress on the Growth and Physiology of Purple-leaf Lagerstroemia indica Container Seedlings

为探究干旱胁迫对紫叶紫薇容器苗的生长及生理影响,以紫叶紫薇优良新品种‘丹红紫叶’2年生容器苗为研究对象,设计了5个干旱胁迫强度处理,测定不同干旱胁迫处理对容器苗生长及生理相关指标的影响。结果表明:干旱胁迫对紫叶紫薇容器苗的生长及生理的影响显著。随着干旱胁迫强度增加,紫叶紫薇容器苗叶片相对含水量、过氧化物酶活性、超氧化物歧化酶活性、可溶性蛋白含量、净光合速率、气孔导度、蒸腾速率总体上呈现降低趋势,重度干旱时这些指标分别比正常供水显著下降了21.45%、40.45%、31.92%、3.30%、81.25%、89.29%、87.17%,极重度干旱时达到最低值。可溶性糖含量、脯氨酸含量、丙二醛含量随着干旱胁迫程度增强而一直上升,重度干旱时分别比正常供水显著增加了122.92%、74.98%、288.34%,极重度干旱时达到最大值。随着干旱胁迫强度加重,过氧化氢酶活性、叶绿素相对含量、水分利用效率呈现先升高后降低的趋势,中度干旱时过氧化氢酶活性最大,叶绿素相对含量和水分利用效率则是轻度干旱最高,极重度干旱时最低。胞间CO_(2)浓度随着干旱胁迫加强而先降后升,正常供水的胞间CO_(2)浓度最高,中度干旱最低。紫叶紫薇容器苗具有抵御中度干旱的能力,当土壤相对含水量下降至30%~35%时应及时给苗木浇水灌溉。

To investigate how drought stress affects the physiology and growth of purple-leaf Lagerstroemia indica container seedlings,two-year-old L.indica‘Ebony Embers’container seedlings,5 drought stress treat-ments were created to ascertain the impact of various treatments on the growth and physiological indicators.The findings demonstrated the considerable effects of drought stress on the physiology and growth of container seed-lings of purple-leaf L.indica.The drought stress intensity increased,and the purple-leaf L.indica container seed-lings'relative water content,peroxidase activity,superoxide dismutase activity,soluble protein content,net photo-synthetic rate,stomatal conductance,and transpiration rate all showed a general declining trend,these indicators significantly decreased by 21.45%,40.45%,31.92%,3.30%,81.25%,89.29%,and 87.17%respectively during severe drought compared to normal water supply,falling to their lowest values in extremely severe drought.When drought stress intensified,the levels of soluble sugar,proline,and malondialdehyde consistently increased.In severe drought,these levels significantly increased when compared to normal water supply by 122.92%,74.98%,and 288.34%,respectively,and reached their maximum value in extremely severe drought.Catalase activity,relat-ive chlorophyll content,and water use efficiency showed an increasing and then decreasing trend with the intens-ity of drought stress.In moderate drought,catalase activity was highest,relative chlorophyll content and water use efficiency were highest,and in very severe drought,they were all lowest.Intercellular CO_(2) concentration de-creased and then increased with the intensification of drought stress,with the highest intercellular CO_(2) concentra-tion in normal water supply and the lowest in moderate drought.Purple-leaf L.indica container seedlings may tol-erate a moderate amount of drought.However,timely irrigation and watering of the seedlings is required when the relative soil moisture content falls to 35% to 30%.