生境土壤水分变化下梭梭幼苗的生长特征

Growth characteristics of Haloxylon ammodendron seedlings under soil moisture change in habitat

设置不同水分梯度,分析梭梭[Haloxylon ammodendron(C.A.Mey.)Bunge]幼苗根区不同土层土壤水分含量的变化以及梭梭幼苗生长的变化,探究梭梭幼苗在不同时期、不同干旱胁迫下的响应特征。结果表明,梭梭幼苗根区0~20 cm土层土壤水分含量小于20~40 cm土层,各时期土壤水分含量偏度系数和峰度系数均表现为0~20 cm土层大于20~40 cm土层;梭梭幼苗生长期(6月、8月、10月)各土层土壤水分含量变化在0.05的检验水平下符合正态分布。在不同干旱胁迫下,梭梭幼苗植株各形态指标(株高、冠幅面积、基径)的增幅随时间延长均呈递减趋势,6—8月,梭梭幼苗株高增幅表现为轻度干旱处理>中度干旱处理>重度干旱处理>CK,冠幅面积增幅表现为轻度干旱处理>CK>中度干旱处理>重度干旱处理,基径增幅表现为CK>轻度干旱处理>中度干旱处理>重度干旱处理;8—10月,梭梭幼苗株高、冠幅面积、基径增幅均表现为CK>轻度干旱处理>中度干旱处理>重度干旱处理。生长期梭梭幼苗生境不同土层深度土壤水分含量与植物的株高、冠幅和基径均呈负相关,相关系数分别为-0.088、-0.506和-0.711,其中与基径的相关性达显著水平(P<0.05)。

Different water gradients were set up to analyze the changes of soil moisture content in different soil layers of the root zone and the growth of Haloxylon ammodendron seedlings,and to explore the responses characteristics of Haloxylon ammodendron seed-lings at different stages and under different drought stresses.The results showed that the moisture content in 0~20 cm soil layer was less than that in 20~40 cm soil layer in the root zone of Haloxylon ammodendron seedlings,and the skewness coefficient and kurtosis coefficient of soil moisture content at each stage in 0~20 cm soil layer were higher than those in 20~40 cm soil layer.The change of wa-ter content in each soil layer during the growth period of Haloxylon ammodendron seedlings(June,August and October)conformed to normal distribution at the inspection level of 0.05.Under different drought stresses,the increase in various morphological indicators(plant height,crown area,basal diameter)of Haloxylon ammodendron seedlings showed a decreasing trend with time.From June to August,the increase of plant height of Haloxylon ammodendron seedlings showed mild drought treatment>moderate drought treatment>severe drought treatment>CK,the increase of crown area showed mild drought treatment>CK>moderate drought treatment>severe drought treatment,the increase of basal diameter showed CK>mild drought treatment>moderate drought treatment>severe drought treatment.From August to October,the increase of plant height,crown area,and basal diameter of Haloxylon ammodendron seedlings all showed CK>mild drought treatment>moderate drought treatment>severe drought treatment.During the growth period,the soil mois-ture content of different soil depths of Haloxylon ammodendron seedlings habitat was negatively correlation with the plant height,crown width and basal diameter,with correlation coefficients of-0.088,-0.506 and-0.711,respectively,and the correlation with basal diameter was significant(P<0.05).