疏花水柏枝幼苗生物量与构件对模拟土壤地下水位变化的响应

Responses of biomass and components of Myricaria laxiflora seedlings to simulated soil water level changes

通过模拟不同地下水位的方法,对疏花水柏枝(Myricaria laxiflora (Franch.) P. Y. Zhang et Y. J.Zhang)一年生幼苗在不同条件下地上与地下部生物量及构件的变化进行测定,分析幼苗生长对地下水位变化的响应。结果显示:随着地下水位的降低,疏花水柏枝幼苗的生长特征指标均呈先增加后减少的趋势,其中地上、地下部分生物量的最高值分别为0.0438、0.0100 g,最低值分别为0.0177、0.0026 g。幼苗地上部生物量在-10 cm处理水平最高;地下部生物量在-15 cm处理水平最高。幼苗直径、根表面积、株高、主根长度、根体积、一级枝数、二级枝数等指标也分别在-10 cm或-15 cm处理水平达到最高值。疏花水柏枝幼苗主要构件的生长与地下水位的变化存在显著相关性。主成分分析结果表明,幼苗的地下部分更容易受到土壤地下水位变化的影响,幼苗性状症候群随地下水位的变化而发生移动,说明该物种幼苗在不同地下水位时的生长投资策略具有较大差异。

We studied changes in biomass and components of one-year-old Myricaria laxiflora seedlings under different simulated soil water levels to reveal the response of seedling growth to these changing conditions.Results showed that the growth characteristics(aboveground and underground biomass,plant height,and length of main root)of one-year-old seedlings increased at first and then decreased with decreased soil water level.The highest aboveground and underground biomass values reached 0.0438 g and 0.0100 g,respectively,and the lowest values were 0.0177 g and 0.0026 g,respectively.The highest aboveground biomass was observed in the-10 cm treatment,whereas the highest underground biomass was observed in the-15 cm treatment.The seedling component indicators,including seedling diameter,root surface area,plant height,root volume,primary branch number,and secondary branch number,also reached their highest values in the-10 cm or-15 cm treatments.There was a significant correlation between the growth of the main components of the seedlings and the change in soil water level.Principal component analysis indicated that the underground part of the seedlings was susceptible to changes in soil water level,and that the trait syndromes of seedling growth changed with changing soil water level.This suggests that the investment strategies of seedling growth differed among the different soil water levels.