Abstract:

To investigate the effects of varying precipitation patterns on the growth and root morphological characteristics of Fraxinus malacophylla seedlings during the dry season,artificial precipitation simulation experiments were conducted.1)During the first stage of the dry season(November to the next January),belowground biomass,total biomass,and root-crown ratio,total root length,and root surface area increased asprecipitation levels rose;provided the precipitation interval remained constant.However,when the precipitation interval was extended from 5-day intervals(T)to 10-day intervals(T+)underthe same precipitation,the total root length,root surface area,root volume,and specific root length all decreased.2)During the second stage of the dry season(February to April),total root length initially increased and then decrease as precipitation levels rose,given a constant precipitation interval.Aboveground biomass increased with prolonged interval at the same total precipitation level.3)Under different precipitation treatments,total root length consistently increaseed over the course of dry season,whereas root surface area,root volume,average root diameter,and specific root length gradually decreased.This study demonstrated that precipitation was the primary factor in the different precipitation change experiments,and the precipitation interval played a secondary role,and they were interdependent.The mechanisms of seedling growth and root morphology characteristics of Fraxinus malacophylla responded differently to the precipitation change with the duration of the dry season.

Key words: Fraxinus malacophylla, precipitation, precipitation intervals, root morphology