Nutrient transportation and aging process of ramets in Aster pekinensis populations on Songnen grassland,China
Aims Aging is an important process in the life cycle of plants,and the capacity of different organs to store nutrients and their activities in plants are important in judging individual aging.To date,the changes in these aspects during the aging process of different age-class ramets in clonal plants remain unclear.Methods Aster pekinensis is a typical clonal plant with a root sucker.On the grassland of Northeast China,its ramets are mainly composed of three age classes(la,2a and 3a).In this study,the differences in water soluble carbohydrates(WSC)contents among storage organs(stem base,root collar,and taproot)or among age classes,and the seasonal variation of rhythm in the three ramets of Aster pekinensis populations were analyzed quantitatively.Important findings At the yellow-leaf stage,the WSC content of the taproot was higher than that of the root collar.The WSC content of root collars and taproots in la and 2a ramets was significantly higher than that in 3a ramets.The WSC content of stem bases was significantly lower in la ramets than in 2a and 3a ramets.Throughout the entire growth season,the root collars of 1 a ramets always received priority allocation of nutrients,and their WSC content continued to accumulate in an exponential form.The nutrient contents in the root collars of the 2a and 3a ramets,as well as the taproots of the three age-class ramets,were all consumed first and then accumulated,and the WSC content changed in the form of a quadratic curve.The capacity of the taproot to store nutrients was generally greater than that of the root collar,whereas the activity of the root collar was greater than that of the taproot across the three age-class ramets in Aster pekinensis populations.The nutrient storage capacity and activity of young ramets were strongest.There were no signs of aging in adolescent ramets.The old ramets were dramatically aged,and their nutrient storage capacity and activity reduced significantly.This study provides a new approach that combines qualitative and quantitative analyses to understand the relationship between the spatiotemporal changes in WSC content and the aging process of individuals in plant populations.
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万方数据
