[Age structure of the modules of clonal Heteropappus altaicus population on weedy meadow steppe in Songnen Plain of China].

Heteropappus altaicus is a root sucker type perennial herbaceous clonal plant of compositae. The age structure of its modules on the weedy meadow in Songnen Plain of China was studied by a method, in which, age class was compartmentalized according to the propagared generations in bud section of taproot. The results showed that both ramets and buds of the clonal population consisted of 4 age classes. The modules of ramets showed stable age structure, with the age spectrum being 22.6%, 44.8%, 28.8% and 3.8% from 1st to 4th age classes at flowerbud stage, respectively. At milk stage, the modules of reproductive ramets showed a stable age structure, with the proportion of 2nd age class being the largest (45.6%) and of 4th age class being the least (0.8%), while those of vegetative ramets showed an expansive age structure, with the largest proportion (47.5%) of 1st age class and the least (1.1%) of 4th age class. The taproot of the ramets could survive for five years at most. The productivity of 2nd age class ramets was most vigorous at different growth stages. The ramets of 1st age class had the biggest productive potential, while the ramet productivity of 4th age class was generally weakened at milk stage. The potential population in the bud banks presented an expansive age structure.