干旱区生态环境知识资源中心

Timing of germination and flowering under different environmental conditions was investigated in four coexisting serotinous desert plants: Blepharis grossa (annual herb), Geigeria alata, Geigeria ornativa (facultative perennial herbs) and Petalidium setosum (perennial shrub). Germination patterns were similar under varying environmental conditions in the study species, except for P. setosum, which germinated later when conditions were less favourable. B. grossa always germinated early, G. alata and G. ornativa later, which could be explained by differences in their seed dispersal mode. Thus no obvious niche separation in timing of germination was indicated in the study species. Flowering periods varied between seasons rather than between species and no niche separation in flowering times existed between the study plants. This might indicate that either interspecific competition plays a minor role in a community of desert serotinous plant or that niche separation exists in other components of the plants’ niche, such as seed dispersal, seedling establishment and/or microhabitat selection.