自然条件下风箱果的克隆构型

在自然条件下,风箱果(Physocarpus amurensis)主要靠克隆繁殖维持种群。植物克隆构型的可塑性变化对于其适应环境异质性具有重要意义。为探求风箱果的克隆构型及根茎生长动态,研究了其地下根茎的构筑型、形态特征、根茎的直径随长度变化的规律和地下根茎间的夹角。结果表明:风箱果的地下根茎的构筑型基本上属于游击型;风箱果无性系平均含有(6±2)个分株和(9.33±3.48)个根茎;根茎的直径随长度变化的曲线为抛物线型;分枝夹角较为稳定,多为30°和70°。风箱果生产大量的根茎系统,每一个克隆片段能够占据一定的空间,以保证自身生存和维持种群繁衍。

CLONAL ARCHITECTURE OF PHYSOCARPUS AMURENSIS IN NATURAL CONDITIONS

Aims Few studies have investigated the clonal growth patterns of shrubs. Physocarpus amurensis is a rhizomatous, endangered shrub with an extremely narrow distribution in Heilongjiang Province of China. Its sexual reproductive capacity is low, and seedling recruitment has rarely been observed under natural conditions. Therefore, clonal growth seems to be important in maintaining populations. Morphological plasticity is important for clonal plants to exploit environmental heterogeneity. This study investigates the clonal architecture and ramet growth dynamics of P. amurensis to provide useful information for protection of this species. Methods Variations in clonal architecture were studied by field investigation and laboratory analysis: architectural form of rhizomes, configuration characteristics of rhizomes, variations in diameters of rhizomata with increasing rhizome length, and branching angle between rhizomes.  Important findings The architectural form of rhizomes of P. amurensis belongs to the sparse guerrilla linear system. Ramets and rhizomes per clone averaged 6±2 and 9.33±3.48, respectively. The distribution of diameters of rhizomata with increasing rhizome length was parabolic. Branching angle between rhizomes was consistent, usually 30° and 70°. Physocarpus amurensis forms large ramet systems with several interconnected ramets, covering a large area. This may be an adaptation to exploiting different habitats, allowing exploration of open space, which may ensure population survival and evolution.