Plant clonality: Biology and diversity

The current approaches to the study of clonal plants are reviewed. Most studies concentrate at the level of the ramet and clonal fragment exploring the “microscopic” view of clonal plants, dealing with the translocation of resources, clonal integration, plasticity of growth etc. The information gained, by this approach can be used in the understanding of higher levels of organization within the clonal system either with the help of spatially explicit modelling techniques, or by using means and distributions of size within a population instead of studying individual ramets separately. Plant scientists use the term clone with two meanings, viz. (a) a set of physiologically connected, but potentially independent ramets, and (b) a set of genetically identical, but potentially physically separated individuals. The overlap of these terms differs between individual plant species, depending on the extent of physical separation of the ramets and the degree of physiological integration between the ramets; the lower the frequency of ramet separation, the closer are the physiological and genetic concepts of the clone. Three critical areas seem to be neglected in clonal plant research: (a) the interrelationship between hierarchical levels in clonal plants, (b) the particular spatial structure of their environment, and (c) the importance of clonal plants in different ecological communities.