Developmental Constraints: Effect on Population Growth and Patterns of Resource Allocation in a Clonal Plant

Abstract

A comparison of ramet population growth rates in a flowering and a nonflowering population of Eichhornia crassipes Solms., the water hyacinth, indicates that inflorescence production is inversely correlated with ramet population growth rate. The differences in patterns of resource allocation exhibited by the 2 populations are explained in terms of developmental constraints acting on the differentiation and growth of a limited meristem population. The meristem population is limited in size by the developmental morphology of the ramets. This interpretation contrasts with more traditional ones in which fixed C, measured as dry weight, is viewed as the limiting currency. The inadequacy of fixed C as a limiting currency for plant resource allocation studies is discussed in relation to the origins of its use in the zoological literature. While most animals must acquire all usable C through a single mouth and then apportion it among competing needs, herbaceous plants generate new mouths (= C acquiring organs) as they build aboveground structure.