LEAF DEMOGRAPHY, FLOWER PRODUCTION AND BIOMASS OF DIPLOID AND TETRAPLOID POPULATIONS OF <i>PHLOX DRUMMONDII</i> HOOK. ON A SOIL MOISTURE GRADIENT

Abstract

S ummary We investigated the effects of chromosome doubling upon leaf demography, flower production, biomass and response breadth on a soil moisture gradient of three varieties of Phlox drummondii , each variety being represented by two cytotypes. Increased chromosome number produced slower growth rates, increased leaf and plant longevity, and a tendency to flower later, less synchronously and produce fewer flowers. The loss of the ability to reproduce in hydric environments was also observed in all tetraploids. Other factors such as degree of response breadth, overlap and increased vigour due to increased chromosome number were found to be genotype dependent. Level of polyploidy had no effect upon the number of pre‐reproductive deaths.