Clone specific differences in a Phragmites australis stand : II. Seasonal development of morphological and physiological characteristics at the natural site and after transplantation

Abstract

Two Phragmites clones, growing adjacent to each other but differing conspicuously in stand structure, were investigated in 1996 regarding seasonal change in morphological and physiological parameters. Both clones showed significant differences in shoot morphology (length, diameter, dry weight, leaf area), maximum above-ground (420 versus 152 g DW m −2) and below-ground biomass (2.4 versus 1.5 kg DW m −2). Furthermore, physiological parameters (N concentration, N and P content per shoot and m 2, content of dissolved amino acids, N translocation rate) varied between clones in their time course. Clone-specific variations in these characteristics were significant even after transplantation to another field site. Overall, these results suggest that the distinct growth forms and levels of productivity of the two Phragmites clones are the result of genotypic variation. It is hypothesized that both clones follow distinct ecophysiological strategies causing their morphotypic differentiation. Implications of genotypic determination of growth forms are discussed in relation to nutrient supply, N limitation, population plasticity, eutrophication and reed regression.