MORPHOGENETIC CHANGES INDUCED BY A LOW RED-FAR-RED RATIO AND THEIR GROWTH CONSEQUENCES IN WATER HYACINTH (EICHHORNIA-CRASSIPES)

Plants of water hyacinth (Eichhornia crassipes) were grown under two r ed/far-red ratios (Z) to investigate the effects on morphology and gro wth of the light quality component of canopy shade. Experiments were c onducted in diffuse sunlight in the presence or absence of far-red rad iation. Under low Z conditions, fewer new ramets were produced and the ir stolons were shorter. The number of leaves per ramet was unchanged, but petiole length and blade area were increased. This change in biom ass partitioning resulted in a lower investment in the main resource-a cquiring organs (leaf blades and roots). The lower allocation of bioma ss to the leaf blades was compensated for by a higher net assimilation rate, such that relative growth rate remained unchanged.