Environmental and Chemical Control of Vegetative Dormant Bud Production in Hydrilla verticillata

Bud production was investigated using algal-free cultures ofthe aquatic weed, Hydrilla verticillata. Vegetative dormantbud production in hydrilla is stimulated by a shortened photoperiodand is not temperature-dependent between 15 and 30 C. The phytochromesystem appears to be involved in this process and ABA stimulatesbud production. Artificial illumination throughout the nightprevented dormant bud production. Ethylene, applied as ethephon,reduced bud production in greenhouse cultures by 80 per centwhen applied at a level of 0.1 mgl^–1 ethephon at 2-d intervals. Hydrilla verticillata, aquatic plants, dormant buds, ethephon, ethylene, abscisic acid