Vegetative spread of dioecious hydrilla colonies in experimental ponds

摘要

Stolon formation and fragmentation, vegetative mechanisms by which hydrilla colonies spread, were studied in ponds located in Lewisville, Texas, over a two year period (1994-95). Stolons were determined to be the predominant mechanism for localizedexpansion in undisturbed areas. While some fragments were produced, they accounted for only 0.1% of the establishment of rooted plants in new quadrats. Peak production of fragments occurred in October and November, with fragment densities of 0.15 N m-2 day-1. Expansion by stolons occurred between June and November of each year, with higher rates of spread (up to 4.0 cm day-1 radial growth) observed in the second season.