Plant Growth Regulators as Potential Tools in Aquatic Plant Management: Efficacy and Persistence in Small-Scale Tests
PURDUE UNIV LAFAYETTE IN DEPT OF BOTANY AND PLANT PATHOLOGY
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Bioassay and small-scale test systems were used to determine the efficacy and persistence of plant growth regulators with potential for aquatic plant management. The goal of the project was to identify compounds that reduce plant height and thus weediness of the submersed flowering plants hydrilla Hydrilla verticillata Royle and Eurasian watermilfoil Myriophyllum spicatum L.. Laboratory bioassays indicated that triclopyr and imazapyr were herbicidal rather than growth regulatory on these species. Bensulfuron-methyl and amidochlor showed growth re properties on Eurasian watermilfoil, and further research may be warranted on these compounds. A number of studies were conducted on flurprimidol, a gibberellin synthesis inhibitor which reduces stem internode length, thereby effectively reducing vertical stem length. Two-hour exposures to flurprimidol significantly reduced vertical stem length at concentrations of 750 ug L-1 for hydrilla and 200 ug L-1 for Eurasian watermilfoil for at least 28 days post-treatment, suggesting that short-term exposures may be efficacious under certain circumstances. Flurprimidol was less effective at reducing stem lengths under low light intensities 4-18 uE m-2 sec- than under high light 8001000 uE m-2 sec-1, but stem lengths were shorter under low fight than in the untreated controls. As the plants reach the more well-lit portions of the water column, vertical growth should be reduced if flurprimidol is still present at physiologically active concentrations.
- Agronomy, Horticulture and Aquiculture
- Jet and Gas Turbine Engines