The Effects of Plant Growth Regulators On Invasive Species.

The technical objectiveof this project was to investigate the role of plant growth regulators on seed germination and plant responsiveness of invasive species. Two plant growth regulators, abscisic acid and gibberellic acid were evaluated for their effects on the imbibition, germination and growth rates of cheatgrass (Bromus tectorum), yellow starthistle (Centaurea solstitialis) and Sericea Lespedeza (Lespedeza cuneata) seeds. 

 

The experimental design included several treatments at differing concentrations of plant growth regulators, compared to a control, to investigate variations in seed germination rates and growth rates of the three invasive plants.  For the germination studies 20 seeds of each plant species were placed into Petri dishes containing either distilled water or treatment solutions of 0, 0.1, 1 and 10 mM gibberellic acid (GA) and treatment solutions of 0, 0.1, 1 and 10 mM abscisic acid (ABA).  Germination was judged visually by cracking of the seed coat, determined on a daily basis throughout 1 to 28 days of incubation. ABA was shown to promote and maintain seed dormancy, while GA reduced seed dormancy in the invasive plant species.

 A major problem in preventing invasion by undesirable species is our ability to manage plant establishment, which is largely controlled by the timing of seed germination and rapid growth rates.  These attributes provide a selective advantage over native species by contributing to an invasive species ability to establish itself on disturbed lands and reproduce.  While commercially available growth regulators are commonly used to suppress seed germination and reduce vegetative growth in turfgrass such as tall fescue (Lolium arundinaceum), very little work has been done looking at the use of growth regulators for the control and management of invasive weeds. The results of this study will provide information about the control and management of invasive plant species using phytohormones.