Germination Stimulation of Kentucky Bluegrass Seed Permeated with Plant‐Growth Regulators Dissolved in Acetone1

Abstract

Freshly harvested Kentucky bluegrass (Poa pratensis L.) seed generally fail to germinate rapidly. Such seed germinate poorly under warm temperatures. The objective of this study was to permeate seeds with vartous plant‐growth regulators and determine their effects on speed and total germination under favorable and unfavorable conditions. Freshly harvested ‘Merion’ and ‘H.1’ Kentucky bluegrass seed were used in this study. Samples of seed were soaked for 1 hour in acetone containing gibberllic acid (0.5 mM), kinetin (0.1 mM), ethephon (500 ppm), abscisic acid (0.04 mM), or fusicoccin (25 ppm) alone, or in various combinations. Seeds were vacuum‐dried after treatment.In both laboratory and greenhouse studies, permeation of gibberellic acid alone, or in combination with kinetin and/or ethephon dissolved in acetone, generally increased the speed and/or total germination. At a sub‐optimal temperature, none of the treatments was effective in improving germination. At supra‐optimal temperature, germination of the control was almost completely inhibited. Kinetin and ethephon by themselves or in combination did not improve the germination. Gibberellic acid, on the other hand, by itself or in combination with kinetin and/or ethephon, improved germination significantly.