Plant growth regulators for enhancing Alberta native grass and forb seed germination

Abstract

A germination trial was conducted to screen effects of plant growth regulators (PGRs) on 9 Alberta native grass and forb species with the aim of identifying PGRs with the capacity to improve seed germination and early plant development in disturbed and reconstructed soil conditions. Seeds were treated with 500 mg/L of various gibberellins (GA3_40 [40% GA3], GA3_90 [90% GA3], and GA4/7), 5 mg/L cytokinin (kinetin), and 0.1 mg/L brassinosteroids (brassinolide). Experiments were conducted in a growth chamber following a 24 h soaking period. PGR seed treatment did not significantly increase percent (%) germination for the majority of species, but rather assisted in breaking seed dormancy and enhancing early radical emergence. Early germination at day 7 was measured for Fragaria virginiana (130–150% increase over the control for GA3_40, GA3_90, GA4/7, and brassinolide), Koeleria macrantha (36% increase for GA3 40), Poa palustris (98–123% increase for all PGRs), Agrostis scabra (42–56% increase for all PGRs) and Festuca hallii (85–93% increase for kinetin and brassinolide). Gibberellin treatments were significantly more effective in improving shoot growth; kinetin and brassinolide were significantly more effective in enhancing root development for the majority of tested plant species. PGRs having the greatest overall impact on seed germination and plant development, as measured by vigor index were brassinolide and GA4/7. Tested PGRs have the potential to benefit native grass and forb restoration and revegetation efforts, improving the efficacy of planting prescriptions, with the aim of increasing early ground cover, stabilizing soils, enhancing biodiversity, and reducing the time to reclamation certification.