Seed soaking in exogenous gibberellin and auxin and their impact on seed germination and seedling physiology of Buchloe dactyloides (Nutt.) Engelm.

In order to study the effects of exogenous hormones on breaking seed dormancy, and seedling growth of buffalo grass, seeds were soaked in three concentrations of gibberellic acid(GA3) and auxin(IAA) separately. After soaking, seed germination, seedling growth, non-structural carbohydrates, and endogenous hormone levels were measured. Our results showed: 1) Seed germination GA3 increased germination vigor and increased germination, germination rate, germination index and seed vigour index. Based on the treatment effects, gibberellin at 2 000 mg·L-1 had the most significant impact. Auxin also effectively enhanced the viability of the seeds, of which 450 mg·L-1 auxin yielded the best results. 2) Seedling growth GA3 treatment promoted the growth of aerial parts. IAA effectively increased buffalo grass seedling root length and root to bud ratio, at a low concentration of 250 mg·L-1, which yielded the best results. 3) Seedling non-structural carbohydrates-optimal GA3 concentration was 1 500 mg·L-1 while for IAA it was 450 mg·L-1, which could effectively increase the content of soluble sugars and starch in buffalo grass seedlings. 4) Seedling endogenous hormones ——IAA, GA3 and ABA, all increased with the treatment with exogenous gibberellin and auxin, of which GA3 at 2 000 mg·L-1 and IAA at 450 mg·L-1 provided best results. In summary, the best phytochemical to break dormancy in buffalo grass seeds and promote the growth of seedlings, buds and endogenous gibberellin is GA3 at a concentration of 2 000 mg·L-1. The best reagent to enhance soluble sugars and starch content in buffalo grass seedlings is also GA3 at a concentration of 1 500 mg·L-1. The best reagent to promote the growth of the buffalo grass seedlings and shoot growth is IAA, when applied at a concentration of 250 mg·L-1. Auxin at a concentration of 450 mg·L-1 was found to be the best hormone to increase endogenous IAA and ABA levels in buffalo grass.