Stimulation of germination by gibberellic acid and bacillus subtilis on common bean, maize, wheat and okra exposed to acid mine water at different temperature regimes

Abstract

Seed quality management is considered the key to boosting agricultural production, which may be quickly done using seed improvement technologies. Comprehensive seed priming techniques is one of the tools that enhance fast germination and improve plant yields. On the other hand, access to heavy metals from acid mine drainage water can cause germination to be delayed and impair its pace and uniformity, resulting in poor crop production. Plants’ diverse biochemical processes such as enzyme and antioxidant production, protein mobilization, and photosynthesis may be disturbed. Herein, sowing common bean, maize, wheat, and okra treated with substantial acid mine drainage water at different concentrations (0 %, 25 %, 50 %, 75 %, 100 %) at 25 °C and 35 °C was carried out to assess the effects of gibberellic acid and B. subtilis BD234 on seed germination and seedling growth, for better seedling establishment. Seeds that had not been primed were also exposed to various levels of AMD and used as controls. The results indicated that seed germination parameters (Final germination percentage; germination speed; emergence rate index, vigour index) were reduced with higher acid mine drainage (AMD) concentrations (75 % and 100 %) compared with low AMD concentrations (0 %, 25 % and 50 %) for common bean, maize, wheat, and okra. In contrast, the germination indices were improved by applying gibberellic acid and B. subtilis, while increase in AMD concentrations had adverse effects on root and shoot length. The results also showed that temperature influenced all crops' germination speed and percentage. Overall, the results suggest that gibberellic acid and B. subtilis BD234 priming agents can be a practical approach to improve seed germination and seedling growth in bean, maize, wheat, and okra under acid mine water drainage contaminated environments.