Biochemical changes associated with gibberellic acid-like activity of smoke-water, karrikinolide and vermicompost leachate during seedling development of Phaseolus vulgaris L.

Smoke-water (SW), karrikinolide (KAR(1)) and vermicompost leachate (VCL) have been reported to possess gibberellic acid-like activity. The effects of these plant growth-promoting substances (PGPSs) on biochemical changes occurring during seed germination of Phaseolus vulgaris were assessed. Seeds were incubated/germinated under dark conditions in water (control) or with different concentrations of SW, KAR(1), VCL and gibberellic acid (GA(3)) for 7d. The maximum seedling fresh weight (1.863g) was recorded for the SW (1:750 v/v) treatment. The longest seedling axes (9.9cm) and the highest number of adventitious roots (16.3) were recorded for VCL-treated seedlings (1:10 and 1:5 v/v, respectively). Analysis of two important hydrolytic enzymes, acid phosphatase and alpha-amylase, showed maximum activity [1856nkatmg(-1) and 3.225mgmin(-1)(gFW)(-1), respectively] in the seeds incubated with 10(-8)M KAR(1). In all the treated seedlings, proline content was significantly reduced [43.67 mu g(gFW)(-1); VCL (1:20 v/v)] in comparison to the control [87 mu g(gFW)(-1)] but there was an increase in amino acids with some concentrations of PGPSs. The tested PGPSs significantly influenced various biochemical parameters that play a significant role in seed germination and plant growth. This study indicates that PGPSs may act via stress-relieving biochemical pathways during seed germination.