Cresols are ubiquitous due to industrial production and natural presence. o-cresol (2-methyl phenol) is highly toxic to both fauna and flora. It has been included in the EPA list as one of the priority pollutants. The deleterious effects of pesticides, herbicides, and many other chemical compounds on seed germination are known. However, the effect of o-cresol on seed germination is not known. Therefore, it is of interest to study the effect of o-cresol on germination of 13 different vegetable crop seeds using standard Filter Paper Method. There is no effect on germination for brinjal, red chili, and (green gram, chickpea, cucumber, tomato, fenugreek, cowpea, Green pea, coriander, and spinach, seeds even at 1500 mg/l of o-cresol However, okra and mustard were found to be sensitive to ocresol. Germination of mustard under controlled concentration of o-cresol showed similar results by soil method. It was found that germination percentage and seedling vigour (Vigour Index) was reduced by o-cresol. The percent germination was reduced to 64 and 12 at 25 and 50 mg o-cresol/kg soil as against 100% in the case of untreated control. The vigour index was reduced to 160 and 10, respectively as against of 646 that for the control. The viability of seeds by 2,3,5 - tetrazolium trichloride (TTC) test showed that a considerable reduction was observed at 200mg/l o-cresol. Reduced protease and amylase activity in o-cresol shows inhibited mustard generation. However, mustard generation inhibition was restored by the bioremediation of o-cresol using Pseudomonas monteilii SHY. Thus, the biodegradation effects of o-cresol by Pseudomonas monteilii SHY on mustard seed germination are shown.
Keywords: Brassica juncea; Pseudomonas monteilii SHY; bioremediation; germination inhibition; mustard; seeds.