Modifying effect of indole-3-acetic acid on furadan toxicity on two species of rice field cyanobacteria

It has been reported earlier that hormones are secreted by cyanobacteria under water logged rice fields, and thus when cyanobacterial populations are abundant in such environment, might be secreting such substance in considerable amounts which possibly ameliorate the toxic effect of the pesticide on these non-target organisms present in the same environment. The present study infers that the exogenous hormone IAA supported growth and chlorophyll-a content of Nostoc sp and Anabaena sp when supplemented at a concentration of 0.01mM /10ml culture to the nitrogen free BG 11 medium though their effect to stimulate growth differ among the two experimental organisms. However,exogenous hormone induced growth increase was only about 12 and 13 per cent more in the test species than the control. The concentration of IAA which supported growth increase of experimental organisms could decrease the toxic effect of mostly the lower concentration of Furadan on the growth, chlorophyll-a content and carotenoid content whereas at higher concentration no such promising result was observed in both the organisms.