RAHUL SHRIVASTAVA, RAMA SARKAR AND UGAM K. CHAUHAN
Abstract
Chemical herbicides which inhibit photo system II used for evaluating growth inhibition of OscilIntoria laete-virens. In each of the herbicides used LC250 for growth and '50 for long term effect on photosynthesis are of similar values. The lc° values against 0.lnete-virens for atrazine, bentazone, diuron and metribuzin respectively are 48 nM, 6.4 nM, 2 nM and 11 nM which are considerably less than the corresponding concentration for spinach thylakoids. The secondary manifestation of herbicides effect on 0. Inete-virens is the changes in pigment profiles, phycocyanin concentration increased many fold compared to chlorophyll. The other major change is that the non-polar lipid fractions triglycerides (TAG) is lost and new lipid free cholestrol (Fe) has appeared which could be an indication of herbicide effect.