3. Results
3.1. Growth characteristics and pigments analysis Treatment of seedlings with higher concentrations of dimethoate (100 and 200 ppm) alone and in combination with UV-B (30 min) caused a concentration dependent decrease in growth measured as shoot and root length, fresh and dry mass of shoot, root and leaves (P < 0.05) (Fig. 1).
Simultaneous exposure of dimethoate and UV-B (30 min) further declined the growth.
Low concentration (50 ppm) of dimethoate stimulated the growth of seedlings. Interestingly, in combination with UV-B and 50 ppm of dimethoate mitigates the inhibitory effect of UV-B.
Significant decrease in Chl a and Chl b contents was also observed (P < 0.05) in response to individual treatments of
dimethoate (100 and 200 ppm) and UV-B (30 min) and thecontents further declined following combined treatments, however, the deleterious effect was found to be less than the additive effect (Table 1).