Toxicity of arsenic (As) on seed germination of sunflower (Helianthus annuus L.)

Abstract

The effect of different levels (2, 4, 6, 8 and 10 mg/L) of arsenic (as sodium arsenate and sodium arsenite) on germination percentage, mean germination time, days to 50% germination, plumule and radicle length and seedling vigour index of four sunflower cultivars (FH-331, FH-385, FH-405 and FH-415) was determined under laboratory conditions. Germination percentage was gradually decreased with the increase in arsenic concentration in case of all sunflower cultivars. Low concentrations (2 and 4 mg/L arsenic) increased while higher concentrations (6, 8 and 10 mg/L arsenic) posed stress and caused reduction in plumule and radicle length (mm) of seedlings as compared to control. Out of all the four sunflower cultivars, H1 (FH-331) proved the most sensitive one by giving least values for plumule length, radicle length and seedling vigour index as observed during the course of this experiment.     Key words: Sodium arsenate, sodium arsenite, sunflower, seed germination, seedling growth.