Effect of alpha-naphthalene acetic acid and thidiazuron on seedling of economic crops grown in endosulfan sulfate-spiked sand.

The effect of two plant growth regulators, alpha-naphthalene acetic acid (NAA) and thidiazuron (TDZ) on the growth of sweet corn (Zea mays), cowpea (Vigna sinensis) and cucumber (Cucurmis sativus) seedling planted in 1-100 mg kg(-1) of endosulfan sulfate spiked sand was investigated. Endosulfan sulfate had no apparent toxicity as seedlings of these crop plants grew normally in endosulfan sulfate spiked sand. Concentration of endosulfan sulfate in sand affected the response of seedling induction by NAA or TDZ. Induction of crop seeds by NAA or TDZ did not promote growth of sweet corn, cowpea and cucumber to an appreciable extent. Both plant regulators at concentration of 10 mg l(-1) seemed to exert adverse effect on crop seedling. TDZ decreased shoot length, root length and chlorophyll contents in leaves of sweet corn and cowpea growing in endosulfan sulfate spiked sand. In contrast, NAA was not toxic and promoted growth of sweet corn and cowpea seedling. However, cucumber was affected by NAA and TDZ more than other plants. TDZ significantly decreased biomass and root length of cucumber. Also, NAA significantly decreased cucumber root length and tended to increase cucumber root dried weight when grown in 100 mg kg(-1) of endosulfan sulfate spiked sand.