Abstract

A greenhouse experiment was carried out to evaluate possible adverse impacts of transgenic cotton on ecosystems and the environment via effects of transgenic Bt+CpTI cotton root exudates on the growth and defense enzymes activity of conventional parental cotton (Zhong 1423-6). Results indicated elevated defense enzymes activities in the leaves of conventional parental cotton seedlings treated with varying concentrations of transgenic cotton root exudates. Compared to controls, increases were 7.5 to 9.9% for catalase (CAT), 27.5 to 86.3% for peroxidase (POD), 1.3 to 5.4% for superoxidative dismutase (SOD) and 1.8 to 5.8 fold for ascorbate specific peroxidase (APX). However, biomass and height of conventional cotton seedlings were not affected by any concentrations of transgenic cotton root exudates. These results suggested that the cultivation of transgenic Bt+CpTI cotton plants posed little risk to conventional parental cotton based on their root interactions.