ACCUMULATION OF WEATHERED P,P '-DDE IN XYLEM SAP OF GRAFTED WATERMELON

Abstract

An average p,p'- DDE concentrations in pore water of contaminated soil ranged from 0.36 mu g/L to 0.55 mu g/L and there were no statistically significant among the cultivars. Conversely, the xylem sap p,p'- DDE concentration of heterografted watermelon having a zucchini rootstock and watermelon scion was 71 mu g/L and it was greater than intact watermelon plants (0.49 mu g/L) but less than that of intact plants of zucchini (141 mu g/L). Homografting showed no effect on xylem sap p,p'- DDE concentrations of the identical cultivars. The bio- concentration factors (BCFs) which is an average p,p'- DDE concentration in xylem sap over average p,p'- DDE in pore water were 344, 325, 197, 1.28, and 0.89 for intact plant of zucchini, homografted zucchini, heterografted watermelon, homografted watermelon, and intact plant of watermelon, respectively. Xylem sap p,p'-DDE concentrations of the heterografted watermelon plants were clearly influenced by plant phylogeny and enhanced by the zucchini rootstock compared to intact watermelon plants.