The response of shoot accumulation of trace elements in Chinese cabbage tomicroclimate modification

In three consecutive years of field experiments (1994-96), three different environmental conditions for the growth of Chinese cabbage (Brassica pekine nsis (Lour) Rupr. cv. Nagaoka 50) were established by using two cover treat ments (T-1 and T-2) and a control uncovered cultivation (T-0). The T-1 [50 Vm polyethylene cover; 20 degreesC air temperature; 61.9% relative moisture ; 207 Wm(-)2 irradiance] and T-2 [a 17gm(-2) non-woven fleece; 18 degreesC; 63.4%; 205Wm(-2)] gave rise to differences in environmental conditions wit h respect to T-0 [14 degreesC; 57.5%; 237 Wm(-2)]. We analysed chloride (CI ), barium (Ba), rubidium (Rb) and tin (Sn) in the whole tops of experimenta l plants. Chloride removal was high for Brassica pekinensis but considerabl y lower for Rb, giving intermediate values for Ba and Sn. The influence of environmental factors under T-1 increased trace-element removal and enhance d the usefulness for phytoremedation.