Effects of Leaf Area and Transpiration Rate on Accumulation and Compartmentalization of Cadmium in Impatiens walleriana

The efficiency of phytoextraction is limited because of the low growth exhibited by plants under the stress of heavy metals. Impatiens (Impatiens walleriana) cuttings were grown in soils artificially contaminated with cadmium (Cd) and modified with chemical fertilizer to study the relationship among the leaf area, transpiration rate, and Cd accumulation. The subcellular distribution of Cd in various impatiens organs was also measured. Experimental results showed that there were positive, linear relationships between the leaf area and the transpiration rate. A similar relationship was found between the transpiration rate and the Cd accumulation in the shoots. Suitable management practices can be conducted to increase the transpiration rate and thus the plant's phytoextraction efficiency. In the roots and leaves, Cd was mainly compartmentalized in the soluble fraction and the cell wall fraction, respectively. The varied subcellular distribution of Cd in the different organs was responsible for the high accumulation capacity.