Growth and water movement in silver maple seedlings affected by cadmium

Effect of cadmium chloride on dry weight accumulation, height growth, and relative conductivity of stems of silver maple seedlings exposed to 0. 5, 10, or 20 ppm CdCl//2 multiplied by (times) 2 one-half H//2O (on weight basis of rooting media) was determined. Leaf, stem, and root dry weight were significantly reduced by all CdCl//2 treatments. Seedling height at 8 weeks was severely reduced and strongly correlated with applied CdCl//2 levels. Relative conductivity of excised stem sections was significantly reduced by Cd treatment. The reduction was caused by (i) a progressive decrease in the proportion of xylem tissue available for water conduction, (ii) reduced size of vessels and tracheids, and (iii) reduced size of (iii) partial blockage of xylem elements by cellular debris or gums. These findings are discussed in relation to water stress.