Effects of chromium on hypocotyl elongation, wall components, and peroxidase activity of Phaseolus vulgaris seedlings

摘要

Abstract In this investigation, the effect of the heavy metal chromium (Cr) on hypocotyl elongation of Phaseolus vulgaris seedlings in light was studied. The seedlings were subjected to two concentrations of Cr (0.5 and 1.0 mM) in the form of K2Cr2O7. Hypocotyl elongation (growth) was measured in terms of length. Change in wall components (pectic polysaccharides and xyloglucan) and peroxidase activity (soluble and bound) were also studied. Both concentrations of Cr inhibited hypocotyl length and a clear concentration effect was observed. Maximum pectic polysaccharide content was observed at a high concentration of Cr and a minimum was observed in the distilled water control. A clear inverse correlation was observed, supporting the conclusion that pectic polysaccharides may be involved in cell wall loosening. Even xyloglucan (high and low) content showed a clear inverse correlation with hypocotyl length. It appears that Cr inhibits hypocotyl elongation and xyloglucan and pectic polysaccharide contents are ...