... and proportional in- crease in the levels of histidine in the xylem sap. Histidine in the xylem sapwas shown to be coordinated with Ni, although the concentration of histidinewas enough to ... Malate was found not to be involved in Zn complexation in the roots, shoots, or xylem sap. These results suggest thathistidine may be important in detoxifying Zn in the root cells; however, ... version:April 24, 2000PrefaceVolume 75 contains four outstanding reviews dealing with phytoremediation,issues related to water use in China, humic substances, and remote sensing. Chap-ter 1 is an...