Boron contamination in the agricultural lands is an important problem for Western Turkey, which has rich boron deposits. This study was carried out in Nazilli regions upon orange (Citrus sinensis L. Osbeck) plants irrigated with relatively high boron laden channel waters (LCI) and with well waters (LWI) which contain lower amounts of boron. The leaves of the plants irrigated with channel water were found to contain twice the amount of boron compared with those irrigated with well waters. Boron content of leaves in both groups were approximately ten times the boron content in the soil on which they are grown. In the leaves of the plants irrigated with channel waters there were approximately 50% chlorophyll loss and higher chlorophyll a/b and caretonoid/chlorophyll ratios. In the excessive b...