Effect of copper stress on photosynthesis of navel orange seedlings

Abstract

The hydroponic method was used to study the photosynthetic characteristics of navel orange No.52 seedlings under Cu stress. The study shows that chlorophyll (Chl.) content under 0.1 μmol・L −1 of Cu increases significantly, but decreases under 5 μmol・L −1 , 20 μmol・L −1 and 40 μmol・L −1 of Cu. Carotenoid content decreases with increasing Cu concentration. Net photosynthetic rate and light saturation point reduces under Cu stress as Cu concentration exceeds 5 μmol・L −1 . 0.1 μmol・L −1 of Cu improves, but 5 μmol・L −1 and 20 μmol・L −1 of Cu decrease transpiration rate and stomatal conductance of orange. These parameters do not change significantly under 40 μmol・L −1 of Cu. At the same time, high Cu concentration (5 μmol・L −1 , 20 μmol・L −1 and 40 μmol・L −1 )