Investigation on Biochemical Changes of Iron and Zinc Sulfats Injections to Trunk of Sour Orange Trees for Removing Chlorosis

Due to chlorosis in leaves of sour orange trees in Eram Botanical Garden of Shiraz University, in a 2-year experiment, the trunk injection of various concentrations of iron and zinc sulfate fertilizers was examined. Experiment was conducted in a randomized complete block design with six treatments and four replications during two successive years of 201 and 2013. Treatments were injections of two concentrations of iron and zinc sulfates (. and 1%) separately, a combination of iron and zinc sulfates (with the concentration of 0.5%) and distilled water as control. In each replication, the amount of 600 ml of fertilizer was injected into each tree. Two and six weeks after injection, leaf area, chlorophyll and carotenoid contents, photosynthesis rate, sugar, starch, catalase and peroxidase activities, iron and zinc contents of leaves and total soluble solid of fruits were measured. The results showed that trunk injection of 1% of iron sulfate significantly increased photosynthesis rate, chlorophyll, starch, iron contents of leaves, catalase and peroxidase activities compared to control. While combination of 0.5% of iron and zinc sulfates had the most effect on leaf area in comparison to control. Iron sulfate injection significantly increased the amount of chlorophyll and corrected the sour orange chlorosis. On the basis of the results of this experiment, trunk injection of iron sulfate at the rate of 1% had the greatest effect on removing chlorosis in sour orange leaves.