Document Type : Research Paper
Authors
1 Ph.D. Student of Horticultural Science Tarbiat Modares University, Tehran
2 Professor of Horticultural Science Tarbiat Modares University, Tehran
3 Professor of Horticultural Department, Shahid Chamran University
4 Associate Professor respectively, of Food Science, Tarbiat Modares University, Tehran.
Abstract
With respect to arid and semi-arid climate of Iran, using methods which mitigate detrimental effects of water deficit on horticultural products would be of significant importance. Kaolin is an anti-transpiration material the application of which has been expanded during the recent years. For this purpose, the effect of three different levels of kaolin (0, 3 and 6%) as well as three different levels of irrigation (100, 65 and 40% potential ETcrop) on chlorophyll content and chlorophyll fluorescence in olive leaves “Dezful’ were examined as factorial test based on a completely randomized design in three replications (each replication including 3 pots) in the greenhouse of Horticulture Department, Faculty of Agriculture, Tarbiat Modares University (Tehran, Iran). The obtained results demonstrated that chlorophyll a and total chlorophyll were reduced under water deficit. The amount of reducing of chlorophyll a and total chlorophyll in 80 days after treatment was greater than that in 40 days after treatment. In addition, the amount of total chlorophyll in the sprayed plants with 6% kaolin was the highest (1.425 mg/g fresh weigh of leaf) in 80 days after treatment. Furthermore, it was shown that by reducing of water content to 65 and 40% ETcrop the content of chlorophyll “a” was greater than the plants which were sprayed at kaolin concentrations of 3 and 6% in comparison with the control. Meanwhile, the results of fluorescence parameters showed that maximum fluorescence indices (Fm), fluorescence variable (Fv) and ratio of fluorescence variable to maximum fluorescence (Fv/Fm) were reduced under drought stress. However, the kaolin treatment had no significant effect on these indices. Generally, it can be expected that spraying of the olive gardens in Iran with kaolin, especially in regions exposed to water deficit can moderate the drought stress and mitigate the detrimental effects of water deficit, while improving photosynthesis efficiency of the leaf.
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