Narges Shafiei; Esmaeil Khaleghi; Noorollah Moallemi
Abstract
Abstract Background and Objectives Olive (Olea europaea) is one of the most important fruit trees in the pomology industry of Iran. Statistics shows that this fruit tree is cultivated ...
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Abstract Background and Objectives Olive (Olea europaea) is one of the most important fruit trees in the pomology industry of Iran. Statistics shows that this fruit tree is cultivated in more than of 102 thousand hectares of territory of Iran. Due to severe water shortages, it is necessary to make use of methods with objectives to reducing the negative effects of drought on plant and to increasing water use efficiency. Previous studies stated that plant growth regulators such as salicylic acid could apply to reducing the adverse effects of environmental stresses. Salicylic acid (SA) influences various physiological and biochemical functions in plants and has diverse effects on the tolerance to biotic and abiotic stress. The objective of this study was to investigate the effects of exogenous SA application on biochemical traits of ‘Konservalia' olive leaf under 100 %, 66 % and 33 % ETcrop by analyzing chlorophyll content, total soluble carbohydrate and proline. Materials and Methods The study was conducted in order to investigate the effect of different levels of water deficit (100, 66 and 33 percent of evapotranspiration (ETcrop)) and four concentrations of salicylic acid (0, 0.5, 1 and 2 mM) on fresh and dry root weight, stem and leaf and leaf number, leaf area, stem diameter, leaf proline, total soluble sugars, chlorophyll content as a factorial experiment based on a randomized complete block design with three replications. Two- year old olive trees (Olea europaea cv. ‘Konservalia’) were used. Seventy- plants were grown in 11 L pots, containing a mixture of field soil (73.2 % sand, 13.3 % silt and 13.5 % clay) and manure. Plants were sprayed with four concentrations of salicylic acid and irrigated every ten days, according to the amount of evatranspiration of plants (ETcrop). Parameters such as leaf proline and total soluble carbohydrates content, chlorophyll content were measured three times at intervals of once every 30 days after treatment. Data analysis was performed using MSTATC and SAS software and mean comparison was done by Duncan's multiple range test at 5 and 1 % probability Results The results showed that leaf proline and total soluble carbohydrates increased while chlorophyll content (chlorophyll a, b and total) decreased with increasing levels of water deficit. Results also showed that the interaction of salicylic acid and irrigation had a significant effect on fresh and dry root weight, stem and leaf, leaf area and plant height at p Discussion In this study, the role of SA in plant tolerance to abiotic stresses such as heat, heavy metal, and osmotic stress was reported. The results showed that 2 mM SA application alleviated the adverse effects of drought stress (66 and 33 % ETcrop) in young olive trees through the improvement of chlorophyll content, enhancing leaf total soluble carbohydrate and proline content which can lead to osmotic adjustment.
