علی پاداش

The aim of this study was to evaluate the effects of salicylic acid on lead toxicity in basil following lead addition to soil. This experiment was conducted as Randomized Complete Block with Factorial arrangement. Factors included the 4 levels of lead nitrate; 0 (control), 100, 200 and 300 mg per kg of soil and foliar application of salicylic acid at 3 levels of 0, 50 and 100 ppm. Phytotoxicity of Lead was determined as plant growth, concentration of photosynthetic pigments and catalase enzymes. Addition of lead significantly reduced dry weight of shoots and roots and photosynthetic pigments and increased soluble carbohydrates, catalase and peroxidase. In addition, salicilic acid spraying had a significant influence on all traits. In this study the interaction between salicylic acid and lead on shoot fresh and dry weight, root fresh weight, chlorophyll a and b, carotenoids, carbohydrates, catalase and peroxidase were significant, and salicilic acid play moderating role and reducing the negative effects of lead toxicity. The results of this experiment suggested salicylic acid application in basil can be reduced lead toxicity by increasing growth and concentration of photosynthetic pigments.

Nowadays, phenolic compounds and plant growth regulators such as salicylic acid has been prescribed to reduce the adverse effects of different stresses. This greenhouse experiment was conducted in 2013, as a factorial randomized complete block design with 3 replications, to examine the effects of lead and salicylic acid on basil (Ocimum basilicum) plant, cv. Keshkeni Luvelou. Factors included 4 levels of lead [0 (control), 100, 200 and 300 mg/kg of soil] and foliar application of salicylic acid at 3 levels [0 (control), 50 and 100 ml/L]. Results showed that addition of lead significantly reduced leaf area, number of leaves, plant hight, fluorescence and chlorophyll content of the plants and increased proline, soluble carbohydrates and guaiacol and ascorbate peroxidase enzymes. In addition, salicilic acid spraying had significant (P≤0.01) influence on all traits. Spraying salysilic acid at concentration of 100 ml/L at the fourth level of lead (300 mg/kg soil) decreased guaiacol, ascorbate peroxidase and soluble carbohydrates by 78.6, 73.8 and 24.3%, respectively, compared to the control. In this study, the interaction between salicylic acid and lead on leaf area, plant height, leaf chlorophyll content, fluorescence, proline, soluble carbohydrates, guaiacol and ascorbate peroxidase was significant. In general, the results of this experiment suggested that salicilic acid plays a moderating role, reducing the negative effects of lead toxicity on the studied traits of basil.

Today, phenolic compounds and plant growth regulator has been proposed, to reduce the negative effects of stress. Salicylic acid is a substance that causes plant resistance to biotic and abiotic stresses. This experiment was conducted in Zabol University during 2013 as factorial randomized complete block design with 3 replications. Factors included 4 levels of lead nitrate; 0 (control), 100, 200 and 300 mg per kg of soil and foliar application of salicylic acid at 3 levels of 0, 50 and 100 ppm. Addition of lead significantly reduced concentrations of potassium, magnesium, calcium, phosphorous and nitrogen and increased concentrations of sodium, polyphenol oxidase, ascorbate peroxidase, superoxide dismutase and peroxidase. In addition, salicylic acid spraying had a significant influence on all traits, and salicylic acid spraying at 100 mL/L increased concentrations of potassium, magnesium, calcium, phosphorus, nitrogen and decreased concentrations of polyphenol oxidase, ascorbate peroxidase, superoxide dismutase and peroxidase. In this study the interaction between salicylic acid and lead on potassium, magnesium, calcium, phosphorus, nitrogen, sodium and catalase, guaiacol peroxidase and polyphenol oxidase were significant, and salicylic acid play moderating role and reducing the negative effects of lead toxicity. The results suggested salicylic acid application in basil can increase uptake of macro and micro nutrients required for plant growth and reduce the negative effects of stress lead-induced oxidative damage.