تاثیر سالیسیلیک اسید و کینتین بر برخی صفات فیزیولوژیک، بیوشیمیایی و انباشت کادمیوم در گندم دوروم

برای بررسی تاثیر سالیسیلیک اسید و کینتین بر برخی صفات فیزیولوژیک، بیوشیمیایی و انباشت کادمیوم در گندم دوروم، پژوهشی گلدانی به‌صورت فاکتوریل در قالب طرح پایه بلوک های کامل تصادفی در سه تکرار در سال زراعی 1402- 1401 انجام شد. فاکتورها شامل سطوح کادمیوم (0 و 20 میلی‌گرم کلرید کادمیوم بر کیلوگرم خاک) و سطوح مختلف هورمونی (شامل 0، 50 و 75 میکرو‌مولار کینتین و 200 و 400 میکرو‌مولار سالیسیلیک اسید) به صورت مجزا و توام در نظر گرفته شد. تیمار کادمیوم سبب کاهش معنی دار هدایت روزنه ای، سرعت فتوسنتز، تعرق، شاخص کلروفیل و فعالیت کاتالاز شد، ولی فعالیت آسکوربات پراکسیداز، غلظت مالون دی آلدئید، محتوای قندهای محلول و انباشت کادمیوم در ریشه و برگ را افزایش داد. کاربرد هورمون های سالیسیلیک اسید و کینتین توانست سبب بهبود صفات فیزیولوژیک و بیوشیمیایی شده و تاثیر نامطلوب کادمیوم را تعدیل نماید و جذب و انباشت کادمیوم در ریشه و برگ را کاهش دهد. فعالیت کاتالاز و آسکوربات پراکسیداز در واکنش به تیمارهای سالیسیلیک اسید و کینتین افزایش یافت. از این رو، کاهش غلظت مالون دی آلدئید مشاهده شد. تیمار توام کادمیوم با 400 میکرو مولار سالیسیلیک اسید و 50 میکرومولار کینتین به عنوان غلظت مطلوب هورمونی تعیین شد و در تیمار با کادمیوم، سبب بهبود فعالیت آنتی اکسیدانی و ویژگی های فتوسنتزی و کاهش انباشت کادمیوم در ریشه و برگ در مقایسه با تیمار کادمیوم به تنهایی شد. در مجموع، یافته‌ها نشان داد محلول‌پاشی سالیسیلیک اسید و کینتین می‌تواند به عنوان راهکاری برای افزایش کارایی گندم در خاک های آلوده به کادمیوم در نظر گرفته شود.

effects of salicylic acid and kinetin on some physiological, biochemical traits and the accumulation of cadmium in durum wheat

to study the effects of salicylic acid and kinetin on some physiological and biochemical traits as well as the accumulation of cadmium in durum wheat, a pot experiment was carried out using a factorial experiment based on a randomized complete block design with three replications during the 2022-2023 growing season. cadmium treatments (0 and 20 mg cd kg-1 soil (cdcl2)) and different concentrations of kinetin and salicylic acid (0, 50, and 75 μm, kinetin; and 200 and 400 μm, salicylic acid) were assigned in plots. cadmium treatment significantly reduced stomatal conductance, photosynthesis, transpiration, chlorophyll index, and catalase activity. however, it increased ascorbate peroxidase activity, malondialdehyde concentration, electrolyte leakage, soluble carbohydrate content, and cadmium accumulation in root and flag leaf. foliar application of kinetin and salicylic acid mitigated the adverse effects caused by cadmium stress on physiological and biochemical parameters significantly when root and flag leaf cadmium concentrations decreased compared to the cadmium treatment. catalase and ascorbate peroxidase activity increased in response to salicylic acid and kinetin treatment. hence, a decrease in lipid peroxidation and malondialdehyde concentrations was observed. the optimum hormone concentrations needed to exhibit a considerable increase in studied traits were 50 μm and 400 μm salicylic acid, particularly in cadmium treatments. foliar application of kinetin alleviated symptoms of the cadmium treatments by enhancing the activities of antioxidant enzymes and photosynthetic properties compared with individual cadmium treatments. overall, these findings showed that foliar application of kinetin and salicylic acid can be considered a strategy to enhance the performance of wheat cultivars in soil contaminated with cadmium. introductioncadmium contamination of soil and food crops is one of the most serious environmental problems in recent years, and it has resulted from industrialization, wastewater irrigation, and extensive agricultural systems. high concentrations of cadmium in the soil can potentially threaten human health because it can be easily absorbed and accumulated in different parts of crops such as the root, stem, leaf, and grain. finally, it can enter the food chain and enter the human body. plants respond to the presence of cadmium in the soil. cadmium influences morphological, physiological, biochemical, and structural processes and inhibits plant growth and crop production. cadmium toxicity severely reduces the growth and yield traits of plants. cadmium toxicity is caused by changes in the concentration of nutrients in roots and leaves, the formation of reactive oxygen species, and a decrease in transpiration, photosynthesis rate, and chlorophyll concentration, which subsequently reduces crop productivity. plant hormones, including salicylic acid and kinetin, are crucial in responding to cadmium toxicity. exogenous treatment with salicylic acid and kinetin alleviates the effects of cadmium toxicity in plants exposed to cadmium. this study aimed to explore optimum hormone concentrations in enhancing cadmium tolerance at wheat plants’ physiological and biochemical levels.materials and methodsto study the effects of salicylic acid and kinetin on some physiological and biochemical traits as well as the accumulation of cadmium in roots and leaves of durum wheat, a pot experiment was carried out using a factorial experiment based on a randomized complete block design with three replications during the 2022-2023 growing season. cadmium treatments (0 and 20 mg cd kg-1 soil (cdcl2)) and different concentrations of kinetin and salicylic acid (0, 50, and 75 μm, kinetin; and 200 and 400 μm, salicylic acid) were assigned in plots. the study site was located at the research farm of shahid chamran university of ahvaz, iran. at first, the soil needed for the experiment was weighed. the content of cd2+ (mg kg-1) in the soil was calculated according to the dry weight of the soil, and cdcl2 was sprayed close to the soil surface in the form of the solution. cadmium was thoroughly mixed with the soil placed into each pot. hormonal treatments were applied at the beginning of stem elongation (stage 33 of the bbch scale). the plants were grown under natural environmental conditions. plants were watered with sufficient water until the end of the experiment. the data regarding stomatal conductance, photosynthesis rate, transpiration, chlorophyll index, catalase and ascorbate peroxidase activity, malondialdehyde concentration, soluble carbohydrate content, and cadmium accumulation in roots and flag leaf was recorded. the transfer factor was computed as the ratio of the cadmium concentration in leaves and roots. results and discussionthe results showed a significant difference among cadmium treatments regarding the most studied traits. cadmium treatment significantly reduced stomatal conductance, photosynthesis, transpiration, chlorophyll index, and catalase activity. however, it increased ascorbate peroxidase activity, malondialdehyde concentration, electrolyte leakage, soluble carbohydrate content, and cadmium accumulation in root and flag leaf. foliar application of kinetin and salicylic acid mitigated the adverse effects caused by cadmium stress on physiological and biochemical parameters significantly when root and flag leaf cadmium concentrations decreased compared to the cadmium treatment. cadmium caused a significant increase in flag leaf cadmium concentrations by 31 times compared to control, while the increase in flag leaf cadmium concentrations at 50 and 75 μm, kinetin; and 200 and 400 μm, salicylic acid treatments were by 18, 19, 17 and 20 times, respectively, when compared to cadmium-deficient plants. catalase and ascorbate peroxidase activity increased in response to salicylic acid and kinetin treatment. hence, a decrease in lipid peroxidation and malondialdehyde concentrations was observed. hormonal treatments of 50 and 75 μm, kinetin, and 200 and 400 μm, salicylic acid reduced transfer factor by 21, 24, 24 and 27 %, respectively, compared to hormone-deficient plants. conclusionoverall, the results of this experiment showed that the optimum hormone concentrations needed to exhibit a considerable increase in studied traits were 50 μm kinetin and 400 μm salicylic acid; remarkably, in cadmium treatments, foliar application of kinetin and salicylic acid alleviated symptoms of the cadmium treatments by enhancing the activity of antioxidant enzymes and photosynthetic properties compared with individual cadmium treatment. moreover, foliar application of kinetin and salicylic acid can be considered a strategy to enhance the performance of wheat cultivars in soil contaminated with cadmium.