تاثیر کاربرد کود زیستی حل‌کننده پتاسیم در مقایسه با سولفات پتاسیم بر رشد و برخی صفات فیزیولوژیکی تربچه قرمز (Raphanus Sativus L.) تحت تنش خشکی

استفاده ازکودهای زیستی افزون بر افزایش بهره وری و افزایش عملکرد گیاهان، به کاهش مصرف کودهای شیمیایی و حفظ محیط زیست کمک می کند. در این راستا، هدف از این پژوهش تاثیر کاربرد کودهای زیستی محتوی باکتری های حل کننده پتاسیم (pseudomonas koreensis و pseudomonas vancouverensis)، باکتری های حل کننده فسفر (pseudomonas putida) و باکتری های تثبیت کننده نیتروژن (pantoea agglomerans) به عنوان یک نهاده سازگار با محیط زیست بر رشد و عملکرد تربچه قرمز و تاثیر آن بر تحمل این گیاه به تنش خشکی بود. بدین منظور آزمایشی در قالب طرح کاملاَ تصادفی در شرایط گلخانه و در گلدان با 10 تیمار کاربرد کود سولفات پتاسیم، کاربرد کود زیستی باکتری حل کننده پتاسیم و کودهای زیستی باکتری های محرک رشد در سه تکرار مورد ارزیابی قرار گرفت. نتایج این پژوهش نشان داد که اعمال تنش خشکی موجب کاهش وزن تر غده به میزان 65 درصد در تیمار شاهد شد ولی در وزن تر بخش هوایی، کاهش ناشی از تنش دیده نشد. در تیمار کاربرد سولفات پتاسیم این مقدار کاهش 55 درصد و در تیمار کود زیستی مقدار کاهش 48 درصد بود. کاربرد توام کود حل کننده پتاسیم و سایر کودهای محرک رشد نسبت غده به بخش هوایی را 34 درصد افزایش داد در حالیکه کاربرد سولفات پتاسیم تاثیر معنی داری بر این مورد نداشت. تنش خشکی غلظت پرولین، آمینواسیدها، قندهای محلول و نشت یونی را در برگ ها افزایش داد اما کاربرد سولفات پتاسیم و کودهای زیستی اثرات تنش خشکی را تعدیل نمود. بر اساس نتایج این پژوهش می توان کاربرد کودهای زیستی فوق را در برنامه تغذیه گیاه تربچه قرار داد.

Effect of Potassium Solubilizing Biofertilizers Application Compared to Potassium Sulfate on Growth and Some Physiological Traits of Radish (Raphanus sativus L.) under Drought Stress

Introduction: Plant growth promoting bacteria are beneficial microorganisms that produce plant resistance to a variety of biological and nonbiological stresses, including drought, extreme temperatures, salinity, toxic metals, etc, and increase plant productivity and yield. The use of these microorganisms as biological agents in increasing soil fertility and improving agricultural productivity has been studied by many researchers, so a proper understanding of their effect on drought resistance can be effective in water resources management. Useful in field and reducing environmental effects of using chemical fertilizers. The purpose of this study was to investigate the effect of some biofertilizers on growth and some physiological and biochemical characteristics of red radish and in comparison with potassium sulfate application under drought stress.Material and Methods: In other to investigate the effect of application of biofertilizers containing potassiumsoluble bacteria (Pseudomonas koreensis and Pseudomonas vancouverensis), phosphorussolubilizing bacteria (Pseudomonas putida) and nitrogenfixing bacteria (Pantoea agglomerans) on plant growth and function, this experiment was done with 10 treatments and three replications in the form of completely randomized design in greenhouse. Finally the statistical population consisted of 30 pots of 10 treatments and three replications for red radish. Drought stress was applied in such a way that the apparent symptoms of stress were seen in the plants and the amount of water used was the same for all plants. The experiment was carried out in greenhouses and nylon pots with a capacity of 6.5 kg were used. The soil was prepared using a calcareous soil of Zanjan University research field. Its absorption was less than critical. Organic matter content was 0.4% and lime equivalent was 14.1% pH of soil 7.57 and EC of abstract soil paste was 2.21. Pots were treated with municipal water for 25 days after planting. EC values of water was 400 µS / cm that irrigated the plants every three days. The desired biofertilizers were added to the pots with irrigation water. After 25 days, 15 pots of treatments 4 to 6 were subjected to drought stress. 40 days after planting before drying of the plants, weight, moisture content of plant tissue, leaf proline content, total free amino acid, and total soluble sugars in leaf extract were measured. Analysis of variance was performed using SAS software and LSD test at the 5% level was used to compare the means.Results and Discussion: Results of analysis of variance showed that the effect of different treatments on aerial fresh weight was significant at 1% level. Fertilizer treatments under stress and nonstress conditions significantly increased aerial fresh weight. Among nonstress treatments, the highest fresh weight was obtained from treatment 2 (10.03 g / pot) and the lowest was in control treatment (6.55 g / pot). Among the drought stress treatments with application of different fertilizers used, treatment 8 (9.19 g / pot) had the highest and treatment 6 (7.04 g / pot) had the lowest fresh weight. Application of potassium sulfate fertilizer increased the fresh weight of aerial part both under stress and nonstress condition. Potassium soluble biofertilizer alone and in combination with other biofertilizers increased radish aerial fresh weight, which was not significantly different from potassium sulfate fertilizer. In radish, drought stress affected the tuber fresh weight more. The radish plant uses the water of the tuber reserve in drought stress so that the leaves are less susceptible to stress. In nonstress conditions, application of potassium sulfate fertilizer and biofertilizers in radish increased yield. Potassium sulfate effect was greater. In stress conditions, the effect of biofertilizers was more than potassium sulfate in stress condition. The effect of potassium soluble biofertilizer application was almost identical with the combined application of different biofertilizers. Drought stress increased the concentration of proline, amino acids and soluble sugars in leaves and tubers of radish. Increasing concentration of these compounds indicated that plants were resistant to drought. Application of potassium sulfate and biofertilizers decreased these concentration and the effect of biofertilizers was more than that of potassium sulfate. The amount of ion leakage also increased under drought stress but leakage decreased by using potassium sulfate and biofertilizers. Drought stress also reduced the starch concentration in leaves and tubers of radish, which is a consequence of drought stress.Conclusion: In general, application of potassium sulfate and biofertilizers moderated the effects of drought stress and in some cases the effect of biofertilizers was greater. Integrated use of biofertilizers was not significantly different from the use of potassium soluble biofertilizer alone. So, the results of this study showed that the use of biofertilizers can be included in the plant nutrition program as a factor in reducing the negative effects of stress on plants.