تاثیر باکتری‌های ریزوسفری محرک رشد گیاه و فیلتر‌کیک بر رشد و غلظت عناصر غذایی در گیاه اسفناج در برهم‌کنش با علف‌کش

گیاه اسفناج گیاهی حساس به علف های هرز بوده و علف کش اختصاصی برای آن وجود نداشته و استفاده از علف کش های پیشنهادی مانند متری بیوزین باعث اختلالات متابولیکی در اسفناج شده که نتیجه آن کاهش مولفه های رشدی و تغذیه ای در این گیاه می باشد. در این پژوهش تاثیر باکتری های ریزوسفری محرک رشد گیاه از گروه سودوموناس (جدایه هایrum14  و cha0) و فیلتر کیک به عنوان محصول جانبی کارخانه شکر (f) و ماده ای غنی بر غلظت عناصر غذایی و وزن خشک در گیاه اسفناج بررسی شد. همچنین تاثیر باکتری های ذکر شده و فیلتر کیک بر کاهش اثرات منفی تنش ناشی از علف کش متری بیوزین مورد مطالعه قرار گرفت. نتایج این پژوهش نشان داد که استفاده از باکتری های ریزوسفری محرک رشد و فیلترکیک هر کدام به تنهایی و یا با استفاده همزمان باعث افزایش غلظت عناصر پرمصرف (فسفر، پتاسیم، کلسیم و منیزیم) و کم مصرف (مس، روی و آهن) و همچنین افزایش وزن خشک در گیاه اسفناج می گردد. از نظر آماری بیشترین افزایش غلظت عناصر و وزن خشک در تیمار استفاده همزمان جدایه rum14 و فیلترکیک (rum14+f) مشاهده گردید. همچنین مشخص گردید استفاده از علف کش متری بیوزین باعث کاهش غلظت عناصر و وزن خشک می گردد و از نظر آماری با افزایش مصرف علف کش این تغییرات افزایش می یابد. بررسی های آماری نشان داد که استفاده از باکتری های ریزوسفری محرک رشد و فیلتر کیک به تنهایی و یا با هم، اثر تنش ناشی از استفاده علف کش (کاهش وزن خشک و همچنین کاهش غلظت عناصر) را به میزان زیادی در گیاه اسفناج کاهش می دهد و از نظر اماری تیمار rum14+f  موثرترین تیمار بود. نتایج این تحقیق نشان می دهد که جدایه های باکتری سودوموناس و فیلترکیک در افزایش رشد گیاه اسفناج، افزایش عناصر پر مصرف و کم مصرف در گیاه اسفناج و همچنین در کاهش تنش ناشی از استفاده از علف کش موثر می باشند.

Effect of Plant Growth Promoting Rhizobacteria and Filter Cake on Growth and Nutrient Concentration in Spinach Plant in Interaction with Herbicide

Background and Objectives: In recent years, the production of healthy foods through environmentally friendly methods has received much attention. Spinach is a vegetable plant rich in minerals and vitamins which is used in green and cooked forms. Thus, healthy production of this plant with the greatest quantitative and qualitative yield is of particular importance. Weeds as unwanted plants in spinach fields can damage this plant significantly. Nevertheless, spinach is severely sensitive to different herbicides. The goal of this study was to investigate the effect of plant growth promoting rhizobacteria (PGPR), filter cake and metribuzin herbicide on growth and mineral nutrition of spinach plant. In this study, the growth and nutritional parameters of spinach interact with PGPR, filter cake and metribuzin herbicide was also aimed.Materials and Methods: The spinach seeds (Spinacia oleracea L. Varamin cultivar) were sown in pots containing 40% field soil and 60% sand (10 seeds in each pots). To investigate the impact of PGPR isolates and filter cake on concentration of macronutrients (K, Ca, Mg, and P), micronutrients (Cu, Zn, and Fe) and leaves dry weight, Pseudomonas protogenes CHA0 (CHA0) as a reference strain, P. alloputida RUM14 (RUM14) which was collected from Iranian field soil and 3% by weight of fresh filter cake (F3%) were used. Spinach seedlings were inoculated for 14 days with 50 mL of bacteria strains suspension with optical density one (OD600=1). 3% by weight of filter cake were mixed to soil of pots before sowing the seeds. Metribuzin herbicide at three levels (0 (H0), 50 (H1) and 100 (H2) grams per hectare) were used. The effects of PGPR, filter cake and metribuzin herbicides and their interactions were also studied (CHA0 + F0 + H1, RUM14 + F0+ H1, CHA0 + F0 + H2, RUM14 + F0 + H2, B0 + F3% + H0, B0 + F3% + H1, B0 + F3% + H2, CHA0 + F3% + H1, RUM14 + F3% + H1, CHA0 + F3% + H2, RUM14 + F3% + H2). The experiment had a randomized complete block design with three replications. The treatments (3 metribuzin herbicide × 2 filter cake × 3 PGPR) were arranged in factorial combination. The statistical analysis was performed using Duncan’s multiple range test at 5% probability level.Results: Statistical analysis revealed that the application of PGPR (CHA0 and RUB14), filter cake, and their interaction increased tissue plant concentration of macronutrients, micronutrient and leaf dry weight of spinach plant. Statistically, the highest concentration of P, K, Ca, and Mg macronutrients (5583.30, 83000.00, 10886.70, 10766.60 mg kg1 dry matter, respectively), Cu, Zn, and Fe micronutrients (22.73, 73.00, and 221.36 mg kg1 dry matter, respectively) and dry weight of leaves (8.76 g) was observed in treatment of combination of PGPR and filter cake. The application of Metribuzin herbicide led to decline the concentration of macronutrients, micronutrient, and leaf dry weight of spinach plant. The decline increased with increasing herbicide concentration. The lowest concentration of P, K, Ca, and Mg macronutrients (3233.30, 48867.00, 6403.30, and 6283.30 mg kg1 leaf dry weight, respectively), Cu, Zn, and Fe micronutrient (4.40, 19.50, and 132.66 mg kg1, respectively), and leaf dry weight (2.83 g) was observed in B0+F0+H2 treatment (using just herbicide 100 g ha1). However, the detrimental effect of herbicide on leaf dry weight and mineral nutrition of spinach plant were alleviated using the PGPR (CHA0 and RUB14) and filter cake (F3%) either alone or together (RUM14+F3%, CHA0+F3%). Statistically, the greatest alleviation of the detrimental effect of herbicide was observed in the treatment of RUM14+F3%.Conclusion: The results of this research showed that inoculation of spinach with Pseudomonas PGPR (P. protogenes CHA0, P. alloputida RUM14) with and without filter cake not only improved the growth and mineral nutrition of spinach plant, but also alleviated the detrimental effect of herbicide in the plant. In general, the proper function of PGPR and filter cake in spinach plant growth is due to 1 Supplying more nutrients to the spinach plant due to filter cake rich in nutrients 2 The ability of Pseudomonas bacteria to induce resistance of the plants to stress and supply of some nutrients such as iron due to its ability to produce siderophore 3 Supply of food by filter cake for further growth of PGPR and the possibility of increasing the population of these bacteria. 4 Filter cake rich in organic matter can improve the physical and biological properties of the soil and can provide the better conditions for plant growth and nutrition. The results of this research showed that P. alloputida RUM14 and filter cake can be used as biological and organic fertilizers.