اثر مایه‌زنی باکتری‌های محرک رشد بر برخی از صفات رشدی برگ و عناصر غذایی نهال‌های فندق در شرایط عرصه

باکتری‌های محرک رشد از جمله ریزجانداران مفید خاک هستند که از راه بهبود کیفیت خاک، سبب افزایش صفات رشدی و تغذیه‌ای گیاه می‌شوند. از این‌رو، به‌منظور بررسی تاثیر باکتری‌های محرک رشد بر سطح برگ، سطح ویژه برگ و جذب عناصر غذایی نهال‌های فندق، یک آزمایش فاکتوریل در قالب طرح بلوک‌های کامل تصادفی در شرایط عرصه اجرا شد. فاکتورهای مورد بررسی شامل مبدا نهال در دو سطح (فندقلو و مکش) و مایه‌زنی باکتریایی در پنج سطح (pseudomonas putida،وbacillus subtilis و enterobacter cloaca به‌طور جداگانه، ترکیب سه باکتری و شاهد) با سه تکرار 12 تایی با فاصله 3×3 متر در چاله‌هایی به ابعاد 50×50×50 سانتی‌متر در سطح 3240 مترمربع بود که در زمین‌های زراعی حاشیه جنگل فندقلوی اردبیل کاشته شدند. پس از گذشت چهار سال نتایج نشان داد که نهال‌های مایه‌زنی شده هر دو مبدا، از لحاظ همه صفات مورد بررسی در مقایسه با نهال شاهد (مایه‌زنی نشده) برتر بودند. بیش‌ترین میزان صفات مورد بررسی به نهال‌های مبدا فندقلو با مایه‌زنی ترکیبی هر سه باکتری (p. putida،وb. subtilis و e. cloaca) اختصاص داشت. به‌طوری‌که در این نهال‌ها، سطح برگ و سطح ویژه برگ به‌ترتیب 53/1 و 37/7 درصد، جذب عناصر غذایی نیتروژن، فسفر، پتاسیم، آهن و روی به‌ترتیب 59/4، 89/5، 23/7، 45/4 و 60/6 درصد در مقایسه با نهال‌های شاهد افزایش یافت. در نهایت می‌توان نتیجه‌گیری کرد کاشت نهال‌های فندق مایه‌زنی شده با باکتری‌های محرک رشد (ترکیب سه باکتری مذکور) به دلیل افزایش صفات رشدی برگ و نیز بهبود وضعیت تغذیه‌ای، رشد رویشی بیش‌تری خواهند داشت.

the effect of inoculation of growth-stimulating bacteria on some leaf growth traits and nutritional elements of hazelnut seedlings under field conditions

abstractgrowth-promoting bacteria are among the beneficial soil microorganisms, and by improving the soil quality, they increase the growth and nutritional traits of the plant. therefore, in order to investigate the effect of growth-promoting bacteria on the leaf surface, specific leaf surface and absorption of nutritional elements of hazelnut seedlings, a factorial experiment was carried out in the form of a randomized complete block design in the field conditions. the main factor was the origin of the seedling (at two levels: fandoglou and makesh) and bacterial inoculation (at five levels: p. putida, b. subtilis and e. cloaca, combination of them and control) with three replications. twelve seedlings were planted at a distance of 3 × 3 m in holes with dimensions of 50 × 50 × 50 cm on an area of 3240 m2 in the agricultural lands at the neighborhood of fandoglou forest in ardabil. the results after four years showed that the inoculated seedlings of both origins were superior in terms of all investigated traits compared to the control (un-inoculated) seedlings. the highest amount of traits was assigned to the seedlings of fandoglou origin inoculated with the combination of all three bacteria (p. putida, b. subtilis and e. cloaca). the leaf area and specific leaf area were 53.1 and 37.7% more in the inoculated seedling compared to the control, respectively. the concentration of nitrogen, potassium, phosphorous, iron and zinc in the seedling leaf increased by 59.4, 89.5, 23.7, 45.4 and 60.6% compared to the control, respectively. finally, it can be concluded that the planting of hazelnut seedlings inoculated with growth-stimulating bacteria (combination of the three mentioned bacteria) will have more vegetative growth.background and objective: hazelnut (corylus avellana l.) is considered one of the most significant species of ardabil fandoglou forest in iran. this species is ecologically and economically important and also is one of the most valuable medicinal plants in the traditional medicine. hazelnut kernel is very important in human nutrition and health as it has different kind of vitamins, healthy oils (mostly oleic acid), protein, fiber and antioxidants. unfortunately, in recent years, conversion of land use, animal grazing, fire, and excessive cutting of trees (for charcoal production) are among the most important factors in destroying the habitats of this species. therefore, it is necessary to restore and develop the habitats of hazelnut through the production of healthy and quality seedlings. to increase successful planting programs, the ability of seedlings against environmental stresses should be increased by improving the uptake of water and nutrients (arias et al., 2007). one of the solutions that has been noticed in recent years, is the application of growth-promoting bacteria. plant growth-stimulating bacteria are a group of free-living and non-symbiotic rhizosphere bacteria that could improve plant growth by one or more direct and indirect mechanisms (backer et al., 2018). the present research was conducted to investigate the effect of these microorganisms on the leaf growth and nutrients concentration of hazelnut seedlings in order to provide practical solutions for the development of hazelnut nursery in the neighborhood of the fandoglou forest of ardabil.methods: in november, similar seedlings were transferred to the area adjacent to the nursery, located in the barren lands of the forest neighborhood. experiment was carried in randomized complete block design with two main factors including the origin of seedlings (at two levels: fandoglou and makesh) and bacterial inoculation (at five levels: p. putida, b. subtilis e. cloaca separately, the combination of three bacteria, and control). the seedlings were planted at a distance of 3 × 3 m in holes with dimensions of 50 × 50 × 50 cm in the agricultural lands at the neighborhood of fandoglou forest of ardabil. in the fourth year, the leaf area, specific leaf area, and leaf concentration of nutritional elements (nitrogen, phosphorous, potassium, iron and zinc) in the hazelnut seedlings were measured.results: the results showed that inoculation of hazelnut seedlings (from both origins) with bacteria separately and in combination had a significant effect on the leaf growth traits and concentration of nutritional elements. the maximum leaf area (24.5 cm2) and specific leaf area (135.3 cm2/g) were observed in the seedlings (fandoglou origin) inoculated with a combination of three bacteria. in addition, the highest concentrations of nitrogen (3.56 %), phosphorous (0.36 mg/g), potassium (135.3 mg/g), iron (1.35 mg/g) and zinc (26.10 mg/g) were obtained in the seedlings (fandoglou origin) inoculated with a combination of three bacteriaconclusions: with considering the positive effect of growth-stimulating bacteria on leaf growth traits and nutritional conditions of hazelnut seedlings, the combined inoculation of three bacteria (p. putida, b. subtilis and e. cloacae) is suggested for the successful planting of hazelnut seedlings in the nursery and also in the field.references:1. arias, d., calvo-alvarado, j. and dohrenbusch, a., 2007. calibration of lai-2000 to estimate leaf area index (lai) and assessment of its relationship with stand productivity in six native and introduced tree species in costa rica. for. ecol. manage. 247, 185–193.2. backer, r., rokem, j.s., ilangumaran, g., lamont, j., praslickova, d., ricci, e., subramanian, s., smith, d.l., 2018. plant growth-promoting rhizobacteria: context, mechanisms of action, and roadmap to commercialization of bio-stimulants for sustainable agriculture. front. plant sci. 9, 1473–1485.