ارزیابی صفات فیزیویولوژیک نهال‌های مایه‌زنی شده فندق با قارچ trichoderma harzianum rifai در شرایط عرصه

استفاده از ریزجانداران افزاینده رشد، یکی از روش‌های زیستی به منظور افزایش عملکرد گیاهان و کاهش مصرف کودهای شیمیایی محسوب می‌شود. بر این اساس، به منظور بررسی اثر بخشی harzanium trichodermaبر برخی از صفات رویشی برگ و مشخصه‌های فیزیولوژیک نهال‌های فندق، یک آزمایش فاکتوریل در قالب طرح بلوک‌های کامل تصادفی در شرایط عرصه اجرا شد. فاکتورهای مورد بررسی شامل مبداء نهال در سه سطح (فندقلو، مکش و مکیدی) و مایه‌زنی قارچ در دو سطح (harzanium t. و شاهد) با سه تکرار 25 تایی با فاصله 3 × 3 متر، در اراضی زراعی حاشیه جنگل فندقلوی اردبیل کاشته شدند. نتایج پس از چهار سال نشان داد نهال‌های مایه‌زنی شده هر سه مبدا، از لحاظ همه مشخصه‌های مورد بررسی در مقایسه با نهال شاهد (مایه-زنی نشده) برتر بودند. بیشترین مقدار صفات مورد بررسی به نهال‌های مبداء فندقلو تعلق داشت. به‌طوری که در این نهال‌ها، سطح برگ و سطح ویژه برگ به‌ترتیب 40.9 و 21.3 درصد و مشخصه‌های فیزیولوژیک شامل فتوسنتز، هدایت روزنه‌ای، کلروفیل و کارایی مصرف آب به‌ترتیب 66.8، 65، 40.8 و 146.5 درصد در مقایسه با نهال‌های شاهد افزایش داشت. در نهایت می‌توان نتیجه‌گیری کرد کاشت نهال‌های فندق مایه‌زنی شده با قارچ harzanium t. رشد رویشی بیشتری خواهد داشت.

evaluation of physiological traits of hazelnut seedlings inoculated with trichoderma harzianum rifai under field conditions

background and objectives: hazelnut (corylus avellana l.) is one of the most prominent species in the ardabil fandoghlou forest. this species holds significant ecological and economic importance and is highly valued in traditional medicine and the pharmaceutical industry. unfortunately, in recent years, factors such as land conversion, livestock grazing, fire, and deforestation have contributed to the decline of this valuable species. given the ecological and economic significance of hazelnut trees, it is crucial to restore their habitats through the use of seedlings. the success of planting efforts largely depends on the establishment and survival of the seedlings (espahbodi, 2019), which traditionally rely on chemical fertilizers. however, the use of these fertilizers has adverse effects on the soil ecosystem. they can destroy beneficial soil microorganisms, hinder seedling growth, and lead to various negative impacts on the environment and human health. to address these issues, the application of growth-promoting microorganisms is considered one of the biological methods to enhance plant yield and reduce reliance on chemical fertilizers. trichoderma species, particularly trichoderma harzianum, have been recognized not only as plant growth promoters but also for their primary role as pathogen inhibitors. this research aims to investigate the effects of t. harzianum on the physiological properties of hazelnut seedlings under field condition. materials and methods: in early may 2016, potted hazelnut seedlings were inoculated with trichoderma harzianum at the ardabil hazelnut nursery. these seedlings were sourced from three different locations: fandoglou (ardabil hazelnut forest), makesh (guilan), and makidi (arasbaran). by november 2017, the one-year-old hazelnut seedlings were transferred to a field adjacent to the nursery, situated on the forest edge, covering an area of 4,050 m². the seedlings were planted in a factorial arrangement using a randomized complete block design, which included two factors: three seed sources and t. harzianum inoculation (with control seedlings receiving no inoculation). each treatment was replicated three times, with a total of 25 seedlings per replication, resulting in 450 seedlings planted at a spacing of 3 × 3 m under rain-fed conditions. the following physiological properties were measured: leaf area, specific leaf area, photosynthesis rate, stomatal conductance, transpiration rate, water use efficiency (wue), and chlorophyll content. for these measurements, three seedlings from each treatment were randomly selected. the fourth and fifth healthy, fully mature leaves from the tips of the plants were analyzed using a photosynthesis meter on a sunny day in mid-september. measurements were conducted in natural conditions of temperature, light, and relative humidity between 9:30 and 11:30 a.m., ensuring that leaf temperatures remained constant between 20 and 25°c results: after four years, all measured properties were significantly influenced by fungal inoculation. inoculated seedlings from all three origins exhibited higher values for all investigated traits compared to the control group. the seedlings of fandoglou origin inoculated with t. harzianum showed the highest leaf area (22.4 cm²), specific leaf area (119.2 cm² g⁻¹), photosynthesis rate (18.45 μmol co₂ m² s⁻¹), stomatal conductance (0.198 mmol m² s⁻¹), transpiration rate (mmol h₂o m² s⁻¹), and water use efficiency (7.69 μmol co₂ mol h₂o⁻¹). furthermore, chlorophyll content increased by 26.49% compared to the control (non-inoculated seedlings). in contrast, the lowest measurements for leaf area (12.4 cm²), specific leaf area (85.5 cm² g⁻¹), photosynthesis rate (8.01 μmol co₂ m² s⁻¹), stomatal conductance (0.101 mmol m² s⁻¹), water use efficiency (2.41 μmol co₂ mol h₂o⁻¹), and chlorophyll content, which increased by 14.15%, were observed in non-inoculated seedlings from the makidi origin. conclusion: the present study demonstrated that hazelnut seedlings of fandoghlou origin, when inoculated with t. harzianum, exhibited superior traits compared to the seedlings from the other two origins, makseh and makidi. therefore, for the production of healthy and robust hazelnut seedlings in nurseries, the fandoghlou origin is recommended. a notable finding was the significant increase in water use efficiency (wue) among the fandoghlou-origin hazelnut seedlings, which showed a 150% increase compared to the control seedlings. this improvement can be attributed to the enhanced rate of photosynthesis and reduced transpiration rate in the inoculated seedlings, leading to increased water use efficiency. consequently, this results in greater vegetative growth and improved physiological traits, which are beneficial for reforestation efforts or the establishment of hazelnut gardens in the susceptible areas of the fandoghlou forest.