نوع مقاله : مقالات پژوهشی
نویسندگان
1 دانشگاه فردوسی مشهد
2 بخش تحقیقات بیولوژی و بیوتکنولوژی خاک، موسسه تحقیقات خاک و آب، سازمان تحقیقات، آموزش و ترویج کشاورزی، کرج، ایران
3 بخش تحقیقات خاک و آب، مرکز تحقیقات و آموزش کشاورزی و منابع طبیعی استان خراسان رضوی، سازمان تحقیقات، آموزش و ترویج کشاورزی، مشهد، ایران
چکیده
یاین آزمایش با هدف انتخاب نوع کود زیستی (باکتریایی یا قارچی) و فرمولاسیون کودی مناسب برای گیاه گندم به صورت اسپلیت پلات در قالب طرح بلوک‌های کامل تصادفی با سه تکرار در ایستگاه تحقیقاتی طرق، واقع در مرکز تحقیقات و آموزش کشاورزی و منابع طبیعی خراسان رضوی در طی سال زراعی 1401-1402 اجرا شد. کرت‌های اصلی شامل سطوح آبیاری بودند: آبیاری کامل، تنش آبی ملایم و شدید که به ترتیب معادل 100% (5438 مترمکعب در هکتار)، 85% و 65% نیاز آبی گیاه بود. کرت‌های فرعی شامل سطوح کود زیستی بودند: بدون کود زیستی (F1)، باکتری Pseudomonas fluorescens تولیدکننده آنزیم ACC-دآمیناز (F2)، باکتری P. fluorescens فاقد ACC-دآمیناز (F3)، قارچ میکوریز آربسکولار (AM) به صورت مایع (F4)، و پودری (F5). ویژگی‌های مورد مطالعه شامل درصد کلنیزاسیون ریشه، وزن هزار دانه، عملکرد دانه، عملکرد زیستی، شاخص برداشت و کارایی مصرف آب بود. نتایج نشان داد که در بین کودهای زیستی باکتریایی، تنها کاربرد تیمار F2 در تنش آبی شدید موجب افزایش 9% عملکرد دانه، 7% عملکرد زیستی، 6/8% کارایی مصرف آب دانه و 7% کارایی مصرف آب بر حسب عملکرد زیستی نسبت به شاهد شد. کارایی کودهای زیستی قارچی نسبت به باکتریایی به طورقابل توجهی بیشتر بود. همچنین شکل پودری قارچ AM نسبت به مایع آن کارایی بیشتری داشت به طوریکه این تیمار موجب افزایش 26% و 21% عملکرد دانه و عملکرد زیستی، و افزایش 26% و 22% کارایی مصرف آب برحسب عملکرد دانه و عملکرد زیستی در تنش آبی شدید شد. به‌طور کلی، تفاوت‌های مشاهده شده در کارایی کودهای زیستی نشان می‌دهد که انتخاب مناسب نوع و فرم این کودها می‌تواند نقش قابل‌توجهی در مدیریت تنش آبی و بهبود تولید محصول داشته باشد. با این حال، انجام پژوهش‌های بلند مدت برای تأیید و تقویت این نتایج ضروری است.
کلیدواژه‌ها
موضوعات
عنوان مقاله [English]
Comparing the Effects of Bacterial and Fungal Biofertilizers on Wheat Yield and Water Use Efficiency under Drought Stress: The Role of ACC-deaminase and Various Fungal Formulations
نویسندگان [English]
- seyed sajjad hosseini 1
- Farhad Rejali 2
- Payman Keshavarz 3
1 Ferdowsi University of Mashhad
2 Department of Soil Biology and Biotechnology, Soil and Water Research Institute, AREEO, Karaj, Iran
3 Department of Soil and Water, Khorasan Razavi Agricultural and Natural Resources Research and Education Center, AREEO, Mashhad, Iran
چکیده [English]
Introduction: Water scarcity is a major challenge in Iran, with annual rainfall averaging 235 to 260 mm, only a third of the global average. Wheat, a staple crop in Iran, faces severe yield reduction under drought conditions. Utilizing biofertilizers like plant growth-promoting rhizobacteria (PGPR) and arbuscular mycorrhizal (AM) fungi could help enhance water use efficiency (WUE) and yield in such environments. However, the effectiveness of biofertilizers varies based on several factors, including the type of biofertilizer (bacterial or fungal), the strain or species used, and the formulation (solid or liquid). Despite the established benefits of both PGPR and AM fungi in enhancing drought tolerance and WUE, there is a lack of comparative studies that examine the specific performance of bacterial versus fungal biofertilizers and their formulations under varying levels of water stress. Thus, the objectives of this study are as follows: 1) To identify the most suitable type of biofertilizer (bacterial or fungal) for improving wheat yield and WUE under drought conditions in Mashhad's climatic conditions; 2) to determine the effect of ACC deaminase enzyme on the efficiency of PGPR in enhancing wheat yield and WUE; 3) To compare the performance of AM fungal biofertilizers in two formulations (powder and liquid) and between single-species and multi-species inoculants.
Material and methods: The experiment was conducted as a split-plot design with three replicates, where irrigation levels constituted the main plots, and biofertilizer treatments formed the subplots. The irrigation treatments included full irrigation (100% of wheat’s water requirement), mild drought stress (85%), and severe drought stress (65%). The biofertilizer treatments were: no biofertilizer (F1), serving as a control; Pseudomonas fluorescens producing ACC-deaminase (F2); P. fluorescens without ACC-deaminase (F3); AM fungi (Rhizophagus irregularis) in liquid form (F4); and (5) AM fungi (R. irregularis, Funneliformis mosseae, and Claroideoglomus etunicatum) in powdered form (F5).
Results and discussion: Both irrigation levels and biofertilizer types had significant impacts on root colonization, yield, and WUE. Reducing irrigation from 100% to 85% and 65% of crop water requirements significantly reduced root colonization across all treatments. Among the bacterial treatments, only P. fluorescens producing ACC-deaminase (F2) showed a significant positive effect under severe drought (65% irrigation). This treatment increased grain yield by 9%, biological yield by 7%, and WUE by 6.8% compared to the control (F1). The presence of ACC-deaminase likely contributed to mitigating the effects of drought-induced ethylene, promoting better root growth and nutrient uptake under water stress. In contrast, P. fluorescens without ACC-deaminase (F3) did not significantly improve yield or WUE, emphasizing the importance of ACC-deaminase in promoting drought tolerance. Fungal biofertilizers outperformed bacterial treatments in grain and biological yield, as well as WUE. Under severe drought, powdered AM fungi (F5) increased grain yield by 26% and biological yield by 21% compared to the control, and WUE based on grain yield improved by 26%. This superior performance of AM fungi, particularly in powdered form, can be attributed to their ability to enhance nutrient and water uptake under drought conditions. These findings corroborate earlier studies that demonstrated AM fungi's ability to improve crop yield and WUE under drought stress by enhancing water uptake, nutrient availability, and improving the plant's physiological responses, such as maintaining cell membrane stability and increasing antioxidant activity. The powdered formulation of AM fungi (F5) showed greater effectiveness than the liquid form (F4). The higher colonization rates and performance in yield improvement may be due to the inclusion of multiple fungal species in the powdered form. The performance differences between the liquid and powdered AM fungi formulations may also be influenced by the physical properties of the biofertilizer since powdered inoculants are most effective when applied to the seeds of grasses like wheat and barley, as the structure of these seeds allows for better adhesion of the powder.
Conclusion: In conclusion, among the bacterial biofertilizers, only P. fluorescens producing ACC-deaminase significantly enhanced plant performance under severe drought, underscoring the importance of ACC-deaminase in alleviating drought stress. However, fungal biofertilizers, especially in powdered form, were more effective overall in improving yield, biological productivity, and WUE under varying levels of water stress. This research confirms that the application of AM fungi can serve as an effective strategy for improving wheat yield and increasing WUE in the climatic conditions of Mashhad. Overall, the observed differences in the effectiveness of these biofertilizers suggest that the appropriate selection of both type and formulation of biofertilizers can significantly contribute to managing water stress and improving crop production.
کلیدواژه‌ها [English]
- PGPR
- drought stress
- microorganisms
- irrigation levels
- arbuscular mycorrhizal fungi
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