| چکیده انگلیسی مقاله |
Plant growth and yield enhancement can be evoked in crops by the exploitation of beneficial microorganisms and the optimal provision of plant nutrients. The effect of inoculation with Serendipita indica and the application of zinc and phosphorus on the growth and yield of strawberries in the aeroponic system was the goal of the present experiment. The study was conducted in a completely randomized design with different levels of inoculation with endophytic fungus S. indica (non-inoculated and inoculated with fungus mycelium) as the first factor and different levels of fertilizer application (0.8 gr zinc sulfate, 1.2 gr monopotassium phosphate, combined zinc-phosphorus and control) as the second factors with three replications. The results showed that the main effects of fertilizer and fungus treatment as well as their interaction effect were significant in all traits except for total protein content. The results also showed that fungus inoculation and zinc and phosphorus application increased traits such as flower and fruit number, shoot and root biomass, chlorophyll, total soluble sugars, protein content, and antioxidant enzymes. In sum, it can be concluded that the effect of phosphorus and zinc fertilizer treatments along with the endophytic fungus S. indica has improved the physiological traits and yield of strawberries. On the other hand, the effects of the simultaneous application of fertilizer and fungus inoculation are more positive than the single application of fertilizer and fungus. Therefore, the optimal application of important elements such as phosphorus and zinc along with the exploration of endophytic symbiotic fungi can be considered a suitable strategy to increase the growth and yield of strawberries. Introduction Strawberry (Fragaria ananassa Duch) is a perennial and herbaceous plant belonging to the Rosaceae family. This plant is widely cultivated because of its high economic and nutritional value. Mycorrhizal symbiosis is one of the most significant mutualisms on earth, in which mycorrhizal fungi increase the absorption of nutrients by the roots of plants and improve their growth and development.. In recent years, the endophytic fungus, Serendipita indica, has attracted the attention of researchers due to its mycorrhizal-like functions, broader host range than mycorrhizal fungi, and the possibility of cultivation in synthetic cultures. This fungus has been successfully used in seedling breeding, growth promotion, and fruit quality improvement of many horticultural crops, including strawberry. Mineral nutrients like phosphorus and zinc play an important role in the growth and yield of strawberry plants. In recent years, farmers have used chemical fertilizers to increase crop production. There are reports of the residual accumulation of these harmful chemicals in fruits and other edible parts. Therefore, the management of nutrient solutions is critical to the success of the production of this plant in soilless cultures. In addition, beneficial microorganisms can stimulate plant growth and yield in crops. Since beneficial microorganisms can play an important role as biofertilizers, this study aimed to evaluate the effects of inoculation of strawberry plants with Serendipita indica and the application of zinc and phosphorus on the growth and yield of strawberries in the aeroponic system. Materials and Methods The study was conducted in a completely randomized design with different levels of inoculation with endophytic fungus S. indica (non-inoculated and inoculated with fungus mycelium) as the first factor and different levels of fertilizer application (0.8 gr zinc sulfate, 1.2 gr monopotassium phosphate, combined zinc-phosphorus and control) as the second factors with three replications. Strawberry seedlings (Sabrina as a short-day variety) were divided into two groups. Group number one was inoculated with fungus mycelium before being transferred to aeroponic tanks, while autoclaved mycelium was used for the other group (as a control). The plants were kept in the same nutritional conditions, and after ensuring the complete establishment of the plants, the treatments were applied. At this stage, 1.2 g of monopotassium phosphate (phosphorus) was added to the nutrient solution of tank number one. 0.8 g of zinc sulfate per liter was added to the nutrient solution of tank number two. 1.2 g of phosphorus plus 0.8 g of zinc per liter were added to the nutrient solution of tank number three, and plants in tank number four received regular nutrient solution as a control. After the emergence of fruits, shoot samples were harvested, and traits like the number of flowers and fruits, shoot and root dry weight, photosynthetic pigments, protein, soluble sugar, elements content, and antioxidant enzymes were measured. Results and Discussion The results showed that the main effects of fertilizer, fungus treatment, and their interaction effect were significant in all traits except for dry weight and total protein content. According to the results, fungus inoculation and zinc and phosphorus application increased traits, such as the number of flowers and fruits, shoot weight, and root biomass. Phosphorus might increase the number of flowers and fruits by interfering with the transfer of photosynthetic materials. In addition, it seems the symbiotic relationship has increased the number of flowers and fruits by enhancing the absorption of nutrients and biomass of the strawberry plants. Fungus and zinc may stimulate root growth and increase its biomass by influencing the production of auxin hormones. Inoculation by affecting photosynthesis-related proteins and the application of zinc by affecting the amount of effective elements in the formation of chlorophyll caused a significant increase in the content of chlorophyll. The results showed that inoculation with S. indica and foliar application of zinc and phosphorus increased leaf and fruit soluble sugar content. The fungus seems to increase carbohydrate uptake through some hexose transporters. Besides, phosphorus plays an important role in transferring sugars in the plant. The results showed that inoculation with S. indica and the application of zinc and phosphorus fertilizers increased the content of antioxidant enzymes (except fruit catalase). Combined treatment of S. indica and fertilizers had a positive effect on leaf and fruit peroxidase and ascorbate peroxidase of strawberry fruits. Conclusion The effects of phosphorus and zinc fertilizer treatments combined with the endophytic fungus S. indica have improved the physiological traits and yield of strawberries. In other words,the effects of the simultaneous application of fertilizer and fungus inoculation are more positive than the single application of fertilizer and fungus. Therefore, the optimal application of important elements such as phosphorus and zinc combined with the exploration of endophytic symbiotic fungi can be considered a suitable strategy to increase the growth and yield of strawberries. |