ارزیابی اثر تنش شوری و دما بر رشد گونه های قارچ بیوکنترلی تریکودرما در شرایط آزمایشگاهی

Environmental stresses are one of the most important factors in reducing agricultural production in worldwide, which reduces the growth and yield of plants. In addition to plants are affected by environmental stresses, microorganisms are also affected by these stresses. The development of the presence of microorganisms in the ecosystem depends on their ability to deploy and reproduce in adverse environmental conditions such as drought, high temperatures, food shortages, the presence of heavy metals and salinity. Trichoderma biocontrol fungi exist in almost types of moderate and tropical soils. This fungus is usually able to survive in various soils, and its species lives in all climatic zones. Trichoderma species are able to control the pathogen by inducing resistance or direct attack on plant pathogenic fungi, changes in the microflora of the root, increasing the absorption and solubility of the soil nutrients, increasing root development and formation of capillary roots and increasing tolerance to stress. In this study, various species of Trichoderma fungi were evaluated for salt tolerance at different levels of sodium chloride (0.8, 1 and 2 Molar), and among them, salt tolerant isolates were used to evaluation the temperature tolerance. The effect of salinity on growth of Trichoderma isolates was determined by PDA medium containing various salt concentrations. Then, the isolates were screened for temperature tolerance at 25, 35, 40 and 45 ° C. The results indicated the inhibitory effect of salinity and temperature on the growth of isolates and showed significant difference between them. The results also showed that none of the isolates were able to grow at a salinity level of 2 M and temperatures of 40 and 45 ° C, but they had different growth rate at 35 ° C than the temperature of 25 ° C. The results showed that isolates belonging to T. aureoviridae were more tolerated for salinity and temperature than other species (T. harzianum, T. brevicompactum, T. virens). According to the obtained results, it can be said that isolates of Trichoderma biocontrol fungi are highly tolerated in terms of temperature and salinity. Their application can have a significant effect in reducing the effects of environmental stresses.