عنوان مقاله [English]
نویسندگان [English]چکیده [English]
Background and objective:Tall fescue (Festuca arundinacea schreb) is one of the most extensive genus in the Gramineae family, and herbaceous endophytes are fungi of the Clavicipitaceae family and Neotyphodium genus that infect systematically the Poaceae grasses and discover the symbiotic relationship between festuca and endophytic fungi has encouraged plant breeding experts to use this relationship to create plants that have optimal performance and more effective growth habits in stress conditions. In this study, the effect of drought stress (14 days drought and control) and endophyte fungi and plant genotype (parent and offspring) on physiological and morphological changes such as proline, chlorophyll, carotenoids, fresh and dry weight and the comparison of length of plant growth have been investigated.
Materials and Methods: Seedlings of tall-fescue genotypes were prepared from the collection of Research Institute of Agricultural Biotechnology in the North West and West of the country. In order to match the samples, an E+ seedling was reproduced for 2 months by using the paw division method and for preparing E- seedlings, a number of E+ samples were propagated twice in 10 days intervals by propiconazole fungicide with 2 g/L of active ingredient concentrations . After testing the presence or absence of endophytic fungi, by using Rosebangal staining, water treatments including (control) 100% field capacity), drought stress for 14 days (25% field capacity) and 14 days recharge after retrieval for two genotypes of parent and offspring, after 20 days of settling in pots, in two replications in the form of a completely randomized design was applied. Then the traits mentioned were measured and analyzed by SAS statistical software. Duncan's test was used to compare the means.
Results: The results showed that proline content for water stress and species type was significant at 0.01% probability level and the highest amount of proline (2.96 mg/g fresh weight) was obtained under stress and for offspring and the effect of endophyte fungi was not significant. On the other hand, chlorophyll, carotenoids content and vegetative growth of the plant before the stress about the effects of the trial were not significant. In terms of fresh and dry weight of the plant, the effects of water stress, endophytic fungus, plant genotype and interaction of these three effects were significant (P <0.01) and the highest fresh weight (1.167 g) and dry weight (0.184 g) were related to offspring genotype and parent genotype without endophyte and under control conditions. The lowest dry weight (0.225 g) was in endophytic offspring and under stress conditions. For growth of shoot, two weeks after stress, the effect of water stress and interactions between stress and plant genotype was significant at 0.01% level and the highest height (31.25 cm) was observed in the offspring under control conditions.
Conclusion: In order to manage this stress, it is better to use the parent species, which had higher dry weight under stress conditions and better growth after two weeks. On the other hand, about the role of endophyte in this study, as seen, no significant effect has been observed.