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Hadadinejad M.,University of Agriculture science and Natural Resources | Ebadi A.,University of Tehran | Fatahi R.,University of Tehran | Santesteban L.G.,Public University of Navarra
Acta Horticulturae | Year: 2014

Grapevine rootstocks are able to increase cultivar adaptation to different climates, soil types and a variety of adverse conditions. The main objective of this study was to study the photosynthetic traits and gene expression of candidate genes in drought tolerant rootstock cultivars. Three selected Iranian candidate rootstocks ('Yaquti', 'Askari' and 'Rotabi') as well as Sultana (control) were exposed to moderate (-1 MPa), severe (-1.5 MPa) and very severe (≤1.5 MPa) drought stress, based on predawn soil water potential. Results showed that drought stress and cultivar had significant effect on leaf photosynthesis rate, internal concentration of CO2, chlorophyll A content, as well as Rubisco activase gene expression. Drought stress reduced photosynthesis rate, internal concentration of CO2 and chlorophyll A compared to control. Cultivars showed two distinct behaviors under stress levels. 'Yaquti' and 'Rotabi', as tolerant cultivars, showed higher photosynthesis rate than 'Askari' and 'Sultana', semi tolerant and sensitive respectively. The concentration of CO2 was more stable in 'Yaquti' and 'Rotabi' under stress levels than in 'Askari' and 'Sultana'. The relative expression of Rubisco activase gene increased rapidly in tolerant cultivars ('Rotabi' and 'Yaquti') after exposition to moderate stress, but these reactions occurred later in semi tolerant and sensitive cultivars ('Askari' and 'Sultana') after severe stress. Increase of Rubisco activase resulted in higher photosynthetic rate under stress conditions and reduced negative effects of low stomatal conductivity. The timing and intensity of the responses to different levels of drought stress could discriminate tolerant cultivars ('Yaquti' and 'Rotabi') from semi tolerant ('Askari') and sensitive ('Sultana') cultivars, especially at gene expression level. Source


Bari E.,University of Agriculture science and Natural Resources | Nazarnezhad N.,University of Agriculture science and Natural Resources | Kazemi S.M.,University of Agriculture science and Natural Resources | Tajick Ghanbary M.A.,Agriculture and Natural Resources University | And 3 more authors.
International Biodeterioration and Biodegradation | Year: 2015

The degradation capabilities of two white rot fungi, Pleurotus ostreatus and Trametes versicolor, obtained from natural stands of Fagus orientalis (beech) in Northern Iran were studied. Fruiting bodies of P. ostreatus and T. versicolor were collected from fallen beech in the Alamdardeh forest, Iran. Beech wood samples were exposed to both fungi for 120 days according to EN113. Mass loss, resistance to compression parallel to grain, impact load resistance, as well as lignin, cellulose and hemicellulose content were determined in the samples before and after fungal exposure. FT-IR spectroscopy was used to collect spectra after fungal decay. Light and electron microscopy were used to study white-rot decay patterns in wood and compare the mechanism of attack for both fungi. Both fungi reduced wood mass and chemical constituents in similar quantities. Chemical analyses indicated similar reductions in cellulose, lignin and total carbohydrates. Both fungi had negligible affect on the hemicelluloses, arabinan, galactan, and glucan. Patterns of white decay were the same for both fungi. Thinning of the cell walls, colonization of fungal hyphae as well as formation of bore holes on the cell wallswere also similar for both fungi. The results demonstrated that both fungi produced a simultaneous white rot in beech wood. © 2015 Elsevier Ltd. Source

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