Ph.D. Tezi Görüntüleme

      Soil salinity is one of the major factors that limits agricultural production worldwide which is becoming more important with climate changes and population explotion. One approach that provides salt tolerance to plants is, to accumulate excess Na into the vacuoles of plant cell, and another one is efflux Na from cytoplasm to the apoplastic area through plasma membrane. The success of these two approaches were demonstrated in several plants, up to 200mM NaCl tolerance when AtNHX1 and SOS1 genes were expressed seperately. Herein, these two genes both were assembled in one binary vector, introduced into Arabidopsis thaliana via Agrobacterium tumefaciens mediated transformation and co-overexpressed simultaneously for the first time. Transgenic plants produced more biomass, silique number, yield and germination rate when grown in the presence of 250 mM NaCl for 3 weeks. Chlorophyll degredation was less than control plants when salt stress increased up to 300 mM NaCl. Plants also were performing better than controls with longer roots and height when 28C mild heat combined with 150 mM salt stress. In this study, the increased characteristics were likely due to better water extraction from roots, more K uptake, better photosynthetic performance and higher nitrogen assimilation rate observed in the AtNHX1 and SOS1 expressing plants as compared to wild type and single gene transgenics under saline conditions.