اثرات تنش شوري بر روي شاخص هاي رشد و تبعيض ايزوتوپ كربن در 3 پايه پسته

Effects of salinity stress on growth performance and Carbon Isotope discrimination in three Pistachio rootstocks

To determine the effects of salinity on growth performance and carbon isotope discrimination three pistachio rootstocks (Badami-e-zarand, Sarakhsi and Ghazvini were used. Rootstocks were grown in soil in polyethylene pots. Soduim chloride treatments were 0, 75,150 and 225 mM NaCl. Plants were harvested before and after 30 and 60 days of exposure to the salinity treatments. Results indicated that relative growth rate decreased with time for all treatments and rootstocks. Salt treatment significantly reduced both relative growth rate (RGR), net assimilation rate on a leaf weight basis (NARw) but not leaf weight ratio (LWR) was significantly correlated with RGR, indicating that NARw was an important factor underlying the salinity-induced differences in RGR among the pistachio rootstocks. Salinity did not effects on leaf water potential, chlorophyll content and Fv:Fa ratio but with increasing of NaCl, proline accumulation in the leaves was increased, from selected rootstocks, so Ghazvini rootstocks accumulated more proline in compare with other rootstocks indicated more resistant to salinity. Results showed that carbon isotope discrimination reduced by salinity treatments in both leaves and stems, however no significant differences were observed between rootstocks. Carbon isotope discrimination in the second harvest was more than the first harvest, but this variation observed in leaf but not in the stems. We conclude that carbon isotope discrimination in pistachio rootstocks will be indicator of cumulative salinity history of plant but not a suitable indicator for prescreening of pistachio rootstocks to salinity resistance.