Effects of long-term salinity on growth and performance of two pistachio (Pistacia L.) rootstocks.

Abstract

Salinization is one of the most important problems that restrict cultivation of crops in arid and semi-arid regions; Pistachio (Pistacia vera L.) is one of the most important trees that grown in these restricts. In this greenhouse study, the effects of salinity on growth of 2 pistachio rootstocks 'Badami' and 'Ghazvini' evaluated. Seedlings of these cultivars were grown in 25×30cm plastic bags containing 4.5kg soil. Salinity was imposed, by adding salt (NaCl) to the pots at 6 leaf stage (about 1 month after planting) to obtain concentration of 0, 800, 1600, and 3200 mg NaCl kg-1 soil. Plants irrigated with 7 days intervals. Ninety days after salt treatment, pistachio seedlings were harvested and length of shoots and roots, number of leaves, relative water content, plant biomass, chlorophyll content, photosynthesis rate, reducing sugar concentration, and proline content of leaves were measured. Salinity decreased shoots and roots growth, number of leaves per plant, plant biomass, net photosynthesis rate, and chlorophyll content in comparison with the control. These parameters had higher value in the 'Ghazvini' rootstock than in the 'Badami' rootstock. The concentrations of reducing sugars in the leaves of the both rootstock improved with increasing salinity concentration up to 3200. Free proline content in the leaves of pistachio cultivars also increased with the increased salnity level. Proline content and reducing sugars in 'Ghazvini' rootstock was much higher than 'Badami'. Data obtained in present study emphasised that 'Ghazvini' rootstock is more tolerant to salinity than 'Badami'.