Effect of Salinity on Growth and Gas Exchanges in Seedlings of Pinus nigra Subsp. Pallasiana

Aims: Salinity, due to its remarkable effects on physiology and performance of plant is considered as a world major problem in arid zone ecosystems. Pinus nigra subspecies pallasiana is known as a nurse and pioneer species. The aims of this study were to determine growth responses and gas exchanges of the seedlings of Pinus nigra subspecies under different salinity stress in the greenhouse environment. Materials and Methods: In this experimental Study, Seedlings of Pinus nigra was investigated under salinity stress in ۶ NaCl levels including ۰, ۵۰, ۱۰۰, ۱۵۰, ۲۰۰ and ۲۵۰mM as completely randomized design in greenhouse conditions. Height and diameter growth and gas exchanges parameters were determined in day ۹۰ (August) and biomass allocations in day ۱۵۰ (November). For data analysis One-Way ANOVA, Duncan’s test and SPSS ۱۹ software were used. Findings: The highest survival appeared in zero and ۵۰mM with ۱۰۰ and ۹۳.۳۳%, respectively. Salinity stress decreased survival, height and diameter growth and also biomass of root, shoot, root:shoot and total of seedling. With increasing salinity, photosynthesis, stomatal conductance, transpiration reduced. Higher survival, better growth and gas exchanges were detected below ۵۰mM NaCl salinity. Conclusion: Salinity has adverse effects on growth and gas exchanges of P. nigra seedlings during the studied period. Survival in ۵۰mM NaCl has a high percentage, but in higher salt concentrations (۲۰۰ and ۲۵۰mM NaCl) it drastically reduce. Similarly, decrease in seedling performance was found in severe salinity levels. This species has a relatively good resistance to ۵۰mM NaCl.

کلیدواژه ها:

Biomass ، Growth ، Photosynthesis ، Turkish Black Pine ، Stomatal Conductance