Study the Responses of Some Plum Rootstock Genotypes to NaCl Salinity Stress

Salinity has a negative effect on plant growth and metabolism that results in reducing yield. So, understanding the mechanisms of salinity tolerant is a valuable tool for alleviating the destructive impacts of salinity. This research was conducted as a pot-plant outdoor experiment to investigate the responses of eight different plum (Prunus cerasifera) genotypes to different concentrations of NaCl (0, 40, and 80 mM) in a factorial experiment (genotype × salinity concentration) based on a randomized complete block design. The concentration of 80 mM NaCl compared to control caused a decrease in the leaf area (5-28%), total dry matter (13-41%), chlorophyll fluorescence (Fv/Fm) (18.7-21.6%), total chlorophyll content (30.7-49.7%) and Carotenoids content (22.3-46.5%) and an increase in the shoot Na+ content (28.6-72%), ion leakage (11.3-33.8%), leaf flavonoids content (17-44%), root flavonoids content (5.2-47.7%) and PPO activity (9.6-30.2%). In some genotypes, there was a non-significant increase (2.4-8.8%) in shoot K+ content, while there was a decrease (13.3-21.7%) in others. The shoot K+/Na+ (4-5.3), Na+ content (shoot/root) (1-2.5%) and K+ content (shoot/root) (4.9-8.2) in the control plants, respectively, reached 0.9-4, 1.4-8.15 and 7.6-12.5 in the treatment of 80 mM NaCl. Total protein content in some genotypes showed an increase of 11-14.2% and in others it showed a decrease of 7-13%. All genotypes experienced a decrease in growth and damage to their photosynthetic apparatus when exposed to salinity stress, but they displayed differences in the response rate to other traits. In this study, Genotypes UTPR1 and UTPR5 were recognized as the most sensitive and tolerant, respectively.