Investigation of physiological and biochemical changes of safflower plant (Carthamus tinctorius L.) grown with microbial fertilizer under salt stress

The aim of this study is to investigate the seedling and seed development of two different varieties (Asol, Linas) of the salt stress-resistant safflower (Carthamus tinctorius L.) plant under both microbial fertilizer and salinity conditions. For germination and seedling development, seeds were grown at 20-24⁰C and exposed to different NaCl concentrations (0, 100 and 150 mM NaCl). In addition to salt stress, microbial fertilizer was applied to both the control group and the groups with different combinations of fertilizer and salt. The microbial fertilizer used in the application contained live Azotobacter vinelandii and Bacillus megaterium bacteria. Seedling germination rate, shoot length, relative water content and pigment measurement values were negatively affected under high salt concentrations. A decrease in chlorophyll a and chlorophyll b amounts was detected with increasing salinity. Similar results were also seen for anthocyanin pigment. However, no difference was detected between the groups in the carotenoid pigment and fresh and dry weight values of the seedlings. Malondialdehyde (MDA) values increased significantly with increasing salt stress. It was observed that there was a decrease in catalase (CAT) activity values, which can be defined as the defense system formed against stress, and that microbial fertilizer caused an increase in enzyme activity in ascorbate peroxidase (APX) activity values. The results show that both varieties have different tolerance to stress and that microbial fertilizer application has different effects on both varieties.