Effect of salinity stress levels on some Growth parameters, Mineral ion concentration, Osmolytes, Non-enzymatic antioxidants and phenylalanine ammonialyase activity in three genotypes of (Chenopodium quinoa Willd)

Salinity is one of the most important stresses that has affected food security. (Chenopodium quinoa) is a plant that is currently considered worldwide as a food substitute for wheat, rice, barley and corn. The aim of this study was to investigate the activity of antioxidants, some osmolites, ions and minerals to identify salinity resistant genotypes that can be grown by cultivating quinoa in hot and dry regions of the country that face temperature, drought and salinity stresses. This plant was used as food for humans and fodder for livestock.

In this study, physiological responses of 3 genotypes (Q18 ,Rosada ,Sajama) with relatively high yields were investigated at different levels of salinity stress (control (EC=1.5) and 8, 16, 32 dS/m) in greenhouse conditions and Plants were harvested in the twelfth week for morphophysiological and biochemical measurements and studies were performed on the plant.

By studying the results of Na+ content in salinity stress, it seems that Sajama and Rosada have more ability to prevent Na+ transfer from root to shoot and prevent K+ reduction, also the total amount of elements (Cu+2, Mn+2, Ca+2, Zn+2, Fe+2) decreased at salinity 32 dS/m. The results showed that comparing the growth parameters and increasing proline and decreasing the protein content at salinity 32 dS/m can be associated with reduction of chlorophyll, carotenoids, reduced sugars, total carbohydrates, increased oxidative stress and H2O2 content. However, total ascorbate and glutathione content remained constant at salinity 32 dS/m in Q18, but Sajama and Rosada decreased and phenylalanine ammonialyase activity increased in all genotypes and all salinity levels. Phenolic compounds, flavonoids and anthocyanins in genotyp Rosada showed a greater increase in salinity stress than the other two genotypes.

The total results showed according to the rate of reduction of growth parameters, genotype Sajama seems to be more tolerant of salt than the other two genotypes and the salinity tolerance of Rosada genotype is lower than the other two genotypes but there is no relationship between increased phenolic compounds, flavonoids and anthocyanins and salinity resistance in this genotype