Effect of salinity stress on biochemical parameters and growth of borage (Borago officinalis L.)

Salinity is one of the most important limiting factors for growth and product of plants around the world. Identification of salt tolerant varieties and improvement of plants tolerance are the most effective way to increase its performance. Experiments were conducted in a hydroponic system in order to study the reaction of borage (Borago officinalis L.) to salinity in terms of developmental changes and pigment content. Salinity was applied by 100 mM Sodium Chloride and Sodium Sulfate salts by the ratio of two to one on borage at the 4-leaf stage. Wet and dry weights of shoots and roots, chlorophyll, protein, proline, anthocyanins, soluble carbohydrate, and reducing carbohydrates were determined. Decrease in fresh and dry weights of shoots and roots was observed in the salinity condition and the fresh weight loss in shoots was significant (p<0.05). Chlorophyll content also decreased but this was not significant. Salinity stress decreased the amount of protein in shoots and roots compared to control. Proline contents in leaves and roots increased significantly under salt stress compared to control. On the average, in comparison to control, salinity stress decreased the amount of soluble carbohydrates in roots and shoots but this reduction was not significant.The amount of reducing sugars under salinity stress increased in shoots in comparison with control but they decreased in roots. Moreover, the amount of anthocyanin increased under salinity stress in comparison with control plants. It was concluded that borage was able to resist against stress due to the changes in the contents of these compounds under salinity.