Enzymatic Response, Mucilage Compounds, and Fatty Acids of Lallemantia to Chemical and Biological Nitrogen Sources under Salinity Stress Conditions

Dragon's head, one of the mint family plants with 30% oil and mucilage in its seeds. In order to evaluate the response of plant to nitrogen fertilizers in saline soils, a factorial experiment was conducted based on randomized complete block design with three replications in 2018 at Urmia University. Treatments included nitrogen fertilizer (urea, Azotobacter as a foliar application and Azotobacter as a seeds inoculant and no-fertilizer as control), and two planting bed, saline and normal, with conductivity of 6.7 and 0.91 ds/m respectively. The highest amount of catalase, ascorbate peroxidase and activity total phenol content wasto plants grown under saline soil without any nitrogen fertilizer. However, their values decreased significantly for all fertilizer treatments. All constituents of seed mucilage were higher in non-saline conditions. While application of urea increased rhamnose content, Azotobacter inoculation caused xylose, glucose and galactose content to be increased under non-saline condition. Urea was preferred for the production of raffinose, arabinose, galacturonic acid and glucuronic acid. Salinity, likewise fertilizer treatments had no significant effect on oil content and mucilage. In all treatments, salinity increased the antioxidants, which was related to plant response to stress conditions. In the case of soluble sugars, nitrogen fertilizers prevented excessive reduction and moderated this amount. Despite increasing saturated and unsaturated fatty acids under soil salinity, fertilizer treatments increased the saturated fatty acids (stearic, palmitoleic, palmitic and myristic) against decreasing unsaturated fatty acids (linolenic, linoleic and oleic).