Bhardwaj, Rachana D.Harsimran Kaur2017-08-212017-08-212016http://krishikosh.egranth.ac.in/handle/1/5810029175In the present study, effect of exogenous phenolic acids on antioxidative defense system of salt stressed wheat seedlings was investigated at 7th day of growth. Electrical conductivity of 10 dS/m was used for imposing salt stress. For observing stress mitigating effects of various phenolic acids, 20 ppm of ferulic, 10 ppm of caffeic, 10 ppm of p-coumaric, 5 ppm of salicylic and 15 ppm of sinapic acids were selected for biochemical studies. Catalase and POX activities were upregulated in the stressed shoots of salt tolerant cultivar by the exogenous use of caffeic and sinapic acids. In comparison to stress, APX activity was also upregulated in stressed seedlings of both cultivars by exogenous use of caffeic and sinapic acids. In stressed seedlings of salt sensitive cultivar, MDHAR activity increased by exogenous use of caffeic, p-coumaric, salicylic and sinapic acids. In roots of Kharchia Local, use of ferulic, para-coumaric and caffeic acids resulted into upregulation of GR activity, whereas in salt sensitive cultivar only caffeic acid caused upregulation of this enzyme. Total phenols also increased in salt stressed seedlings of both the cultivars on application of ferulic, caffeic and salicylic acids which was partially attributed to the downregulation of PPO activity. Proline content increased in HD 2329 by use of different exogenous phenolic acids whereas, in Kharchia Local use of sinapic acid led to enhanced proline content. Glycine betaine content was increased by use of different phenolic acids in the stressed roots of Kharchia Local. On the other hand, exogenous application of sinapic acid led to enhanced glycine betaine content in salt sensitive cultivar. In the shoots of both cultivars, MDA content either decreased or remained unaffected whereas H2O2 decreased in both cultivars by exogenous use of different phenolic acids.ennullThesis