Differential variations in total flavonoid content and antioxidant enzymes activities in pea under different salt and drought stresses

Salt and drought are serious environmental stresses that restrict plant yield and productivity of many crops including pea which is considered as sensitive plant to these stresses. There is need to evaluate the underlying effects of salt and drought stresses on the pea plant and present study is focused to evaluate the harmful effects of salt and drought stresses on three pea varieties, i.e., Climax, Green grass and Meteor. For this purpose, plants were exposed to different levels of salt stress (5.4 mM (Control), 50 mM, 75 mM and 100 mM of NaCl) and drought stress (by watering 100%, 75% and 50% of field capacity). Metabolic analysis was carried out for total flavonoid content while antioxidant enzymatic assay involved study of superoxide dismutase (SOD), guaiacol peroxidase (GPX) and catalase (CAT) activities. Aluminum chloride colorimetric assay was used to calculate the total flavonoid content (TFC) while for enzymes assay UV–visible spectrophotometer was used. Application of high stress levels of both salt and drought caused significant rise (P ≤ 0.05) in TFC. Enzymatic assay for GPX showed significant enhanced (P ≤ 0.05) activity while SOD and CAT showed decrease activity at high levels of both kinds of stresses. TFC and GPX showed positive correlation with respect to increased accumulation both under salt and drought stress thus indicating their main role in antioxidant activities. The current study will help in understanding of salt and drought stress impact on pea plant with reference to role of total flavonoids and antioxidant enzymes.