Physiological responses of fennel seedling to four environmental stresses

Fennel (Foeniculum vulgare Mill.) is widely cultivated for its edible, strongly-flavored leaves, fruits, seeds and medicinal uses. As the wild and cultivated plants are influenced by environmental stresses, the effects of salt (25, 50 and 75 mM NaCl), nitrogen and iron deficiency (0 N, 0.5 N of Hoagland’s solution, 0 Fe and 0.5 Fe of Hoagland’s solution), 2°C cold (2, 3 and 4 h) and drought (3, 5 and 7 days) stresses on growth, pigment content, and antioxidant activity of fennel at the seedling stage were evaluated. All four stresses resulted in a significant reduction of fresh and dry weights, and chlorophyll a and b and β-carotene content of seedlings. The antioxidant activity of seedling extracts also increased significantly (P ≤ 0.05) in all stresses except for 5 and 7 days of drought.