PJB-2017-82
Dynamics of seed germination, seedling growth and physiological responses of sweet corn under PEG-induced water stress
Wu Li, Xiaolan Zhang, Umair Ashraf, Zhaowen Mo, Haicui Suo and Gaoke Li
Abstract
Stress induced variations in seed germination of various crops has been well reported but germination potential of sweet corn seeds under osmotic stress with relation to time dynamics is still elusive. Present study explored the water absorption, germination potential and physiological indices and of sweet corn seeds exposed to five different levels of PEG-induced water stress i.e., 0, -0.3, -0.6, -0.9 and -1.2 M Pa water potential (Yw) with respect to time dynamics. Results showed that enhanced water stress for prolonged time period (96 h) led to substantial reduction in water absorption and seed moisture contents, seed germination and vigor index as well as seedlings growth and fresh and dry biomass. Osmotic stress triggered antioxidant defense system like super-oxide dismutase (SOD), peroxidase (POD) and catalase (CAT) and accumulation of soluble sugars, proline and protein contents considerably. Initially, activities of SOD and CAT were higher but then reduced as stress persisted, however, POD showed a linear increase with respect to stress exposure time. Water stress also increased MDA contents up to 36 h then declined. Further, α- amylase activity and soluble protein showed significant correlations with maize seed germination. Overall, germination potential decreased with increase in osmotic stress in sweet corn seeds
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