Desiccation induced physiological and biochemical changes of Gymnacranthera canarica (King.) Warb. seeds in the Myristica swamp forests, Southern Western Ghats, India

Abstract

Gymnacranthera canarica (King.) Warb. is an endemic tree species that dominates the Myristica swamp ecosystem of southern Western Ghats. This tropical tree species has become more threatened due to limited natural seed germination and habitat loss. Mature seeds were collected from the myristica swamp ecosystem subjected to desiccation study. This research evaluated the physiological (moisture content, tetrazolium reduction, lipid peroxidation, electrolyte leakage) and biochemical response of seeds during different desiccation treatments. Results showed that G. canarica seeds are highly sensitive to desiccation and total viability loss was seen within 15 days following harvest indicating the active seed metabolism of mature seeds showing absence of metabolic arrest. Desiccation enhanced malondialdehyde and electrolyte leakage while reducing formazan formation. Seed desiccation increases protease activity, which peaks when viability is lost. Desiccation reduced the quantity of phenol and starch, whereas proline, fat, sucrose and total soluble carbohydrates increased. The early viability loss in G. canarica seeds could be due to loss of membrane integrity, which was linked to ROS formation and associated lipid peroxidation products indicating seeds are truly recalcitrant.