Seed storage physiology of Himalayan elm (Ulmus wallichiana): an endangered tree species of tropical highlands

Abstract

To understand the seed storage physiology of U. wallichiana, mature seeds were stored at different combinations of seed moisture content (10.46 and 3.09%), storage temperature (-5, 5, 15°C and RT i.e. ambient room temperature) and storage container (open and air tight sealed). Storability was quantified by different viability and vigour test methods up to 678 days of storage. The half viability period (p 50 ) which quantifies the relationship between viability, storage temperature and seed moisture content exhibited maximum p 50 of 998 days when seeds were desiccated to 3.09% moisture content and stored at -5°C in air tight container. In contrast a minimum p 50 of 34 days was recorded when seed stored with original moisture content of 10.46% at RT. The vigor of seed during storage quantified by mean germination time (MGT), electrical conductivity of seed leachates (EC), rate of deterioration (d-') and germination index (GI) further revealed that the consideration of - 5°C and 3.09% seed moisture content was the best for long term storage. The study reveals U. wallichiana seeds are short lived if stored in open containers under ambient (room) conditions and the original moisture content. The seeds, can however be stored for a comparatively longer period at RT, provided they are properly dried to approximate 3.0% moisture content and stored in airtight containers. From the overall response of storage behavior of U. wallichiana it may be conclude that this species is possess orthodox storage physiology.