Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: April 10, 2011
Publication Date: April 10, 2011
Citation: Crane, J., Walters, C.T. 2011. Changes within lipid fractions offer a new way to non-invasively monitor seed viability during storage. Meeting Abstract. International Society for Seed Science, Bahia Brazil, April 10-15, 2011. pp. 278. Technical Abstract: Monitoring seed viability using germination tests consumes large quantities of seeds and does not predict when seed viability will crash. Non-invasive tests that show the progress of seed aging would provide greater efficiency. This study investigates the changes in the chemical and physical properties of the lipid component in lettuce (Lactuca sativa) seed as a function of storage time, with the ultimate goal of developing non-invasive assays of seed aging. Seed lots of lettuce (cv ‘Black Seeded Simpson’) harvested between 1987 and 2009 were stored at 5°C and about 35% RH. Decreases in percent germination and development of normal seedlings declined after about 4 years of storage and seeds were mostly nonviable after 9 years. Significant changes to the triacylglycerol (TAG) fraction of the seeds were detectable only after most seeds had died and indicate lipid oxidation, including a reduction in the proportion of linoleic acid, an increase in free fatty acids, the appearance of epoxidized byproducts, and increases in hexane insoluble fraction. However, changes in the crystallization behavior of TAG, measured using differential scanning calorimetry (DSC), were evident concurrent with losses of viability. TAG from aged seeds had significantly slower rates of nucleation and crystal growth. The reduced tendency for TAG to crystallize may result from subtle and undetected changes in TAG chemistry or greater mixing between TAG and non-TAG components. The high correlation between percent germination and TAG melting enthalpy introduces the possibility of a potentially new and non-invasive assay of the progress of seed aging.