Interactions between water and triacylglycerols may explain faster aging rates in stored germplasm at low temperature

ALINE SCHNEIDER TEIXEIRA; DANIEL BALLESTEROS; ANTONIO D. MOLINA-GARCÍA; CHRISTINA WALTERS

Rosario

Congreso; 49th Annual Meeting of the Society for Cryobiology; 2012

Cryobiology

Longevity of orthodox (desiccation tolerant) seeds, pollen and fern spores characteristically increases with decreasing storage temperature. We have discovered numerous seed and fern spore species that age faster when stored in the freezer near 20 C compared to storage at higher or lower temperatures. Seeds exhibiting this temperature anomaly are considered to be intermediate between orthodox and recalcitrant physiologies. Intermediate traits are often associated with high proportions of saturated fatty acids within the triacylglycerols (TAG), accumulated into cells as food reserves. TAG high in saturated fatty acids crystallize and melt within the temperature range of the observed longevity anomalies and we have hypothesized a link between TAG phase change and increased damage to germplasm cells. Damage is exacerbated as water content within stored seeds and fern spores increases from near 5% to about 12%. These observations have led us to hypothesize that damage results from an interaction between TAG, water, temperature and time.faster when stored in the freezer near 20 C compared to storage at higher or lower temperatures. Seeds exhibiting this temperature anomaly are considered to be intermediate between orthodox and recalcitrant physiologies. Intermediate traits are often associated with high proportions of saturated fatty acids within the triacylglycerols (TAG), accumulated into cells as food reserves. TAG high in saturated fatty acids crystallize and melt within the temperature range of the observed longevity anomalies and we have hypothesized a link between TAG phase change and increased damage to germplasm cells. Damage is exacerbated as water content within stored seeds and fern spores increases from near 5% to about 12%. These observations have led us to hypothesize that damage results from an interaction between TAG, water, temperature and time.