Southern
Research Station

• Authors: Sowa, Sharon; Connor, Kristina F.
• Publication Year: 2003
• Publication Series: Miscellaneous Publication
• Source: Seed Technology Vol. 25, No. 2, 2003 p. 110-123

Abstract

The recalcitrant behavior of cherrybark oak (Quercus pagoda Raf.) acorns was examined in terms of effects of moisture content on seed storage longevity and (short term) seed germination. Seed samples collected over two consecutive years were fully hydrated, then subjected to drying under ambient conditions of temperature and relative humidity on the lab bench and sampled regularly for moisture determination (gravimetric analysis) and germination (greenhouse conditions). Fourier transform infrared spectroscopy (FT-IR) was used to follow changes in macromolecular structure as moisture and viability were lost. Transmission spectra were collected on dry and rehydrated samples of separate embryonic axis and cotyledon tissue. Long-term storage longevity was highly dependent on initial acorn moisture content. Germination was also highly dependent on short-term moisture content, and severely declined when seed moisture dropped below 17% (fresh weight basis). FT-IR analyses revealed significant differences in moisture and lipid profiles between embryonic axis and cotyledon tissue during short term drying. A strong absorbance near 1740 cm-t in cotyledon tissue indicated a high concentration of ester carbonyl groups (storage lipids). Membrane lipid structure exhibited reversible shifts between gel and liquid crystalline phases upon drying and rehydration in both axes and cotyledons (peak frequency and bandwidth near 2850 cm-t); however, reversibility declined as viability was lost. Irreversible changes in protein secondary structure, illustrated by shifts in the amide absorbance near 1650 cm-r, were the most sensitive indicators of viability loss.

• Citation: Sowa, Sharon; Connor, Kristina F. 2003. Recalcitrant Behavior of Cherrybark Oak Seed: An FT-IR Study of Desiccation Sensitivity in Quercus pagoda Raf. Acorns. Seed Technology Vol. 25, No. 2, 2003 p. 110-123
• Posted Date: April 1, 1980
• Modified Date: August 22, 2006

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