Characterizing critical phases of germination in winterfat and malting barley with isothermal calorimetry

作者：Youming Qiao, Ruojing Wang, Yuguang Bal, Lee D. Hansen · 发表于：Seed Science Research · 年份：2005 · DOI：10.1079/ssr2005213 · 被引用次数：6 · 研究领域：Seed Germination and Physiology、thermodynamics and calorimetric analyses、Magnetic and Electromagnetic Effects

The heat production of seeds during germination comes from metabolism as well as hydration. Previous studies either lack continuous measurements, or are based on samples composed of more than one seed, thus failing to characterize differences among the critical phases of germination. This study examines the potential of isothermal calorimetry to characterize water uptake and metabolism in single seeds. Seeds of malting barley ( Hordeum vulgare L.) and winterfat [ Krascheninnikovia lanata (Pursh) A.D.J. Meeuse & Smit], two species with contrasting seed size, structure, composition and selection history, were used to determine patterns of heat production rate by isothermal calorimetry during water uptake and germination. Embryos of malting barley contributed less than 4% of total seed weight, and metabolic heat production during Phase I of germination was negligible compared to that due to hydration. Embryos accounted for 74% of seed mass for winterfat, and the majority of heat produced in Phase I was due to metabolic heat release. The total heat production rate in Phase I decreased rapidly in malting barley due to slowing of hydration reactions, but increased gradually in winterfat due to an increasing metabolic rate. The heat production rate at the end of Phase II was about twice as high in malting barley as in winterfat. This indicates a higher metabolic activity for malting barley than for winterfat seeds during germination, which may have also contributed to the rapid ...