Frost damage and or cold stress to crops in the United States runs more than $1 billion per year. In North Carolina during 1983, about 30,000 t of peanuts valued at $16 million were diverted from the edible market due to freeze damage. It is difficult to distinguish if a lot of peanut seed has been exposed to cold or heat stress because in both cases anaerobic respiration predominates. This research was undertaken to distinguish between cold and heat stresses at the cellular level on peanut seed by using dynamic headspace analysis, specific conductivity of the seed leachate, ion chromatography for cations and organic acids, ninhydrin detection for amino acids, and light microscopic techniques. Acetaldehyde, ethanol, and ethyl acetate are produced by both stress conditions. Two isomers of 2,3-butanediol and short-chain acids were identified from cold-stressed seed. These isomers were not found in heat-stressed peanut tissues and can be used to differentiate between the two environmental stresses. Specific conductivity of the leachate was higher from cold-stressed seed than from normal or heat-stressed seed, due to a higher efflux of potassium and acetic acid from the cells. Plasmolysis of the cold-stressed seed cells was consistently observed. Aleurone grains appeared to be larger, more dispersed, and tended to migrate towards the cell wall in the heat-treated samples, whereas the aleurone grains in the cold-stressed samples were smaller and more concentrated at the center of the cell. Irregular cell shape was common to both stresses.
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Keywords: Cell structure, cold stress, heat stress, volatiles
How to Cite:
Singleton, J. & Pattee, H.,
(1997) “Effects of Cold and Heat Stress on the Chemistry and Cell Structure of Peanut Seeds¹”,
Peanut Science 24(1),
01 Jan 1997