Aging of Soybean Seeds in Relation to Metabolism at Different Relative

The present study was carried out to clarify the relationships between respiration, moisture content and the aging of dry soybean (Glycine max) seeds under different storage conditions. Ethanolic fermentation increased with increasing relative humidity (RH) during storage. How-ever, at 75 % RH which corresponded to a water content of 15.2 % in seeds, the production of eth-anol ceased after one month of storage. The ethanol that had accumulated within the container was re-absorbed by the seeds themselves and disappeared entirely within 3 months, unless the seeds were exposed to HCN gas. Similar changes were also found for methanol. The activity of mitochondria increased only in seeds stored at 15 % RH, it reached a maximum after the third month of storage and then rapidly declined. The amounts of both CoA and acetyl Co A in seeds that had been stored for 4 months were far lower at 15 % RH than at 53 % RH, and the viability of soybean seeds started to decrease after the fourth month at 75 % RH. Therefore, a major cause of the rapid deterioration of seeds at 15 % RH at room temperature seems to be the rapid develop-ment of mitochondrial respiration, which is accompanied by the consumption of CoA and its acetyl derivatives. By contrast, the slow deterioration of seeds during long-term storage at 33 % to 68 % RH and/or at subzero temperatures seems to be due to the toxic action of acetaldehyde, a