Deteriorative Changes in Pea Seeds (Pisum sativumL.) Stored in Humid or Dry Conditions

Abstract

Seeds stored under various conditions showed deteriorative changes in extremely dry (1% r.h. at 10 °C) or humid (93% r.h. at 25 °C) conditions after 6 weeks storage, when little or no loss of viability had taken place; no changes were detected in intermediate conditions (45% r.h. at 10 °C). The loss of electrolytes from seeds into water increased after 3 weeks of humid storage, and subsequently dead areas developed on the cotyledons of seeds held in either humid or dry conditions. With time in storage some of the seeds in dry conditions showed a reduction in the rate of imbibition, and consequently a low level of electrolyte leakage. Other seeds showed an increase in leakage following dry storage. No change in solute content (sugars, potassium, and electrolytes) was detected in seeds stored in humid conditions, suggesting that the increased electrolyte leakage was caused by an impaired ability to retain solutes. Thus increased leakage was recorded in seeds whose cotyledons contained no dead areas as revealed by vital staining, and was therefore attributable to changes in living cells, possibly deterioration in cell membranes. Viability began to decline after 6 weeks in humid storage at 25 °C and after 2 d in 94% r.h. at 45 °C, but was maintained in both dry and intermediate conditions. The rate at which viability fell in humid storage was greatly influenced by the initial condition of the seed.