Physiology of Oil Seeds. VIII. Germination of Peanut Seeds Exposed to Subfreezing Temperatures while Drying in the Windrow.1,2

During November 1976, freshly dug, high-moisture (30–40%) peanuts drying in the windrow in North Texas were exposed to subfreezing overnight temperatures for 6 days. The effects of that exposure on germination of the seeds were studied. Samples of the subsequently cured and hand-shelled peanut seeds were tested for germination, seedling emergence, ethylene and carbon dioxide production, and certain enzyme activities. Laboratory germination was 42%, greenhouse seedling emergence 32%, and most of the freeze-damaged seeds that germinated grew at a slow rate. Germination and greenhouse seedling emergence of controls were 96 and 100%, respectively. At their maximum rates, ethylene and carbon dioxide production by freeze-damaged seeds were reduced 83 and 36%, respectively. Mean enzyme activities measured from protein extracts of the freeze-damaged seeds were reduced, but they were not always significantly different from the control. However, isocitric lyase activity, which depends on de novo protein synthesis, was significantly less for freeze-damaged than for control seeds, particularly during initial stages of germination. Thus, low-temperature exposure of high-moisture peanut seeds interfered with the initial biochemical and developmental processes, such as synthesis of new proteins, that determine seedling growth.