Interaction of Temperature and Light in Germination of Seeds

Abstract

Effects on germination of light and of holding at several temperatures were measured on seeds of Lepidium virginicum L. campestre Sisvmbrium officinale, Fragaria virginiana Verbascum thapsus Nicotiana tabacum, and Brassica iuncea. Germination of seeds of each species is enhanced by exposure to red radiation and by diurnal alternation of temperature. Germination of seeds of Lepidium virginicum is greatly enhanced by a temperature change from 15[degree] to 25oC or by soaking the seeds in 0.2% KNO3 solution. Holding imbibed seeds at 35[degree] for 2 hours increases the sensitivity of the photoreaction to radiation and increases total germination in response to light. The germination process is controlled at different points by the several factors. The photoreaction controls the levels of two compounds which are also under control by other reactions that are subject to influence by temperature.