A SHIFT OF THE RESPONSE THRESHOLD TO RED IRRADIATION IN DORMANT LETTUCE SEEDS

Abstract

Seeds of lettuce of the cultivars Noran and Meikoningin germinate readily in darkness, but a requirement for red light can be induced by long exposure to far-red irradiation or by exposure to temperatures above 30°C. After the first treatment the response threshold to red irradiation is several orders of magnitude higher than after the second treatment.