Monselise, S.P., Hebrew University, Faculty of Agriculture, Volcani Institute of Agricultural Research, Rehovot, Israel
Kadman‐Zahavi, A., Hebrew University, Faculty of Agriculture, Volcani Institute of Agricultural Research, Rehovot, Israel

Abstract— Dark germinated citrus seeds produce a characteristic epicotyl hook which opens in white light. The effects of white, red and far red irradiation, in different combinations on the opening of hooks, the increase in length of primary leaves and the reduction in length of epicotyl have been studied. Broadly speaking, morphogenetic effects of light are similar to those usual for annual plants. One single red cycle coming after a long period of intermittent far red seems to be more effective than coming after a long period of darkness. It is also at least as effective as a long period of intermittent red irradiance. These features are of interest and deserve further study. Elongation of leaves and opening of hooks are correlated when treatment means are considered, but not in individual seedlings, possibly indicating independence of these two effects of radiation. Copyright © 1965, Wiley Blackwell. All rights reserved