Interaction of radiation and photoperiodism in Xanthium pensylvánicum Effects of radiation during the light and dark periods of photoinduction

Abstract

Two groups of Xanthium pensylvánicum plants received a dose of 1927 rad 60Co γ-radiation during either the dark or light period of short day photoinduction. Another group of plants was photoinduced but not irradiated. Vegetative growth was initially stimulated in both groups of irradiated plants, but later responses were not observed. Both pistillate and staminate flowering were inhibited in both groups of irradiated plants, but pistillate flowering was inhibited to a greater extent. Staminate and pistillate development were retarded in both groups of irradiated plants with the greatest inhibition occurring in plants irradiated during the light period. Results are interpreted as responses to radiation-induced changes in nucleic acid and growth hormone metabolism.