Date of this Version
In recent years a number of reports (for example, Caldecott et al., 1952, 1954, 1955; Schmidt and Frolik, 1951; Schwartz, 1954; Schwartz and Bay, 1956; Spencer and Cabanillas, 1956; Yagyu and Morris, 1957) have appeared which deal with the effects of treating seeds with various high energy radiations. In all cases it is reported that seedlings grown from appropriately-irradiated seeds are reduced in stature. This reduction in stature must necessarily result from irradiation-induced decreases in number and/or size of the cells comprising the seedlings. Although some quantitative data relating to irradiation-induced changes in cell size and mitotic activity are available in the literature (Lea, 1955), there is a paucity of this type of information dealing with the seedlings grown from irradiated seeds. This report deals with a study in which cell size and mitotic activity have been measured in tips of roots grown from control and irradiated maize seeds.