Plumular morphology and seedling morphogenesis of irradiated and nonirradiated embryos of barley (Hardeum vulgare L.)

Barley (Hordeum vulgare L.) is frequently used as an experimental organism in radiation biology. Considerable information has been accumulated about the dormant barley embryo, but most of the work has little bearing upon plumular ontogeny. Furthermore, there is a paucity of data available relevant to varietal differences in numbers of leaves and axillary buds present in the dormant embryo. The developing seedling has received some attention regarding date of leaf and tiller emergence (macroscopic observations); however, there is little information in the literature pertaining to the sites of origin and chronological initiation of primary and secondary tiller meristems. The purpose of this study is to describe the embryonic and seedling morphology of several varieties of barley. Histological examinations were made of dormant embryos and developing seedlings from irradiated and nonirradiated grains, with the prospect of determining the effects of gamma radiation on the growth of meristems from the dormant embryo following germination. Other meristems which differentiated during the ten day post sowing period were also studied in relation to their number and origin.