THE SHOOT APICAL ONTOGENY OF THE PICEA ABIES SEEDLING. I. ANATOMY, APICAL DOME DIAMETER, AND PLASTOCHRON DURATION

摘要: A B S T R C Developing embryos in immature Picea abies seeds already have well-delineated shoot apical meristems with clearly evident cytohistological zonation. During early seedling development the zonation characteristic of gymnospermous is attained. Seedling also accompanied by an approximately threefold increase dome diameter. The latter approaches a steady state about 140 days after germination. Seedlings display spiral phyllotaxis consisting contact parastichy system, usually primary Fibonacci series. As seedlings age and domes enlarge, higher number-pairs characterize their phyllotaxis. Mathematical analysis relation between cumulative leaf number revealed that length plastochronic time interval declines from 18.5 hr to 5.7 as increases 20 days. MAJOR AREA study this laboratory con