Abstract
Embryos of Pinus nigra Arnold and Tsuga canadensis Carr. (Pinaceae) at different stages of development were dissected from fresh, unfixed seeds and examined in a fluorescence microscope with 400 nm excitation light. The embryos of the investigated species showed cutin fluorescence after auramine 0 staining. At first the fluorescing cutin layer was formed on the apical part of the embryo with a well developed secondary suspensor, then it extended over the lateral surface of the embryo; the suspensor remained nonfluorescent. The fluorescing cutin layer occurred on the apical and side surface of the embryo, undergoing differentiation into the shoot axis and root initials. It is assumed that polarization and nutrition of the embryo may be influenced by presence of the cuticle.
Keywords
embryonic cutin; gymnosperm embryogenesis