Seed structure and in vitro seedling development of certain Laeliinae species (Orchidaceae)

Seeds and seedlings of neotropical Laeliinae species (Cattleya loddigesii, Cattleya tigrina, Hadrolaelia purpurata, Laelia anceps, Schomburgkiagloriosa, and Sophronitis cernua) were studied. The seed germination process and the seedling grown in vitro are described. Seeds of the studied species are unitegmic and have conspicuous thickening in the anticlinal and inner periclinal cell walls. The embryo consists of a relatively long and multicellular suspensor. At first stage of seedling development, the embryo differentiates into a protocorm with rhizoids and meristematic tissue.The budding occurs on the protocorms. The endogenous taproot is produced after the first leaves have emerged. The root is triarch or tetrarchand it possesses velamen. Structural characters related to seed coat, suspensor, ontogeny of leaves, and vascular system of the root are significant indicators for the separation of Laeliinae species.