Osservazioni carioembriologiche in Ornithogalum di Sardegna: Nota I. - Sporogenesi e sviluppo dei gametofiti in Ornithogalum caudatum Ait |
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| Authors: | Manlio Chiappini |
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| Affiliation: | Istituto di Botanica Farmaceutica dell'Università di Sassari |
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| Abstract: | Abstract CARYOEMBRYOLOGICAL STUDIES in ORNITHOGALUM OF SARDINIA. I. - SPOROGENESIS AND DEVELOPMENT OF THE GAMETOPHYTES IN ÒRNITHOGALUM CAUDATUM AIT. — After a concise synthesis of the caryoembryological knowledges regarding the taxa of Ornithogalum present in Sardinia, the embryology and morphology of Ornithogalum caudatum Ait., have been investigated. In a three-locular ovary the ovules are anatropous, epitropous with nucellus crassinucellate and only one archesporial cell evolves a mother cell. The development of the female gametophyte tallies with the Polygonum (Normal) Type. The homoetypical division presents an asynchronous proceeding in the cellules of the dyad with a considerable delay in the two-nucleate arrangement, especially in the chalazal cell. Antipodal cells present a hypertrophic growing, but they present no tendency to polyantipody. The endosperm is of the Helobiae Type. The divisions of the pollen mother-cells are of the successive Type. Longest axis of 1-sulcate pollen grains about 76 micron. A true tapetal periplasmodium isn't formed in the anthers. The chromosome number is 2n = 54. Raphides accour in the cataphylls, in the parenchymatous tissues of the leaf and in several parts of the floral region. |
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