Fruit Growth and Female Gametophyte Development in Paphiopedilum barbigerum Tang et Wang

Abstract:

In order to understand the development of ovule and female gametophyte in Paphiopedilum barbigerum Tang et Wang, an endangered species in Orchidaceae, the growth dynamic of its capsule was studied by conventional paraffin section method. The results showed that the number of seeds in capsule increased rapidly during 60-75 days after pollination, and its capsule would be full of seeds at 120 days after pollination. The ovule primordium, a row of cells surrounded by a layer of epidermal cell, began to differentiate at 40 days after pollination. The archesporial cell under the epidermal cells at the end of placenta finger structure differentiated into megaspore mother cell at 60 days after pollination. The megaspore mother cell eventually formed the mature embryo sac after meiosis and mitosis. It took about 135 days from pollination to maturation of embryo sac, and seeds attached to placenta had differentiated obviously. The development of embryo sac was Allium type. The mature ovule was anatropous with thin nucellus and single integument. The mature embryo sac had 8 nuclei. These would provide theoretical basis for studying in reproductive biology and establishment of reproductive system.