Genesis of megaspore and microspore as well as development of female gametophyte and male gametophyte in Liriope spicata (Thunberg) Loureiro

Abstract

The megasporogenesis and microsporogenesis, development of male and female gametophytes, pollen morphology and changes of anther wall structure during pollen development and ovary wall structure during ovule development in Liriope spicata (Thunberg) Loureiro of genus Liriope Loureiro in family Ruscaceae Spreng were studied using paraffin sections, scanning electron microscopy and fluorescence microscopy. The main results can be concluded as follows: 1) the cytokinesis of microsporocyte is successive; 2) the tetrads of microspores are mostly symmetrical and occasionally tetrahedral; 3) the mature pollen grain is oval or oblong, 2- or 3-celled, and has a sulcus and a rugulate–perforate ornamentation; 4) anther wall is of monocot type with secretory tapetum; 5) ovary is superior and has axial placentation and anatropous, bitegmic ovule; 6) the tetrads of megaspores are arranged most in a straight line and occasionally in T-shape; 7) the megaspore at the chalazal end develops into a functional megaspore; 8) development of embryo sac is of the polygonum type; 9) the floral morphology of both genera Liriope Loureiro and Ophiopogon Ker Gawler supports that each of them should be an independent genus.