See New TB Image Gallery

*
  

2011 Plant Systematics and Evolution; Embryology of Iris mandshurica Maxim. (Iridaceae) and its systematic relationships

https://link.springer.com/article/10.1007/s00606-011-0427-1

Abstract

Sporogenesis, gametogenesis, fertilization and embryogenesis of Iris mandshurica Maxim. were observed using the normal paraffin method. The results are as follows: the development of the anther wall following the dicotyledonous type consisting of four layers, the epidermis, the endothecium, one middle layer and the secretory tapetum. Fibrous thickenings develop in the endothecium when the anther is shed. Simultaneous cytokinesis during microsporogenesis results in a tetrahedral tetrad of microspores. Mature pollen grains are two-celled. The ovary is inferior and trilocular with axial placenta. The ovule is anatropous, bitegminous and crassinucellate. The archesporial cell below the nucellar epidermis undergoes periclinal division producing the primary parietal cell and the primary sporogenous cell. The primary parietal cell participates in the nucellar formation; the primary sporogenous cell differentiates directly as the megasporocyte. Successive cytokinesis in the megasporocyte usually produces the linear tetrad, and the chalazal megaspore of the tetrad develops into a Polygonum-type embryo sac. The fertilization mode is porogamy. The pollen tube enters into the embryo sac and discharges two sperm 16–20 h after pollination. The fertilization is the postmitotic type of syngamy. The first division of the zygote is transversal. Endosperm formation is of the nuclear type. The systematic significance of the embryological characters of I. mandshurica is discussed.

-- BobPries - 19 Dec 2018
Topic revision: r1 - 19 Dec 2018, BobPries
This site is powered by FoswikiCopyright © by the contributing authors. All material on this collaboration platform is the property of the contributing authors.
Ideas, requests, problems regarding Iris Wiki? Send feedback