The archespore, which is directly under the nucellar epidermis, develops into the megaspore mother cell
. The megaspore tetrad is arranged linearly, and the megaspore at the chazlazal end is the functional megaspore.
Abbreviations: MMC, megaspore mother cell; PMC, pollen mother cell.
In addition, the megaspore mother cells (MMCs) in ms1ms1 plants were observed to undergo meiotic division without cytokinesis after Telophase II and thus produced multiple nuclei in megagametophytes (Cutter and Bingham, 1977; Kennell and Horner, 1985; Chen and Palmer, 1985; Zhang and Palmer, 1990).
On June 20 a typical megaspore mother cell was first observed which could be easily recognized by its large nucleus with dense cytoplasm (Fig.
The nucellus beneath the megaspore mother cells continuously elongated and developed into mature finger- like shape (Fig.
The inner integument initiates first, and then the outer integument develops into a small protuberance at the megaspore mother cell
In this primordium, an archeosporial cell produces a megaspore mother cell, which undergoes meiosis, forming a linear tetrad.
It is larger and differentiated from the neighboring cells and then become the megaspore mother cell (mc).
Reproductive modifications like apomixis, which involves the parthenogenetic development of apomeiotic eggs of unreduced embryo sacs that arise either from a somatic cell of the nucellus (apospory) or from a megaspore mother cell (MMC) with modified (meiotic diplospory) or absent meiosis (mitotic diplospory) (Nogler, 1984), have the potential of preserving heterosis over generations (Jongedijk, 1991).
Abbreviations: MMC, megaspore mother cell; SDR, second division restitution; FDR, first division restitution; 2nP, 2n pollen mutant; RAPD, random amplified polymorphic DNA; RFLP, restriction fragment length polymorphism.
gnemon two to eight megaspore mother cells
(megasporocytes) differentiate within each ovule.