Synchronous organization of two preprophase microtubule bands and final cell plate arrangement in subsidiary cell mother cells of someTriticum species

Abstract

In the primary leaves of threeTriticum species examined, two successive guard cell mother cells (GMCs) are often laterally flanked by one epidermal cell which is induced twice by them and forms two subsidiary cells (SCs). In the case of simultaneous induction of the common subsidiary cell mother cell (SMC) by the GMCs, its nucleus does not migrate towards either of the GMCs, but occupies a position between them. Unexpectedly, in a number of the above “double-polarized” SMCs, two preprophase microtubule bands (PMBs) are organized at the same time, apposed on the GMCs at the expected positions. In some of those cells the daughter wall exhibits aberrant dispositions and either a small lens-shaped cell adjacent to the intervening cell between the GMCs or a large SC alongside both the GMCs and the intervening cell, or an SC flanking one GMC and a part of the intervening cell between the GMCs are separated. Obviously, the sites of fusion of the cell plate with the parent walls do not coincide completely with those of either of the PMB cortical zones. These cell plates appear to intersect those parental walls which are common with the intervening cells at PMB cortical sites belonging to two PMBs. Besides, the one end of the cell plate may pass from the cortical zone of the one PMB to another of the other PMB.