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CELL PATTERNS IN EARLY EMBRYOGENY OF THE McINTOSH APPLE
- Source :
- American Journal of Botany. 45:341-349
- Publication Year :
- 1958
- Publisher :
- Wiley, 1958.
-
Abstract
- THERE HAS long been a need for more detailed investigations of all phases of embryology, as there are serious gaps in the literature. Most papers in the field either report studies of the very early sequences of cell division, or they describe the events leading up to fertilization and may also include some early embryonic stages. Only a few describe in detail the origin and development of meristems, tissues, and organs as they arise in ontogeny. This study aims to describe the ontogeny of a dicotyledonous embryo, that of the McIntosh apple, by determining the number, kind, and sequence of events and their possible interrelationships. Such a study should lead to a clearer understanding of the anatomy of the mature plant, since it provides a basis for further studies of factors which operate to bring about the organization of the mature plant. The McIntosh apple was chosen for study because it is readily available and is a dicotyledon of considerable economic importance about which a great deal already is known. This study started out to be a detailed description of the sequence of cell divisions which produce the embryo, but the embryos do not grow by a single sequence of predetermined cell divisions. The embryo as a whole goes through a sequence of growth periods. In apple four major stages of growth occur: (1) the embryo grows as a filament; (2) the embryo tends to grow like a sphere; (3) new centers of growth are established, and primary meristems are initiated, as some of the cells become morphologically altered; and (4) the cotyledonary primordia grow rapidly, as the shoot apex, leaf primordia, and procambia develop. The first three stages are described in this paper. The filamentous stage is divided into two phases. The first begins with the zygote (fig. 1) which without increasing in size is divided by three transverse divisions into four cells (fig. 2, 9, 23-27). In the second phase the embryo increases its size only in length (fig. 3). Transverse divisions divide the em
Details
- ISSN :
- 00029122
- Volume :
- 45
- Database :
- OpenAIRE
- Journal :
- American Journal of Botany
- Accession number :
- edsair.doi...........952a83ef64b5f0521d07552402488964
- Full Text :
- https://doi.org/10.1002/j.1537-2197.1958.tb13135.x