This whole process requires a fine regulation of many elements of development nike air max plus tn all white , leading to the development of basic morphologies ( morphogenesis ), the establishment of functionally organized structures ( organogenesis ) and differentiation tissue.
The generation of a functional body from a cell, and requires the acquisition of spatial coordination number of cell identities. The study of patterns in the embryology of plants, to understand the cellular organization in growth of these and so it gives us tools for handling. During embryogenesis of plants gives rise to a structure called a seed which is the initial unit that serves as a reference for future positional modeled structures. The adult develops from the guidelines dictated by the apical meristem nike air max tn black and green , which is visible in embryos that are about 100 cells. Therefore the study of these early stages to elucidate the mechanisms that generate different axes of growth and pre-structured functional patterns.
Capsella bursa-pastoris is the model used to describe the embryogenesis of dicotyledons. It was one of the first species in which we studied the process, and belongs to the family of cruciferous vegetables , like Arabidopsis thaliana , a species in which there have been numerous experimental studies on the molecular biology of embryogenesis.
The zygote nike air max tn black orange , diploid cell produced by the double fertilization , is divided transversely into two cells: the cell micropylar or basal cell which is divided transversely repeatedly to form a structure of the embryo known hanger , and chalazal cell or terminal that is divided vertically.
In the suspensor can distinguish a basal cell closest to the micropyle , very large nike air max tn black and red , vacuolated , with an extensive network of projections in its cell wall , which is involved in the nutrition of the embryo, and various cells calazales soon degenerate. The basal cell lives a little longer but eventually also disappears. As the suspending grows nike air max tn black white , pushes the embryo into the tissue being formed nutrient.
In cells derived from another cell division occurs chalazal vertically in a plane perpendicular to the first. Then these four cells (called quadrant ) are divided transversely into eight cells (called octant ). These are divided periclinalmente to form a globular structure. Divisions continue until the globular embryo consists of 64 cells. In this state differ protodermis from the surface cells.
Cells of the embryo then initiate a continuing program divisions and morphogenesis leading to the formation of meristems apical. The divisions are located side two prominences are the cotyledons . The embryo takes the form of body and heart-shaped.
Cell divisions continue and enlarge the cotyledons and hypocotyl . The embryo takes the form of torpedo . The vertical divisions outlined the procambium delimiting the fundamental meristem. Growth continues, the cotyledons reach the chalazal pole of the embryo sac and the embryo is curved