Types of embryogeny, Biology

Types of Embryogeny

On the basis of the plane of division of the zygote and of the cells of the 2-celled proembryo, and also taking into account the relative contributions of the cells of the 4-celled proembryo to the mature embryo, six chief types of Embryogeny have been recognized.

A. Division of the zygote is vertical - Piperade type (e.g. Loranthaceae, Piperaceae).

AA. Division of the zygote is transverse.

B. Apical cell of the 2-celled proembryo divides vertically to form a T-shaped, 4-celled proembryo.

C. Basal cell plays no role at all or only an insignificant role in subsequent development of the proembryo-(Crucifer or Onagrad type (e.g., Ranunculaceae, Brassicaceae).

CC. Basal cell and apical cell both contribute to the development of the embryo - Asterad type (e.g., Asteraceae, Violaceae).

BB. Apical cell of 2- celled proembryo divides transversely so that the 4-celled proembryo is usually linear.

D. Basal cell does not participate or only contributes a little to development of embryo proper.

E. Basal cell usually forms a suspensor - Solanad type (e.g., Solanaceae, Linaceae).

EE. Basal does not divide further and the suspensor, if present, is derived from the apical cell - Caryophyllata type (e.g., Caryophyllaceae, Crassulaceae).

DD. Basal cell and apical cell both divide and contribute to formation of the embryo - Chenopodium type (Chenopodiaceae, Boraginaceae).

Posted Date: 1/23/2013 7:23:52 AM | Location : United States







Related Discussions:- Types of embryogeny, Assignment Help, Ask Question on Types of embryogeny, Get Answer, Expert's Help, Types of embryogeny Discussions

Write discussion on Types of embryogeny
Your posts are moderated
Related Questions
Why is carbon monoxide toxic for humans? Hemoglobin "likes" carbon monoxide (CO) much more than it likes oxygen. When there is carbon monoxide in the inhaled air it binds to he

What is digestion? Digestion is the breaking down of larger organic molecules obtained from the diet, e.g. carbohydrates, fats, proteins, into smaller ones, as glucose, fatty a

Explain the Reduction in cancer risk? Different cancers, especially colon and breast cancer, has been linked not only to phytates but also to protease inhibitors. In vitro stud

Within the cytosol which series of enzymes in order convert citrate back into pyruvate: -citrate lyase, malate dehydrogenase, malic enzyme - citrate synthase malate dehydroge

what are the general characters of nonchordates, explain

Limitations of Ecological Pyramids The pyramid of energy is a significant improvement over the previous two types of ecological pyramids, yet all of them overlook one or anot

nervous system of vertebrates

Blood Pressure Blood pressure may be defined as the force or pressure which the blood exerts on the walls of the artery. Blood pressure varies with the age of the individual. B

Clathrin-coated pits and vesicles are included in both the endocytosis   of material   at the plasma membrane and the exocytosis of proteins from the Golgi   apparatus.  Electron

Enumerate about the Mycotic Infections Invasion of the nervous system by a fungus is known as a mycotic infection. A fungus is any member of a large group of lower plants (in s