The embryo or seedling is developing in plants resulting from the fertilized egg ( zygote ) germ, which is still nourished from the mother plant. In land plants, the formation of an embryo is a distinctive feature compared to the green algae from which they emerged. That is why they are also called Embryophyta.
In the mosses and ferns, the embryo continues to develop. In the seed plants, the embryo in the seed sets up a resting stage, is so clearly against other growth stages delineated. The development of the embryo from the zygote to the final shape in the seed embryo is called embryogenesis or genius.
After orientation, there are two types:
- Endoscopes embryos have a Sprosspol directed inwards. They are found in the seeds of plants and most ferns.
- In exoskopen embryos, the inward cell is the foot, the outer becoming the Sprosspol and on to the sporangium. Exoskope embryos occur in mosses and horsetails.
In the following, only the embryo of seed plants is treated.
The finished embryo is usually of the following parts:
- The suspensor pushes the developing embryo from the micropyle into the endosperm. The connection between the embryo and the actual suspensor consists of one or more cells and is called pituitary. In mature seeds suspensor and hypophysis are usually no longer recognizable.
- The cotyledons or seed leaves are present in varying numbers.
- The hypocotyl is the offspring section and connects the cotyledons with the
- Radicle or root system.
- The plumule between the cotyledons and the first leaf Achsenmeristem with the plants.
The position of the radicle compared to the cotyledons in some clans of systematic importance, especially in the mustard family ( Brassicaceae). It can be divided as follows:
- Notorrhiz or rückenwurzelig: the two cotyledons are flat against each other, one of them is the Radicula to.
- Pleurorrhiz or seitenwurzelig: the radicle is up to the side edge of the flat cotyledons.
- Orthoplok or longitudinally folded: the radicle is up to or between the two cotyledons, which are folded.
- Spirolob or rolled in a spiral: the cotyledons are rolled spirally, the radicle is up to them.
- Diplecolob or double-folded: the radicle is up to the S-shaped curved cotyledons.
- Gerhard Wagenitz: Dictionary of Botany. 2nd Edition, Spektrum Akademischer Verlag, Heidelberg, Berlin, 2003, pp. 92f. ISBN 3-8274-1398-2
- Plant morphology