What is a monoembryonic example?

What is a monoembryonic example?

The sprouting of one and only one seedling from a seed is known as monoembryony. Polyembryonic seeds are those that produce two or more seedlings. Some of the nuclear cells that surround the embryo sac begin to divide and protrude into the embryo sac, where they develop into embryos. These are called polyembryonic embryos. The other nuclear cells degenerate and are lost when the seed matures.

Monoembryonic seeds usually arise by division of monospermous pollen, which produces an egg cell and a central nucleus without any companion sperm cell. The egg cell divides once to produce two identical daughter cells that go on to become plant tissue. However, if the single egg cell divides again before fertilization, then this would result in a third cell that also becomes plant tissue. Seeds produced by such monoecious plants as corn and cotton can be either monoembryonic or dicentric (having two centromeres). If pollen is monospermic (with one sperm nucleus) then the ovules will be monoecious (with one egg cell) and the seeds will be monoembryonic.

Seeds produced by dioecious plants have two separate sexes (male and female), each with their own gametes (sperm and eggs). Division of these nuclei results in four cells: two sperm cells and two egg cells.

How is polyembryony formed?

Polyembryony is the formation of two or more embryos from a single fertilized egg. Because the embryos are derived from the same egg, they are similar to one another yet genetically distinct from the parents. Polyembryony occurs often in many vertebrate, invertebrate, and plant species. It can be classified into three main types: monophyllous, diphyllous, and polyphyllous.

In monophyllous polyembryony each embryo grows from a separate seed. This type is common in some lilies and orchids. In diphyllous polyembryony two or more embryos grow from the same seed but at different times. These embryos usually develop into separate plants. A good example is the blackberry; it has two sets of embryos (diploids) for each fruit (red diploid and white diploid). Blackberries can also form triploids by combining a red diploid with a white diploid, which results in an embryo that is half red and half white. Triploids can then become tetraploids, etc..

In polyphyllous polyembryony several embryos grow on separate plants or trees. For example, in some papaya seeds there are up to 100 embryos growing on one fruit. Most of these will degenerate during development but some may remain alive as spares.

What is polyembryony? Give two examples.?

Polyembryony is a phenomena that occurs when two or more embryos grow from a single fertilized egg. It leads in the production of two identical twins in the case of humans. The nine-banded armadillo is the greatest example of polyembryony in the animal realm. Each of its four arms has a fully functional set of limbs, but only three of them are used at once because it can only use three of its babies at a time.

Human beings are also subject to this phenomenon. When human beings are born they usually have all their organs; however, sometimes two people will be born with part of their organs such as a hand or an eye on separate sides of their body. These cases result from polyembryony because eggs are normally only activated when they reach a certain stage of development. If multiple eggs are released from one ovary, then some of them will develop further and some won't. Humans who are born with multiple copies of their organs survived because they were not exposed to harmful factors during their early stages of development. Other animals that are subject to polyembryony often die before they are able to reproduce because they do not receive enough care from their parents. Humans who are born with multiple copies of their organs survive because doctors are able to take measures to prevent them from receiving additional doses of radiation or drugs that could harm their developing bodies.

Polyembryony is very common in plants.

About Article Author

Mary Farrar

Mary Farrar is a specialist in the field of Evolutionary Biology. She has a PhD in Evolutionary Biology from UC Berkeley. She's studied how organisms evolve over time, how they use energy and resources, how they survive in their environment, and how they reproduce. She's been studying these topics for over 25 years, and has published over 30 peer-reviewed articles in scientific journals.

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