Tag Archives: Embryology

Polyembryony: Multiple Embryos in a Seed

The phenomenon of polyembryony, i.e., the occurrence of more than one embryo in a seed, has attracted much attention ever since its initial discovery in the orange (Citrus sinensis) by Leeuwenhoek (1719). Ernst (1918) and Schnarf (1929), who have reviewed the older literature, classify it into two types—”true” and “false”—depending …

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Apomixis: A Subistitution for Sexual Reproduction

Apomixis maybe defined (Winkler, 1908, 1934) as the substitution for sexual reproduction (amphimixis) of an asexual process which does not involve any nuclear fusion. For the sake of convenience it may be subdivided into four classes. Non-recurrent apomixis Recurrent apomixis Adventive embryony Vegetative propagation Non-recurrent apomixis In the first, or …

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Steps of Fertilization

Fertilization is the union of male and female gametes to produce a zygote. There are several steps of fertilization. They are described below. Germination of Pollen. Course of pollen tube. Entry of pollen tube into ovule. Entry of pollen tube into embryo sac. Gametic fusion. Germination of pollen Exact information …

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Female Gametophyte: The Embryo Sac with Its Types

The angiosperm female gametophyte is critical for plant reproduction. It contains the egg cell and central cell that become fertilized and give rise to the embryo and endosperm of the seed, respectively. Female gametophyte development begins early in ovule development with the formation of a diploid megaspore mother cell that …

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Nemec Phenomenon: Embryo Sac Like Pollen Grain

In 1898, Nemec noted that in the petaloid anthers of Hyacinthus orientalis, the pollen grains sometimes form large eight-nucleate structures showing a surprising resemblance to embryo sacs. He believed that they arose as the result of a degeneration of the generative nucleus and three divisions of the vegetative nucleus of …

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Discovery about the Male, Female Gametophytes & Syngamy

Among early students of the development of pollen, Hofmeister (1848) presented some surprisingly good illustrations of the process of tetrad formation (microspore tetrad), and Reichenbach, Hartig and several other workers noted the presence of two nuclei in whole mounts of the mature pollen grains of several angiosperms. Discovery of nature …

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Pollen Tube Discovery by G. B. Amici

Giovanni Battista Amici (1824) who was also a good microscope maker, found that the stigma of Portulaca oleracea was covered with hairs which contained some granules or particles inside them. Curiosity prompted him to ascertain whether they moved in the same way as the granules he had seen in the …

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The Megasporangium: Types, Parts and Functions

Megasporangium is the structure of a plant body which contains female reproductive organ . It can be called ovule .  It consists of nucellus and integument . The ovule can be formed in different size and shape . Many times it changes its form during the course of its development. …

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