Table of Contents
In plants, fertilization is defined as the fusion of the male and the female gamete to develop into a diploid zygote. After fertilization, a series of events occurs in the zygote to develop into a seed. Let us take an overview of the process of post-fertilization, endosperm and embryo formation.
What Is Post-Fertilization?
Post-fertilization is a series of events that takes place after fertilization to develop a seed from an ovule and a fruit from an ovary.
The following events occur in post-fertilization.
- Endosperm development
The endosperm is a type of tissue, which is present in the seeds of flowering plants during the time of seed development. Reserve food materials are present in the cells of endosperm tissue. It provides nutrition to the developing embryo in the form of starch. Endosperm development is classified into three types. These are as follows:
- Nuclear endosperm formation: In this process, the primary nucleus of the endosperm undergoes a nuclear division repeatedly to produce free nuclei without wall formation.
- Cellular endosperm formation: During nuclear division, the formation of the cell occurs and it leads to cellular endosperm formation. Cellular endosperm is seen in coconut meat.
- Helobial endosperm formation: It is an intermediate type of endosperm formation between cellular and nuclear type endosperm formation.
During seed maturation or in the mature seed, the developing embryo may either utilize the endosperm completely or it is used by the seed during seed germination.
Embryogeny is defined as the process of growth and development of an embryo from a zygote in flowering plants. Embryo development stages are the same in both monocot and dicot plants.
In the dicot plant embryo, an embryonal axis and two cotyledons are present. Two parts are present in the embryonal axis. These are as follows:
- Epicotyl: It is located above the cotyledon level.
- Hypocotyl: It is located below the cotyledon level.
A monocot plant embryo consists of only one cotyledon. The cotyledon is termed scutellum in the grass family. The root cap of grass is covered with an undifferentiated sheath which is called coleorhiza. A portion of the embryonic axis, which is located above the scutellum is called epicotyl. Epicotyl consists of shoot apex and coleoptiles.
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