Significance of seed and fruit formation

Introduction

Like humans, seeds and fruits are also formed through fertilization. Since the world’s inception, the process of formation of a human being, seed, or fruit has remained the same.

Significance of seed and fruit formation definition

Reproduction is a biological process where every new individual is produced through the sperm of the father and the mother’s eggs. Similarly, the plant produces in two ways, either asexually or sexually. Asexually, the seed is produced without the seed formation, whereas sexually, the seed is produced with the seed formation. Vegetative parts such as roots, leaves and stems are involved in asexual reproduction, whereas the flower’s reproductive part is involved in the sexual reproduction of the seed. 

When a fertilized ovule gets divided by mitosis, it forms the seed. It can store food and can be developed into a new plant under favorable conditions. When a male and a female gamete combine to form a zygote, the process is called fertilization. Stigma gets transferred to the Pollen grains through several pollinating agents, including water, wind, butterflies, insects, animals, birds, among others. Once it reaches the stigma, the male sex cells contact the egg in the ovule to form a zygote that later develops in an embryo and then a fetus. 

Once the fertilization is completed, the entered flower sheds off except the ovary. In contrast, it turns into a fruit and the ovules into seeds. Once the seeds are produced, it completes the reproduction process. In these seeds, the embryo develops and turns into a flower.

Seed dispersal

There are chances that the formed seeds can be dispersed onto the ground due to several natural factors such as wind, water, animals etc. Seeds require enough wind, water, minerals and space to grow. Therefore, it is suggested to distribute the seeds for the healthy growth of the plant. The dispersal of seeds can take place either artificially or naturally. Garden-keepers and botanists perform the artificial method of seed dispersal. Some of the natural seed dispersal methods are listed below. 

  1. Wind Dispersal – Dandelions are a plant that has feathery bristles. The seeds of it can be dispersed through the wind. E.g. Orchid,cottonwood etc.
  2. Water Dispersal – The seeds sometimes flow in the water away from the parent plant and grow somewhere else .E.g sea kale,sea rocket etc.
  3. Animal Dispersal – Sometimes, plants produce seeds in animals’ fresh fruits. Squirrels tend to bury seeds that never come out. Whereas these later grow into plants.
  4. Bird Dispersal-The seeds sometimes disperse by birds(fruit eating birds) and grow somewhere else.E.g.parrot,pigeon etc.
  5. Gravity Dispersal– Sometimes, fruit and their seed fall on soil after ripening of fruit and disperse seed.E,g-Apples, Commelina etc.
  6. Explosions Dispersal– Some plants have pods and the seeds burst out after ripen and seed dispersed by explosion.E.g.pea,bean etc.

What is a fruit? 

In simple terms, the flowers are the reproductive units, whereas the fruits are reproduction results. The fruits are developed from a ripened ovary. Since these are a rich source of minerals, vitamins and nutrients, they are highly recommended. Some of the common fruits humans primarily consume are grapes, bananas, papaya and watermelon.

Parts of a fruit 

The fruit is majorly divided into two parts:

Pericarp : After ripening, the ovarian wall changes into pericarp. This pericarp may be thick and fleshy or thick and hard or thin and soft.

Pericarp is made up of 3 layers :-

(a)   Outermost layer    =   Epicarp

(b)   Middle layer     =   Mesocarp

(c) Innermost layer  =   Endocar

 Epicarp – It is the outermost layer. It is thin and hard or soft. It forms outermost layer of fruit which is also called rind

Mesocarp : It is the middle layer which is thick and fleshy in mango, peach, date palm. In coconut, this layer is made up of fibres which is also called coir

Endocarp : It forms the innermost layer it may be thin membrane (eg. Orange, date palm)  or thick and hard (eg. Mango, Coconut)

Seeds–  Seeds can be defined as ripened fertilized ovules. It comes with a protective outer layer.

Types of fruit

Depending on the number of flowers and ovaries involved in the formation of the fruit, they are majorly classified into three different types:

  • Simple Fruits
  • Aggregate Fruits
  • Composite Fruits

Let’s discuss each of these in detail:

  • Simple fruits

The simple fruits are developed in only one matured ovary into a single flower. Some examples of simple fruits are Apple, banana, cherry pear, plum, tomato. These are further classified into four parts:

  • Drupes
  • Berries
  • Pomes
  • Hesperidium and Pepos

Drupe fruit : In these fruits endocarp is hard and stony so these fruits are also called stony fruits. Eg. Mango, coconut, almond, peach walnut, plum.In jujube, Epicarp and Mesocarp both are edible part while endocarp is drupe.

Berry :. In these Epicarp is thin like a membrane and seeds are embedded in the fleshy part initially seeds are attached with placenta of fruit but after maturation these seeds are detached with placenta and are spread randomly in the fleshy part. E.g.Date palm, banana etc

Pepo: These fruits are fleshy and spongy. Eg. fruits of the Cucurbitaceae family like cucumber, melon, bitter gourd etc.

Pome :The rind and sponge are made up of thalamus. The main part of the ovary is like cartilage. It means it is hard and dry remain   inside the   fruit seeds are present in it. Eg. Apple, Pear. These are false fruits. 

Hesperidium :  Epicarp of these is made up of thick rind which is leathery and many oil glands are found in it. Mesocarp is the white fibrous structure which is attached with epicarp. Membranous endocarp projects inward and formed many chambers. Many glandular hairs are present on the inner side of the endocarp. These glandular hairs are only edible parts.Eg. Orange, Lemon      

  • Aggregate fruits  

The aggregate fruits are developed from several matured ovaries in a single flower. These ovaries are known as “fruitlets.” common examples are Blackberry, raspberry and strawberry. 

  • Composite fruits 

The composite fruits or the multiple fruits are developed from an entire inflorescence. Further, it is divided into two parts:

  • Sorosis
  • Syconus

Conclusion

Seeds and fruits are formed by fertilization. In angiosperms, two structures are formed as a result of double fertilization – a diploid zygote and a triploid primary endosperm cell. Both fruits and seeds are an important part of angiosperms

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