Fruits Formation, Parts, and Types of Fruits

Importance of Fruits

An apple a day keeps the doctor away! You must have heard this classic saying and understood the importance of fruits in keeping ourselves healthy and keeping the doctors at bay. Fruits are wholesome food. They are rich in vitamins and other nutrients. It is almost impossible to even think of any doctor who does not recommend fruits for good health and diet. Fruits do not just have health benefits, but they also have a taste. They taste delicious. But have you ever wondered how they are formed, what are their different parts, and how many types of fruits are there? 

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How are Fruits Formed?

The first condition for the fruits to grow is the blooming of flowers. It is the flowers that bear the reproductive parts for the formation of fruits. Generally, it is the same flower that has both male and female units, but you can also find situations where flowers grow as having male or female reproductive parts on separate plants. In flower, the stamen is the male part which consists of the pollen sac called anther, and the pistil is the female part which consists of a stigma, style, and ovary. For the fertilization (reproduction process in flowers) to occur, the pollen must be transferred from the anther to the stigma. This process is called pollination. 

If pollination does not occur, the pollen or male sperm will not be able to unite with the ovule, that is, the female egg in the ovary. Once the pollen has traveled down to the base of the pistil where the ovule resides, the nucleus of the male sperm unites or fertilizes with the ovule combining the female and male genetic material that goes on to form an embryo.

As the embryo crosses its two-cell stage, it is called a zygote, which later develops into a seed. As the zygote grows, the structure of the flower begins to change- the ovary starts to change into the fruit. The outside part of the ovary and the pistil becomes the skin of the fruit, or in some cases, the material outside the ovary wall becomes the fleshy and edible part of the fruit and parts like petals and sepals become the outer covering.

The fruit will survive only if the plant will. If the plant does not bear flowers, there will be no fruit formation.        

What are the Different Parts of a Fruit?

To have an easier understanding of the structure or the parts of fruit, it is divided into two parts- first, the pericarp and second, the seed.

  • The pericarp is that region of a fruit which is located outside the seed. It comprises the skin and flesh part of a fruit. It is, in turn, divided into three layers endocarp (the innermost layer around the seed), Mesocarp (middle layer), Epicarp (outermost layer).

  • Epicarp layer: It is also called the exocarp. It is the outermost layer of the fruit and the pericarp, which makes the fruit covering or the skin. In citrus fruits, the epicarp layer (the tough, thick skin) is called flavedo. 

  • Mesocarp layer: It is the middle layer between the exocarp and the endocarp of the pericarp. It usually consists of the fleshy part of the edible part of the fruit like in apples and peaches. In citrus fruits like lemons, the white-colored portion just after the flavedo is the mesocarp layer, and it is called albedo. It is not the main edible part but is still eaten. 

  • Endocarp is the innermost layer of the pericarp. It surrounds the part of the seeds. It is generally not consumed, but in citrus fruits, they make the main edible part like in oranges, the pulpy part, which has the juice vesicles make most of the endocarp. 

  • Seed: Seed has three parts- the seed coat, the embryo, and the endosperm. The seed coat is developed from the female reproductive part, but the endosperm and embryo are developed through the cross-fertilization of both male and female units.  The outermost covering is the seed coat that protects the seed. The next layer, the endosperm, provides nutrition to the embryo, which is the innermost part of the seed. 

FAQ (Frequently Asked Questions)

1. Explain Different Types of Fruits, Along with Examples.

Fruits are classified into four groups, i.e., simple fruits, aggregate fruits, multiple fruits, and accessory fruits.  

  • Simple Fruits: Simple fruits are fruits that are produced from one ovary. These fruits generally have one or a smaller number of seeds. Examples of simple fruits can be mangoes, pears, apples, etc. These fruits can either be fleshy or dry. The fleshy fruits are further divided into drupes, pomes, and berries. 

  • Drupe Fruits: These fruits have one seed and a fleshy mesocarp, which is edible. This fleshy part is developed from the ovary. The best examples are mangoes and peaches.

  • Aggregate Fruits: These are fruits that are formed by the aggregation of more than one ovary in the single flower—examples- Raspberries, custard apples, etc.

  • Multiple Fruits: Multiple fruits are also called composite fruits. These fruits are formed from the fusion of more than one ovary of separate flowers. Composite fruit examples are pineapple, jackfruit, and mulberry, etc.

  • Accessory Fruits: Accessory fruits are those fruits whose flesh is developed from the accessory parts of flowers like sepals, petals, etc. Example- strawberries 

2. What are the Different Types of Composite Fruits? Is the Tomato a Type of Fruit?

Composite fruits are fruits that formed from the fusion of more than one ovary of separate plants. These are of two types- Sorosis and Syconus. 

  • Sorosis- These grow from catkin, spikes, and padix type of inflorescence. Examples are pineapples and jackfruits.

  • Syconus- These grow from hypanthodium type of inflorescence. Examples are figs.

Yes, botanically speaking, tomato is considered to be a fruit. It is a fruit because it develops itself from flowers of the tomato plant. It is considered to belong to the berry category of plants as most of its pericarp is in fleshy form.