Fruit vs Seed
During pollination, pollen grains from a flower fall on the stigma of the same flower or another flower. They are stimulated by a sugary fluid on the stigma and starts germinating. The intine of the pollen grain grows out through a small pore in the extine to produce the pollen tube. Pollen tube grows down and enters the ovule through the micropyle. Then the apex of the pollen tube degrades and the two male nuclei are released in to the ovule. The double fertilization takes place by the fusion of one male nucleus with the egg cell nucleus, giving rise to the diploid zygote. The fusion of the other male nucleus with the diploid secondary nucleus gives rise to the triploid primary endosperm nucleus. After the fertilization, the ovule becomes the seed and the ovary becomes the fruit.
Fruits are of three types. Those are simple fruits, aggregate fruits and multiple fruits. In single fruits, there is only one single ovary. It may contain one or more seeds. Simple fruits may be fleshy or dry. Berry is a popular example for a single fruit. Aggregate fruits are derived from a single compound flower. It contains many ovaries. One example for aggregate fruits is blackberry. Multiple fruits are derived from multiple flowers with fused ovaries. The pericarp of the fruit has 3 layers. Those are the exocarp, mesocarp and the endocarp. Exocarp is also known as the peel, and the endocarp is known as the pith. Exocarp is the outermost layer of the pericarp. It is more like a tougher outer skin. Exocarp is also called the epicarp. Mesocarp is the fleshy middle layer. It is found in between the exocarp and the endocarp. Endocarp is the innermost layer of the pericarp. It surrounds the seeds. The endocarp may be membranous or thick and hard.
After fertilization, the ovule develops in to the seed. The two integuments of the ovule become the two seed coats. The outer seed coat is called the testa, and the inner seed coat is called the tegmen. Some seeds contain only one seed coat. The stalk of the seed is developed from the funicle. Nucellus is generally being used up completely but, in some seeds, it may remain as a thin layer. Egg cell, after fertilization, gives rise to the embryo, and synergid and antipodal cells get completely disorganized after fertilization.
What is the difference between Fruits and Seeds?
• After the fertilization, the ovule becomes the seed and the ovary becomes the fruit.
• The outer layer of the fruit is the exocarp, and the outer layer of the seed is the testa.
• Seeds are found inside the fruits and the layer of pericarp that surrounds the seed is the pericarp.
• Fruits play an important role in the seed dispersal by attracting the animals.
• Without the fruit, the seed can grow in to a new plant but, without the seeds, the fruit cannot grow in to a new plant. This is because the embryo is found inside the seed, and the embryo is the one that gives rise to a new plant.