Significance of Fruit:
1. Fruit protects immature seeds from unfavorable environmental conditions. The seeds remain enclosed in the fruit until they are ready to germinate.
2. Green color of young fruit is also a measure for the protection of seeds because they remain hidden within the foliage.
3. The immature fruits offer chemical defense against the animal because they contain unpalatable and repelling substances like astringents, tannins, sour acids, and bitter alkaloids.
4. Mature fruits acquire bright colors to attract the seed-dispersing animals.
5. Certain fruits on maturity burst with great pressure so that the seeds are dispersed to a distance.
6. Fruits are in use since prehistoric times as the main food of man. Even today fruits comprise the main part of the human diet.
Significance of Seed:
1. Dependable Method: Unlike cryptogams, pollination and fertilization of seed plants are free from the requirement of water. Seed formation is, therefore, more dependable.
2. Evolved Structure: The structure of the seed is highly evolved as it provides protection to the embryo.
3. Perennation: Thick protective seed coat and dormant embryo of seed are most suitable for perennation.
4. Reserve Food: Seeds have reserve food for nourishing the young seedlings till they become nutritionally independent.
5. Dispersal: Seeds possess suitable mechanisms for their own dispersal so that they may be spread to distant areas for colonization.
6. Variations: Seeds carry a number of variations as they are the products of sexual reproduction. Variations are important for adaptation to diverse environmental conditions.
7. Storage: Seeds can be stored for later use. This is helpful for the supply of food throughout the year and to overcome drought and famine conditions.
8. Agriculture: Seed is the basis of agriculture. It originated when humans learned to eat, store and sow seeds. Agriculture proved to be the turning point for the evolution of human civilization, industrialization, science, and technology.