Seed and Fruit - Practice Questions & MCQ

Seed:

• The seed is the name of a ripened ovule which contains an embryo or miniature plant in suspended animation, adequate reserve food for the future development of the embryo and a covering for protection against mechanical injury, loss of water, pathogens, etc.
• A seed typically consists of the seed coat(s), cotyledon(s) and an embryo axis.
• The cotyledons of the embryo are simple structures, generally thick and swollen due to storage of food reserves (as in legumes).
• Mature seeds may be non-albuminous or exalbuminous. 
• Non Albuminous seeds have no residual endosperm as it is completely consumed during embryo development (e.g., pea, groundnut).
• Albuminous seeds retain a part of endosperm as it is not completely used up during embryo development (e.g., wheat, maize, barley, castor).
• Occasionally, in some seeds such as black pepper and beet, remnants of nucellus are also persistent. This residual, persistent nucellus is the perisperm.
• Integuments of ovules harden as tough protective seed coats. 
• The outer seed coat is called testa and the inner one is called tegmen.
• The micropyle remains as a small pore in the seed coat.
• This facilitates entry of oxygen and water into the seed during germination.
• As the seed matures, its water content is reduced and seeds become relatively dry (10-15 per cent moisture by mass). 
• The general metabolic activity of the embryo slows down. 
• The embryo may enter a state of inactivity called dormancy, or if favourable conditions are available (adequate moisture, oxygen and suitable temperature), they germinate.

Fruit:

• As ovules mature into seeds, the ovary develops into a fruit, i.e., the transformation of ovules into seeds and ovary into fruit proceeds simultaneously. 
• The wall of the ovary develops into the wall of fruit called the pericarp. 
• The fruits may be fleshy as in guava, orange, mango, etc., or maybe dry, as in groundnut, mustard, etc. 
• Many fruits have evolved mechanisms for dispersal of seeds. 
• In most plants, by the time the fruit develops from the ovary, other floral parts degenerate and fall off. 
• However, a few species such as apples, strawberries, cashews, etc., the thalamus also contributes to fruit formation.
• Such fruits are called false fruits.
• Most fruits, however, develop only from the ovary and are called true fruits.