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pericarp is divided into outer skin which covers the pulp with many seeds scattered within. Bananas are seedless as the plants get propagated through rhizome and not through the seeds. In peas, beans, and other pulses, the fruit has a dry pericarp with several seeds. In groundnut, soon after fertilization, the flower-stalk goes underground and further development takes place below the ground level. The fruit which is a legume, like peas and beans, has a hard pericarp and looks beaded due to constructions between the seeds. After the seeds are mature, they get separated from the parent and germinate into new offsprings. External agents like wind, water and animals disperse them to avoid competition for space, food and light. Some seeds, as of cotton, are provided with hairy outgrowth which help them fly long distances. Some seeds, as of drumstick, have wings. Seeds which are dispersed by water as coconut have a waterproof coat and float to long distances, In lotus, small oneseeded fruits by spongy top shaped thalamus which floats in ponds and lakes. Birds eat berries pulp but viscid seeds stick to their beaks, they wipe their beaks on tree trunks where the seeds are left to germinate on the? tree trunks and thus become parasites.
SEED STRUCTURE AND GERMINATION: A seed possesses an embryo or the juvenile plant and is covered by one or two seed coats. The embryo consists of a primary axis within embryonic root or radicle, at one end and the embryonic shoot or the plumule with a pair of tiny leaves at the other end. It has one or two cotyledons also. Seeds store reserve foods as carbohydrates, proteins and fats.
The embryo in the seed is a young plant in an inactive state. Seeds remain viable, i.e., capable of germination for a period of 10 to 25 years (dormant period), if stored in a cool dry place. Under suitable conditions of temperature water and oxygen, the embryo grows into a tiny plant called the seedling.
Germination commences by entry of water which activates dehydrated enzymes in the storage cells and the insoluble reserves are converted into soluble forms (digestion). The digested food is absorbed. Soaked in water, the seed swells and the seed coat bursts open. The radicle is the
JAIN BIOLOGY
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