Post Fertilization Changes in the Flower

The petals and stamen withers off, however the calyx may be present in some cases. Style and stigma degenerates. Ovary develops into fruit and ovule grows into seed. The seed contains the future plant or embryo which develops into a seedling under appropriate conditions. This process is called germination.

True fruits are those which are formed from ovary of a flower e.g. Guava, grapes. While if any other part of flower like thalamus or other modifies into fruit, it is called false fruit e.g. apple, pineapple.

1.0Seed

A typical seed is formed from the ovule of a flower. It includes two basic parts an embryo and a seed coat. Embryo is the fertilized egg formed by repeated division of zygote. Seed contains one cotyledon or seed leaf in monocots and two cotyledons in dicots. In angiosperms usually, there is store of nutrients for the embryo called endosperm. The seed coat develops from the integuments, originally surrounding the ovule. The seed coat is either bitegmic or unitegmic. Bitegmic seeds have two integuments outer testa and inner tegmen while unitegmic seed have only one integument.

Seed remains inactive for sometimes, this resting period is called dormancy. Dormancy protects seed from all unfavourable conditions. On germination, first the radicle come out which later develop into roots and then plumule which later develop into shoots.

Some plants, like wheat and marigold, produce seeds only once in a year and die out, while others continue to produce seeds for many years such as mango, apple, etc.

2.0Fruit 

• Fleshy fruit: Fruit wall is thick and fleshy e.g. Tomato, Brinjal, Orange, Coconut, Plum.

• Dry fruit: Fruit wall is thin and dry e.g. Cotton, Lady finger, Maize, Sunflower, Bean.

Functions of Fruits

• The fruit wall gives protection to the seeds and therefore, to the embryo.

• The fruit is a store house of food material.

• The fruit helps in the dispersal of seeds.

3.0Dispersal of Seeds and Fruits

For a seed to give rise to a new plant, certain favourable conditions are necessary. A seed must fall on a suitable place where favourable conditions are present. 

Mechanism of Dispersion

• In some cases, like light seeds of grasses or hairy seeds of aak (Madar) and hairy fruit of sunflower are carried to far-off places by wind.

• In some cases, like Madar, the seeds are small and dry. A tuft of fine hairs is present on the tip of each seed. These seeds are carried to far-off places by wind. 

• The seeds of Drumstick and Maple have flat, wing-like light structures. Like Madar, these seeds are also dispersed by wind.

4.0Also Read