As soon as the pollen grain falls on the stigma, it starts germinating and forms a pollen tube. This pollen tube passes through style and reaches the ovary. The pollen tube contains male gamete which are released and one of them fuse with the egg to form zygote.

The dispersal of seeds occurs in different ways:
1. By the wind: Some plants, like drumstick have winged seeds, while other plant like milkweed have tufts of hair which help them ride on the wind.
2. By water: The fibrous covering of coconut, helps it float in water and is carried far away from the parent plant.
3. By animals: Birds, monkeys and other animals eat the fruit of many plants and throw away the seeds. Some plants have fruits or seeds with hooks, bristles or spines. These get attached to the fur of animals or to our clothes. They are carried a long way before they fall off or are brushed off.
4. By exploding fruits: The fruits of the rubber tree, balsam and beans explode when they ripen. The sudden bursting of the fruit scatters the seeds away from the parent plant.

Plant produces large number of seeds. When these seeds fall down they start growing. The process by which the seeds are scattered to different place (far and wide from their parents) is called seed dispersal.
The seeds and fruits are dispersed away through various agencies like air, water and animals. Sometimes dispersal takes place by the explosion or bursting of fruits. If all the seeds of a plant were to fall at the same place and grow, there will be a severe competition for sunlight, water, mineral and space. As a result, the survival for the plants will be difficult and the plants who survive will not grow into a healthy plant.

Flowers have nectars that attract insects. Insects suck these nectars as their food. When insects like bee, butterfly, etc., sit on the flower for sucking nectar, the sticky pollen grains get attached to their legs and wings. When these insects again sit on another flower, these pollen grains are transferred to the stigma of that flower from the body of the insects. In this way, insects help in pollination.

The following advantages of vegetative reproduction makes it a preferred method
(i) It takes less time to grow and bear flower and fruits than those produced from seeds.
(ii) The new plants are the exact copies of parent plant because they are produced from a single parent.

The small plants which were not there in the garden a weak ago have grown up due to seed dispersal. The seeds from the tree may have fallen below or have been dispersed by wind or animals on the ground, which on germination developed into new small plants.

Sugarcane and rose are propagated by stem cutting that is a method of vegetative propagation, in which stem is capable of growing into a mature independent plants that are identical to their parents.
Potato is an underground modified stem having bud called eyes, which sprout and develop into a new identical plant.
Thus, the plants which cannot produce seeds can be propagated vegetatively with the help of vegetative parts such as stem, roots, buds and leaves.

Buds are small bulb-like projections of yeast cell.
These are asexual reproducing bodies of yeast. Diagrammatic representation of budding in yeast

(a) Unisexual flowers are papaya, cucumber, corn.
(b) Bisexual flowers are rose, mustard, lady's finger, Petunia, pea.
(c) Unisexual flowers are also called as incomplete flower while bisexual flowers are called hermaphrodite or complete flowers.

The steps involved in the process of fertilisation are
(i) After pollination, pollen grains start growing into a pollen tube on the stigma passing through pistil.
(ii) The tube extends through the style and reaches to the ovules.
(iii) The pollen tube carries the male gametes called pollen grains.
(iv) Male gametes fuse with the egg (female gamete) present inside ovule and forms a zygote. This process is called fertilisation.
(v) Later zygote develops into an embryo and ovules develop into a seed.
(vi) Thus, seed carries an embryo with stored food and is covered by a hard protective covering called seed coat.

The main differences between asexual and sexual reproduction are

Sexual reproduction is a process of formation of new individuals by involving two parents or gamete formation. In sexually reproducing plants, new plants are produced from seeds.
In this method, gametes fuses to form zygote that gives rise to new individual.