Describe the various ways by which seeds are dispersed.
Seed dispersal occurs by the following agencies.
Dispersal by animals − There are many ways by which birds and animals can disperse seeds. For example, birds and animals can eat the fruits and excrete the seeds away from the parent plant. Some seeds have barbs or other structures that get attached to the animal’s body and are carried to new sites. Some fruits have hooks on them which cling to fur or clothes.
Dispersal by wind − Seeds that get dispersed by wind are usually smaller in size or they have wings or hair-like structures. For example, winged seeds of drumsticks, hairy fruit of sunflower, etc. are dispersed by wind.
Dispersal by water − Many aquatic plants or plants that live near water has seeds that can float and are carried away by water. For example, coconuts can float and are dispersed by water.
Dispersal by explosion − Sometimes the seeds are dispersed by the bursting of fruits with sudden jerks. The seeds get scattered or distributed far from the parent plant. Examples of such plants are castor and balsam.
Following are the ways in which the seeds are dispersed:
1) Some light seeds like that of madar, which are hairy, dry and small are carried away by the wind to different places.
2) Spiny seeds and fruits like that of xanthium and urena, stick to the clothes of passers by and animals. These seeds are carried away by these agents to different places.
3) In some plants having heavy seeds like that of coconut, water acts as the dispersing agents.
4) Some seeds are dispersed with the fruit burst like in case of balsam and castor