explain the factors responsible for the seed dispersal
Answers
A plant produces a large number of seeds, if all these will fall below the plant and start growing, they will not get enough space, water, Minerals and the sunlight and they will not develop into healthy plants. Many of them even die. Nature has arranged some agents of dispersal by which the seeds of a plant get scattered over a large area. This is called dispersal of seeds.
Here are some means of dispersal of seeds -
• Dispersal by wind - seeds of cotton or Dandelion have tiny hairs surrounding them. While the Maple seed has wings attached to it. these adaptations help the seeds to be carried out by wind.
• Dispersal by water - the coconut seed has a thick coat of fibre that enables it to float in water, the Lotus fruit has a spongy part that enables it to float. these plants grow near water and their seeds are carried to far off places by water.
• Dispersal of seeds by animals - Some seeds such as xanthium and tiger nail have hooks or spines which help them to stick to the fur of animals or to our clothes with the fruit pass out unharmed in the waste and germinate where they fall.
• Dispersal by explosion of fruit - the fruit of geranium, blasam and pea burst on drying. This causes the seeds to be thrown away from the parent plant.
There are different agents of the seed dispersal:
Dispersal through wind :
Seeds that are dispersed through wind are usually light and are either very small or light with wings on them or some hairy structures on them. Seeds that adopted in such a way that they get carried away easily by wind. Some seeds float in air some propel to travel short distances. In some plants back or chips seats are minute with inflated covering
Example :milkweed ,Dandelion ,maple.
Dispersal by water:
Seeds adopted to float on water are usually light. The outer covering of the seed has empty spaces filled with air and some are fibrous with a spaces that encloses the whole SEED or fruit.
Example : coconut, seeds of lotus
Dispersal of seeds by birds and other animal:
Seeds are dispersed by animals in many ways . in case of fleshy fruits, the fruit is eaten by animals while some dry fruits, which specialised structures like hooks, thorns , hairy parts, get stuck to the bodies of animals and get carried two distant places.
Birds like bulbuls, mynahs, crows eat some fruits the outer flashy part gets digested in the foot canal and the seed coats of them become tender. They are then dispersed to other places has bird droppings. Many fleshy fruits are meant to be eaten by animals. The fleshy part of the fruit is eaten leaving the seeds uninjured. Some seeds get dispersed through animal excretions.
Dispersal by bursting of fruits that throw the seed out:
some seeds grow in capsules which when touched the burst and uncoil with a force in such a way that they scatter the seeds all around.
Dispersal of seeds through human beings:
Everyone is aware of tomatoes. It is a common vegetable cooked in every home. In tomato pickles, tomato curry excetra we find tomatoes. when your European travelers came to trade in India, DLF the seeds of vegetables like tomato cauliflower, Goa on their return. nowadays we see different kinds of fruits and vegetables around us. Import and export of grains like wheat pulses, maze, paddy is a common practice through which many seats get dispersed all over the world. It is funny to think that she is also travel by aeroplanes and ships.
Hope the answer is helpful.....
Done.