Adaptation of plants to the fixed life

Adaptation of plants to the fixed life :

Reproduction :

The flower is the reproductive organ of plants. A flower can have the male organs, the female organs or both. Plants can’t go see a partner. Only pollen, the male organ, which contains two spermatozoids, can move. Pollen will deposit on the carpel, either by being transposed by insects, either by wind or water. Pollen deposed on the stigma will do a pollen tube will fertilize the sexual cell present in ovule. When the flower will wither, the ovary become a fruit and his ovum, seeds.

The coevolution of plants and pollinators :

To promote the dispersion of the pollen, plants will adapt to attract insects. Flower will then be attractive by odour, colour or form and the pollen will be large and sticky. Insects will develop in return characteristics to collect pollen.

For flowers whose pollen is transported by wind, flower will then be reduced, with a long and feathery stigma, and light pollen in large quantities.

This the co-adaptation will lead to a greater diversification of the species of flowers and insects.

Dandelion : example of

plant whose pollen is

transported by wind

The seed dispersal :

Differents adaptations favor this dispersion in order to the seed doesn’t fall too near to its genitor and compete with it.

There are differents carriers: animals, wind or water. The fruit can be light, to fly more easily. The fruit can also cling on mammals or even be sweet to be consumed by birds and develop at the place where the bird will defecate.

As well as, the seed can develop without competition with its genitor.

Plant exchange surfaces :

Exchange surfaces of plants are very important because this is what ensures the nutrition of the plant so they are an an important factor in its development. There is as much exchange surfaces with the ground as exchange surfaces with the air.

Exchanges with the ground are ensured thanks to root hairs.

Exchanges with the air are ensure leafs whose their disposition and their structure promote these exchanges.

Exchanges are made mainly by stoma which manage water inlet and outlet and so ensure the regulation of evapotranspiration and the gaseous exchanges.

The number of stoma varies according on the type of plants but generally there are more stoma on the underside of the leaf.

The conductive systems :

The engine of the rise of sap in plants is evapotranspiration. There are 2 types of sap : the raw sap (composed of water and ions) and the elaborated sap (composed of glucose, sucrose …). The xylem is the raw sap conductive tissue and the phloem, that of elaborated sap.

The

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