Here, the pollen germinates and gives rise to the pollen tube.
Pollination means or it can be defined as the transfer of pollen grains from the stamen of flower to its ovule bearing organisms. In cycads and conifers in which the ovules are exposed the pollen is caught in a drop of fluid which is secreted by the ovule. In flowering plants, the ovules are in a hollow organ called the pistil and the pollen is deposited on the pistil’s surface called the stigma. Here, the pollen germinates and gives rise to the pollen tube. The pollen tube grows towards the ovule base and through double fertilisation, one sperm cell fertilises the egg cell of the ovule which starts the development of the embryo. There is also another sperm cell in the pollen tube which combines with two subsidiary sexual nuclei of the ovule. This initiates the formation of reserve food tissue. The growing ovule eventually develops to seed.
In general terms, pollination is the process of reproduction in plants. It is the transfer of pollen to an ovule which enables fertilisation and the production of seeds and this process requires at least one pollination agent. In this article, we will discuss what are the most important agents for pollen grain transfer. There are three types of agents than can be observed :
There are various factors which play a part in zoophily. Such as the scent of the flower, nectar position, edible sap and pollen which attracts insects. Whilst in ornithophily tiny birds like the hummingbird and honey thrushes feed on the nectar of flowers like Begonia and thereby pollinate them. In chiropterophily, trees like java and bauhinia are pollinated by bats. Image will be uploaded soon
There are Two Modes of Pollination in Plants
Advantages and disadvantages of self-pollination Self-pollination has both advantages and disadvantages. In this section, we will discuss both. The Advantages of Self-Pollination include :
The Disadvantages of Self-Pollination Include :
Plants which have adapted for cross-pollination have several mechanisms to prevent self-pollination. Their reproductive organs may be arranged in a way that self-pollination is unlikely, or the stamens and carpels may mature at different times. Advantages and Disadvantages of Cross-Pollination The Advantages of Cross-Pollination are:
The Disadvantage of Cross-Pollination include:
A: Pollination in plants is important due to many reasons. Some of them are mentioned below.
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