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Diagram illustrating the process of pollination Female carpenter bee with pollen collected from a night-blooming cereus. Pollination is the transfer of pollen from an anther of a plant to the stigma of a plant, later enabling fertilisation and the production of seeds. [1]
Reproductive isolation is the process of species evolving mechanisms to prevent reproduction with other species. In plants, this is accomplished through the manipulation of the pollinator’s behavior (ethological isolation) or through morphological characteristics of flowers that favor intraspecific pollen transfer (morphological isolation).
The plant attracts these insects by producing a scent that mimics the scent of the female bee. In addition, the lip acts as a decoy, as the male bee confuses it with a female that is visiting a pink flower. Pollen transfer occurs during the ensuing pseudocopulation. [19]
Synchronously-flowering species in a community may evolve other divergent traits to avoid competition and prevent the transfer of heterospecific pollen. [ 11 ] [ 15 ] Because overlap in flowering times can lead to pollinators maintaining site fidelity, [ 16 ] there could be selection for overlapping, but not synchronous flowering in a community.
In order for fertilization to occur, there is rapid tip growth in pollen tubes which delivers the male gametes into the ovules. A pollen tube consists of three different regions: the apex which is the growth region, the subapex which is the transition region, and the shank which acts like normal plant cells with the specific organelles.
For plants, this relationship has resulted in more precise attraction of specific pollinators, facilitating the transfer of pollen to the stigmas of other plants and reducing the overall production of pollen. In contrast to anemophilous plants, which may produce around one million pollen grains per ovule, orchids typically produce a one-to-one ...
Hummingbird Phaethornis longirostris on an Etlingera inflorescence. Ornithophily or bird pollination is the pollination of flowering plants by birds.This sometimes (but not always) coevolutionary association is derived from insect pollination (entomophily) and is particularly well developed in some parts of the world, especially in the tropics, Southern Africa, and on some island chains. [1]
Pollen itself is not the male gamete. [4] It is a gametophyte, something that could be considered an entire organism, which then produces the male gamete.Each pollen grain contains vegetative (non-reproductive) cells (only a single cell in most flowering plants but several in other seed plants) and a generative (reproductive) cell.