Conception (biology)

Fertilisation or fertilization (see spelling differences), also known as generative fertilisation, conception, fecundation, syngamy and impregnation, is the fusion of gametes to initiate the development of a new individual organism. The cycle of fertilisation and development of new individuals is called sexual reproduction. During double fertilisation in angiosperms the haploid male gamete combines with two haploid polar nuclei to form a triploid primary endosperm nucleus by the process of vegetative fertilisation.

In 1784, Spallanzani established the need of interaction between the female's ovum and male's sperm to form a zygote. Oscar Hertwig (1876), in Germany, described the fusion of nuclei of spermatozoa and of ova from sea urchin.

The gametes that participate in fertilisation of plants are the sperm (male), and the egg cell, and in flowering plants a second fertilisation event involves another sperm cell and the central cell which is a second female gamete. In flowering plants there are two sperm from each pollen grain.

In seed plants, after pollination, a pollen grain germinates, and a pollen tube grows and penetrates the ovule through a tiny pore called a micropyle. The sperm are transferred from the pollen through the pollen tube.

Bryophyte is a traditional name used to refer to all embryophytes (land plants) that do not have true vascular tissue and are therefore called "non-vascular plants". Some bryophytes do have specialised tissues for the transport of water; however, since these do not contain lignin, they are not considered true vascular tissue.

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