The pollen tube nucleus directs the growth of the pollen tube down through the pistil to the ovary
The tube nucleus in the pollen tube typically disintegrates as it moves downwards in the pollen tube to ensure that the sperm cells reach the ovule without interference. This allows for successful fertilization to occur by facilitating the fusion of the sperm cells with the egg cell and central cell in the ovule.
The structure grown by a pollen grain that contains two sperm nuclei is called the pollen tube. The pollen tube is responsible for delivering the sperm nuclei to the ovule for fertilization in plants.
Ungerminated pollen grain is inactive and has not started the process of fertilization, while germinated pollen grain has started growing a pollen tube towards the ovule for fertilization. Germinated pollen grain is actively involved in the fertilization process, while ungerminated pollen grain is not.
When they land on the style they begin to bore their way through the stigma all the way to the ovule. Through the tube made by the tube nucleus of the pollen grain: each pollen grain has two nuclei, one called generative nucleus which combines with the nuclei of the ovule, and the other called tube nucleus tube nucleus which forms a tube that penetrates the stigma till it reaches ovule then it degenerates.
Pollen grows a tube that travels down to the flowers ovary. From there, the nucleus of the pollen grains passes through the pollen tube to join the nucleus of the ovule to fertilize.
Fertilization in plants is achieved by union of male gamete with an egg nucleus. The first step in fertilization is formation of male and female gametes, Second step is transfer of male gametes containing pollen to stigma of female reproductive organ by pollination. The third step is germination of pollen grain for movement of male gamete to the vicinity of female gamete. The fourth step is the union of the nucleus of male gamete with egg nucleus in the embryo sac. The fourth step of fertilization in angiosperms is the act of double fertilization. During this process one of the two gametes released by a pollen tube fuses with secondary nucleus. The secondary nucleus is formed by fusion of two nuclei of embryo sac. Thus double fertilization is also called triple fusion.
this is because premature pollen grain do not contain the sperm cell for fertilization. only the generative nucleus in mature pollen grain will divide mitosisly to form sperm cell for fertilization
By swimming in watery fluid through the neck of archegonium the sperm reaches to the egg in seedless plants.
the pollen grain lands ot the tip of pistle called as stigma and then pollen tube from pollen grain germinates and it reaches the ovary through style(containing 2 male gamets).. then fertilisation takes place... or is when the male sex cells inside the pollen grains fuses with the female sex cells inside to produce a seed embryo Pollination transfers the pollen grain to the stigma. However, for hertilisation to take place, the nucleus of the pollen grain must fuse with the nucleus of the ovum, which is inside an ovule in the ovary. To transfer the nucleus to the ovum, the pollen grain grows a tube, which digest its way through the tissue of the style and into the ovary. Here it grows around the opening in an ovule. The tip of the tube dissolves and allows the pollen grain nucleus to move out of the tube and into the ovule. Here it fertilises the ovum (egg cell) nucleus.
The long tube
1. Germination of pollen grain 2. formation of gametes by pollen mitosis 3. pollen tube elongation across the style reaching the embryo sac/archegonium 4. syngamy (union of male gamete nucleus with the egg nucleus)
Pollen grows a tube that travels down to the flowers ovary. From there, the nucleus of the pollen grains passes through the pollen tube to join the nucleus of the ovule to fertilize.