`star` Dialogue between pollen grains and Pistil
`star` Generation of Pollen tube
`star` Study of Pollen Germination


● Pollination does not `color{Violet}"guarantee"` the transfer of the `color{Violet}"right type"` of pollen (`color{Violet}"compatible pollen"` of the `color{Violet}"same species"` as the stigma).

● Often, pollen of the wrong type, either from `color{Violet}"other species"` or from the same plant (if it is `color{Violet}"self-incompatible"`), also land on the stigma.

●The pistil has the ability to `color{Violet}"recognise the pollen"`, whether it is of the right type ( `color{Violet}"compatible"`) or of the wrong type ( `color{Violet}"incompatible"`).

● If it is of the right type, the pistil accepts the pollen and `color{Violet}"promotes post-pollination"` events that leads to fertilisation.

● If the pollen is of the wrong type, the pistil `color{Violet}"rejects the pollen"` by preventing pollen germination on the stigma or the pollen tube growth in the style.

● The `color{Violet}"ability of the pistil"` to recognise the pollen followed by its acceptance or rejection is the result of a `color{Violet}"continuous dialogue"` between pollen grain and the pistil.

● This dialogue is mediated by `color{Violet}"chemical components"` of the pollen interacting with those of the pistil.


● It is only in recent years that botanists have been able to `color{Violet}"identify"` some of the pollen and pistil components and the `color{Violet}"interactions"` leading to the `color{Violet}"recognition"`, followed by `color{Violet}"acceptance or rejection"`.

● Following `color{Violet}"compatible pollination"`, the pollen grain `color{Violet}"germinates on the stigma"` to produce a pollen tube through one of the germ pores.

●The contents of the pollen grain move into the pollen tube.

● Pollen tube grows through the `color{Violet}"tissues of the stigma and style"` and reaches the ovary.

● In some plants, pollen grains are shed at `color{Violet}"two-celled condition"` (a vegetative cell and a generative cell).

● In such plants, the `color{Violet}"generative cell divides"` and forms the two `color{Violet}"male gametes"` during the `color{Violet}"growth"` of pollen tube in the stigma.

● In plants which shed pollen in the `color{Violet}"three-celled condition"`, pollen tubes carry the two male gametes from the `color{Violet}"beginning"`.

● Pollen tube, after reaching the ovary, `color{Violet}"enters"` the ovule through the `color{Violet}"micropyle"` and then enters one of the `color{Violet}"synergids"` through the `color{Violet}"filiform apparatus"`.

● Many recent studies have shown that `color{Violet}"filiform apparatus"` present at the micropylar part of the synergids `color{Violet}"guides the entry"` of pollen tube.

● All these events–from `color{Violet}"pollen deposition"` on the stigma until pollen tubes `color{Violet}"enter the ovule"`–are together referred to as `color{Violet}" Pollen-pistil interaction"`.

● Pollen-pistil interaction is a `color{Violet}"dynamic process"` involving pollen `color{Violet}"recognition"` followed by `color{Violet}"promotion or inhibition"` of the pollen.

● The knowledge gained in this area would help the plant breeder in `color{Violet}"manipulating pollen-pistil interaction"`, even in incompatible pollinations, to get `color{Violet}"desired hybrids"`.


● One can easily study pollen germination by `color{Violet}"dusting some pollen"` from flowers such as pea, chickpea, Crotalaria, balsam and Vinca on a `color{Violet}"glass slide"` containing a drop of sugar solution (about 10 per cent).

● After about 15–30 minutes, one needs to observe the slide under the `color{Violet}"low power lens"` of the microscope.

● We are likely to see `color{Violet}"pollen tubes"` coming out of the pollen grains.

● A breeder is interested in `color{Violet}"crossing different species"` and often genera to combine desirable characters to produce `color{Violet}"commercially ‘superior’ varieties"`.