pollen tube

views updated

pollen tube An outgrowth of a pollen grain, which transports the male gametes to the ovule. It will only grow if the pollen grain is compatible with the female tissue. In angiosperms, the pollen grain is deposited on the stigma and the pollen tube grows down through the style and into the ovule. In some conifers, e.g. Pinus (pines), the pollen tube penetrates the nucellus but does not develop further until the following year, when the female part of the plant is mature. See also embryo sac; fertilization; tube nucleus.

More From encyclopedia.com