All About Pollen
Pollen and bees have been associated very closely throughout the years. The
reason why there are actually mixed flower breeds is because bees continually move from one flowering plant to
the next bringing pollen. The process of pollination is done primarily by bees, so it is important to know all
about pollen so you can observe and understand how bees work and carry out their specific tasks. Learning about
the process and pollen can help.
What is Pollen?
Pollen is described as a type of powder ranging anywhere from fine to coarse, which consists of
pollen grains or microgametophytes. These produce the male sperm cells or gametes of seed plants. There is a hard
coat that covers the pollen grain and protects the sperm cells during the movement process between the stamens of
the flower to the pistil of the next available flowering plant. Single pollen grains are very small that you will
need to magnify before you see the characteristics.
Every pollen grain has vegetative or non-reproductive cells and a generative or reproductive cell
that contains two nuclei. The nuclei involve 1 tube nucleus and 1 generative nucleus. The group of cells is
surrounded by a cell wall filled with cellulose called intine. There is a tough outer wall made of sporopollenin
Pollen is manufactured in the microsporangium found in the anther of a male cone of seed plants or
coniferous plants or an angiosperm flower. Pollen grains appear in different shapes, surface markings and sizes.
Pollen grains of firs, pines and spruces have wings. The smallest pollen grain is that of the plant called
Forget-me-not, measuring only about 0.006 in diameter. There are wind-borne pollen grains that are huge as well.
People studying pollen are called palynologists. The practice is very handy in paleontology, paleoecology and
More Pollen Details
The pollen walls functions to protect the sperm nucleus as the pollen grain moves from the anther
to the stigma. It keeps the important genetic matter from solar radiation and drying out. The grain surface of the
pollen is full of proteins and wax that are held together by sculpture elements on the grain surface. The outer
wall of the pollen keeps the pollen grain from reducing in size and crushing the genetic matter in the desiccation
Structures of Pollen
The outer wall has two layeres called the tectum and the foot layer. The columella is the region,
made of strengthening rods, separating the two layers. The pollen tube goes through the wall through apertures.
Pollen apertures are described as an alteration of the pollen grain wall. Some of the changes may
include ridges, pores and thinning. As a result, the pollen grain may shrink or swell because of the alterations in
moisture content. Furrows are called colpi and can be used to identify the different classes of pollen. The pollen
may be classified via the furrows as either sulcate or colpate.
Pollination is the popular process wherein pollen grains are transferred to the pistil or female
reproductive structures in plants. The transfer can be done by the wind or by insects. If the transfer is done by
the wind, the plant can be described as anemophilous. These types of plants create large quantities of very
lightweight pollen grains, in some cases with air sacs. Transfers done by insects or bees are called entomophilous
and produce pollen grains that are stick, heavy and full of protein. Insects and mites that feed on pollen are
More on Pollination
Among non-flowering plants, pollen germinates first in the pollen chamber found under and inside
the micropyle. The pollen tube is created, thereby growing into the nucellus to create nutrients for developing
sperm cells. Some sperm cells may be carried by the pollen tube or driven by their own flagella.
A pollen grain creates a pollen tube that moves down the tissue of the style into the ovary and is
guided by hair projections along the placenta to the micropyle of an ovule. The nucleus of the tube cell is passed
through the tube. The generative nucleus will divide to create 2 sperm cells. The tip of the pollen tube will be
the destination of the sperm cells.