The Pollination of a Flower Introduction
People appreciate the beauty of flowers. Their fragrance and aesthetic appeal are
enjoyable. People know
how to plant flowers and about their general upkeep. Many flowers once planted can reproduce through pollination.
Pollination is the process of moving the pollen grain from the
anther of a stamen to the stigma of a carpel.
There are few flowers that can self-pollinate; the rest depend
on several factors. First, the make-up of the flower and different
organs are important to the pollination process. Second, the environment in which the flower
is located is important to whether or not pollination will occur. Flower Organs The organs of a flower are necessary for pollination
to occur. The pedicel is
the stalk of the flower, up from the pedicel from the petals. These play a large part in attracting animals or insects to
the flower. The sepals
serve as a connector between the pedicel and petals.
The stamen is the male sex part.
The collective stamens are known as the andorecium. The stigma is the receptive surface for
the pollen to be collected. It
is connected to the ovary by the style.
The ovary is located at the bottom of the pistils and develops
into the fruit. The cells
containing the ovules are located in the ovary.
The ovules are attached to the ovary using the placenta. The pistils are comprised of all the carpels,
which enclose the ovules. Vector Attraction The pollination process depends greatly on the vector.
The vector is the agent which moves pollen from the anther to
the stigma. Vectors can be almost anything ranging from wind and water
to animals. The most common
vector would be an insect or animal.
Before the pollination process can occur [,]
the flower must attract a vector that will transfer the pollen
from one flower to another or from one part of the flower to another. There are several ways to attract a vector. When the vector is an animal, the flower
will use olfactory or visual signs. An example of a visual sign would be a color pattern that attracts
the animal's attention to the pollen. This is also known as a bulls eye pattern. The color of the flower and its center
affect the type of vector that it attracts. Different animals see some colors better than others. Butterflies, for example, are attracted
to the red/yellow color pattern.
Another visual sign is a nectar guide. Nectar guides are color patterns that are emitted from the
source of the nectar. The
nectar is an incentive and reward for the vector. Olfactory signs are geared towards animals that have weak visual
senses and stronger olfactory senses. The fragrance of a flower serves the purpose of an olfactory
clue. The scent of flowers
attracts animals that will transfer the pollen to other flowers with
an appealing scent. The
type of scent or color a flower uses to attract a vector depends on
the type of vector that they are trying to attract.
The make-up of individual flowers is built to cater to specific
animals or insects that will effectively pollinate the flower. Retaining a Vector After
a vector is attracted, many flowers encompass some typed of reward system
to ensure that the vector will continue to visit flowers of that type
and spread the pollen. Nectar
is a common reward for the pollinator.
This sugary liquid serves as a food source for many birds and
insects and therefore is an incentive for these animals to continuously
visit the flowers. The actual pollen of a flower can also
serve as a reward. Many
insects depend on pollen to provide protein and vitamins to their diet. Though they are eating the pollen, there
is plenty of it. When flying
from flower to flower they ultimately deposit the pollen that has stuck
to them into other flowers. The
effect of some flowers on animals is also a reward.
Some flowers have pouches that contain liquid to intoxicate insects.
The insects are prone to visit more of these flowers to achieve
the intoxicating feeling. Other flowers release scents similar to
sex hormones of certain insects.
The female insects gather the scent and the males are attracted
to the flower by the scent. They
find the females there and mate.
The mating behavior is a reward for visiting and pollinating
the flower. Pollination Process The pollination process encompasses both vectors and
flower organs. Pollination
is the transfer of pollen grains in plants from the stamens to the pistil.
When an animal or insect visits a plant, they deposit pollen from a
previous plan onto the stigma at the end of the pistils.
The pollen grains germinate on the surface of the stigma. The germinated stigmas form pollen tubes
that grow downward toward the ovules. When fertilization occurs a sperm cell in the pollen tube fuses
with an egg cell in an ovule.
The fusing creates the plant embryo. The ovule carrying the embryo turns into a seed.
Source: "How to Identify Plants. Important Features of Flowering Plants."
Botany Online. 24 July 2002. © Peter v. Sengbusch
. http://www.biologie.uni-hamburg.de/b-online/e02/02d.htm Conclusion Pollination is an important process to the reproduction
of plants. It greatly depends
on a separate entity to transfer pollen from plant to plant. Each flower has a specified and unique
method of attracting organisms to them.
Once the pollen is transferred, the pollination process can begin. Now formed, the seeds can produce more
flowers. Bonnie Bridges |