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. 

 


           

 

Figure 1: Parts of a Flower

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