Blog Post #9: A Matter of Selection      

Kale plant

Brussel Sprout plant

Broccoli Romanesco

     









       Leaves tend to exhibit the most variation, not only on the type of Brassica Oleracea plants, but on almost every species of plants. As you can see up above, the leaves from all the different types of Brassica Oleracea plants seem to contain different physical characteristics, such as leaf structure, color, texture, and the number of xylem/phloem roots. For example, the biggest leaf on the Broccoli Romanesco has a length of 1 foot and the width of 9 inches. The biggest leaf on the kale plant has a length of 1 foot and approximately 6 inches. A characteristic of the Brassica Oleracea plants that show the greatest range of variation is the structure of the plant. In the photo of the cabbage plant, the leaves are structured in more of a spiral pattern, while the kale plant shows the leaves growing out the base of the stem. These structures vary genetically in each of the plants and cannot be influenced by factors in the environment.

         There is so much variability in the domestic forms of Brassica Oleracea due to selected traits and developed mutations that have been gathered from an environment over time. Variety in the Brassica Oleracea probably developed over time due to a change in the environment. Whether or not the environment changed temperature or if there was a change in the number of organisms, mutations will develop due to descent with modification. Another way in which the Brassica Oleracea species could increase variability is by artificial selection. When farmers grow wish to modify the variety of the species, they may selectively breed it by only picking the desired traits. These acquired genes will increase the variability of the species because overtime, the selected traits will be spread into its offspring, which eventually will become the types of Brassica Oleracea which we know of today.

       For the most part, color seems to be almost similar throughout the types of Brassica Oleracea. Even though the shade of leaves from the Brussel Sprout plant is lighter than that of the Kale plant, they both contain chlorophyll which makes the color of the leaves green. You can see in the pictures above the similarity in color of stem and/or leaves. Due to the genotype of each of the types of Brassica Oleracea plants, the shades of the leaves, stems, flowers will always vary, however they all contain a similar genetic structure, such as green stems or green leaves, which makes them similar to each other.

          In order to modify a species of plants, someone would have to selectively pick the desired traits of a group of offspring. If there is an offspring that bests shows a desired trait, you would only allow those plants to reproduce and so on. In order for it to survive as well, you may have to change the environment in which it is growing. By Genetically modifying an organism or plant, you could add other genes from another similar organism from the same species to the plant in order for it to best acquire this gene and pass it on to its offspring. Over time, each of these genes or traits, both naturally or artificially will cause the plant type to change in its phenotype.