Blogpost #7: Anthers and Stigmas, Oh My! - Sydney Stitt

Introduction 

Brassica oleracea, the plant group in which our own cabbage plants fit into, is quite an extensive group. However, the flowers in which the grown plant originated from, is a perfect example of the reproductive system in plants. A few weeks ago, I dissected a flower to locate multiple important parts of the flower, such as the stigma, anther, and filament.

Reproductive Parts 

Here is an image of the petals of the flower, with the ends of the filaments sticking out. The petals are sort of 'shields' for the stigma and the filament/anther.

Here are the multiple stamens of the flower. This is the male reproductive system of a flower. Shown are the anthers, or the little yellow ends to the green stalks. Anthers contain pollen, the male gamete (sperm). The filament, the long light-green tube connected to the anther, is connected to the base of the flower.

Here are the images of the carpel, or also known as the pistil. This is the female reproductive system, which consists of the stigma, style, and the base (or the ovary). The stigma, which is the bulbous head of the figure, is where other pollen grains enter. The tip is quite sticky, so it's easy for the grains to stick. When the pollen grains does eventually stick to the top, the grains go into the inner tube inside the style (the long tube connected between the stigma and the ovary), called pollen tubes. They then get disposed into the ovary, into the ovules. 


This is the ovary, with small green disks spilling out (the ovules). The ovules are where the sperm are disposed to. The sperm and the egg (which is inside the ovule) is then combined to become a zygote, or a pre-stage to becoming a seedling. It later becomes an embryo, and then a seed.

Fertilization Process 

In a flower similar to this one, fertilization still happens between other plants (despite the fact that this flower contains both a male and female reproductive system). In anthers, meiosis happens and four haploid spore cells are produced. Under mitosis, these then become one haploid nuclei. Then, they become pollen grains (with multiple spores on each grain). Between some forms of transportation (such as wind, sticking to the fur of animals and then placed upon a neighboring flower, etc) the pollen grain sticks onto the stigma. it travels through pollen tubes, into the ovary, into one of the many ovules. Prior to this, the ovule is created when a diploid cell goes through meiosis to make four haploid cells. Three of those disintegrate, leaving the one leftover cell to go through mitosis to create eight nuclei. Protective sacs, or the ovules, form for each eight nuclei. These nuclei combines with the sperm cell, to create a diploid zygote. It then eventually becomes an embryo, and then a seed.