So today i will write about my activity in class on the fifth week. Basically, this week I learnt about Pollination and Development of Plant Embryo. the topic is quite easy because i have learn in secondary school. I just need to recall all the method in this topic. For example, method of pollination and double fertilization.
New things that I learnt in this week class is some plant have florets to ensure the correct pollen is transferred into its stigma. For example, dandelion. This flower can cross pollinate by insects or self pollination. When the floret were growing, the closed stigma of the dandelion flowers grew through the middle of the anthers. So, that pollen was transferred onto the style as it elongated. after period of time if the cross-pollination is not occur. the stigma curls back on itself to pick up its own pollen from the style below.
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Another thing is plant can chemically recognize their own pollen and inhibit its further development in favor of pollen from another source. The example is Tiger Lily which the male and female organs are located called PERFECT FLOWER. While, flower that produces of male and female flowers separated is call IMPERFECT FLOWER.
Next is Double Fertilization
Double Fertilization is the way a flowering plant goes through sexual reproduction. To make the story short, double fertilization occurs with two haploid sperm cells. One of them fuses with a haploid egg cell to form a diploid zygote. This structure eventually develops into an embryo. The other sperm cell fuses with a second cell within the female's reproductive tissue to produce a triploid cell. It eventually becomes the developing embryo's food supply.
The sperm cells come from pollen grains that are produced in the anther, the male part of the flower. The sperm cells join with ovules, which contains a reproductive cell called megaspore. This cell undergo meiosis to produce 4 haploid megaspores; three of which will degenerate. The remaining cell goes through mitosis to produce 8 haploid nuclei, sharing one cytoplasm. The new structure is called the embryo sac. Two fo the nuclei become polar neclei and the rest are become an egg cell. Here is where double fertilization comes in.
The sperm cells goes into the ovary as a pollen grains go down from the stigma to the style. A haploid cell goes through mitosis to form two haploid sperm cells. This leads up to the final step of double fertilization.
The sperm cells come from pollen grains that are produced in the anther, the male part of the flower. The sperm cells join with ovules, which contains a reproductive cell called megaspore. This cell undergo meiosis to produce 4 haploid megaspores; three of which will degenerate. The remaining cell goes through mitosis to produce 8 haploid nuclei, sharing one cytoplasm. The new structure is called the embryo sac. Two fo the nuclei become polar neclei and the rest are become an egg cell. Here is where double fertilization comes in.
The sperm cells goes into the ovary as a pollen grains go down from the stigma to the style. A haploid cell goes through mitosis to form two haploid sperm cells. This leads up to the final step of double fertilization.
For me, this cross pollination is important in order for plant to reproduce. Many method being used and It is kind of interesting to know how plant produce it flower that adorning our garden. That's all. Thank you!
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