Blience Tuesday #2: Trees

    This is number two in the Blience Tuesday series. This post will be about trees. I will be splitting it up into three parts: pollen allergies, why they change color in the fall, and where they get nutrients. In part one, I will explain why the body dislikes pollen. I part two, I will explain chemically why the leaves grow more colorful in the fall. Finally I will explain where trees get the nutrients that they need to grow.

     First of all, pollen. Pollen is a cell made by the plant to let it reproduce. Some types of pollen are carried by insects, such as the pollen of the sunflower or orchid, where as other species of plant have the wind carry their pollen like a pine tree or oak. I a human inhales pollen, the body recognizes it as an unknown cell, and tries to try to get rid of it, and keep any more of it away by making you sneeze, making more mucus, and making your eyes itchy.

     Second, and my favorite of these three, is color-changing leaves. Before I get into why they change, I want to explain why they are green in the first place. There is a chemical called chlorophyll that colors the leaves green. Chlorophyll is present in the leaves because it is helpful in photosynthesis. In late summer, the tree begins to gradually block of the leaves, blocking the chlorophyll supply. There are chemicals called carotenoids presentin the leaves the entire year, but are usually masked by the green. Once the green is gone, these chemicals dye the leaves orange-yellow. There are more chemicals, called anthocyanins, which are produced in late summer and dyes the leaves red-purple. These two chemicals result in beautiful trees in the fall.

     Lastly, nutrients. Now many people have heard of photosynthesis, and probably know that it involves leaves geting energy from the sunlight. What I did not know about photosynthesis until I researched this is that the carbon dioxide that plants absorb from the air and the water that they absorb from the ground via their roots is also a part of this process. The water helps turn the light energy from the sun into chemical energy, which then turns the CO2 into sugars, feeding the plant. I think this process is amazing, and find it very interesting.

Thanks for reading!

Bibliography:
http://en.wikipedia.org/wiki/Pollen
http://en.wikipedia.org/wiki/Allergic_rhinitis
http://en.wikipedia.org/wiki/Tree
http://en.wikipedia.org/wiki/Autumn_leaf_color
http://en.wikipedia.org/wiki/Photosynthesis