Image from Wikimedia Commons
Every year in the fall trees shed their leaves, for what purpose? you ask well they cut off the nutrients flowing into the leaves in order to cut back on how much water and nutrients they use in preparation for winter but luckily every year the leaves grow back to aid the tree once again which will be what this blog post is about how leaves grow and how they help the trees better survive , grow back each year and where their coloration comes from.
First concerning how leaves grow back each year, it all comes back to this small part of the plant called the meristem which contains the “building blocks” or instructions on where leaves need to grow and how to form. This is much like the specialized cells we see in humans which create the heart and the liver they are programmed to create specific organs this same basic concept can be applied to how leaf’s grow back each year. This concept is explained in Dr.Universe’s article linked here. She explains how the meristem contains the instructions for next years leaf growth and then as the cold approaches and the leaves are cut of a protective barrier is formed around the meristem to protect it from the cold.
Image from Wikimedia Commons
The next question to answer, how do leaves work? well the basic premise is that they capture the light and through photosynthesis create energy and food for the tree. However, it is much more complicated than that. To start with the chloroplasts which are specialized cells within the leaf are struck with light from the sun the chlorophyll which many are familiar with as what give leaves their color absorbs the light energy except for the green light which is reflected off of them which is why we perceive them as being colored that earthy green. At the same time the leaves are also absorbing carbon dioxide through their stomata which are openings usually on the undersides of leaves which allows for release of oxygen and intake of carbon dioxide to be used in conjunction of the converted light energy and water to create glucose. After this the chlorophyll uses the chemical energy it converted to change water and carbon dioxide to create useable energy for the plant. They do this by using the chemical energy that was converted from light energy to create the following chemical formula 6CO2+ 6H2O ==> C6H12O6 + 6O2 as explained in the article here. After the chemical reaction above reaches completion the plant is left with glucose which it can then use as energy to grow and perform cellular respiration and other activities and oxygen which it releases into the atmosphere as a waste product.
How else do leaves help the tree, well they are a critical part of the water circulatory system in the trees. Leaves allow for excess water to be released from the true to prevent the tree retaining too much water which could lead to the trees cell being damaged and therefore the tree being damaged as a result of the excess water. Too much water can also result in a lack of oxygen and other minerals from being picked up by the tree as the roots are being “drowned” and there are no air pockets to collect the oxygen as stated here.
As you can see leaves are an essential part of not only the trees ability to photosynthesize but also take in carbon dioxide and release of excess water all of which could lead to the plants death if the leaves weren’t there. As you can see its pretty unbeleafable.