But in the fall, because of changes in the length of daylight and changes in temperature, the leaves stop their food-making process. The chlorophyll breaks down, the green color disappears, and the yellow to orange colors become visible and give the leaves part of their fall splendor.
Temperature, light, and water supply have an influence on the degree and the duration of fall color. Low temperatures above freezing will favor anthocyanin formation producing bright reds in maples. However, early frost will weaken the brilliant red color. Rainy and/or overcast days tend to increase the intensity of fall colors. The best time to enjoy the autumn color would be on a clear, dry, and cool (not freezing) day.
and the genome of the tree affect how quickly the leaves fall
Most of the broad-leaved trees in the North shed their leaves in the fall. However, the dead brown leaves of the oaks and a few other species may stay on the tree until growth starts again in the spring. In the South, where the winters are mild, some of the broad-leaved trees are evergreen; that is, the leaves stay on the trees during winter and keep their green color.
Fall Equinox 2017: Here's Why The leaves Change …
It’s fall! That means shorter days and cooler nights. And, in many parts of the United States, it means that trees are about to shed their leaves after a final colorful salute to summer.
Photosynthesis Lesson Plan | Education World
Plants absorb water through their roots, and carbon dioxide through their leaves. Some glucose is used for respiration, while some is converted into insoluble for storage. The stored starch can later be turned back into glucose and used in respiration. Oxygen is released as a by-product of photosynthesis.
Does Leaf Color Affect the Rate of Photosynthesis?
Did you know that a tree’s leaves are orange and yellow — even in summer? Most leaves include the pigments of all three colors. It’s just that the pigment chlorophyll (the pigment that makes the leaves green) is a much stronger pigment than the others. It covers the yellow (xanthophyll) and orange (carotene) pigments that are natural to a tree’s leaves. But, come fall, a tree’s leaves produce less chlorophyll. Now the other colors can show through in brilliant explosions of color!
Does Leaf Color Affect the Rate of Photosynthesis
Another pigment (anthocyanin), which produces reds and purples, isn’t present all year long in most green leaves. It only shows up as the nights get cooler. In fall when trees are breaking down and reabsorbing important nutrients from their leaves, their photosynthetic tissues are especially unstable and vulnerable to too much light and other stresses. Yet trees need the energy from photosynthesis to drive the processes that allow them to recapture as many of those nutrients as possible. Just as this process begins, leaves start producing large amounts of anthocyanins near the leaf surface. Anthocyanin pigments protect the leaves’ dwindling ability to generate energy during this period.
Rose Nazarian & Shawn Murie
As the fall colors appear, other changes are taking place. At the point where the stem of the leaf is attached to the tree, a special layer of cells develops and gradually severs the tissues that support the leaf. At the same time, the tree seals the cut, so that when the leaf is finally blown off by the wind or falls from its own weight, it leaves behind a leaf scar.