When the abscission layer of a plant grows, it cuts off the circulation of nutrients, sugar and water to the leaves, which causes the chlorophyll that gives the plant its green color to disintegrate and makes carotene shine through. The result is the yellow-colored leaves that are found on maple and other trees, such as birch and aspen, in the fall.Continue Reading
The abscission layer is a band of cells. Auxins control this band of cells, which is located in the leaf's stem. The cooler weather along with the shorter days of fall puts an end to the creation of auxins. The lack of auxin is what causes the abscission layer to grow in the leaves.
Only some trees are affected by the change in weather. Trees such as spruces, hemlocks, firs and pines are evergreen, and their leaves do not change color. Factors that affect fall color include temperature and light. The bright red leaves of fall are created by the pigment anthocyanin. Frost usually causes the bright red color created by this pigment to fade. However, if the day is rainy or overcast, the colors that people see on the leaves of the trees seem a lot more intense.Learn more about Botany
The longer night as summer turns into fall is responsible for the changing color of leaves in the autumn. As days grow shorter, the longer and cooler nights trigger biochemical changes in the leaves that turn them different colors, according to the U.S. Forest Service. Chlorophyll, the chemical that makes leaves green, decreases in response to shorter daylight hours, as other pigment-making chemicals appear more prominently.Full Answer >
Plants adapt to different climates by modifying their leaves or stems or by shedding their leaves en masse in the fall and going dormant during the winter when there is less water available. They may also have root systems and reproductive strategies that are adapted to the climate.Full Answer >
Some of the factors affecting plant growth include availability of nutrients, water, temperature, light, air pollution, gases and plant genetics. These issues can either enable a plant to develop rapidly or much slower.Full Answer >
The two main functions of roots are to deliver water and nutrients to the plant or tree and provide an anchor that keeps the plant or tree in the soil. Roots are generally the first part of any plant that emerges during germination.Full Answer >