Every autumn the leaves change their color, they turn yellow, blush or bagroveyut and gradually fall off, become dry and brittle.Rustling arises precisely because of this their properties.Why do leaves turn yellow in the fall?Some believe that it comes from frost.As if it's cold killed the beauty of summer, and now the leaves fall to the ground, gradually hiding her bright rustling carpet.However, it is not so.If you pay attention, you'll notice that the leaves begin to turn yellow and fall off long before the first frost.Leaf fall - this is only a seasonal phenomenon and its causes are hidden in the trees themselves, their biological mechanism of the struggle for survival in the harsh seasonal conditions.
little child asks his parents why the leaves turn yellow in the fall?It is important to answer this question.After all, based on what the children say in their small years, develops them further outlook.If the leaves are not just fall off, the plant may suffer or die not from peremerzaniya, but from lack of moisture.The cold air can dry at least hot.The liquid in the soil freezes, and suction power of the roots suspended, and in a short time and at all stops.When the influx of water to the leaves stops still ongoing evaporation of water through their surface.That's why leaves turn yellow in autumn.They protect your tree from destruction.If they remain on the tree, the branches through their immediate surface would evaporate all the moisture.Due to this protective mechanism the plants are released from a large area of excess.And to throw them a tree, you must first turn in dead leaves, which then fall off.
When the leaves turn yellow in the fall, all the processes in the plant stop life itself freezes.This is one of the irreversible phenomena of nature.If you change the lighting on the street leaves the biological clock alarm is triggered, and they begin to change color.This process can be divided into three stages:
- some yellowing of the leaves;
- coloring lit side of the crown,
- completion of the process and the first falling off.
impossible not to notice that all the trees do it at different times, and the forest becomes bright uneven.When the leaves begin to turn yellow?Autumn.On the sunlit side of the tree the process is faster, and the shaded leaves for a long time remain green.
terms of a biochemical process, due to the fact that they stop producing chlorophyll.In the summer, the yellow pigment is also present in the leaves, however, compared with green the amount is insignificant.Now it is becoming more and more noticeable.And another interesting feature: the red foliage comes only in well-lit and fairly cool place.For rich color anthocyanins are responsible together with the carotenoids.
This explains why leaves turn yellow in autumn.However, this does not happen with all the trees.Rosemary leaves, cranberries, juniper, heather and cranberries do not turn yellow, under the snow, they remain green, t. To. They evaporate very little moisture.
