Autumn is the season of shedding, tree leaves "change colors" and fall. Even in our dry and sunny country there are few groves where you can see one of the most beautiful and interesting phenomena in nature: autumn!
Autumn is the season of shedding, tree leaves "change colors" and fall. Even in our dry and sunny country there are few groves where you can see one of the most beautiful and interesting phenomena in nature: autumn!
Broad-leaved trees prepare themselves for winter, for the cold season, a season in which the activity of the trees stops, so as not to be damaged by the cold, the trees reduce their surface area, by shedding their leaves. Before the leaves fall to the ground, a spectacular play of colors appears, the green leaves change, followed by yellow, orange, red colors and all the shades in between! How does that happen ? What is the advantage ("why is it good")?
The green color is given to the leaves by the chlorophyll, the chlorophyll enables the absorption of sunlight and its conversion into energy with which the plant produces sugars / nutrients, when the days get shorter and the temperature drops, the plant stops producing chlorophyll, this is because chlorophyll is sensitive to cold. The green color fades and two colors are revealed: yellow and orange, both colors were in the leaf but were "shadowed" by the green.
The leaves are colored orange and yellow due to the presence of carotenoids, the same substances that give the carrot its color are the ones that color the fall leaves in different shades. Less was known about the red color, unlike the carotenoids, the red army is not found in the leaf (green) but is formed in it before the fall, after research and testing it became clear that the red color is obtained from anthocyanin (anthocyanins) which is formed in the leaf towards the fall, before the shedding.
This is the same stuff that dyes strawberry red. Plums, apples. The substance acts in the leaves as a radiation shield and prevents freezing, since the chlorophyll to utilize the light is not high, the exposure to ultraviolet radiation is therefore high and therefore the leaf needs protection, the temperature cools down, and once again the anthocyanin protects against freezing.
In addition, it will be found that anthocyanin is an antioxidant, therefore it is possible to see the appearance of colors (other than green) in trees that are under stress, damage by a pest, lack of water/food, high radiation, all of these may cause the leaves to change color,
There is the question - why invest (energy) in painting leaves that fall anyway? In the case of the autumn fall, the colors of the fall, especially the red, allow the leaf to stay a little longer on the tree and thus allow the tree to "pump" the rest of the nutrients from the leaves and utilize them to the fullest! The appearance of "fall colors" in forests that are not in the fall season allows foresters to spot problems. The appearance of fall in autumn beautifies our surroundings.
