Which leaves turn yellow first? Why do the leaves turn yellow
Our indoor pets need constant care and attention. With their lack, plants begin to suffer and show alarming signs. One of these signs is the yellowing of the leaves of your pets. Consider why the leaves on indoor flowers turn yellow and what to do in this case.
In case of illness or improper care, our pets react primarily by the fact that the edges or the entire leaf plate turn yellow entirely. Consider the main reasons for the occurrence of such phenomena.
Even a novice florist understands that yellowing foliage is an alarming sign.
Improper home care
The most common causes of yellow spots on indoor flowers are mistakes in home care.
Over watering the plant
For most flowers, moderate watering will suffice. Before purchasing a particular copy, you first need to familiarize yourself with the conditions of its maintenance and the rules of care.
Excessive hydration leads to waterlogging of the soil and decay of the root system. As a result, the leaves and shoots turn yellow, the plant may die if measures for treatment are not taken in a timely manner.
Insufficient watering
Often the reason for the yellowing of the leaves of indoor representatives of the flora is an overdried earthen lump. In this case, the plant does not receive enough nutrients and moisture. The tips of the leaves and branches begin to dry and fall off, the roots die off.
drafts
Almost all indoor flowers, especially tropical ones, do not tolerate drafts. They need to be kept away from any sources of floral drafts - open windows, air conditioners, fans, etc.
Our favorite split systems can damage the immunity of flowers temperature fluctuations
Yellowing shoots of a plant can respond to sudden changes in temperature. During the acclimatization period, our green friends usually get sick.
lack of light
From insufficient sunlight, the leaves begin to turn yellow on the side which flower is turned towards the shade.
Sun burns
When exposed to direct sunlight, yellow spots usually appear on the leaves.
Non-compliance with the feeding regimen
With a lack or excess of nutrients in the soil, the leaves of plants begin to turn yellow along the midrib, predominantly at the top of the flower.
Diseases and pests
Often parts of plants turn yellow under the influence of diseases or pests.
- fungal diseases. As a result of infection with late blight or anthracnose, leaf blades may turn yellow.
- Infectious diseases. In this case, yellow spots appear on the foliage.
- Pest infestation. Among such insects are thrips, spider mites, aphids, whiteflies. The spider mite sucks the juices from the leaves and shoots, as a result of which they turn yellow and subsequently fall off.
Reasons for the appearance of spider mites on indoor flowers
The first sign of flower damage is the appearance of white dots on the foliage. In the future, you can see the web in the internodes and on the leaves.
If a spider mite wound up on one copy, then it can easily move to neighboring flowers. So, we urgently need to get rid of it.
First, you need to familiarize yourself with the rules for caring for each indoor flower. Since plants are individual, care for different species will vary significantly.
If the reason for the yellowing of the leaves is a violation of the watering regime, you need to adjust it according to the needs of your green friend. In the case when the flower is flooded, you need to remove it from the pot.
Examine the roots removing damaged and decayed. Transplant the flower into dry, disinfected soil. Follow your watering schedule.
When the leaves turn yellow from a lack or excess of sunlight, it is enough to rearrange the plant pot to another window sill or deep into the room.
With a lack or excess of fertilizers in the soil, it is necessary to replenish the balance: either add the required substances with top dressing, or transplant a flower. If there is an excessive amount of fertilizer in the substrate, you need to clean the root system from the ground and transplant the plant into fresh soil.
Transplanting into new soil is one of the key measures in getting rid of the pest When leaves turn yellow from drafts and temperature changes, you need to monitor the temperature regime of keeping your pets. When airing, it is recommended to take the plants to the next room.
Pest control
At the first sign of damage to the plant by pests, isolate it so as not to infect nearby flowers.
First of all, you need to remove all the affected leaves and stems of the plant. It is no longer possible to save them, but the rest can be secured in this way.
does not tolerate wet environments, so you need to spray the plant with warm water as often as possible or give it a shower. Rubbing the leaves with soapy water can also be an effective way.At the end of the treatment, the leaves are thoroughly washed off. After that, wrap the flower pot with a transparent bag and place it in a sunny place. After two or three days, the plant can be opened.
If there is a neglected case of damage to the flower by pests, there is no way avoid the use of insecticides. Acaricides are used to get rid of spider mites.
When treating plants with chemicals, be sure to use personal protective equipment - a mask and gloves.
For a person, Fitoverm, Vermite, Aktofit can be considered less dangerous. But they only neutralize adults without harming the eggs. Therefore, after 7-10 days, it is recommended to re-process the flower in order to destroy the offspring.
Due to the popularity of insecticides, we have bred.
In order to help your favorite plants, you need to carefully monitor their condition. At the first signs of illness or discomfort, determine the causes that caused them.
Based on the possible reasons, it is necessary in a short time to provide the required assistance to flowers so that they continue to please with lush flowering and a healthy look.
And the way they change their color in autumn. molecules, responsible for the bright shades of yellow and orange, are no longer a mystery, but why the leaves turn red is still a mystery.
Responding to air temperature change and less daylight, the leaves stop producing chlorophyll(which gives green color), absorbing blue and partially red light emitted by the Sun.
Since chlorophyll is sensitive to cold, some weather changes, such as early frosts, will "turn off" its production faster than usual.
Why leaves turn yellow and fall
At this time, orange and yellow pigments called carotenoids(which can also be found in carrots) and xanthophylls shine through leaves that have no green left.
"The yellow color is present in the leaves all summer, but it is not visible until the green disappears," says Paul Shaberg(Paul Schaberg), a plant physiologist with the US Forest Service.
But scientists still have little information about the red color that appears on some leaves in the fall.
It is known that the color red comes from anthocyanides, which, unlike carotenoids, are produced only in autumn. Anthocyanides also give color to strawberries, red apples and plums.
Trees produce anthocyanides when they sense a change in the environment - frost, ultraviolet radiation, drought and/or fungus.
But red leaves are also a sign of illness tree. If you notice that the leaves of the tree turned red earlier than usual (at the end of August), most likely the tree is suffering from a fungus, or it has been damaged by a person somewhere.
Why does a tree expend its energy to produce new anthocyanides in a leaf when that leaf is about to fall off?
Paul Schaberg believes that if anthocyanins help the leaves stay on the tree longer, they may help the tree absorb more nutrients before the leaves fall off. The tree can use the absorbed resources to bloom in the next season.
Anthocyanins
The topic of anthocyanins is a little more difficult to study than the rest of the tree components. While all trees contain chlorophyll, carotene, and xanthophylls, not all produce anthocyanins. Even those trees that have anthocyanins produce them only under certain conditions.
Before a tree gets rid of its leaves, it tries to absorb as much more nutrients of them [leaves], at which point anthocyanin comes into play.
Scientists have several answers to the question of why some trees produce this substance and the leaves change their color.
The most widely held theory suggests that anthocyanins protect the leaves from excess sunlight, while allowing the tree to absorb the beneficial substances stored in the leaves.
On the tree these pigments act as a sunscreen, blocking dangerous radiation and protecting the leaves from an excess of light. They also protect cells from rapid freezing. Their benefits can be compared with the benefits of antioxidants.
Too much sunlight, dry weather, freezing weather, low nutrient levels and other stressors increase the concentration of sugar in tree sap. This kicks off the mechanism to produce large amounts of anthocyanins in a last ditch effort to store energy to get through the winter.
Scientists believe that the study of anthocyanides helps to understand the level of the disease every tree. This, in turn, will give a clearer picture of environmental problems in the future.
As the character of the book and cartoon spoke The Lorax: "The color of the trees will one day be able to tell us how the tree feels at the moment."
Why do leaves dry and fall off
With the coming of winter, part of the globe gets less sunlight and the air gets colder. When such changes occur, the trees prepare for winter.
Trees that shed their leaves clog leaf attachment points. This prevents liquids with useful substances from reaching the leaves, which causes the leaves to change their color and fall off.
Leaf fall symbolizes not only the change of season, this process also helps the tree survive the cold, dry winter air.
In winter, trees do not receive enough liquid to "to contain" leaves. If they did not clog the places where the leaves begin to grow, the trees would simply die.
When spring brings warm air and water, the trees begin to grow new leaves.
Why don't coniferous trees shed their leaves?
Unlike animals, which obtain the substances and energy necessary for life from the food they eat, ordinary plants consume three separate streams of matter / energy, namely:
- minerals and water - come through the root system;
- carbon dioxide, necessary for the synthesis of biomass, comes from the surrounding air through the leaves;
- energy - absorbed by the leaves from the flow of sunlight falling on them.
Assimilation of light energy is possible only due to its interaction with colored substances (plant pigments) in the process of photosynthesis. The main photosynthetic pigments in plants are chlorophylls, which give plants their green color. For photosynthesis of various groups of substances (carbohydrates, proteins), chlorophyll absorbs the blue and red components of the solar spectrum, ignoring the green as "unnecessary" (the real process is even more complex and interesting - which is noticeable from photographs of living plants in the near infrared spectrum).
The remaining groups of pigments (yellow xanthophylls, orange carotenes, as well as red, purple and blue anthocyanins) are present in the leaf of the plant in small quantities. You can see them in etiolated (grown without light and therefore without chlorophyll) plants or their parts - for example, in potato shoots germinating in the dark. The chromophore groups of chlorophyll molecules responsible for the absorption of parts of the light spectrum are very "gentle": a slight chemical / physical effect can easily destroy them - this process is clearly visible when cooking, when greens are scalded, fried or thrown into a boiled soup.
What happens to the foliage in autumn?
Preparing for the period of winter dormancy, the plant, if possible, “pumps out” all potentially useful substances from the biomass of the leaves and stops the synthesis of chlorophylls. Their residual amount in the leaf becomes so small that it can no longer mask the presence of other, more stable coloring pigments and the own color of the cell walls (it is diverse, but typically has a brown tint). Therefore, a fading leaf acquires the color shade that the dyes remaining in the leaf blade provide to it, and in proportion to their quantity / concentration - and it is precisely because of this that the autumn forest is painted in such diverse and bright colors.
How does the plant "learn" about the onset of autumn?
In a living plant, many "internal clocks" function simultaneously - processes tied to the influence of external factors (cyclic fluctuations in temperature, light, and so on). In relation to the leaf, the most important factor here is the relative (as a proportion of the entire daily cycle) and absolute (in hours) daylight hours - this is how the process of preparing the plant for the winter dormant period starts. In addition to changes in biochemical processes, in deciduous trees, the growth of cells of the cork layer is initiated at the base of the leaf, which gradually breaks the connection between the leaf and the tree - and the leaf falls off.
In spring and summer, the leaves of trees are green due to the green substance contained in them in large quantities - chlorophyll. Chlorophyll plays a very important role. Using water and sunlight, it generates nutrition for the entire tree. going on photosynthesis- the process of formation of sugar in the light in chloroplasts, which then turns into starch.
In spring and summer, during the period of active growth and development of plants, chlorophyll is found in large quantities in the leaves, coloring them bright green. In addition to green chlorophyll, there are other substances in the leaves in smaller quantities - yellow, orange and red, in addition, the walls of the cells that form the leaf are brown. But all these colors are drowned out by green and therefore are practically invisible.
With the onset of cold weather, the channels that carried the juices in and out of the leaf gradually close. This reduces the amount of water entering the leaf, and the amount of chlorophyll decreases. Then, hitherto invisible shades of various substances and veins begin to appear. The leaves are suddenly painted in amazing yellow-red, crimson, brown colors. Leaves that have lost chlorophyll will not be able to turn green again. The season of golden autumn is coming.
With the advent of autumn, the length of daylight hours decreases. Consequently, the process of photosynthesis also does not have enough time to develop. The process of photosynthesis is essential for the nutrition of trees. So it turns out that the tree receives less and less nutrients, which entails a slowdown in all processes.
Chlorophyll begins to break down, the green color in the leaves becomes less and less visible. Now comes the turn of other color pigments: yellow xanthophyll, orange carotene and red anthocyanin. Thanks to these pigments, the leaves acquire such a bright color.
Probably, everyone noticed that not all trees “dress” in the same way in autumn. Some are dominated by crimson tones, some are yellow, and some are brown. For example, the leaves of maples and aspens are painted in crimson tones. The leaves of lindens, oaks and birches cast gold.
It is interesting that the leaves of alder, lilac do not have time to change colors, they fall still green. Why? Yes, because in the leaves of these trees there are no coloring pigments, except for chlorophyll.
All life processes in the trees slow down with the advent of autumn, the vitality of the leaves fades. And this process is eternal, like life itself, and just as natural and irreversible. That is, those leaves that have already lost their green pigment chlorophyll will no longer be able to restore their strength.
The leaf coloring process can be divided into three stages:
- Beginning of leaf color change. Some leaves are turning yellow;
- Changing the color of tree crowns. The tops begin to dazzle and differ markedly from the rest of the crown;
- Complete change in leaf color. Almost the entire crown has changed its color.
Falling leaves is the dropping of all harmful substances. Leaves store a lot of nutrients. However, in addition to useful substances, harmful substances also accumulate in the leaves - metabolites, excess mineral salts, which only harm the health of the tree. Autumn is the time when the tree begins to get rid of the harmful ones present in the leaves, and leaves the useful ones for the winter.
In addition, scientists have proven that in winter, when there are no leaves left on the crown, the tree has little chance of suffering from drought. The reason is that the leaves take a lot of moisture, and the roots will not be able to cope with its lack.
When are the brightest leaf colors?
The brightest, juiciest colors of the leaves occur in autumn, when the weather is cold, dry and sunny for a long time (at temperatures from 0 to 7 degrees Celsius, the formation of anthocyanin is enhanced). The beautiful coloring of the leaves in autumn happens in places like Vermont. But, for example, in the UK, where the climate is rainy and the weather is overcast almost all the time, autumn leaves are most often dull yellow or brown. Autumn passes, winter comes. Together with the leaves, the plants lose their colorful colors.
The leaves are attached to the branches with special cuttings. With the onset of winter cold, the connection between the cells that make up the cuttings breaks up. After that, the leaves remain connected with the branch only by thin vessels, through which water and nutrients enter the leaves. A light puff of wind or a drop of rain can break this ephemeral connection, and the leaves will fall to the ground, adding another touch of color to the multicolored thick carpet of fallen leaves. Plants store food for winter, like chipmunks and squirrels, but they accumulate it not in the ground, but in branches, trunks and roots.
The leaves, into which water ceases to flow, dry up, fall from the trees and, picked up by the wind, circle in the air for a long time until they lie down on the forest paths, lining them with a crisp path. The yellow or red coloration of the leaves may persist for several weeks after they have fallen off. But over time, the corresponding pigments are destroyed. The only thing that remains is tannin (yes, it is this that colors the tea).
Why do leaves change color in autumn? Experiment
In order to find the answer to the question why the leaves on the trees change color and turn yellow in autumn, the children will need to collect some leaves.
After that, together you must sort them by color into prepared containers. After that, the leaves are poured with alcohol and ground. After crushing and stirring, alcohol will help the color to show even better.
Hint: The time it takes for the color to fully absorb will depend on how many leaves and alcohol have been used. After 12 hours, the liquid may not yet be completely absorbed, but the effect is already obvious. As the liquid soaks into the filter, the colors from the leaflets diverge.
Explanation of the experiment why the leaves change color
In winter, the days become shorter, which reduces the amount of sunlight for the leaves. Due to the lack of sun, the plants go into a dormant stage and feed on the glucose that they have accumulated over the summer. As soon as the "winter mode" is turned on, the green color of chlorophyll leaves the leaves. And as the bright green tint fades, we begin to see yellows and oranges. A small amount of these pigments were in the leaves all the time. For example, maple leaves are bright red because they have an excess of glucose.
Why do tree leaves turn yellow in summer?
The main nutrients needed for the development of a tree:
- Magnesium;
- Potassium;
- Phosphorus;
Magnesium may be lacking in sandy and sandy soils. Often its imbalance manifests itself in wet weather, with frequent watering - magnesium is quickly washed out.
Potassium is not enough for the leaves, if, in addition to yellowness, a red rim is visible on the leaf plate. The lack of potassium is accompanied by a simultaneous lack of phosphorus.
Phosphorus starvation is manifested in the appearance of a bronze hue and the leaves dry up, covering the entire surface of the leaf.
Feeding the soil mixture with the missing ingredients will solve the problem.
Waterlogging of the soil
The close occurrence of groundwater and waterlogging of the soil due to frequent watering will affect the stagnation of water, the breakdown of oxygen. Fruit trees in the garden will not only begin to turn yellow, but also dry out, wither, it is possible that the root system will rot. Soil drainage, raising the level of planting, and normalizing care will help solve the problem.
Chlorosis of fruit trees
With the development of chlorosis, the leaves of fruit trees become dull, pale, turn yellow, as if there is no sun in the garden.
Chlorosis can appear for many reasons:
- Exceeding the level of lime in the soil;
- Excessive amount of fresh manure;
- Lack of iron salts (chlorophyll is not formed);
- Root freezing;
- Oxygen starvation (due to waterlogging);
If chlorosis did not have time to cover the entire crown of the tree, then it is necessary to restore the gap in care that caused chlorosis, and also feed it with a solution of ferrous sulfate (2%).
Pests and diseases of fruit trees
When aphids or mites appear, the leaves not only turn yellow in the summer near the trees in the garden - deformed shoots appear. Similar symptoms can occur with the development of fungal diseases. In order for garden trees to be healthy, it is necessary to carry out prevention by spraying with solutions before flowering and after it ends.
Damage to the bark of garden trees in summer
In summer, garden trees begin to turn yellow if their bark or root system was previously mechanically damaged. This could happen when transplanting, loosening the soil, pruning or processing. Due to the violation of the vital activity of the tissues of the tree, a general wilting occurs. It is difficult to determine the problem in this case. To restore a fruit tree in the garden in the summer, either top dressing or the use of biological preparations to cover wounds will help.
We are accustomed to the fact that in autumn the foliage turns yellow and the trees drop them until spring. We admire the yellow foliage, admire the romanticism of autumn, but we don’t know why the yellowing of the leaves still occurs. And this, it turns out, has a scientific explanation.
For years, scientists have studied leaves and how they change color in the fall. molecules, responsible for the bright shades of yellow and orange, are no longer a mystery, and why the leaves turn red is still a mystery.
Responding to air temperature change and less daylight, the leaves stop producing chlorophyll(which gives green color), absorbing blue and partially red light emitted by the Sun.Since chlorophyll is sensitive to cold, some weather changes, such as early frosts, will "turn off" its production faster than usual.
At this time, orange and yellow pigments called carotenoids(which can also be found in carrots) and xanthophylls Shine through leaves that have no green left. "Yellow color is present in the leaves all summer, but it is not visible until the green disappears," says Paul Shaberg
"The yellow color is present in the leaves all summer, but it is not visible until the green disappears," says Paul Shaberg(Paul Schaberg), a plant physiologist with the US Forest Service. But scientists still have little information about the red color that appears on some leaves in the fall. It is known that the color red comes from anthocyanides, which, unlike carotenoids, are produced only in autumn. Anthocyanides also give color to strawberries, red apples and plums.
Trees produce anthocyanides when they sense a change in the environment - frost, ultraviolet radiation, drought and/or fungus. But red leaves are also a sign of illness tree. If you notice that the leaves of the tree turned red earlier than usual (at the end of August), most likely the tree is suffering from a fungus, or it has been damaged by a person somewhere.
Why does a tree spend its energy to work out
new anthocyanins in a leaf when that leaf is about to fall off?
Paul Schaberg believes that if anthocyanins help the leaves stay on the tree longer, they may help the tree absorb more nutrients before the leaves fall off. The tree can use the absorbed resources to bloom in the next season.
Anthocyanins
The topic of anthocyanins is a little more difficult to study than the rest of the tree components. While all trees contain chlorophyll, carotene, and xanthophylls, not all produce anthocyanins. Even those trees that have anthocyanins produce them only under certain conditions. Before a tree gets rid of its leaves, it tries to absorb as much more nutrients from the leaves, at which point anthocyanin comes into play.
Scientists have several answers to the question of why some trees produce this substance and the leaves change their color.
The most popular theory suggests that anthocyanins protect the leaves from excess sunlight, while allowing the tree to absorb the beneficial substances stored in the leaves.On the tree these pigments act as a sunscreen, blocking dangerous radiation and protecting the leaves from an excess of light. They also protect cells from rapid freezing. Their benefits can be compared with the benefits of antioxidants.
Too much sunlight, dry weather, freezing weather, low nutrient levels and other stressors increase the concentration of sugar in tree sap. This kicks off the mechanism to produce large amounts of anthocyanins in a last ditch effort to store energy to get through the winter.
Scientists believe that the study of anthocyanides helps to understand the level of the disease every tree. This, in turn, will give a clearer picture of environmental problems in the future.As the character of the book and cartoon spoke The Lorax: "The color of the trees will one day be able to tell us how the tree feels at the moment."