It has long been proven that plants are living things. They, like animals, feed, breathe, breed. Thousands of biochemical reactions take place in them, useful nutrients are formed, and decay products resulting from metabolism are derived from them. That is, all processes that characterize the manifestation of life are also present in plants that make our planet unimaginably beautiful, clean and diverse.
Biological rhythms
How do plants breathe? Why do their leaves turn yellow? What do they eat? How to grow? Many questions arise for those who see these amazing creatures, so diverse, beautiful, vibrant and colorful.
All plants are characterized by certain biological rhythms, as well as other living organisms. These include:
- opening and closing buds under the influence of daylight hours and the chemical composition of the environment;
- intensive build-up of shoot mass;
- squeezing and opening stomata on the leaves;
- increased or weakened respiration, photosynthesis;
- leaf fall and others.
Thus, the answer to the question of why the leaves turn yellow in plants lies in the mechanisms of biological rhythms. It is these processes that allow them to adapt to environmental conditions, survive in them, carry out vital activities as efficiently as possible, grow and develop, respond to chemical and physical influences from nature, humans, animals, and so on.
Why do the leaves on the trees turn yellow, for example? This is also one of the manifestations of the biological rhythm, aimed at maintaining the viability of the individual at low temperatures and reducing the amount of sunlight and moisture. The color of the leaf blade is determined by the special substances in its composition.
Plant pigments contained in leaves
Why do leaves turn yellow and fall? Yes, because there is a restructuring of chemical reactions inside the plant body. Each representative of the flora contains a number of pigments - substances that determine the color of organs (leaves, corollas of flowers, stems, and so on). In total, four main groups of such compounds can be distinguished:
- Chlorophyll . A pigment containing in its structure a magnesium cation and several porphyrin rings. It gives plants and its parts a rich green color, takes an active part in the processes of photosynthesis. It is under its influence that plants in the light transform solar energy into the energy of chemical bonds. This forms a reserve nutrient - starch. Under favorable conditions, in the evergreens, chlorophyll is in the vast majority, therefore, other pigments do not appear.
- Xanthophyll . This compound is contained in all individuals, but does not appear under favorable conditions, as it is inhibited by chlorophyll. In many algae in the corolla of flowers, in the stems, this pigment manifests itself, forming a yellow color.
- Carotenoid . The orange color of the leaves, parts of the shoot, flower corollas is determined by this particular compound. Often suppressed by chlorophyll and manifests itself only at the onset of low temperatures, adverse environmental conditions.
- Anthocyanins are pigments that cause the formation of beautiful red shades in parts of plants. Like the previous two, it appears in its natural form only in the corolla of flowers or algae (red algae). Changing conditions and the destruction of the porphyrin rings of chlorophyll causes a stronger effect of anthocyanins.
All of the above pigments primarily give an external reaction to a change in the state of individuals. Why the leaves turn yellow in plants, which causes such manifestations, we consider in more detail.
Causes of leaf fall in trees
The phenomenon of leaf fall is one of the most beautiful in nature. That is why autumn is the favorite season of many poets. Indeed, the surrounding beauty simply cannot but become a source of inspiration for creative people. The multicolor around, yellow, green, red, orange and even brownish-violet shades just turn your head, and the smell of fallen leaves pleasantly pleases the sense of smell.
What caused such changes and is it always normal? Consider the causes of leaf fall in trees. They can be combined into two groups: natural and forced. Each includes a number of points and explanations to them.
Natural
These reasons include a seasonal change in weather conditions, as well as a change in the length of daylight hours. All summer, the green giants prepare for these rhythmic changes. They accumulate nutrients and store them in the stems and trunk, actively carry out the processes of photosynthesis and respiration, and consume the maximum possible amount of moisture.
With the onset of cold weather, shortened light days inside the sheet plates, transformations begin.
- Chlorophyll pigment begins to act less, the color turns pale. This makes other pigments appear. As a result, the leaves turn yellow, redden and so on. What will be the color of the falling leaves depends on the genetic characteristics of the type of tree. And an interesting fact is that the brighter the sun in the autumn season, the faster chlorophyll is destroyed and the leaves turn yellow. During prolonged rains, trees last longer with greenery.
- During the summer period, a lot of metabolic products, salts, and minerals accumulate in the plates of sheets. This makes the leaf heavy, and it gradually begins to exfoliate in the region of the petiole from the stem.
- At the base of the petiole, between it and the trunk, the formation of a special tissue layer begins, gradually tearing away the leaf.
- Under the influence of mechanical factors (rain, wind, thunder, and so on), of its own gravity, all the leaves begin to fall alternately.
Forced
To the question of why the leaves turn yellow, there is another answer. This is due to compelling reasons, such as:
- sharp fluctuations in temperature;
- lack of mineral nutrition;
- lack of sufficient moisture or its excess;
- harsh exposure to direct sunlight;
- vital activity of parasites.
These reasons lead to a decrease in the viability of trees. That is why leaves turn yellow on them.
Houseplants
Many gardeners also have the question: "Why do flowers turn yellow leaves?" Often you can notice the drooping parts of plants, their unhealthy, faded appearance, and this applies not only to flowering species, but also to ferns, sparsely flowering plants and succulents. What is the reason for this, let's try to figure it out.
The reasons for yellowing
Why does the flower turn yellow leaves?
- Excessive or insufficient watering.
- The sun is too bright or lacking.
- Lack of potassium, magnesium and other minerals.
- Defeat parts of the shoot or roots with pests.
- Excess dust, fungi and bacteria.
These are the most common causes of yellowing of leaves in plants.
Methods to eliminate the phenomenon
Before taking action, you need to determine the specific reason why the leaves turn yellow in the flower. To do this, you should study the materials for caring for each particular plant, because any of them requires an individual approach.
Further, it is necessary to limit the limiting factor of development: if it is insufficient watering, increase it, if it is excessive, reduce it, protect it from the sun or add it, feed it with mineral fertilizers, but do not overdo it. The main thing is to remember that flowers love purity. Therefore, they must be protected from dust, debris and pollution.