THE vegetable nutrition, or plant nutrition, refers to the study of the inorganic nutrients needed for a plant to grow. We call essential elements those chemical elements that are fundamental for the plant to develop. These elements are classified into macronutrients and micronutrients, the macronutrients being those that the plant needs in a large amount and the micronutrients those that the plant needs in a smaller amount.
It is important to remember that, to ensure the necessary amount of organic nutrients, the plant makes the callphotosynthesis, a process in which light energy is used to transform carbon dioxide and water into organic compounds. This process, however, will not be discussed here, the focus of this text being the inorganic nutrients necessary for the plant's development.
Read too: Water transport through the vegetable body
Essential elements for plant nutrition
Plants, to develop, need some chemical elements. Most of these elements are absorbed by the plant as inorganic ions from solutions in the soil. O
carbon, O hydrogen it's the oxygen, however, are derived from air and water. To be considered an essential element, some basic criteria are taken into account.1. The plant needs this nutrient to complete its life cycle.
2. The analyzed nutrient is part of a molecule or constituent of the plant.
3. Emergence of symptoms in the plant if this element is absent.
To determine whether or not a chemical element is essential, researchers used the so-called hydroponic culture, in which plants are grown in nutrient solutions. These solutions can have their composition controlled and, in this way, it is observed whether an element is or is not important for that vegetable.
For this, a control plant is used that will grow in a solution containing all the elements and another plant is cultivated in a solution without any specific element. If the element removed from the solution is essential, the plant will show some deficiency symptoms, such as retarded growth, leaf no pigmentation, among other problems depending on the analyzed element.
Through several studies, it was concluded that 17 chemical elements are considered essential for the development of most vascular plants. Each of these elements has a different function in the plant, existing, for example, elements with structural, regulatory and enzymatic roles. See what the following seventeen elements are.
Essential elements for most vascular plants |
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All the nutrients mentioned have important functions. O magnesium, for example, it is part of the composition of the chlorophyll molecule. O calcium works in opening and closing of stomata. O phosphor it's part of ATP molecule. O nitrogen and sulfur, in turn, are components of proteins. Regardless of the nutrient analyzed, all are essential and their deficiencies can seriously damage plants.
It is worth noting that some inorganic nutrients are essential only for some specific groups of plants, such as aluminum, cobalt and sodium, for example. In this case, the correct denomination is beneficial elements.
Read too: Xylem and phloem — plant tissues specialized in conducting
Macronutrients and micronutrients
The essential elements are classified into macronutrients and micronutrients. The so-called macronutrients are those that the plant needs in a greater amount, while the micronutrients are those that the plant needs in a smaller amount. This does not mean, however, that micronutrients are less important than macronutrients, but that their needs in terms of quantity are different.
- Macronutrients: carbon, oxygen, hydrogen, nitrogen, phosphorus, sulfur, potassium, calcium and magnesium.
- Micronutrient: chlorine, iron, manganese, boron, zinc, copper, nickel and molybdenum.
Symptoms of nutritional deficiency in plants
Plants that are nutritionally deficient have changes in your development. Most symptoms can be noticed when analyzing the stalk and the sheet. We can cite as examples of symptoms of this deficiency:
- yellowing of the leaves;
- tissue death;
- rickety growth of branches.
THE lack of nickel, for example, can provoke necrotic spots on leaf tips, while nitrogen deficiency can cause widespread chlorosis (yellowing due to loss or reduced production of chlorophyll), especially in older leaves.
It is noteworthy that the symptoms of nutritional deficiency in plants are not only related to the role played by that element in the plant, being also related to its mobility in the plant. Those elements that move quickly through the phloem initially promote symptoms in older organs. This is due to the fact that the plant has the ability to move those elements that are being available in low quantities to the places where they are most needed, such as more sheets young.
By Vanessa Sardinha dos Santos
Biology teacher
Source: Brazil School - https://brasilescola.uol.com.br/biologia/nutricao-das-plantas.htm