According to the mobility of essential elements in plants, essential elements can be divided into two types, which are movable, such as N, P, K, Mg, Zn, B, Mo. These elements can be reused in plants, when plants are lacking. These elements are transferred from the old part to the young part, so the symptoms of deficiency are expressed on the old leaves. Hard-to-move elements, including Ca, S, Fe, Mn, and Cu, are difficult to move after they are used. When plants lack these elements, newborn tissues first show symptoms of deficiency due to the lack of these elements.
1. Nitrogen (N)
Nitrogen accounts for 1-3% of plant dry matter. The nitrogen absorbed by plants is mainly inorganic nitrogen (NO-3, NO-2, NH+4), and sometimes absorbs simple organic nitrogen such as urea (CO(NH2)2) and amino acids.
Nitrogen plays an important role in plant life activities because it is a component of many compounds; (1) genetic material - nucleic acid; (2) biocatalyst - enzyme; (3) enzyme activity regulator - vitamin, prosthetic , coenzyme, hormone; (4) cell membrane skeleton - phospholipid; (5) photoreceptor - chlorophyll, photofrin; (6) energy carrier - ADP, ATP, etc.; (7) osmotic material - proline , betaine.
In the absence of nitrogen, older leaves first turn green and yellow, sometimes appear purple on stems, petioles or old leaves. When the nitrogen is severely deficient, the leaves fall off, the short leaves of the plant are yellow and thin, and even the growth stops, and the old leaves die and die.
The metabolism of nitrogen in the body is characterized by being mobile and reusable. When the plant is deficient in nitrogen, the nitrogen in the old leaves is transferred to the new tissue to meet the nitrogen needs of the tissue. Therefore, the symptoms of nitrogen deficiency are first manifested in On the old leaves (the old leaves turn green and turn yellow).
2. Phosphorus (P)
Phosphorus also plays a very important role in plant life activities. Plants primarily absorb phosphorus in the form of H2PO-4. At low pH, it mainly absorbs H2PO-4, and absorbs HPO2-- at high pH.
Phosphorus is also a component of many important compounds: (1) genetic material - nucleic acid; (2) membrane skeleton - phospholipid; (3) enzyme activity regulator - phosphate prosthetic, coenzyme (FAD, NAD, FMN, NADP Etc.) and vitamins, etc.; (4) energy carriers - ATP, ADP, etc.; (5) regulating substance transport (sucrose phosphate); (6) adjusting the pH.
Symptoms of phosphorus deficiency: the leaves are dark green and the stems and leaves appear reddish purple.
Phosphorus is metabolized in plants and can be moved and reused. Therefore, the symptoms of phosphorus deficiency are first manifested in the old leaves.
3. Potassium (K)
Potassium is also an important element in plants. It is the only monovalent metal ion in the body's essential elements and is in an ionic state in the body. The main role of potassium in the body is to regulate: (1) regulate stomatal opening and closing; (2) regulate root water absorption and water transport (root pressure); (3) osmotic adjustment; (4) regulate enzyme activity - many enzymes Activators, such as glutathione synthetase, succinic acid CoA synthetase, starch synthase, succinate dehydrogenase, fructokinase, pyruvate kinase and other more than 60 enzymes; (5) balance electrical: in oxidative phosphorylation Among them, K+ and Ca2+ act as the corresponding ion balance H+ charge of H+. In photosynthetic phosphorylation, K+ and Mg2+ act as the corresponding ions of H+, balance the charge of H+; (6) regulate the transport of substances (the phloem contains a large amount of K+).
Symptoms of potassium deficiency: the tip of the leaf and the edge of the leaf are withered and gradually burnt. Another major symptom: Potassium is mobile in the body and can be reused. The symptoms of potassium deficiency first appear on the old leaves.
4. Sulfur (S)
Plants primarily absorb sulfur in the form of SO42-. Sulfur is a component of many important compounds: 91) protein (sulfurous amino acid, cysteine, methionine); (2) component of the membrane - sulfite; (3) component of electron transporter - Fd, Fe - s; (4) vitamins (thiamine Vb1, pantothenic acid VB3).
The main symptoms of sulfur deficiency: the plant is short, the leaves are yellow and easy to fall off. Sulfur is difficult to move in the body, so the symptoms of sulfur deficiency are first manifested on new leaves.
5. Calcium (Ca)
The plant ion form (Ca2+) absorbs calcium. The main physiological roles of calcium are: (1) compound component - calcium pectate; (2) structural components - membrane, chromosome; (3) enzyme activator - ATP hydrolase, succinate dehydrogenase; 4) Second messenger - an important transmitter of intracellular information - regulates the activity of many enzymes alone or with CaM; (5) Balanced electrical: balances H+ (mitochondria) with K+.
Ca deficiency symptoms: necrosis of growth point, the plants are clustered, the tip of the leaf and the edge of the leaf turn yellow, and the coke is necrotic. Ca is not easy to move in the body, and Ca+ deficiency symptoms are first manifested on the leaves.
6. Magnesium (Mg)
The main physiological effects of magnesium: (1) the composition of chlorophyll; (2) the corresponding ion of H+ in photosynthetic phosphorylation, balanced electrical; (3) the activator of enzyme - Rubisco, PEPCase, etc.; (4) regulating protein Synthesis (promotes ribosome size subunit binding).
Symptoms of magnesium deficiency: lack of green between veins, sometimes reddish purple, magnesium can move in the body, the symptoms of magnesium deficiency first manifested in the old leaves.
7. Iron (Fe)
Plants primarily absorb iron in the form of Fe2+ chelates. The main property of iron is that the valence is variable, Fe2+/Fe3+, so iron acts as an electron transporter. (1) components of the enzyme - CAT, POD, cyanide oxidase, cytochrome oxidase; (2) components of electron transporters, Fd, FS, Cyt, etc.; (3) regulators of enzyme activity - An essential factor in the synthesis of chlorophyll.
Deficiency of Fe: There is a lack of green between the veins. When severe, the whole leaf turns yellow-white, iron is not easy to move in the body, and the symptoms of Fe deficiency are first manifested in the old.
8. Copper (Cu)
Plants absorb copper in the form of Cu2+. The main property of copper is the change in valence, Cu2+/Cu+. Its main role is as an electron transporter for redox reactions. (1) The components of the enzyme - SOD ascorbate oxidase, polyphenol oxidase, cytochrome oxidase; (2) electron transport component - PC.
Symptoms of copper deficiency: The tip of the leaf becomes white and necrotic, and then develops along the vein to the base of the leaf, and the leaf is easy to fall off. Copper is not easy to move in the body, and the symptoms of copper deficiency are first manifested on the old leaves.
9. Zinc (Zn)
The main physiological role of zinc: components of enzymes, such as tryptophan synthase, carbonic anhydrase. Zinc is an essential element in the synthesis of tryptophan, which is a precursor of indole acetic acid.
Zinc deficiency symptoms: The plant grows slowly, the leaves are curled, the branches are increased, the stems are cracked, and the fertilization is poor. There is a lack of green between the veins, and mosaic disease occurs in the corn. The fruit trees are prone to lobular disease, the growth of auxin is blocked, and the old leaves first appear.
10. Manganese (Mn)
Physiological effects of manganese: (1) components of the oxygen-releasing complex; (2) activators of enzymes such as transphosphatase (hexose kinase), dehydrogenase (a-ketoglutarate dehydrogenase), nitric acid Reductase, dipeptidase; (3) essential factor for chlorophyll biosynthesis.
Symptoms of Mn deficiency: First, there is a lack of green between the veins, and then necrotic spots appear. Symptoms first appear on new leaves (not easy to move).
11. Boron (B)
The main effects of boron: (1) related to the formation of reproductive organs, the formation of pollen mother cells in the absence of boron is blocked; the tissue of the tapetum is destabilized; (2) participating in the fertilization process, boron promotes pollen germination and pollen tube elongation (3) boron promotes the transport of sugar (complex with sugar); (4) inhibits CTK synthesis.
In the absence of boron, the symptoms are lacking: the plant grows slowly, the leaves are curled, the branches are increased, the stems are cracked, and the fertilization is poor. Specifically, the rapeseed flower is not real, the wheat ear is not real, the cotton bud is not flowered, and the brown spot is formed inside the root, such as the heart rot of the beet. Brown heart disease of radish.
12. Molybdenum (Mo)
The main physiological role of molybdenum: the components of nitrate reductase
In the absence of molybdenum, the plant lacks growth, the leaf color is dim, the leaf surface is uneven, and there are necrotic spots.
13. Chlorine (Cl)
The light involved in photosynthesis water explains the process of oxygen release and, in addition, has an effect on root growth.
Lack of symptoms: leaves are green, plants are wilting
14. Carbon (C)
Role: participate in the metabolism of all macromolecular substances in plants.
Lack of symptoms: In the absence of carbon supply, plant photosynthesis is blocked, plant growth is slow, and tissue is not full.
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