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- Melissa Ha, Maria Morrow and Kammy Argel
- Yuba College, College of the Redwoods and Ventura CollegeaboveASCCC Open Educational Resources-Initiative
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learning goals
- List the essential elements that plants need and summarize their functions.
- Describe how plants obtain nutrients, including the cation exchange mechanism.
- Distinguish macronutrients from micronutrients.
Plants are unique organisms that can absorb nutrients and water as well as carbon dioxide from the atmosphere through their root system. Soil quality and climate are the most important determinants of plant dispersal and growth. The combination of soil nutrients, water and carbon dioxide, and sunlight allows plants to grow.
The chemical composition of the plants reflects thatessential elements, which are necessary for plant growth and reproduction. For an element to be considered asBasicthree criteria are required: 1) a plant cannot complete its life cycle without the element; 2) no other element can fulfill the function of the element; and 3) the element is directly involved in plant nutrition. There is some disagreement about the number of essential elements for plants, with experts only listing 15 or 20. Nineteen essential elements are discussed here. While identifying essential elements may seem straightforward, the nutritional needs of plants vary somewhat by species and environmental conditions. As a result, some might argue that certain elements like cobalt (Co) are essential, but it's usually considered just one.beneficial element.
chemical composition of plants
Most of the plant body is made up of carbon (C), hydrogen (H) and oxygen (O). Plants get carbon from carbon dioxide in the atmosphere and hydrogen from water taken up by the roots. Oxygen atoms come from carbon dioxide and oxygen gas in the atmosphere, as well as from water. Water typically makes up 80 to 90 percent of the total weight of the plant. However, carbon and oxygen each make up about 45% of dry plant tissue (biomass) and hydrogen makes up 6%. The remaining 4% of dry biomass consists of elements extracted from the soil. Thismineral nutrientsThey are divided into macronutrients and micronutrients.
macronutrientsthey are required in relatively large quantities (more than 0.1% of dry biomass). The macronutrients, in order of their contribution to dry biomass, are nitrogen (N), potassium (K), calcium (Ca), magnesium (Mg), phosphorus (P), sulfur (S), and silicon (Si). Nitrogen, potassium and phosphorus are the main components of fertilizers (Figure \(\PageIndex{1}\)). Silicon is only absolutely necessary for horsetail, but many other plant species contain silicon and benefit from its presence. Some sources consider carbon, oxygen, and hydrogen macronutrients. However, this text does not do this as they are extracted from the atmosphere and/or water and not from minerals in the soil.
micronutrientsare required in small quantities (less than 0.01% of the dry biomass). Plant micronutrients are chlorine (Cl), iron (Fe), boron (B), manganese (Mn), sodium (Na), zinc (Zn), copper (Cu), nickel (Ni) and molybdenum (Mo). Sodium is mainly required by plants that use certain photosynthetic pathways (C4and CAM), but like silicon, it benefits many plant species.
absorption of minerals
Plants absorb most of the mineral nutrients from the soil in the form of ions. Some of these essential elements arecations, including potassium (K+), calcium (approx.2+), Magnesium (Mg2+), Ferro (Fe3+about total2+), Manganese (Mn2+), Natrium (Na+), Zinko (Zn2+), Kupfer (Cu+and with2+) and nickel (Ni2+). Other nutrients are in the form ofanions, including dihydrogen phosphate (H2AFTER4-) or hydrogen phosphate (HPO42-), Sulfat (SO42-), Chloride (Cl-) e molibdato (MoO42-). Plants get nitrogen from the soil in the form of nitrate (NO3-) or ammonium (SMALL)4+). Boron is known as boric acid (H3BO3) are approximateconjugate base, Diidrogenborato (H2BO3-). Silicon is available as silicic acid (H4SiO4).
Cations in soil are bound to negative charges.TonParticles or organic acids that formHumus(verFloors), which hinders uptake by plants. Plants have a mechanism calledcation exchange, which releases cations and releases them for uptake (Figure \(\PageIndex{2}\)). This happens when the roots produce protons (H+) down in the soil. Protons bind to clay and humus replacing cationic nutrients such as K.+,California2+and magnesium2+. These nutrients freely dissolve in the soil water and can get into the roots. Roots can also indirectly increase soil proton concentration (lower pH) by releasing carbon dioxide, which reacts with water to form carbonic acid. Protons released when carbonic acid molecules dissociate can contribute to cation exchange.
To take up iron, plants must liberate protons by creating acidic conditions that promote the conversion (oxidation) of Fe.3+about Fe2+, or produce special compounds calledSiderophore. These join the faith3+Formation of a complex which can then be transported to the root.
Because anions are not attracted to clay and humus in the soil, they have it easierFilterof the soil when it is watered or rained. Because of this, anions like nitrates and phosphates are common causes of iteutrophication(verThreats to Biodiversity).
Mykorrhiza, symbiotic fungi that grow around or in root cells, help plants absorb a variety of mineral nutrients, especially phosphorus.
Functions of the essential elements
Each essential element has several functions. For example, calcium acts as a second messenger that transmits signals within a cell and as a cofactor that supports enzyme function. While some features are outlined below for the most important basics, they are organized based on one of their main features.
Elements in biological macromolecules
Carbon dioxide is a reagent in photosynthesis, and carbon is required to form biological macromolecules (carbohydrates, lipids, proteins, and nucleic acids). For example, the carbohydrate cellulose is the main structural component of plant cell walls and makes up over thirty percent of the plant substance (Figure \(\PageIndex{3}\)). In addition to biological macromolecules, plants contain many other organic molecules such as chlorophyll and plastoquinone, all of which contain carbon. As a matter of fact,organic moleculesThey are defined as those that contain both carbon and hydrogen, usually have carbon-carbon bonds, and are generally larger and more complex than inorganic molecules.
Hydrogen and oxygen are components of water and all biological macromolecules. Hydrogen is found in all organic compounds, and oxygen is also found in many. Gaseous oxygen is also a reactant in aerobic cellular respiration.
Nitrogen is part of proteins, nucleic acids and chlorophyll. Nitrogen is also used in the synthesis of some vitamins such as vitamin B6, which acts as a coenzyme in protein synthesis.
Phosphorus is needed to synthesize nucleic acids andPhospholipide, which make up the plasma membrane, chloroplasts, and many other plant cell structures.Adenosintriphosphat (ATP), the main form of ready-to-use energy in the cell, contains three phosphate groups, each with a phosphate in the middle (Figure \(\PageIndex{4}\)). Plants that produce ATP by adding a phosphate group to adenosine diphosphate (ADP).oxidative phosphorylationduring cellular respiration and duringphotophosphorylationin photosynthesis.
Sulfur is a component of certain amino acids such as cysteine and methionine and is present in several coenzymes. For example, it combines coenzyme A with acetyl groups to form acetyl-CoA, the starting molecule in the Krebs cycle (tricarboxylic acid cycle) of cellular respiration. Sulfur also plays a role in photosynthesis as a component of iron-sulfur proteins that transfer electrons from photosystem I to NADP.+.
Elements that maintain ionic balance
Potassium and chlorine play a role in regulating the opening and closing of stomata. As openings for gas exchange, stomata contribute to a healthy water balance. This process is assisted by a potassium ion pump and movement of chloride through anion and symport channels. Potassium is also a cofactor for many enzymes, including those involved in photosynthesis. Chlorine, along with calcium, is important forwater photolysis, which produces oxygen during photosynthesis. Calcium also transmits signals within the cell (including as a second messenger during stoma closure), acts as a cofactor for many enzymes, and contributes to cell wall structure in stomata.middle slatsbetween neighboring cells.
Elements involved in enzymatic function
Magnesium, zinc, nickel, copper and manganese act as cofactors. In particular, manganese helps in the photolysis of water. Zinc helps in the synthesis of chlorophyll. Nickel is involved in the breakdown of urea. Copper can serve as a cofactor or as a component of the enzyme itself. For example, plastocyanin copper allows electron transport during photophosphorylation. In addition to supporting enzyme function, magnesium is also important for the photosynthesis process because it is part of chlorophyll (Figure \(\PageIndex{5}\)).
Like copper, iron facilitates electron transport in enzymes. It is found in cytochromes involved in oxidative phosphorylation and photophosphorylation. Iron also plays a role in chlorophyll synthesis. Molybdenum is a component of some enzymes in plants, including one that helps plants use nitrate.
Sodium helps some plants synthesize phosphoenolpyruvate (PEP). Carbon dioxide is added to PEP to form oxaloacetate during C4and CAM photosynthesis.
elements in cell walls
Of course, polysaccharides like cellulose, which contain carbon, hydrogen, and nitrogen, are the main components of plant cell walls. However, other elements play rather subordinate roles. Calcium in the median lamina has already been mentioned. In addition, silicon plays a role in the cell wall structure of horsetails. Boron is involved in cell wall structure and stretching.
nutritional deficiencies
A lack of any of these nutrients, especially macronutrients, can negatively affect plant growth (Figure \(\PageIndex{6}\)). Depending on the specific nutrient, a deficiency can result in stunted growth, slow growth, orChlorosis(yellowing of the leaves). Extreme deficiencies can cause leaves to show signs ofNecrosis(tissue death). The location of the symptoms, such as B. old leaves versus young leaves can be instructive. Some nutrients, like iron, are immobile, so iron deficiency would cause chlorosis on young leaves. On the other hand, magnesium can be transported from old leaves to developing ones. As a result, a magnesium deficiency would manifest itself as chlorosis on old leaves.
Daily Connection: Hydroponics
Hydroponikis a method of growing plants in a solution of water and nutrients instead of soil (Figure \(\PageIndex{7}\)). Since its inception, hydroponics has evolved into a growing technique that is widely used by researchers. Scientists interested in studying nutrient deficiencies in plants can use hydroponics to study the effects of different nutrient combinations under tightly controlled conditions. Hydroponics was also developed to grow flowers, vegetables and other crops in greenhouse environments. You can find hydroponically grown products at your local grocery store. Today many lettuce and tomatoes in your market are grown hydroponically.
assignment
Curated and co-written by Melissa Ha31.1 Nutrient requirements of plantsvonBiology 2ndby OpenStax (CC-BY). Access freeopenstax.org.
FAQs
What are 21 essential elements? ›
Calcium, carbon, chlorine, cobalt, copper, fluorine, hydrogen, iodine, iron, magnesium, manganese, molybdenum, nitrogen, oxygen, phosphorus, potassium, selenium, sodium, sulfur, and zinc are regarded as the 21 elements essential for life.
What are the 16 essential elements? ›Sixteen elements are considered essential nutrients for plants. These are carbon (C), oxygen (O), hydrogen (H), nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sulfur (S), iron (Fe), manganese (Mn), zinc (Zn), copper (Cu), boron (B), molybdenum (Mo) and chlorine (Cl).
What are the 17 essential elements discuss? ›The 17 Essential Plant Elements include nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, boron, chlorine, iron, manganese, zinc, copper, molybdenum, and nickel. The non-mineral essential plant elements include hydrogen, oxygen, and carbon. These are either taken up as a gas or water.
What are the 18 essential elements? ›Summary. Plants require 18 essential nutrients to grow and survive, classified by their importance into macronutrients (C, H, O, N, P, K, Ca, Mg, S) and micronutrients (B, Cu, Fe, Mn, Zn, Mo, Cl, Co, Ni).
What are the 25 elements of life? ›- The Big 4.
- Carbon, oxygen, Hydrogen, and Nitrogen.
- 96%
- The Major elements.
- CAlcium, Phosphorous, Potassium, sulfur, Sodium, Chlorine and Magnesium.
- 3.5%
- Trace Elements.
- Boron, chromium, cobalt, copper, fluorine, iodine, iron, manganese, molybdenum, selenium, silicon, tin, & vanadium.
scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc. In this lesson you will learn the names and chemical symbols of all chemical elements from atomic number 21 to atomic number 30, which you can see in the table below.
What are the 11 essential elements for life? ›Almost 99% of the mass of the human body is made up of six elements: oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus. Only about 0.85% is composed of another five elements: potassium, sulfur, sodium, chlorine, and magnesium. All 11 are necessary for life.
How many essential elements are there? ›Scientists believe that about 25 of the known elements are essential to life. Just four of these – carbon (C), oxygen (O), hydrogen (H) and nitrogen (N) – make up about 96% of the human body. 25 elements are known to be essential to life.
What are the 6 most important elements of life? ›The six most common elements of life on Earth (including more than 97% of the mass of a human body) are carbon, hydrogen, nitrogen, oxygen, sulphur and phosphorus.
What are the 20 essential elements? ›Nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, boron, chlorine, iron, manganese, zinc, copper, molybdenum, and nickel. Other elements that have been proposed as candidates for essential or beneficial elements include chromium, vanadium, and titanium, although strong evidence is lacking at this time.
What are the 8 essential elements of life? ›
Living organisms contain relatively large amounts of oxygen, carbon, hydrogen, nitrogen, and sulfur (these five elements are known as the bulk elements), along with sodium, magnesium, potassium, calcium, chlorine, and phosphorus (these six elements are known as macrominerals).
What are the 4 essential elements? ›Carbon, hydrogen, oxygen, and nitrogen are four elements essential to life. They form the building blocks that make life possible and account for 96% of all atoms in living things.
What are the 13 essential elements to man? ›...
Elemental composition list.
| Element | Carbon |
|---|---|
| Mass (kg) | 13 |
| Atomic percent | 12 |
| Essential in humans | Yes (organic compounds) |
Air is the most essential element of life as it contains oxygen which is responsible for life-sustaining on the earth.
What are the 17 elements that make up dirt? ›There are 17 Essential Elements that act as essential plant nutrients for growth are: Carbon (C), Hydrogen (H), Oxygen (O), Nitrogen (N), Phosphorus (P), Potassium (K), Sulfur (S), Calcium (Ca), Magnesium (Mg), Boron (B), Chlorine (Cl), Copper (Cu), Iron (Fe), Manganese (Mn), Molybdenum (Mo), Nickel (Ni), and Zinc (Zn) ...
What are the 45 elements? ›| Atomic Number | Symbol | Name |
|---|---|---|
| 43 | Tc | Technetium |
| 44 | Ru | Ruthenium |
| 45 | Rh | Rhodium |
| 46 | Pd | Palladium |
Molybdenum (Mo) - Atomic Number 42.
What are the 23 elements? ›Hence, the 23rd element on the periodic table is Vanadium, and 23 stands for atomic number or number of protons of the Vanadium atom.
What are the first 21 elements? ›Lithium, Beryllium, Sodium, Magnesium, Aluminium, Potassium, and Calcium are metals in the first twenty elements. Hydrogen, Helium, Carbon, Nitrogen, Oxygen, Fluorine, Neon, Phosphorous, Sulphur, Chlorine, and Argon are the non-metals in the first twenty elements.
Which of the 20 elements are important to living things? ›Carbon, hydrogen, oxygen, and nitrogen are the most important elements. Small quantities of other elements are necessary for life. Carbon is the most abundant element in living matter. Nitrogen is continually re-circulated.
What are the 22 elements? ›
| Atomic Number | Symbol | Name |
|---|---|---|
| 22 | Ti | Titanium |
| 23 | V | Vanadium |
| 24 | Cr | Chromium |
| 25 | Mn | Manganese |
- Hydrogen (H)
- Helium (He)
- Lithium (Li)
- Beryllium (Be)
- Boron (B)
- Carbon (C)
- Nitrogen (N)
- Oxygen (O)
The 5th period of the periodic table contains 18 elements not 32. Reason n=5, l=0, 1, 2 , 3 . The order in which the energy of available orbitals 4d, 5s, and 5p increases is 5s<4d<5p. and the total number of orbitals available are 9 and thus 18 electrons can be accommodated.
What are 5 important essential elements? ›1. Note that most living matter consists primarily of the so-called bulk elements: oxygen, carbon, hydrogen, nitrogen, and sulfur—the building blocks of the compounds that constitute our organs and muscles. These five elements also constitute the bulk of our diet; tens of grams per day are required for humans.
What are the five spiritual elements? ›According to some traditions, everything in the universe comes from the five elements: wood, fire, earth, water, and metal.
What are the 4 most important elements? ›Scientists believe that about 25 of the known elements are essential to life. Just four of these – carbon (C), oxygen (O), hydrogen (H) and nitrogen (N) – make up about 96% of the human body.