Boron deficiency (plant disorder)

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Boron deficiency is a common deficiency of the micronutrient boron in plants. It is the most widespread micronutrient deficiency around the world and causes large losses in crop production and crop quality. [1] Boron deficiency affects vegetative and reproductive growth of plants, resulting in inhibition of cell expansion, death of meristem, and reduced fertility. [2]

Contents

Plants contain boron both in a water-soluble and insoluble form. In intact plants, the amount of water-soluble boron fluctuates with the amount of boron supplied, while insoluble boron does not. The appearance of boron deficiency coincides with the decrease of water-insoluble boron. It appears that the insoluble boron is the functional form while the soluble boron represents the surplus. [3]

Boron is essential for the growth of higher plants. The primary function of the element is to provide structural integrity to the cell wall in plants. Other functions likely include the maintenance of the plasma membrane and other metabolic pathways. [4]

Symptoms

Symptoms include dying growing tips and bushy, stunted growth; extreme cases may prevent fruit set. Crop-specific symptoms include:

Soil conditions

Boron is present in the soil in many forms, the most common being Boric Acid (H3BO3). An adequate amount of boron in the soil is 12 mg/kg. If the boron content of the soil drops below 0.14 mg/kg then boron deficiency is likely to be observed. Boron deficiency is also observed in basic soils with a high pH because in basic conditions boric acid exists in an undissociated form which the plant is unable to absorb. [5] Soils with low organic matter content (<1.5%) are also susceptible to boron deficiency. Highly leached sandy soils are also characteristic of boron deficiency because the boron will not be retained in the soil. [6] Boron toxicity is also possible if the boron content of the soil is high enough that the plant cannot cope with the excess boron. The levels at which boron is toxic to plants varies with different species of plants. [7]

Boron requirements

Boron is an essential micronutrient which means it is essential for plant growth and development, but is required in very small quantities. Although Boron requirements vary among crops, the optimum boron content of the leaves for most crops is 20-100 ppm. [8] Excess boron can result in boron toxicity and the toxicity level varies between plants. [7]

Treatment

Boric acid (16.5% boron), borax (11.3% boron) or Solubor (20.5% boron) [9] can be applied to soils to correct boron deficiency. Typical applications of actual boron are about 1.1 kg/hectare or 1.0 lb/acre but optimum levels of boron vary with plant type. [6] Borax, Boric Acid or Solubor can be dissolved in water and sprayed or applied to soil in blended dry fertilizer. Excess boron is toxic to plants so care must be taken to ensure correct application rate and even coverage. [7] While boron may be sprayed on leaves, excess will cause plant damage. Application of boron may not correct boron deficiency in alkaline soils because even with the addition of boron, it may remain unavailable for plant absorption. [5] [6] Continued application of boron may be necessary in soils that are susceptible to leaching such as sandy soils. [6] Flushing soils containing toxic levels of boron with water can remove the boron through leaching. [5]

A boron-containing granular potash fertilizer, called Aspire, [10] has been developed to evenly distribute boron through potassium chloride granules. This product contains two forms of boron - sodium borate for quick release and calcium borate for gradual release - to ensure season-long boron availability. These boron-infused potash granules prevent localized boron toxicity, while the granular size allows it to be distributed by common fertilizer equipment along with typical granular NPK fertilizer blends.

Functions

Once boron has been absorbed by the plant and incorporated into the various structures that require boron, the plant is unable to disassemble these structures and re-transport boron through the plant resulting in boron being a non-mobile nutrient. Due to translocation difficulties the youngest leaves often show deficiency symptoms first. [5]

Cell wall

Boron is part of the dRG-II-B complex which is involved in the cross linking for pectin located in the primary cell wall and the middle lamella of plant cells. [11] This cross linking is thought to stabilize the matrix of plant cell walls. [11]

Enhances protein synthesis

Germination and pollination

The B requirement is much higher for reproductive growth than for vegetative growth in most plant species. Boron increases flower production and retention, pollen tube elongation and germination, and seed and fruit development. [12]

A deficiency of B can cause incomplete pollination of corn or prevent maximum pod-set in soybeans. [12]

Sugar translocation

Photosynthesis transforms sunlight energy into plant energy compounds such as sugars. For this process to continue in plants, the sugars must be moved away from the site of their development, and stored or used to make other compounds. [12]

Boron increases the rate of transport of sugars (which are produced by photosynthesis in mature plant leaves) to actively growing regions and also in developing fruits. [12] Boron is essential for providing sugars which are needed for root growth in all plants and also for normal development of root nodules in legumes such as alfalfa, soybeans and peanuts. [12]

Related Research Articles

<span class="mw-page-title-main">Boron</span> Chemical element, symbol B and atomic number 5

Boron is a chemical element with the symbol B and atomic number 5. In its crystalline form it is a brittle, dark, lustrous metalloid; in its amorphous form it is a brown powder. As the lightest element of the boron group it has three valence electrons for forming covalent bonds, resulting in many compounds such as boric acid, the mineral sodium borate, and the ultra-hard crystals of boron carbide and boron nitride.

<span class="mw-page-title-main">Fertilizer</span> Substance added to soils to supply plant nutrients for a better growth

A fertilizer or fertiliser is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply plant nutrients. Fertilizers may be distinct from liming materials or other non-nutrient soil amendments. Many sources of fertilizer exist, both natural and industrially produced. For most modern agricultural practices, fertilization focuses on three main macro nutrients: Nitrogen (N), Phosphorus (P), and Potassium (K) with occasional addition of supplements like rock dust for micronutrients. Farmers applying these fertilizers in a variety of ways: through dry or pelletized or liquid application processes, using large agricultural equipment or hand-tool methods.

<span class="mw-page-title-main">Borax</span> Boron compound, a salt of boric acid

Borax is a salt (ionic compound), a hydrated borate of sodium, with chemical formula Na2H20B4O17 often written Na2B4O7·10H2O. It is a colorless crystalline solid, that dissolves in water to make a basic solution. It is commonly available in powder or granular form, and has many industrial and household uses, including as a pesticide, as a metal soldering flux, as a component of glass, enamel, and pottery glazes, for tanning of skins and hides, for artificial aging of wood, as a preservative against wood fungus, and as a pharmaceutic alkalizer. In chemical laboratories, it is used as a buffering agent.

A nutrient is a substance used by an organism to survive, grow, and reproduce. The requirement for dietary nutrient intake applies to animals, plants, fungi, and protists. Nutrients can be incorporated into cells for metabolic purposes or excreted by cells to create non-cellular structures, such as hair, scales, feathers, or exoskeletons. Some nutrients can be metabolically converted to smaller molecules in the process of releasing energy, such as for carbohydrates, lipids, proteins, and fermentation products, leading to end-products of water and carbon dioxide. All organisms require water. Essential nutrients for animals are the energy sources, some of the amino acids that are combined to create proteins, a subset of fatty acids, vitamins and certain minerals. Plants require more diverse minerals absorbed through roots, plus carbon dioxide and oxygen absorbed through leaves. Fungi live on dead or living organic matter and meet nutrient needs from their host.

<span class="mw-page-title-main">Soil pH</span> Measure of the acidity or alkalinity in soils

Soil pH is a measure of the acidity or basicity (alkalinity) of a soil. Soil pH is a key characteristic that can be used to make informative analysis both qualitative and quantitatively regarding soil characteristics. pH is defined as the negative logarithm (base 10) of the activity of hydronium ions in a solution. In soils, it is measured in a slurry of soil mixed with water, and normally falls between 3 and 10, with 7 being neutral. Acid soils have a pH below 7 and alkaline soils have a pH above 7. Ultra-acidic soils and very strongly alkaline soils are rare.

Calcium deficiency (plant disorder)

Calcium (Ca) deficiency is a plant disorder that can be caused by insufficient level of biologically available calcium in the growing medium, but is more frequently a product of low transpiration of the whole plant or more commonly the affected tissue. Plants are susceptible to such localized calcium deficiencies in low or non-transpiring tissues because calcium is not transported in the phloem. This may be due to water shortages, which slow the transportation of calcium to the plant, poor uptake of calcium through the stem, or too much nitrogen in the soil.

Potassium deficiency (plants)

Potassium deficiency, also known as potash deficiency, is a plant disorder that is most common on light, sandy soils, because potassium ions (K+) are highly soluble and will easily leach from soils without colloids. Potassium deficiency is also common in chalky or peaty soils with a low clay content. It is also found on heavy clays with a poor structure.

A period 2 element is one of the chemical elements in the second row of the periodic table of the chemical elements. The periodic table is laid out in rows to illustrate recurring (periodic) trends in the chemical behavior of the elements as their atomic number increases; a new row is started when chemical behavior begins to repeat, creating columns of elements with similar properties.

<span class="mw-page-title-main">Plant nutrition</span> Study of the chemical elements and compounds necessary for normal plant life

Plant nutrition is the study of the chemical elements and compounds necessary for plant growth and reproduction, plant metabolism and their external supply. In its absence the plant is unable to complete a normal life cycle, or that the element is part of some essential plant constituent or metabolite. This is in accordance with Justus von Liebig’s law of the minimum. The total essential plant nutrients include seventeen different elements: carbon, oxygen and hydrogen which are absorbed from the air, whereas other nutrients including nitrogen are typically obtained from the soil.

Micronutrients are essential dietary elements required by organisms in varying quantities throughout life to orchestrate a range of physiological functions to maintain health. Micronutrient requirements differ between organisms; for example, humans and other animals require numerous vitamins and dietary minerals, whereas plants require specific minerals. For human nutrition, micronutrient requirements are in amounts generally less than 100 milligrams per day, whereas macronutrients are required in gram quantities daily.

<span class="mw-page-title-main">Soil fertility</span> The ability of a soil to sustain agricultural plant growth

Soil fertility refers to the ability of soil to sustain agricultural plant growth, i.e. to provide plant habitat and result in sustained and consistent yields of high quality. A fertile soil has the following properties:

Agrogeology is the study of the origins of minerals known as agrominerals and their applications. These minerals are of importance to farming and horticulture, especially with regard to soil fertility and fertilizer components. These minerals are usually essential plant nutrients. Agrogeology can also be defined as the application of geology to problems in agriculture, particularly in reference to soil productivity and health. This field is a combination of a few different fields, including geology, soil science, agronomy, and chemistry. The overall objective is to advance agricultural production by using geological resources to improve chemical and physical aspects of soil.

Disodium octaborate is a borate of sodium, a chemical compound of sodium, boron, and oxygen — a salt with elemental formula Na2B8O13 or (Na+)2[B8O13]2−, also written as Na2O·4B2O3. It is a transparent colorless crystalline solid, soluble in water.

<span class="mw-page-title-main">Leaching (agriculture)</span> Loss of water-soluble plant nutrients from soil due to rain and irrigation

In agriculture, leaching is the loss of water-soluble plant nutrients from the soil, due to rain and irrigation. Soil structure, crop planting, type and application rates of fertilizers, and other factors are taken into account to avoid excessive nutrient loss. Leaching may also refer to the practice of applying a small amount of excess irrigation where the water has a high salt content to avoid salts from building up in the soil. Where this is practiced, drainage must also usually be employed, to carry away the excess water.

Phosphate rich organic manure is a type of fertilizer used as an alternative to diammonium phosphate and single super phosphate.

<span class="mw-page-title-main">Haifa Group</span>

Haifa Group is a private international corporation which primarily manufactures Potassium Nitrate for agriculture and industry, specialty plant nutrients and food phosphates. Haifa Group (Haifa) is the world pioneer in developing and supplying Potassium Nitrate and Specialty Plant Nutrients for advanced agriculture in various climates, weather, and soil conditions. Haifa also manufactures Controlled Release Fertilizers (CRF) for agriculture, horticulture, ornamentals, and turf. Haifa's products are used on high-value crops such as fruit trees and vegetables. Many of Haifa's fertilizers can be used as a fertilizer solution that is applied through drip irrigation. This latter application is the principal driver of demand today, now that more countries are turning to controlled irrigation systems that make more efficient use of water.

Korean natural farming (KNF) is an organic agricultural practice that takes advantage of indigenous microorganisms (IMO) to produce fertile soils that yield high output without the use of herbicides or pesticides. A result is an improvement in soil health, improving loaminess, tilth and structure, and attracting large numbers of earthworms. KNF also enables odour-free hog and poultry farming without the need to dispose of effluent.

Zinc deficiency (plant disorder)

Zinc deficiency occurs when plant growth is limited because the plant cannot take up sufficient quantities of this essential micronutrient from its growing medium. It is one of the most widespread micronutrient deficiencies in crops and pastures worldwide and causes large losses in crop production and crop quality.

Molybdenum deficiency (plant disorder)

Molybdenum (Mo) deficiency occurs when plant growth is limited because the plant cannot take up sufficient quantities of this essential micronutrient from its growing medium. For crops growing in soil, this may be a result of low concentrations of Mo in the soil as a whole, or because the soil Mo is held in forms that are not available to plants – sorption of Mo is strongest in acid soils.

Seventeen elements or nutrients are essential for plant growth and reproduction. They are carbon (C), hydrogen (H), oxygen (O), nitrogen (N), phosphorus (P), potassium (K), sulfur (S), calcium (Ca), magnesium (Mg), iron (Fe), boron (B), manganese (Mn), copper (Cu), zinc (Zn), molybdenum (Mo), nickel (Ni) and chlorine (Cl). Nutrients required for plants to complete their life cycle are considered essential nutrients. Nutrients that enhance the growth of plants but are not necessary to complete the plant's life cycle are considered non-essential. With the exception of carbon, hydrogen and oxygen, which are supplied by carbon dioxide and water, and nitrogen, provided through nitrogen fixation, the nutrients derive originally from the mineral component of the soil. The Law of the Minimum expresses that when the available form of a nutrient is not in enough proportion in the soil solution, then other nutrients cannot be taken up at an optimum rate by a plant. A particular nutrient ratio of the soil solution is thus mandatory for optimizing plant growth, a value which might differ from nutrient ratios calculated from plant composition.

References

  1. Shorrocks VM (1997). "The occurrence and correction of boron deficiency". Plant and Soil. 193 (1): 121–148. doi:10.1023/A:1004216126069. S2CID   23647011.
  2. Marschner H (1995). Mineral Nutrition of Higher Plants (2nd ed.). San Diego: Academic Press. pp. 379–396. Retrieved 2012-11-21.
  3. Koshiba, T; Kobayashi, M; Matoh, T (2009). "Boron deficiency". Plant Signal Behav. 4 (6): 557–8. doi:10.1093/pcp/pcn184. PMC   2688312 . PMID   19816136.
  4. Camacho-Cristóbal, Juan J.; Jesús Rexach; Agustín González-Fontes. "Boron in plants: deficiency and toxicity" (PDF). Journal of Integrative Plant Science. Archived from the original (PDF) on 2012-06-12. Retrieved 2012-11-21.
  5. 1 2 3 4 Boron the Overlooked Essential Element Archived 2011-07-14 at the Wayback Machine
  6. 1 2 3 4 www.agnet.org Archived 2011-07-24 at the Wayback Machine
  7. 1 2 3 Boron Toxicity Archived July 15, 2011, at the Wayback Machine
  8. "Plant Analysis Handbook for Georgia". Archived from the original on 2013-04-23. Retrieved 2010-11-15.
  9. "Solubor". USBorax. Retrieved 2019-01-14.
  10. "Aspire".
  11. 1 2 Toshiro Matsunaga, D.Agr. Archived July 20, 2011, at the Wayback Machine
  12. 1 2 3 4 5 "Agriculture". Archived from the original on 2013-12-02. Retrieved 2013-11-23.