Sunday, November 11, 2018
Plant Nutrition
Author: Muhammad Afiq Mustaqim Bin
Rosli, 2018680922 (Plant Nutrition)
There are seventeen most important nutrients for plants. Plants must obtain the following mineral nutrients from their growing medium:
- The micronutrient: nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), sulphur(S), magnesium(Mg), carbon(C), Oxygen(O), hydrogen(H).
- The micronutrient (or trace minerals): iron (Fe), boron (B), chlorine (Cl), manganese (Mn), Zinc (Zn), copper (Cu), Molybdenum (Mo), Nickel (Ni).
These elements stay beneath soil as
salts, so plants consume these elements as ions. The macronutrients are consumed in larger quantities (hydrogen, oxygen,
nitrogen and carbon) contribute to over 95% of a plants' entire biomass on a
dry matter weight basis. Micronutrients
are present in plant tissue in quantities measured in parts per million,
ranging from 0.1 to 200 ppm, or less than 0.02% dry weight.
Plants take
up essential elements from the soil
through their roots and from the air (mainly consisting of nitrogen and oxygen)
through their leaves. Nutrient uptake in the soil is achieved by cations
exchange, where in root hairs pump hydrogen
ions (H+) into the soil through proton. These hydrogen ions displace
cations attached to negatively charged soil particles so that the cations are
available for uptake by the root. In the leaves, stomata open to take
in carbon dioxide and expel oxygen. The carbon dioxide molecules are used as
the carbon source in photosynthesis.
The root, especially the
root hair, is the essential organ for the uptake of nutrients. The structure
and architecture of the root can alter the rate of nutrient uptake. Nutrient
ions are transported to the centre of the root, the stele, in order for the
nutrients to reach the conducting tissues, xylem and phloem. The cell wall
outside the stele but within the root, prevents passive flow of water and
nutrients, helping to regulate the uptake of nutrients and water. Xylem moves water
and mineral ions within the plant and phloem for
organic molecule transportation. Water potential plays a key
role in a plant's nutrient uptake. If the water potential is more negative
within the plant than the surrounding soils, the nutrients will move from the
region of higher solute concentration in the soil to the area of lower solute
concentration in the plant.
There are three fundamental ways
plants uptake nutrients through the root:
1.
Simple diffusion occurs when a
nonpolar molecule, such as O2, CO2, and NH3 follows
a concentration gradient, moving passively through the cell lipid bilayer
membrane without the use of transport proteins.
2.
Facilitated
diffusion is the rapid
movement of solutes or ions following a concentration gradient, facilitated by
transport proteins.
3.
Active transport is the uptake
by cells of ions or molecules against a concentration gradient; this requires
an energy source, usually ATP, to power molecular pumps that move the ions or
molecules through the membrane.
Plants obtain food
in two different ways. Autotrophic plants can make their own food from
inorganic raw materials, such as carbon dioxide and water, through
photosynthesis in the presence of sunlight. Green plants are included in this
group. Some plants, however, are heterotrophic,they are totally parasitic and
lacking in chlorophyll. These plants, referred to as holo-parasitic plants, are
unable to synthesize organic carbon and draw all of their nutrients from the
host plant.
Plants may also
enlist the help of microbial partners in nutrient acquisition. Particular
species of bacteria and fungi have evolved along with certain plants to create
a mutualistic symbiotic relationship with roots. This improves the nutrition of
both the plant and the microbe. The formation of nodules in legume plants and
mycorrhization can be considered among the nutritional adaptations of plants.
However, these are not the only type of adaptations that we may find many
plants have other adaptations that allow them to thrive under specific
conditions.
Plant cells need
essential substances, collectively called nutrients, to sustain life. Plant
nutrients may be composed of either organic or inorganic compounds. An organic compound is a chemical compound that
contains carbon, such as carbon dioxide obtained from the atmosphere. Carbon
that was obtained from atmospheric CO2composes the
majority of the dry mass within most plants. An inorganic
compound does not contain carbon and is not part of, or produced
by, a living organism. Inorganic substances, which form the majority of the
soil solution, are commonly called minerals: those required by plants include
nitrogen (N) and potassium (K) for structure and regulation.
Essential
Nutrients
Plants require only light, water and about 20 elements to support all their biochemical needs, these 20 elements are called essential nutrients.
Plants require only light, water and about 20 elements to support all their biochemical needs, these 20 elements are called essential nutrients.
Macronutrients
Carbon (C)
Hydrogen (H)
Oxygen (O)
Nitrogen (N)
Phosphorus (P)
Potassium (K)
Calcium (Ca)
Magnesium (Mg)
Sulfur (S)
Micronutrients
Iron (Fe)
Manganese (Mn)
Boron (B)
Molybdenum (Mn)
Copper (Cu)
Zinc (Zn)
Chlorine (Cl)
Sodium (Na)
Silicon (Si)
References:
- ARTICLE FOR PLANT NUTRITION Filed June 27, 1935 GRn / vars
BASI
Patented May 17, 193s PATENT l .OFFICE ARTICLE FOR
PLANT NUTRITION Linus H.
Jones, Amherst, Mass.,
assigner to W. Bartlett Jones, Chicago, Ill. Application
June 27, 1935, Serial No. 28,760
-Plant
Nutrition: Macronutrient and Micronutrient, Retrieved November 6,
2018, from http://www.biologyreference.com/
Ph-Po/Plant-Nutrition.html
