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Chapter 14: Soil And Mineral Nutrition - Coggle Diagram
Chapter 14: Soil And Mineral Nutrition
Concepts
Plants require elements in the form of minerals. This is called mineral nutrition
Essential Elements
Elements are found through hydroponic solution experiments
major/macro essential elements are those needed by plants in large quantities
Minor/Micro essential elements or trace elements are those needed by plants in very small amounts
Criteria for essentiality
The element itself must be necessary and no substitute can be effective
The element must be acting inside the plant, not outside of it.
The element must be necessary for complete, normal plant development through a full life-cycle
Mineral Deficiency Diseases
Causes of Deficiency Diseases
It is uncommon to find plant disrupted by lack/excess of mineral elements
Most commonly encountered with nonnative crop plants or ornamentals
Symptoms of Deficiency Diseases
Symptoms usually related to particular mineral that is lacked
Chlorosis - A lack of chlorophyll where leaves appear to be yellowish and brittle
Necrosis - The death of patches of tissue. Location depends on particular deficiency
Potassium deficiency causes death at tips and margins of leaves
Manganese deficiency causes the leaf tissues to die between veins
Mobile and Immobile Elements
Immobile elements - elements which cannot move after being incorporated into plant tissue
Examples include iron, calcium, and boron
Mobile Elements - elements which can be translocated to younger tissue even after being incorporated into a tissue
Examples include chlrorine, magnesium, nitrogen, phosphorus, and sulfur.
Soils and Mineral Availability
Weathering - The process by which soils are derived from rock. There are two types of weathering.
Physical Weathering - The process of breaking down rock with physical forces such as wind, water, and temperature change
Produces are variety of soil particle sizes
Fine Sand: 0.2 - 0.02 mm
Silt: 0.02 - 0.002 mm
Course sand: 2.0 - 0.2 mm
Clay particles/micelles: >0.002
Chemical Weathering - weathering involving chemical reactions. These typically involve acids
Cation Exchange
Cation Exchange - is the dissolving of cations in the soil solution
Soil Acidity
Soil Ph is the concentration of free protons in the soil solution. This is important for cation exchange and retention
The Endodermis and Selective Absorption of Substances
The endodermis prevents uncontrolled, apoplastic diffusion in roots
Mycorrhizae and the Absorption of Phosphorus
Mycorrhiza - the relationship 90% of plant's roots form with soil fungi.
This allows plants to absorb phosphorus efficiently
Nitrogen Metabolism
Nitrogen does not occur as a component of rock
Nitrogen largely occurs as an inert gas in the atmosphere. This gas must be converted to chemically active forms
Nitrogen Metabolism is the process of this conversion which consists of three steps
Nitrogen reduction
Nitrogen Assimilation
Nitrogen Fixation
Nitrogen Fixation - Is the conversion of N2 gas into nitrate, nitrite, or ammonium
Can be done through human manufacturing or by natural processes
Bacteria and Cyanobacteria can do this because they have the enzyme nitrogenase
Nitrogen Reduction - the process of reducing nitrogen in the nitrate ion, NO3-, from an oxidation state of +5 to the -3 oxidation state of ammonium
Nitrogen Assimilation - the actual incorporation of ammonium into organic molecules of the plant body
Other Aspects of Prokaryotes and Nitrogen
Nitrifying Bacteria - bacteria which oxidise ammonium to nitrate or nitrate to nitrate through a process called nitrification
Obtaining Nitrogen From Animals
Carnivorous plants obtain nitrogen by catching animals
Storage Of Minerals Within Plants
Most parts of plants store minerals in soluble forms in the central vacuoles of cells
