C8: Mineral Nutrition (Pt 1) Flashcards
Plant ____ are essential components of higher plants, performing vital functions
like anchorage, water and nutrient absorption, and storage
root systems
A plant’s ___originates in the embryo
formed within the seed.
root
section of the embryo that is root tissue is called the ___.
radicle
root that forms from the embryonic radicle
is called the ___
primary root
embryonic shoot.
plumule
two types of root systems:
tap root or fibrous root.
is a persistent root that remains throughout the plant’s life; a strong primary root that grows downward the soil, acting as the central axis.
tap root
branch off irregularly from the tap root, responding to soil
conditions like moisture, nutrients, and soil structure.
Lateral (secondary) roots
type of root:
=grows perpendicular to the soil surface
= grow
parallel to the soil surface.
Primary (tap) root;
lateral roots
are thin, extensive, and web like making them effective at holding soil
in place and preventing erosion, especially in grasses
Fibrous root systems
are those that emerge from the main stem instead of the primary root.
Adventitious roots
two types of adventitious roots: (beans)
Basal roots
Hypocotyl roots
– emerge just above where the main stem transitions to the root, located at the
base of the main stem.
Basal roots
– form above the basal roots, emerging from the ___(the stem
portion above the root-shoot transition zone)
Hypocotyl roots; hypocotyl
Zones of the Root (4)
Root cap zone
Zone of cell division
Zone of elongation
Zone of maturation
– outermost region at the tip of the root, protecting the delicate growing cells
behind it as the root pushes through the soil. It secretes a slimy substance that lubricates the
root’s path and senses gravity, guiding the root’s direction.
Root cap zone
– located just behind the root cap, this zone contains meristematic cells
that rapidly divide to form new cells.
Zone of cell division
– in this region, cells produced in the cell division zone expand, pushing
the root further into the soil.
Zone of elongation
primarily responsible for the root’s vertical
growth and is where most of the increase in root length occurs.
root elongation
– located above the elongation zone, cells here differentiate into
specialized cells for functions like nutrient absorption, water transport, and food storage; Root hairs also develop
Zone of maturation
are tiny hair-like structures that increase the surface area for water and nutrient
uptake. They are found near the root tip and are crucial for efficient absorption.
Root hairs
serve as the
primary interface between plants and the soil environment
roots
Roots also release ___—organic compounds such as
acids, sugars, and amino acids—into the surrounding soil, modifying its chemistry to improve
nutrient availability
exudates
relationship between mycorrhizal fungi and plants; symbiotic and mutualistic interaction
Mycorrhizal Associations
In this association, fungi colonize plant roots,
forming extensive networks that penetrate the soil, facilitating the uptake of nutrients and water
for the host plant. The fungi benefit by receiving essential carbon compounds from the plant,
Mycorrhizal Associations
provide plants with several vital advantages, including enhanced
nutrient acquisition, improved tolerance to abiotic stresses (such as drought and salinity), and
protection against soil-borne pathogens.
Mycorrhizal fungi
, the most common
type of mycorrhizae, interact with about 80% of terrestrial plant species, including many
agricultural crops, significantly improving phosphorus, calcium, magnesium, and iron uptake.
Arbuscular mycorrhizal fungi (AMF)
two types of mycorrhizae
Arbuscular Mycorrhizae (AM)
Ectomycorrhizae (ECM)
form intracellular associations with plant roots, penetrating the root cells and
creating specialized structures called ___(tree-like formations) within the root
cortex cells.
Arbuscular Mycorrhizae (AM); arbuscules
this type of mycorrhizae form an __ or __ around the roots, without
penetrating root cells. They establish a network called the ___, which extends
between the root cortex cells, allowing nutrient transfer.
Ectomycorrhizae (ECM)
external sheath or mantle;
Hartig net;
is the narrow region of soil that directly surrounds and is influenced by
plant roots.
rhizosphere
It is a highly dynamic area where root secretions (exudates) interact with soil particles,
nutrients, and microorganisms, creating a microenvironment that differs chemically and
biologically from the bulk soil.
rhizosphere
___for iron, __ for phosphorus
coumarins; organic acids
Nutrient Acquisitions (3)
Phosphorus Solubilization
Iron Acquisition
Nitrogen Fixation
Certain rhizosphere microbes produce ___ and
___that release phosphorus from soil minerals, making it accessible to plant
roots.
organic acids (like oxalate and citrate); phosphatases
microbes example:
Phosphorus solubilization=
Nitrogen fixation=
Phosphorus solubilization= Burkholderia
Nitrogen fixation= Rhizobium
Some microbes, particularly ___ bacteria, help plants access this nutrient by producing
compounds like ___—small molecules that bind and transport iron.
iron-reducing;
siderophores
recruit iron-reducing bacteria, thus improving iron uptake during
deficiency periods
coumarins
Abiotic Stress
Rhizosphere microbes can produce ___(e.g., auxins, cytokinins, gibberellins)
that regulate plant growth and enhance stress resilience. For instance, microbes like
____ produce hormones that stimulate root growth and
improve tolerance to drought, salinity, and other abiotic stresses.
phytohormones;
Pseudomonas and Bacillus strains
___ is one whose absence prevents a plant from completing its life cycle.
Essential element
classification of essential elements
macronutrients or micronutrients,
The first group of essential elements are part of the ____ of the plant.
organic (carbon) compounds
The second group of essential elements is important in __ reactions or in maintaining ___
energy storage; structural integrity.
The third group of essential elements is present in plant tissue as either ____Of
particular importance are their roles as ___
free ions or ions bound to substances. ;
enzyme cofactors.
The fourth group of essential elements has important roles in reactions involving ____
electron transfer.
Group 1: Nutrients that are part of carbon compounds. (2)
Nitrogen
sulfur
– a constituent of proteins (amino group) and nucleic acids (nitrogenous bases).
Nitrogen
– it is a component of some amino acids such as cysteine and methionine.
Sulfur
Group 2: Nutrients that are important in energy storage or structural integrity. (3)
Phosphorus
Silicon
Boron
– Component of nucleic acids and phospholipids as phosphate group. Has a
key role in reactions that involve ATP.
Phosphorus
– Contributes to cell wall mechanical properties, including rigidity and elasticity
Silicon
– Constituents of cell walls; involved in cell elongation.
Boron
Group 3: Nutrients that remain in ionic form (6)
Potassium
Calcium
Magnesium
Chlorine
Manganese
Sodium
– Required as a cofactor for more than 40 enzymes such as pyruvate kinase in
glycolysis.
Potassium
– Constituent of the middle lamella of cell walls. Required as a cofactor by some
enzymes. Acts as a second messenger in metabolic regulation.
Calcium
– Required by many enzymes involved in phosphate transfer. Constituent of
the chlorophyll molecule.
Magnesium
– involved in ionic balance during the photolysis of water.
Chlorine
– Required for activity of some enzymes such as kinases, and peroxidases.
Manganese
– Involved in the process of C4 and CAM cycle specifically by maintaining
osmotic balance and overall cellular homeostasis.
Sodium
Group 4: Nutrients that are involved in electron transfer (5)
Iron
Zinc
Copper
Nickel
Molybdenum
– Constituent of cytochromes involved in photosynthesis.
Iron
– Constituent of many enzymes in various biochemical processes which helps the
plant grow.
Zinc
– Component of phenolase and plastocyanin involved in oxidation of phenolic
compounds which affect color of fruits and vegetables, and in transferring electrons
between cytochrome b6f and Photosystem I, respectively.
Copper
– In nitrogen-fixing bacteria, __ is a constituent of hydrogenases.
Nickel
– Cofactor of enzymes nitrogenase which is involved in fixing atmospheric
nitrogen (N₂) into ammonia (NH₃).
Molybdenum
– initial phase where plants absorb essential nutrients. This step involves
the uptake of minerals in their ionic form (e.g., nitrate, potassium, magnesium) along with water.
Nutrient Acquisition
– follows acquisition and involves the transformation of these absorbed
nutrients into forms that the plant can use for growth and development.
Nutrient Assimilation
– main organ for nutrient and water uptake;
– primary site for photosynthesis
Roots;
Leaves
– short lived tubular extensions of epidermal cells, where the water and
nutrients first enter the plant; increase surface area of root
Root hairs
Nitrogen and other elements absorbed by roots are used in ___to form proteins and other
compounds.
leaves
