MINERAL NUTRITION

How the plants obtain and use mineral nutrients

Dr. Manoj Kumar Sharma

Department of Botany

November 8, 2022
 Mineral Nutrition
How plants absorb and use mineral nutrients

1. Important of mineral nutrition

2. What are the essential and non essential
mineral nutrients
3. Mineral nutrients in the soil- availability /
adsorption
4. Roots and mineral nutrient gaining- root
structure / depletion zones

November 8, 2022
Nutritional needs of plants

Plant cells contain more than 60 different kinds of elements like

N, P, K, Ca, Mg, S, Fe, Cl, Mn, B, Zn, Cu, Mo etc

November 8, 2022
Essential elements:
 Required for normal growth and  Biochemical role and
reproduction. Their absence physiological function
inhibits plant growth and
development/ life cycle.
 According to relative
 Have a definite biological / concentration in plants :
physiological role, have a direct
or indirect action in plant 17 elements can classified as
metabolism  9 macronutrients
 8 micronutrients
 Part of an essential molecule
i.e., DNA, ATP, Protein Etc.
(macromolecule, metabolite)
 No other element may
substitute / replace it and
correct the deficiency
November 8, 2022
All essential mineral nutrients contribute less than 4% of plant mass, yet
plant growth is very sensitive to mineral deficiency.

(Part 1)

→ Not considered mineral nutrients

November 8, 2022
Micronutrients are present in very low concentrations

(Part 2)

Very low concentrations, but still essential because of specialized roles in

metabolism

November 8, 2022
 The proportional weights of different inorganic
element in plants are

Carbon, hydrogen, oxygen Others

Macronutrients (3-5%) Micronutrients (0.5%)

Minerals found in more than Minerals found in less than
1000 ppm concentration 100 ppm concentration
(present at > 10 mmol / kg dry wt.) (< 10 mmol / kg dry wt.)
N, P, K, Ca, Mg, S Fe, Cl, Mn, B, Zn, Cu, Mo

November 8, 2022
 Generalizations of Nutrition
Requirement :

❖ plants require different amounts of different element

❖ different elements are absorbed in different ionic forms (ex.
cation – anion)
❖ Plants can absorb/ accumulate an element although there is no
specific requirement of such element
❖ Plants can accumulate an element although it is not
considered to be an essential element
❖ Almost all elements have several functions

November 8, 2022
 General functions of
essential elements :

➢ Can be parts of structural molecules (ex. C, N)

➢ Can be parts of compounds, involved in metabolism (ex. Mg, P)
➢ Can be function as enzyme activators or sometimes as inhibitor
➢ Can help to maintain the osmotic balance (ex. K)
➢ Part of organic molecules (ex. N, S)
➢ Important in energy storage
or structural integrity (P, Si, B)
➢ Involved in energy transfer reaction (Fe, Zn, Cu, Ni, Mo)

November 8, 2022
Mineral element deficiencies produce visible
symptoms

 When any mineral is deficient, the growth of the

plant is stunted and the plant also shows other
deficiency symptoms.
 The combination of all observe symptoms can
be traced to the roles that mineral plays in
metabolism or physiology.

November 8, 2022
Mineral defficiensies disrupt metabolism and function

Inadequate supply

Mineral nutritional disorders

All related disorders are the results of essential elements in

normal metabolims

Characteristics defficiencies symptoms

November 8, 2022
Mobility of Mineral Elements in Phloem

 Mobile Nutrients – Nutrient has moved to the younger

parts of the plants. Deficiencies typically appear on older
growth first.
 Immobile nutrients – When the soil is exhausted of
mineral the younger zones suffer the symptoms because the
minerals are held by the older leaves. Deficiencies
typically appear on newer growth and shoot tips first.
initially sequestered in younger leaves which are now the
oldest ones.

November 8, 2022
Mobility and re-translocate

November 8, 2022
 Some common deficiency symptoms
Stunted growth :
N deficiency ~ stem
P deficiency ~ root

Chlorosis
(Mg, N, and Fe deficiencies) :
chlorophyll synthesis 
chlorophyll degradation 

Necrosis :
dead spots or zones on leaf
(Mg, K or Mn deficiency)

Color changes :
ex. excessive anthocyanin production
in stems ~ P deficiency
November 8, 2022
 N deficiency P deficiency K deficiency

Mg deficiency Zn deficiency
November 8, 2022
The shortage in soil of any essential elements causes
deficiency symptoms

 Essential because of their various

metabolic functions
 Characteristic deficiency symptoms shown
because of their specific roles
 Usual deficiency responses are
 Chlorosis: yellowing; precursor to
 Necrosis: tissue death
 Deficiency symptoms become visible when
a supply of an essential metabolite
becomes limiting in the environment
 Element concentrations are limiting for
growth when they are below the critical
concentration

November 8, 2022
Limiting nutrient levels negatively affect growth

 Plant responses to limiting nutrients usually very visible

affects yield/growth
 Chlorosis and/ or necrosis of leaves are typical
symptoms
 Sometimes shows straightforward relationship, e.g., in
chlorosis (lack of green color),
◼ N: chlorophyll component
◼ Mg: co-factor in chlorophyll synthesis

November 8, 2022
Analysis of plant tissues reveals mineral deficiencies
Analysis of nutrient levels

Soil analysis: Plant tissue analysis

Determination of minerals
nutrient content in soil sample
near the root zone

November 8, 2022
 Minerals present in >1000 ppm
concentration are macronutrients
Role Symptoms
P Part of nucleic acid, stunted, dark leaves, necrotic spots, anthocyanin in
phospholipid, ATP stem and leaves, thin weak stem
K ion balance, and part marginal chlorosis, necrosis at tips and edges,
of respiratory curled/crinkled leaves, old leaves first, short weak
enzymes stems, susceptible to diseases
N Part of amino acids, stunted, chlorosis of older leaves, abscission, thin
nucleic acids stems with lignin or anthocyanin as "sink" for
photosynthate
S Part of cysteine, chlorosis of young leaves first
methionine, CoA, etc.
Ca Part of enzyme hooked leaves, necrosis of young meristems, severe
cofactor, cyclosis, stunting as meristems die
pectins
Fe Present in chlorosis between veins on young leaves first
cytochromes in resp.,
photosynth. and
enzymes
November 8, 2022
 Minerals present in <100 ppm
concentration are micronutrients (1)

µmol g-1 Role Symptoms

Co Part of enzyme cofactor controversial?
Mn 1 Part of some chlorosis and small necrotic spots
resp/photolysis enzyme throughout plant
cofactor
Cu 0.1 Part of enzymes, dark green leaves with necrotic
plastocyanin, cytochrome spots at tips of young leaves, early
oxidase abscission
Zn 0.3 Part of enzyme cofactor, decrease internode length (rosette
chlorophyll synthesis, IAA look), puckered leaf margins,
synthesis chlorosis of older leaves with
white necrotic spots
B 2 Required for pollen tube black necrosis at base of young
growth and orientation, leaves and buds, stiff/brittle
nucleic acid synthesis, stems, meristem death followed by
November 8, 2022
membrane synthesis excessive branching
 Minerals found in <100 ppm
concentration are micronutrients (2)
µmol g-1 Uses Symptoms

Mo 0.001 Part of nitrate reductase enzyme converts nitrate into nitrite so

cofactor symptoms are like N deficiency
Si (30) Required for cell wall soft stems that lodge (fall over)
rigidity in Equisetum and
grasses
Ni 0.002 Part of urease cofactor urea accumulates in leaf tips causing
necrosis, unlikely in field

Al Part of enzyme cofactor difficult to have too little-toxicity more

likely

Cl 3 Required for ion balance, wilting leaf tips, bronze leaves, rare to
photolysis, cell division be deficient in field

Na 0.4 Required for chlorosis, necrosis, flowering failure in

regeneration of PEP step C-4 plants only
November 8, 2022
C-4
SOIL
• Most of soils contain five basic components: mineral particles, water,
air, microbes and organic matter. Organic matter can be further sub-
divided into humus, and roots.
• Humus is the decomposing (by fungi and bacteria) organic matter of soil;
biochemical substance that make upper layer of the soil become dark.
Most plants grow best in soil containing 10-20 % humus

Type of Mineral
Size Range
Particle

Sand 2.0 - 0.06 millimeters

0.06 - 0.002
Silt
millimeters

less than 0.002

Clay
millimeters

November 8, 2022 http://www.physicalgeography.net/fundamentals/10t.html

 Components of soil
• Is the decomposing organic material in soil by fungi
and bacteria
Humus • Biochemical substance that make upper layer of the
soil become dark
• Most plants grow best in soil containing 10-20 %
humus

• About 23-30 % of the volume of most soils is air

Air • Critical role: provides oxygens for root
• Compare: clay soil and sandy soil

• Organism mix and refine the soil.

• Organism add humus to the soil
Living • Respiration by these organism increase the amount
organism of CO2 in the soil
• Many organism affect the availability of nutrients in
the soil

November 8, 2022
 SOIL PARTICLES INFLUENCE THE AVAILABILITY OF
NUTRIENTS
 Soil particles have
(-) charge →
allowing to bind
cations (+) and
prevents the cation
from being washed
from the soil by
rainfall
 (-) ions stay in
solution
surrounding roots,
creating a charge
gradients that tends
to pull (+) ions out
off the root cells
November 8, 2022
http://bcs.whfreeman.com/thelifewire8e/content/cat_010/f36006.jpg
 SOIL PARTICLES INFLUENCE THE AVAILABILITY OF
NUTRIENTS
 Plants extract the
cation by
exchanging them
for H+ : CATION
EXCHANGE
 Cation exchange
is enhanced by
roots respiratory:
production of
CO2. Active
transport is
required to
acquire and
maintain positive
ions in the root
November 8, 2022
http://bcs.whfreeman.com/thelifewire8e/content/cat_010/f36006.jpg
 Cation exchange

Cations enter root hairs via Anions enter root hairs via
channels or carriers cotransporters

November 8, 2022 http://housecraft.ca/author/jpriest/page/4/

 Cation exchange is soil pH dependent :
 nutrient availability
 soil microbes : fungi – acidic; bacteria – alkaline
 root growth : slightly acidic soil (pH 5.5 & 6.5)

Acid soil ----- rocks release K+, Mg2+, Ca2+, Mn2+

 solubility of SO42-, H2PO4-, HCO3-
So, availability to roots 
Soil pH  due to : - decomposition of organic matter
- Rainfall

decomposition of org. Matter : CO2 + H2O → H+ + HCO3-

(microbial decomposition) : NH3 + O2 → HNO3 (nitric acid)

H2SO4 (sulfuric acid)

H+ displace K+, Mg2+ ----- K+, Mg2+ etc. Available --- pH 

November 8, 2022
 THANK YOU

November 8, 2022