MINERAL NUTRITION
Syllabus : Essential elements, Non essential elements, Function of elements, Deficiency symptoms and Mechanism of
absorption of mineral elements by plants. (As mentioned for AIPMT)
MINERAL NUTRITION
Chemical analysis of the plant ash (the
residue left after the dry matter of the plant has
been burnt) has shown that plants contain about
40 different elements.
Dry ashing of plant tissue is carried out in
an electric muffle at about 300 C. for an hour
and then at 500-550 for another hour or two,
results in the complete oxidation of tissue
organic matter. Some of them are indispensable
or necessary for the normal growth and
development of the plants and they are called as
Essential Elements. Rests of the elements are
called as Non-essential elements.
It is now known that the following 17
elements are essential for majority of the plants
: C, H, O, N ,P, K, Ca, S, Mg, Fe, Zn, B, Cu,
Mn, Ni, Cl and Mo. Besides these, Al, Si, Na,
Co and Ga may be essential for some plants.
3. MINOR ELEMENTS or
MICRONUTRIENTS or TRACE ELEMENTS
The essential elements required in smaller
amounts or traces by the plants are called as
Minor or Trace Elements. They are : Fe, Mn, Cu,
Zn, Mo, B and Cl. Apart from these elements,
recently some more elements have also been
shown to the essential for the normal growth of
some plants such as Na for Atriplex, Most C4
and CAM plants require sodium ions for
regenerating phosphoenolpyruvate.
Si for rice and Cl for coconut and Al, Va and
Co for ferns.
Micronutrients are usually present in the plants
in different chemical forms as :
1. Inorganic ions
2. Undissociated molecules or
3. Organic complexes as chelates
Essential elements may be classified into three
groups:
General functions of mineral elements
1. MAJOR ELEMENTS
NUTRIENTS
Framework elements: C, H, O, these
constitute the carbohydrates which form cell
walls.
OR
PRIMARY
The essential elements, which are required by
the plants in comparatively larger amounts
(more than 0.01 ppm) are called Major
Elements or Primary Nutrients. The list
includes : C, H ,O ,N , P and K.
Protoplasmic elements: N. P, S,
form part of protoplasm
Catalytic elements: functions as
part of enzyme.
Balancing elements: Ca, Mg, K
counteract the toxic effect of other
minerals by causing ionic balance.
2.SECONDARY NUTRIENTS
These elements are also requited by the plant in
larger quantity next to primary nutrients.
Examples are : Ca, Mg and S.
Mobile elements: N, K, Mg, P,
Cl, Na, Zn, Mo
Cu
www.m-learning.in
Page 1
Immobile elements: Ca, S, Fe, B,
Toxic elements: interfere with
the availability or transport of nutrients.
Al is more available in acidic soils and
complexes with phosphate, creating
phosphate deficiency in soil. The growth
of the tea plant is enhanced by the
presence of available soil aluminum.
Plant show adaptations for the nutrient
characteristics of the soils in which they
grow. Calcicoles are adapted for growth
in
an
alkaline,
high
calcium
environment, where other nutrients are
of low availability, while Calcifuges are
adapted to acidic soils, with high levels
of aluminum and low levels of
phosphate.
higher
calcium
3.
Some varieties of soybean are able to
absorb greater amounts of iron than
other varieties.
c) The chemical composition of the medium in
which a plant is grown affects the mineral
content of plant tissues.
d) The age of a tissue. A mature leaf is likely to
have a higher content than a very young leaf.
Also, a mature leaf may have a higher mineral
content than an old, senescent leaf.
Methods of Studying Plant Nutrients
The methods for study of mineral nutrition of
plant are :
Na, Zn, Cu, Mn, B, Mo, and Fe can all
be toxic, if present at high conc. in the
soil.
Plant analysis, Solution cultures (Hydroponics
or chemical gardening) and Sand culture.
Criteria of Essentiality of Elements (Arnon
and Stout, 1939)
Hydroponics term coined by Gerick (1940)
In order to show that element is truly essential,
it is necessary to show not only that :
The system of growing plants in soil-less
cultures or solution cultures is known as
Hydroponics or tray agriculture, tank
farming or chemical agriculture. This has
certain advantages over geoponics (Soil
culture) Such as :
i. A deficiency of the element makes it
impossible for a plant to complete its vegetative
and reproductive cycle
ii. It cannot be replaced by another element
iii. The element should also have some part to
play in metabolism
a. A controlled composition of nutrient solution
may be provided.
These three requirements form the criteria of
essentiality of mineral elements. However,
recent studies indicated that functions of some of
the elements could be partly replaced by other.
(e.g. potassium by rubidium; magnesium by
manganese).
b. There is no immobilization of nutrients as
there are no colloids for nutrient adsorption
c. It prevents accumulation of toxic organic
decomposition products due to frequent
replacement of culture solution.
d. Minimized growth of fungi and bacteria.
Factors affecting the mineral content of plant
tissues
e. It ensures better environment for plant growth
as the culture solution is kept aerated.
a) Variations in mineral content of plant tissue
are influenced by several factors. One is the
kind of plant. Different species of higher plants,
and also different varieties of the same species,
have different abilities to absorb mineral
nutrients even when rooted in the same soil or
soil solution.
f. There is no weed growth.
g. Natural calamities such as flood, drought,
erosion etc. can be avoided.
Aeroponics (Weathers and Zobel 1992)
It is a system for growing plants with their roots
supplied with moisture in the air. The rooted
plants are placed in a special type of box with
their shoots exposed to air and roots inside the
Dicots have been found to absorb more
boron than monocots.
www.m-learning.in
Legumes usually a
content than grasses.
b) The climatic conditions also affects the
content.
Sodium competes with K and creates its
deficiency and failure to osmoregulate.
1.
2.
Page 2
box
with
computer
controlled
humid
atmosphere. Plants like Citrus and olive have
been successfully grown through this method.
This approach provides easy manipulation of the
gaseous environment around the root, but it
requires higher levels of nutrients than
hydroponic cultures does to sustain rapid plant
growth. For this reason and other technical
difficulties, the use of aeroponics is not
widespread.
the influence of transpiration. Therefore,
transpiration effect on salt absorption is direct.
ii. Ion Exchange Theory
According to this theory, ions from the external
solution in which the tissue is immersed
may exchange with the ions absorbed on the
surface of the cell wall or membranes of the
tissue.
First step in the absorption of mineral salts is the
process of Ion-Exchange which does
Nutrient Availability in Soil and Mechanism
of uptake by plants
Mechanism
Plants
of
Mineral
uptake
not require metabolic energy
facilitates mineral salt absorption.
by
greatly
The ions adsorbed on the sugarcane wall or
membranes of root cells may be exchanged with
the ions of the same sign from external solution.
For example, the cation K+ of the external soil
solution may be exchanged with H+ ion
adsorbed on the surface of the root cells.
Similarly, an anion may be exchanged with OH ion.
Mineral salts are absorbed from the soil solution
in the form of ions. They are chiefly absorbed
through the zone of elongation of the roots near
tips. Plasma membrane of the root cells is not
permeable to all the ions. It is selectively
permeable. All the ions of the same salt are not
absorbed at equal rate but there is unequal
absorption of ions.
There are two theories proposed to explain the
mechanism of ion exchange:]
a. CO2 hypothesis (or) Carbonic Acid Exchange
Theory
Various theories have been proposed to explain
the mechanism of mineral salt absorption, which
can be of two categories :
b. Cation Exchange hypothesis (or) Contact
Exchange Theory.
1. Passive Absorption of Mineral Salts
a. CO 2 hypothesis :
When the concentration of mineral salts is
higher in the outer solution than in the cell sap
of the root cells, the mineral salts are absorbe d
according to the concentration gradient by
simple process of diffusion. This is called as
passive absorption because it does not require
expenditure of metabolic energy.
According to this theory, CO 2 released by the
roots during respiration combines with water to
produce carbonic acid (H 2 CO 3 ). The carbonic
acid dissociates into hydrogen ions(H+) and
bicarbonate ions (HCO 3 ).
These hydrogen ions may be exchanged for
cations adsorbed on clay particles. The cations
thus released into the soil solution from the clay
particles may be absorbed on root cells in
exchange for H+ ions. While the dissociated
bicarbonate ions release the adsorbed anions
(Fig.9). Thus, both cations and anions are made
available to the closeness of the roots of plants.
Thus, soil solution plays an important role in
carbonic acid exchange theory.
This can also be called as Physical Absorption.
This process is not affected by temperature and
metabolic inhibitors. This theory is based on the
movements of ions from the region of its higher
concentration to the lower concentration.
Therefore, The direction of the initial uptake
gets reversed if the tissues are transferred back
to a low concentration.
Important theories are Mass Flow, ion exchange
and Donnan equilibrium.
i. Mass Flow Theory (Bulk Flow)
According to this theory, the ions are taken up
by the roots along with mass flow of water under
www.m-learning.in
but
Page 3
This
equilibrium
is
known
as
Donnans
Equilibrium. In this particular case, there would
be more accumulation of cations inside the cell.
However,
if there
are fixed
cations (pre-
existing)inside the cell, then the Donnans
equilibrium will result in more accumulation of
anions inside
equilibrium.
Figure explaining CO2 hypothesis
the
cell
to
maintain
the
b. Cation Exchange hypothesis
2.Active Absorption of Mineral Salts
This theory states that the ions adsorbed on the
surface of root cells and clay particles (micelles)
are not held tightly but always oscillate within
small volume of space. If the roots and clay
particles are in close contact with each other, the
oscillation volume of ions adsorbed on rootsurface may overlap volume of ions adsorbed on
clay particles. (Fig.10). Then, the ions adsorbed
on clay particle may be exchanged with the ions
adsorbed on root surface directly without first
being dissolved in soil solution.
This process involved the metabolic energy for
the transport of ions from soil solution to the
plants. Based on the nature of participation of
metabolic energy, various theories have been
proposed. It includes the theories related with
carrier concept such as Cytochrome Pump
hypothesis, ATP theories, Protein-Lecithin as
carrier theories etc.
i. Carrier Concept Theory (Honert,1973) (for
movement of both cation & anion)
According to this theory, the ion transport
process is carried out by means of carriers,
which maybe organic molecules or vesicles. This
theory explains that the plasma membrane is
impermeable to free ions. The carrier combines
with ions to form carrier-ion complex, which
Figure explaining cation exchange theory
can move across the membrane.
iii. Donnan Equilibrium
This theory explains the accumulation of ions
inside the cells without involving the
expenditure of the metabolic energy. According
to this theory, there are certain pre-existing ions
inside the cell, which cannot diffuse outside
through membrane. Such ions are called as
indiffusible or fixed ions. However, the
membrane is permeable to both anions and
cations of the outer solution.
On the inner surface of the membrane, this
complex breaks releasing ions into the cell while
Suppose, there are certain fixied anions in the
back.
the carrier goes back to the outer surface to pick
fresh ions (Fig.12).
Here, the metabolic energy is required in the
process of formation of carrier-ion complex, its
transport, breakdown of complex, regeneration
of carrier and movement of carrier molecules
cell which is in contact with the outer solution
containing anions and cations. Normally, equal
ii. Protein-lecithin as Carrier (BennetClark,1956) (for uptake of both cation &
number of anions and cations would have
diffused into the cell through an electrical
anion)
It is suggested that because the cell membranes
chiefly consist of phospholipids and proteins and
potential to balance each other, but to balance
the fixed anions already present in the cell (pre existing), more cations will diffuse into the cell,
www.m-learning.in
also certain enzymes seem to be located on
Page 4
them, the carrier could be a protein associated
4. The electron thus released unites with H+ and
with the phosphotide called as lecithin. This
theory believes in the participation of some
oxygen to form water.
amphoteric compounds as carriers with which
both cations and anions can combine.
chain towards inside.
According to this theory,
becomes reduced by taking an electron
1. The acidic phosphate group in the phosphatide
produced through the dehydrogenase reactions
is regarded as the active centre
and the anion (A+) is released.
binding the cation, and the basic choline group
(N+) as the anion binding centre.
7. As a result of anion absorption, a cation (M+)
moves passively from outside to inside to
2. The ions are liberated on the inner surface of
balance the anion.
the membrane by decomposition of the lecithin
by the enzyme lecithinase.
Factors Affecting Salt Absorption
5. The anion (A+) travels over the cytochrome
6. On the inner surface, the oxidised cytochrome
3. The regeneration of the carrier lecithin from
Absorption of salt by the plants is affected by
several factors. Some of them are discussed
phosphatidic acid and choline takes place in the
presence of the enzymes choline acetylase and
below.
i Temperature
choline esterase and ATP. The ATP acts as a
source of energy.
iii.
Cytochrome-pump
Theory
(For
The increase in temperature increases both
active and passive salt absorption processes and
the
lowering of temperature decreases them.
movement of anions only)
ii. pH
Lundegardh and Burstrom (1933) claimed that a
quantitative relaionship exists between anion
It indirectly affects the salt absorption as the pH
affects the availability of ions in the medium.
absorption and respiration. When a plant is
transferred from water to salt solution, the rate
of respiration increases. They called this
iii. Light
As opened stomata allow more transpiration and
increase in respiration as Salt Respiration. The
actual transport of anions occurs through a
increased mass flow and photosynthesis provides
energy and O2 for salt uptake, light indirectly
cytochrome system (Fig.14)
affects the rate of salt absorption by affecting
the opening and closing of stomata and the
1. Dehydrogenase reactions on inner side of the
membrane give rise to protons (H+) and
process of photosynthesis.
electrons (e_).
iv. O 2 content
2. The electron travels over the cytochrome
The deficiency of O 2 decreases salt uptake as the
active phase of salt absorption is inhibited by
chain towards outside the membrane, so that the
Fe of the cytochrome becomes reduced (Fe++).
the absence of O 2 v. Interaction of other ions
on the outer surface and oxidised (Fe+++) on the
inner surface.
The absorption of one ion may be influenced by
the presence of other ion. The interaction may
3. On the outer surface, the reduced cytochrome
be associatedwith the availability and specificity
is oxidised by oxygen releasing the electron (e -)
and taking an anion (A-)
of binding sites on carriers.
www.m-learning.in
vi. Growth
Page 5
Different types of growth affect salt absorption
Vegetative
in different ways, eg., growth involving increase
in surface area, number of cells, synthesis of
activity
new binding sites or carriers and volumes of
water uptake stimulate salt absorption. Heavily
salt absorption.
suberised
root
is
www.m-learning.in
unable
to
absorb
growth
and
increased
metabolic
accompained with more water uptake enhance
salts.
Page 6
Role of essential elements: Elements
Carbon 45%
Oxygen 43%
Hydrogen 6%
Nitrogen
1.3%
Obtaine
d in the
form
No2-,
No3-,
NH4+
Phosphorous
0.05-1.0%
H 2 PO 4 -
Potassium 0.3
6.0 %
K+
Calcium
1-3.5 %
Ca 2+
Magnesium
0.05- 0.7%
Mg 2+
Sulphur 0.05
1.5%
So 4 2-
Iron 10 -1500
ppm
Fe 3+ ,
Fe 2+
Manganese 51500 ppm
Mn
www.m-learning.in
2+
Role /
Principal function
All cellular constituents
All cellular constituents
-------//------Amino acids, proteins,
purines, pyrimidines,
Hormones, Coenzymes,
chlorophyll, cytochromes
vitamins, ATP
Nucleic acid, nucleoproteins,
phospholipids, AMP, ADP,
ATP, GOP and ATP Co
enzymes NAD, NADP
Opening & closing of stomata
differential permeability
osmotic regulation and
hydration.
1. Cell wall
structure
component of
middle lamella.
2. Permeability of membranes.
3. Organization of mitotic
spindle.
4. Cell elongation.
5. Activators of amylases,
ATPase etc.
1. Component of chlorophyll
2. Cause dimerisation of
ribosome sub units
3. Activator for several
enzymes.
4. Involved in fat and
carbohydrate metabolism
1. Constitutuent of proteins,
containing (Methionine,
cysitne, cysteine)
2. Vitamins, CoA, lipoic acid
ferreodoxin, allyl oils of
onion, garlic, garlic, crucifers.
1. Structural component
of
porphyrin, cytochromes,
hemes, leghaemoglobin.
2. Enzyme system like,
cytochrome oxidase,
aconitase, nitrogenase.
3. Chlorophyll synthesis.
1. Essential for
photolysis of water
Page 7
Deficiency symptoms
Extremely poor growth
-------//--------------//-------1. Suppressed shoot growth.
2. Sparse foliage.
3. Early defoliation.
4. Chlorosis followed by Anthocyanin formation
5. Delayed flowering and Fruiting.
1. Premature leaf falls.
2. Formation of antho-cyanin
3. Sparse branching
4. Flowering is delayed.
1. Scoring & curling of leaves.
2. Chlorosis of tips and margin
3. Destruction of pith
increased differentiation
of
phloem.
1. Degeneration of root meristem.
2. Chlorosis of leaves.
3. Necrosis and distortion of leaf shape.
4. Premature flower fall.
1.
2.
3.
4.
Internveinal chlorosis.
Formation of anthocyanin.
Underdeveloped phloem.
Extensive chlorenchyma development.
1. Stunted plan.
2. Spare foliage.
3. Chlorosis followed by anthocyanin.
Formation.
4. Increase in starch and sugar
accumulation.
1. Pronounced chlorosis with green veins.
2. Young leaves become yellow or white.
3. Grasses show striping effect
( band of yellow
and green.)
1. Interveinal chlorosis, neorosis,
2. Sterile flower.
in hills reaction.
Enzyme activator in
respiration & N 2
metabolism.
1. Tryptophan synthesis
essential for
biosynthesis of
Auxin.
2. Activator of several
enzymes and protein
synthesis.
3. Promotes synthesis
of cytochrome
1. Component of cytochrome
oxidase, RuBP carboxylase.
2. Terminal oxidation by
cytochrome oxidase.
3. Photophos phorylation
mediated by plasto cyanin.
4. Maintenance of
carbohydrate and nitrogen
balance.
1. Component of nitrate
reductase.
2. Ascorbic acid synthesis.
3. Ion absorption and
translocation.
1. Translocation of sugar.
2. RNA and phenol
metabolism.
3. GA and K-amylase activity.
4. Affects flowing, fruiting,
germination.
1. Activator of Z enzyme
complex of photolysis (Hills
reaction)
2. Maintenance of osmotic
potential
2.
Zinc 3-150
ppm
Zn +2
Copper 2-75
ppm
Cu +2
Molybdenum
very minute
Mo 3+ ,
Mo 4+
Boron 2- 75
ppm
Bo 3B 4 O 7 2-
Chorine 100200 ppm
Cl -
3. Causes grey speck of oats.
4. Marshy spots of legumes.
5. Speckled yellow of sugar beet.
1. Interveinal chlorosis.
2. Leaf rosettes due to shortening of internodal length.
3. Little leaf disease in several plants.
4. White bud of maize and mottled leaf of apple and
walnut.
5. Seed formation suppressed.
1. Physiological diseases like die back diseases of
citrus and reclamation disease of cereals.
1. Mottled chlorosis with marginal necrosis.
2. Inhibition of flowering.
3. Whiptail disease of cauliflower.
1.
2.
3.
4.
5.
Reduction in growth of stem and root tips.
Death of meristematic regions.
Stops flowering
Brown heart disease of turnip
Heart rot of sugar beet.
1.
2.
3.
4.
Wilting of leaves.
Chlorosis in leaves
Swollen root tips.
Premature flower abscission.
Role of Non essential Elements: Important in synthesis of nucleoproteins, by regulating the transport of amino acids to the nucleus.
Sodium
Cobalt
Maintenance of water balance. Involvement in stomata opening, Nitrate reductase activity. CAM
cycle.
Part of Vitamine B 12 (Cobalamine). Necessary for the functioning of enzyme ribonucleotide
reductase.
www.m-learning.in
Page 8
Found as in crustation on cell wall. Found in horestail plant equisetam.
Silicon
Nickel
Essential for the functioning of enzyme urease.
Selenium
Essential for growth of certain species of Asparagaus.
O BJECTIVE P ROBLEMS
1. Major part of dry weight of a plant is derived
from elements obtained froma) Soil
b) Air
7. A number of minerals like Ca, Mg and K are
held over the surface of clay particles because
the latter are-
c) Water
d) Decomposing organic matter
a) Negatively charged
b) Positively charged
2. Minerals are absorbed by the plants, through-
c) Neutral
a) Cell membranes
b) Cell wall
c) Enzymes
d) Carbohydrates
d) Having both positive and negative residual
valencies
3. Micronutrients mainly function as-
8. Chlorosis in plants occurs due to-
a) Osmotic constituents of cell sap
a) High sunlight intensity
b) Components of important biochemicals
b) Low sunlight intensity
c) Cofactors of enzymes
c) Absorption of yellow pigments from the soil
d) Constituents of chlorophyll
d) Deficiency of Mg and Fe in the soil
4. Critical elements area) Na, K and Ca
b) N, P and Mg
9. Carbon becomes available to crop plants in
the form of-
c) N, P and K
d) Mn, B and Mo
a) Amino acids
b) Carbonates
c) Carbon dioxide
d) Element carbon
5. A primary deficiency is caused by insufficient
absorption ofa) Magnesium
b) Manganese
10. Plants required two metallic compounds
(minerals) for chlorophyll synthesis. They are -
c) Calcium
d) Potassium
a) Fe and Ca
b) Fe and Mg
c) Cu and Ca
d) Ca and K
6. Downward passage of mineral, from upper
soil layers to lower soil strata is called -.
a) Percolation
b) Leaching
c) Weathering
d) Runaway
11. Hydroponics isa) Growing of aquatic plants
b) Growing of floating aquatic plants
c) Soil-less cultivation of plants
www.m-learning.in
Page 9
d) Growing of plants inside water
b) Is available in soil
c) Improves health
d) Is irreplaceable and indispensable for growth
of plants
12. Rotation of crops is useful fora) Increasing mineral quantity of soil
b) Increasing fertility of soil
19. A micronutrient is the one which is-
c) High protein content
a) More important than any major elements
d) Denitrification of crops
b) Less important than major elements
13. Deficiency of Molybdenum causes.
c) Needed in small quantity but is as important
as a major element
a) Poor development vasculature
d) Found small quantities in the soil
b) Bending of leaf tip
c) Yellowing of leaves
20. Framework elements are-
d) Motting and marginal necrosis of leaves
a) C, H and O
b) Cu, Co and Fe
c) Mg, Cu and Fe
d) Mn, Ca and N
14. In plants a common symptom caused by
deficiency of P, K, Ca and Mg is-
21. A sulphur containing amino acid is-
a) Bending of leaf tips
b) Formation of anthocynin
a) Methionine
b) Asparagine
c) Serine
d) Proline
c) Poor development of vasculature
d) Apperarance of deadnecrotic areas
15. Active uptake of minerals requires-
22. Theory suggesting that carbon dioxide
produced in respiration helps in mineral
absorption is called-
a) Respiration
a) Carbonic acid exchange theory
b) Expenditure of energy
b) Contact exchange theory
c) Root metabolism
c) Active mineral absorption
d) Photophosphorylation
d) Donnana equilibrium
16. Phytotron is meant for-
23. Phosphorus and nitrogen ions generally get
depleted in soil because they usually occur as-
a) Controelled irradiation
b) Induction of mutations
a) Neutral ions
c) Controlled humidity
b) Negatively charged ions
d) Growing plants under controlled environment
c) positively charged ions
d) Both positively and negatively charged but
disproportionate mixture
17. Which is the role of molybdenuma) Nitrogen fixation
b) Flower induction
24. Passage of minerals from top soil to subsoil
through seepage of water is know as-
c) Chromosome contraction
d) Carbon assimilation
18. An essential element is that whicha) Is found in plant ash
www.m-learning.in
Page 10
a) Leaching
b) Percolation
c) Conduction
d) Transpiration
25. Which one is an essential mineral, not
constituent of any enzyme but stimulates the
activity of many enzymes-
31. A trace element, also required for plant
growth, and in the form of radio active isotope
useful in cancer therapy is
a) Zn
b) Mn
a) iron
b) calcium
c) K
d) Mg
c) cobalt
d) sodium
26. In an experiment, a plant was dried, crushed
and heated strongly in a crucible for long/ The
residue contained
32. An essential element is that which
a) oxides and carbonates of about ten elements
b) is available in soil
a) is found in plant ash
b) oxides and carbonates of three elements
c) improves health of plants
c) carbon only
d) starch and related compound
d) is irreplaceable and indispensable for growth
of plants
27. Who proved for the first time that the plants
contain a large number of minerals and
microelements ?
33. Non essential element taking part in plant
growth is
a) De Saussure (1804)
a) Magnesium
b) Calcium
c) Cobalt
d) Chlorine
b) Leibeg (1840)
c) Glauber and Mayhow (1656)
34. The main source of carbon in nature is
through
d) Arnon and Stout (1939)
a) methanogenic archaebacteria
28. Microelements being found in traces have
b) methanogenic bacteria
a) a very significant role in the development of
osmotic potential
c) methanogenic fungi
d) methanotropic slime molds.
b) no significant role in the development of
osmotic potential
35. Which of the following is a micronutrient ?
c) a significant role in the development of
osmotic potential when temperature is between
15-25C
d) a significant role in the development of
osmotic potential when respiration rate is very
high.
b) borate
c) sulphur
d) nitrogen
b) Zn
c) Ca
d) P
36. Which one of the following elements is not
required by plants for their healthy normal
growth ?
29. The ion which is commonly found free in the
cell is
a) potassium
a) Mg
a) Calcium
b) Magnesium
c) Lead
d) Iron
37. NPK denotes
a) Nitrogen, protein and kinetin
30. Which one is an essential mineral, notconstituent of any eneyzme but stimulates the
activity of many enzymes ?
a) Zn
b) Mn
c) K
d) Mg
www.m-learning.in
b) Nitrogen protein and potassium
c) Nitrogen, potassium and kinetin
d) Nitrogen, phosphorus and potassium
38. Which one is a component of ferredoxin ?
Page 11
a) Zn
b) Mn
c) Cu
d) Fe
39. Potassium is involved in
46. Deficiency of molybdenum causes
a) photosynthesis
a) poor development of vasculature
b) promoting many enzymatic activities that
regulate plant processes
b) bending of leaf tip
c) providing reddish pigmentation of fruits
d) mottling and marginal necrosis of leaves
c) yellowing of leaves
d) formation of vascular cambium
40. Phosphorus brings about
47. In crucifers whiptail disease is caused due to
the deficiency of
a) retardation of protein synthesis
a) Manganese
b) Magnesium
b) healthy root growth
c) Molybdneum
d) Iron
c) fruit ripening
d) retarded plant growth
48. Reclamation disease of cereals and legumes
is caused by the deficiency of
41. Phosphorus and nitrogen ions generally get
depleted in soil because they usually occur as
a) manganese
b) phosphorus
c) copper
d) boron
a) neutral ions
b) negatively charged ions
49. The element that plays catalytic action in the
formation of four pyrole rings of chlorophyll
molecule is
c) positively charged ions
d) both positively and negatively charged but
disproportionate mixture
42. In plants a common symptom caused by
deficiency of P, K, Ca and Mg is
a) Magnesium
b) Iron
c) Sulphur
d) Nitrogen
a) bending of leaf tips
50. Minerals are absorbed by the roots from the
soil in the form of
b) formation of anthocyanin
a) very dilute solution
c) poor development of vasculature
b) very concentrated solution
d) appearance of dead necrotic cells
c) in the form of ions
d) in the form of molecules
51. The concentration of various mineral solutes
is found to be several times higher in plant
tissues than in the external solution. This
phenomenon is known as
43. Tea yellow is a disease of tea plants
produced due to the deficiency of
a) Phosphorus
b) Sulphur
c) Potassium
d) Nitrogen
a) salt accumulation
44. Pungent principle, a sinigrin, of crucifers
is a
b) saturation effect
c) state of equilibrium
a) glycoside having sulphur
d) none of these
b) glycoside having cyanide
c) glycoside having special amino acids
52. Ions are transported
membranes by means of
d) tannin
45. White-bud condition in maize in produced
due to the deficiency of
a) Iron
b) Molybdenum
c) Zinc
d) Boron
www.m-learning.in
Page 12
across
the
cell
a) primary proteins
b) secondary proteins
c) tertiary proteins
d) contractile proteins
53. In which type of absorption of minerals the
solutes move into a cell along their chemical
potential gradient without any expenditure of
energy ?
a) Nitrogen fixation
b) Flower induction
c) Chromosome contraction
d) Carbon assimilation
a) Active absorption
b) Passive absorption
61. Plastocyanin contains
c) Both active and passive
d) None of these
a) Mo
b) Fe
c) Cu
d) Zn
54. Active transport from outside to inside of
molecule across a membrance requires
62. Iron deficiency results in
a) cyclic AMP
b) acetyl choline
a) leaf tip necrosis
c) ATP
d) phloroglucinol
b) small leaves
c) decreased protein synthesis
d) intervenal chlorosis appearing first in young
leaves.
55. Active uptake of minerals requires
a) respiration
b) expenditure of energy
c) root metabolism
d) photophosphorylation
ANSWERS
d) ions are active
Objective Problems
56. Passage of minerals from top soil to subsoil
through seepage of water is known as
1a
2a
3c
4c
5a
6b
7d
8d
9c
10b
a) leaching
b) percolation
11cd
12b
13d
14d
15b
c) conduction
d) transpiration
16a
17a
18d
19c
20a
21a
22a
23d
24a
25d
26a
27b
28b
29a
30c
31c
32d
33c
34a
35b
36c
37d
38d
39b
40b
41b
42d
43b
44a
45c
46c
47c
48b
49a
50a
51a
52d
53b
54c
55b
56a
57c
58b
59b
60a
61c
62d
57. Which can function as carrier in active ion
absorption ?
a) Cytochrome
b) Ferredoxin
c) Lectithin
d) Plastoquionone
58. Mg and Fe are needed for plants in the
a) energy transfer
b) synthesis of chlorophyll pigment in the leaves
c) stomatal opening
d) translocation of carbohydrates
59. Plants require two metallic compounds
(minerals) for chlorophyll synthesis. They are
a) Fe and Ca
b) Fe and Mg
c) Cu and Ca
d) Ca and K
60. What is the role of molybdenum?
www.m-learning.in
Page 13
