Plant Physiology 2011. Macronutrients Nitrogen Source: The chief source is the soil. Plants absorbs it either in the form of nitrate or ammoniacal salts.
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Slide 1
Plant Physiology 2011
Slide 2
Macronutrients
Slide 3
Nitrogen Source: The chief source is the soil. Plants absorbs
it either in the form of nitrate or ammoniacal salts. Some bacteria
and heterocysts containing blue green algae fix the nitrogen of the
atmosphere. Functions: Nitrogen is an essential constituent of
different proteins and nucleic acids
Slide 4
Deficiency: The chlorotic symptoms in leaf. A light red cast
can also be seen on the veins and petioles. The older mature leaves
gradually change from their normal characteristic green appearance
to a much paler green. As the deficiency progresses these older
leaves become uniformly yellow (chlorotic). Branching is reduced in
nitrogen deficient plants resulting in short, spindly plants. The
yellowing in nitrogen deficiency is uniform over the entire leaf
including the veins. In some plants the underside of the leaves
and/or the petioles and midribs develop traces of a reddish or
purple color.
Slide 5
Nitrogen
Slide 6
Sulfur. Source: Sulphur is available to plants in the form of
soluble sulphate of soil. Fuction: Sulphur is the constituent of
amino acids ( cystein and methionine), vitamin (B 1 ), co-enzyme A
and volatile oils. The characteristic odour of crucifer plants,
onions, garlic and tropeolae is due to sulphur as a constituent of
volatile oils. Sulphur affects an increase in nodule formation in
root of leguminous plants. Sulphur adversely affects chlorophyll
synthesis.
Slide 7
Deficiency symptoms leaves show a general overall chlorosis
while still retaining some green color. The veins and petioles show
a very distinct reddish color. sulfur deficiency are very similar
to the chlorosis found in nitrogen deficiency. However, in sulfur
deficiency the yellowing is much more uniform over the entire plant
including young leaves. The reddish color often found on the
underside of the leaves and the petioles has a more pinkish tone
and is much less vivid than that found in nitrogen deficiency. with
advanced sulfur deficiency brown lesions and/or necrotic spots
often develop along the petiole, and the leaves tend to become more
erect and often twisted and brittle.
Slide 8
Sulphur deficiency
Slide 9
Phosphorus Source: as H3PO4 and HPO4. Functions. It promotes
healthy root growth and fruit ripening by helping translocation of
carbohydrates. It is an essential participating in the skeleton of
plasma membrane, nucleic acids, many coenzymes and organic
molecules such as ATP and other phosphorylated products. It plays
an important role in the energy transfer reaction and in oxidation
reduction process.
Slide 10
Deficiency symptoms Phosphorus-deficient leaves show some
necrotic spots. A major visual symptom is that the plants are
dwarfed or stunted. Some species such as tomato, lettuce, corn and
the brassica develop a distinct purpling of the stem, petiole and
the under sides of the leaves. Under severe deficiency conditions
there is also a tendency for leaves to develop a blue-gray luster.
In older leaves under very severe deficiency conditions a brown
netted veining of the leaves may develop.
Slide 11
Phosphorous
Slide 12
Calcium. Source. derived from stone or chalk rock contains a
larger percentage of calcium carbonate. Function: Calcium is the
chief constituents of plants as calcium pectate of the middle
lamella of the cell wall. It provides a base for the neutralization
of organic acid and is also concerned with the growing root apices.
It also acts as an activator of ATPase, some kinase, phospholipids
and succinate dehydrogenase. It is essential for fat metabolism.
formation of membrane, carbohydrate metabolism, nitrate
assimilation, binding of nucleic acids with proteins.
Slide 13
Deficiency symptoms Calcium-deficient leaves show necrosis
around the base of the leaves. Classic symptoms of calcium
deficiency include blossom-end rot of tomato (burning of the end
part of tomato fruits), tip burn of lettuce and death of the
growing regions in many plants. All these symptoms show soft dead
necrotic tissue at rapidly growing areas, which is generally
related to poor translocation of calcium to the tissue.
Slide 14
Calcium
Slide 15
Potassium Source: potassium is widely distributed in soil
minerals. Functions. Its utilisation in plant is concerned with
enzyme action synthesis of nucleic acid and chlorophyll oxidative
and photophosphorylation translocation of solutes etc.
Slide 16
Deficiency symptoms potassium Leaves show marginal necrosis
(tip burn), others at a more advanced deficiency status show
necrosis in the interveinal spaces between the main veins along
with interveinal chlorosis. The onset of potassium deficiency is
generally characterized by a marginal chlorosis progressing into a
dry leathery tan scorch on recently matured leaves.
Slide 17
Potassium
Slide 18
Magnesium Source : magnesium occurs as carbonate fairly similar
to that of calcium Functions. It is a constituent of chlorophyll
and, therefore, essential for the formation of this pigment. It
acts as a phosphorous carrier in the plant, particularly in
connection with the formation of seeds of high oil contents which
contain compound lecithin. Magnesium is essential for the synthesis
of fats and metabolism of carbohydrates and phosphorous. It is
required to combine two subunits of ribosomes.
Slide 19
Magnesium The Mg deficient leaves show advanced interveinal
chlorosis, with necrosis developing in the highly chlorotic tissue.
In its advanced form, magnesium deficiency may superficially
resemble potassium deficiency. In the case of magnesium deficiency
the symptoms generally start with mottled chlorotic areas
developing in the interveinal tissue. The interveinal laminae
tissue tends to expand proportionately more than the other leaf
tissues, producing a raised puckered surface, with the top of the
puckers progressively going from chlorotic to necrotic tissue
Slide 20
Magnesium
Slide 21
Microelements
Slide 22
Iron Source: It is fairly present in the form of its oxides
giving red or brown colour to the soil. In well-irrigated areas
ferric compounds are predominantly found and in water logged soils,
ferrous compounds are formed. Functions: Iron also acts as a
catalyst and electron carrier in respiration. Iron is a constituent
of cytochromes, ferredoxin, catalase, peroxidase and etc. It also
acts as an activator of nitrate reductase and aconitase.
Slide 23
Deficiency symptoms These iron-deficient leaves show strong
chlorosis at the base of the leaves with some green netting. The
most common symptom for iron deficiency starts out as an
interveinal chlorosis of the youngest leaves, evolves into an
overall chlorosis, and ends as a totally bleached leaf. The
bleached areas often develop necrotic spots
Slide 24
Iron
Slide 25
Manganese. Source: Like iron, the oxide forms of manganese are
common in soil but the more highly oxidised form ( manganese
dioxide) are of very low availability to plants. Functions: It acts
as an activator of some oxidases, peroxidises, dehydrogenases,
kinases and decarboxylases etc. And is essential for the formation
of chlorophyll. It also decreases the solubility of iron by
oxidation hence in certain cases abundance of manganese leads to
iron deficiency in plants.
Slide 26
Deficiency symptoms In leaves light interveinal chlorosis
developed under a limited supply of Mn. The early stages of the
chlorosis induced by manganese deficiency are somewhat similar to
iron deficiency. As the stress increases, the leaves take on a gray
metallic sheen and develop dark freckled and necrotic areas along
the veins. A purplish luster may also develop on the upper surface
of the leaves.
Slide 27
Manganese
Slide 28
Copper Source: Copper is found in small quantities in soils
Functions: Its specific function in plants largely remains to be
determined but its role as a catalyst and regulator is quite
evident. It is a constituent of ascorbic acid oxidase, laccase,
tryosinase, phenoloxidase, plastocyanin etc. And is essential for
photosynthesis, respiration and carbohydrate/nitrogen balance.
Slide 29
Deficiency symptoms copper-deficient leaves are curled, and
their petioles bend downward. Copper deficiency may be expressed as
a light overall chlorosis along with the permanent loss of turgor
in the young leaves. Recently matured leaves show netted, green
veining with areas bleaching to a whitish gray. Some leaves develop
sunken necrotic spots and have a tendency to bend downward. Trees
under chronic copper deficiency develop a rosette form of growth.
Leaves are small and chlorotic with spotty necrosis.
Slide 30
Copper
Slide 31
zinc Source Like copper, it is also found in soils in very
small quantities and largely results from concentration and
addition from growing plants and added residue. Functions. little
is known about its function like that of iron, manganese or copper
but it is a component of enzymes like carbonic anhydrogenase,
alcohol dehydrogenase, Lactic acid dehydrogenase, glutamic
dehydrogenase, alkaline phosphatise, carboxypeptidase, etc. It has
been found essential for carbon dioxide evolution and utilization,
carbohydrate and phosphorous metabolism and synthesis of RNA and
auxins. A close relationship is found between zinc and chlorophyll
formation.
Slide 32
Deficiency symptoms Leaves show an advanced case of interveinal
necrosis. In the early stages of zinc deficiency the younger leaves
become yellow and pitting develops in the interveinal upper
surfaces of the mature leaves. Guttation is also prevalent. As the
deficiency progress these symptoms develop into an intense
interveinal necrosis
Slide 33
zinc
Slide 34
Molybdenum Source: It is found widely distributed in small
amounts in soils and plants its higher concentration occurs in
mineral oils and coal ashes. Functions: It is an important
constituent of the nitrate reducatse system. It also acts as an
activator of some dehydrogenase and phosphatase and as cofactors in
the synthesis of ascorbic acid. It is found necessary to the nodule
formation in legumes for the fixation of atmospheric nitrogen.
Slide 35
Molybdenum. leaves show some mottled spotting along with some
interveinal chlorosis. In the case of cauliflower, the lamina of
the new leaves fail to develop, resulting in a characteristic
whiptail appearance. In many plants there is an upward cupping of
the leaves and mottled spots developing into large interveinal
chlorotic areas under severe deficiency. At high concentrations,
molybdenum has a very distinctive toxicity symptom in that the
leaves turn a very brilliant orange.
Slide 36
Molybdenum
Slide 37
Boron Source. Boron occurs in rocks and marine sediments. It is
absorbed in the form of borate ions. Function. It is necessary for
translocation of sugars is involved in the reproduction and
germination of pollens. It is concerned with water reactions in
cells and regulate the intake of water into the cell.
Slide 38
Deficiency symptom boron-deficient leaves show a light general
chlorosis.
Slide 39
Deficiency symptoms
Slide 40
Deficiency symptoms of Chloride leaves have abnormal shapes,
with distinct interveinal chlorosis. The most common symptoms of
chlorine deficiency are chlorosis and wilting of the young leaves.
The chlorosis occurs on smooth flat depressions in the interveinal
area of the leaf blade. In more advanced cases there often appears
a characteristic bronzing on the upper side of the mature
leaves.
Slide 41
Chloride
Slide 42
Reference Lincoln Taiz and Eduardo Zeiger, Plant Physiology,
Fifth Edition.