This document discusses manganese, including: 1) Manganese is an essential micronutrient for plants that plays important roles in photosynthesis, enzyme activation, and antioxidant activity. It is present in most soils in concentrations between 300-1600 ppm. 2) Factors like soil pH, aeration, organic matter, and interactions with other nutrients influence manganese availability to plants. Deficiency causes chlorosis between veins while toxicity causes leaf spots. 3) Manganese sulfate is commonly used as a fertilizer to correct deficiencies. The document reviews several studies on manganese transport, accumulation, toxicity, and resistance mechanisms in plants.

2. ACHARYAN.G.RANGAAGRICULTURALUNIVERSITY
AGRICULTURALCOLLEGE-BAPATLA
COURSE NO:- AGRON 502
TOPIC : MANGANESE
SUBMITTED BY-
B.VENKATAKRISHNA
BAM-18-09

5.  Concentration in the earth’s crust averages 1000 ppm
 Indian soils ranges between 92 to 11500 ppm but soils contain 300 to 1600 ppm of Mn.
 Manganese when released through weathering of primary rocks will combine with O2, - and
SiO2 to form a number of secondary minerals including pyrolusite (MnO2), manganite
(MnOOH) and hausmannite (Mn3O4)
 Forms of manganese are usually expressed as water soluble Mn2+, exchangeable Mn2+,
water soluble and insoluble organically bound manganese, easily reducible manganese and
manganese oxides.
 The principal ion species in solution is Mn2+ and its concentration decreases 100 fold for
each unit increase in pH
.
Importence of manganese

6. Factors affecting availability and movement of manganese
 Effect of pH and carbonates
 Excessive water and poor aeration
 Organic matter
 Imbalance of metal ions
 Interrelationship with other nutrients
 Seasonal and climatic effects
 Soil microorganisms
 Plant factors

9. Functions
 Healthy Mn sufficient mature plants contain 20 to 300 ppm of Mn
 Mn plays an important role in the photosynthesis and detoxification of
superoxide free radicals
 Mn is an integral component of the water splitting enzyme associated
with photosystem II
 Mn deficiency is associated with adverse effects on photosynthesis and
O2 evolution
 constituent of superoxide dismutase (Mn-SOD)
 Mn has a role in TCA cycle in oxidative and non oxidative
decarboxylation reactions with Nicotine Adenine Diamide (NAD)

10.  a major contributor to various biological systems including photosynthesis, respiration, and nitrogen
assimilation.
 Involved in pollen germination, pollen tube growth.
 root cell elongation and resistance to root pathogens.
 plays an important role in plant lignin and phenol synthesis
 That structural components of the sclerenchyma are less developed under Mn-deficient conditions than under
non-limiting conditions.
 Polle and Chakrabarti (1994) found less cell wall material but similar lignin content in Mn-deficient
 Involved in activating enzyme-catalysed reactions including phosphorylations, decarboxylations, reductions
and hydrolysis reactions and therefore affects processes such as respiration, amino acid synthesis, lignin
biosynthesis and the level of hormones in plants.
PHYSIOLOGICAL FUNCTIONS

11. Effect of Manganese on plant carbohydrates and lignin content of plant
marschner (2012)

13.  Manganese deficiency symptoms, which often look like those of iron deficiency,
 appear as interveinal chlorosis (yellow leaves with green veins) on the young leaves, tan, sunken spots that appear in the
chlorotic areas between the veins.
 Plant growth may also be reduced and stunted.
 Manganese deficiency can occur when the pH of the growing medium exceeds 6.5, because it is tied up and unavailable for
uptake.
 Deficiency can also occur from low fertilizer application rates, use of general purpose fertilizers (which typically have
reduced micronutrient contents),
 excessive leaching or applying too many iron chelate drenches.
Deficiency symptoms

14.  Mn deficient plants contain less than 25
ppm
 more severe on middle leaves than on the
younger ones
 Interveinal chlorosis in dicotyledons
 Grey speck of Oats
 Speckled yellow of sugar beet
 Marsh spot of peas
 Pahala blight of sugar cane
 Frenching of tung grass

18.  burning of the tips and margins of older leaves or as reddish-brown spots across older leaves.
 Severe toxicity may result in spots becoming more numerous and larger, forming patches on
the older leaves.
 At pH levels below 5.5, manganese is very soluble and toxicity symptoms are probable,
especially in zonal geraniums, marigolds and New Guinea Impatiens.
 Manganese toxicity can occur if the fertilizer application rate is excessive.
Toxicity

19. Corrective measures
 Soil application of Mn SO4. 3 H2O (26-28 % Mn) @ 10-25 kg/ha
 Mn SO4 H2O (30-32 % Mn) @ 10-25 kg/ha
 Application of green manures FYM and other organic manures

20. The main sources of manganese fertilizer

21. MANGANESE AS ESSENTIALAND TOXIC ELEMENT FOR PLANTS: TRANSPORT, ACCUMULATION AND RESISTANCE MECHANISMS
Millaleo at al., (2009)
J. Soil Sci. Plant Nutr. 10 (4): 476 - 494 (2010)

22. Upper panel: photobleaching effects on sugar maple leaves exposed to elevated Mn. Lower panel: the influence of Mn
availability and light intensity (1500 and 500 μmol m−2s−1) on the light and dark reactions of photosynthesis (CER, ETR) and
chlorophyll a + bin sugar maple leaves
Manganese phytotoxicity: new light on an old problem
Fernando

23. Assessment of Some Mineral Elements (Ca, Na, K, Mg, Fe, Mn Cu and Zn) and their Nutritional Intake of Two
Traditional Leafy Vegetables: Leaves of Corchorus Olitotorius (Tiliaceae) and Hibiscus Sabdariffa (Malvaceae)
Alexis Drogba Sahore et al.,(2014)
International Journal of Agriculture Innovations and Research Volume 3, Issue 3, ISSN (Online) 2319-1473

24. Devi et al.,(2005)