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BIOFERTILIZERS AND PHYTO-STIMULANTS

Prof. Narayanappa MGOVERNMENT SCIENCE COLLEGE, HASSAN

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Azospirillum, Azatobacter, Mycorrhizae

GOVERNMENT SCIENCE COLLEGE, HASSAN

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AzospirullumAzospirillum as a non-specific plant-growth-

promoting bacteriumNitrogen fixing Bacteria for all Non –

Leguminous Crops This microorganism fixes the atmospheric

nitrogen and makes it available to plants in asymbiotic manner.

GOVERNMENT SCIENCE COLLEGE, HASSAN

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Azospirillum biofertilizer also secretes some fungicides, enzymes but in minute amount.

Use of Azospirillum biofertilizer increases the crop production in large scale.

Azospirillum is mainly useful for monocot vegetables.

Associative Interaction with Grasses– Azospirillum brasiliense, tropical grasses– Azospirillum lipoferum, tropical grasses, maize

GOVERNMENT SCIENCE COLLEGE, HASSAN

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Recommendations

• Jowar, • Bajra, • Wheat, • Maize, • Paddy, • Cotton, • Sugarcane, • Vegetables, • Grass, Fruit trees and Ornamental

plantsGOVERNMENT SCIENCE COLLEGE, HASSAN

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Azotobacter

• Azotobacter is a genus of usually motile, oval or spherical bacteria that form thick-walled cysts, and may produce large quantities of capsular slime.

• Azotobacter is an aerobic, free-living soil microbe which fixes nitrogen from the atmosphere.

• Beyond Azotobacter’s use as a model organism it has biotechnological applications.

• Examples are its use for alginate production and for nitrogen production in batch fermentations.

• Polyhydroxybutyrate is produced under certain conditions. • Azotobacter are Gram-negative bacteria

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• Azotobacter Vinelandii is a free-living bacterium that can fix atmosferic nitrogen into the soil, being a great source to obtain a natural biofertilizer that can be used in the cultivation of most crops. It is a great source of nitrogen to meet the needs of crops because also has the capabilities to cause a rejuvenation of soil microbiology to tap out the biological fixation of nitrogen

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Benefits

• It improves seed germination and plant growth • Azotobacter are tolerant to high salts. • It can benefit crops by Nitrogen fixation, growth promoting

substances, fungi static substances. • Azotobacter is heaviest breathing organism and requires a

large amount of organic carbon for its growth. • It is poor competitor for nutrients in soil and hence its growth

promoting substances, fungistatic substances. • It thrives even in alkaline soils. • Azotobacter is less effective in soils with poor organic matter

content

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• The species of Azotobacter are known to fix on an average 10 mg.of N/g of sugar in pure culture on a nitrogen free medium. A maximum of 30 mg.

Additional Benefits: • Azotobacter also produces some substances which check the plant

pathogens such as Alternaria, Fusarium and Helminthosporium. Hence Azotobacter also acts as a biological control agent.

• Azotobacter also produces fixation of Thiomin, Riboflavin, Nicotin, indol acitic acid and giberalin. When Azotobacter is applied to seeds, seed germination is improved to a considerable extent, so also it controls plant diseases due to above substances produced by Azotobacter

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MYCORRHIZAE

myco, “fungus”

rhizae, “roots”

The term “mycorrhiza” was coined by A. B.

Frank, a scientist in Germany, more than

100 years ago.

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The term mycorrhiza refers to a symbiotic relationship that can occur between a fungus and the roots of a plant.

This is usually a mutualistic relationship, meaning that it has a positive effect on both the plant and the fungus.

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In most cases of mycorrhiza, nutrients are shared between the plant and the fungus to the benefit of both parties.

It is important to note that this exchange of nutrients is bi-directional; both the plant and the fungus receive nutrients and essential inorganic minerals from each other.

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BENEFITS OF ASSOCIATION

• serve to enhance the uptake of – water– mineral nutrients,

• especially phosphate, by the plants. • The beneficial effect of a mycorrhizal association

is particularly noticeable in soils with a poor phosphorus content.

• In return, the rhizosphere is the region around the surface of a plant’s root system.

• plant supplies reduced carbon in the form of carbohydrates to the fungi.

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• The fungus obtains important organic compounds, such as sugars and amino acids, from the plant

• The fungus may also provide the plant with certain growth hormones and may protect it against attack by microorganisms.

• Plants that have active endomycorrhizae typically are a deeper green and may resist drought and temperature extremes better than plants of the same species that have little mycorrhizal development.

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Endomycorrhizae

• In endomycorrhizae, the fungal (zygomycete) hyphae enter the root and penetrate the root cells, forming tree-like structures inside the cells, which become the primary site of exchange between plant and fungus.

• In endomycorrhizae, the fungal hyphae actually penetrate the cells by releasing cellulolytic enzymes.

• Arbuscular mycorrhizae are found in practically all plant types, including ‘lower’ plants (mosses, ferns).

• They form highly branched arbuscules within the root cells that gradually lyse, releasing nutrients into the plant cells.

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Ectomycorrhizae

• In ectomycorrhizae the plant partner is always a tree; the fungus surrounds the root tip, and hyphae spread between (but do not enter) root cells.

• As with the ectomycorrhizae, the fungus forms a vast web of hyphae leading from the root surface into the surrounding soil.

• Trees without ectomycorrhizae normally will not grow at all, so the health of our forests depends on the presence of ectomycorrhizal fungi.

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