mycorrhiza types, distribution and significance.
- 1. MYCORRHIZA TYPES, DISTRIBUTION, AND SIGNIFICANCE WITHREFERENCE TO AGRICULTURE. PRESENTEDBY SHABNOORSHAIKH MSC1
- 2. OVERVIEWOF MYCORRHIZA Mycorrhiza was first used by German researcher A.B. Frank in 1885. It’s greek word viz mycos- fungus and rhiza-root. Symbiotic mutualisticrelationshipwithbidirectional nutrient exchange. About 90%of all land plants are associated with it except Cruciferae, Chenopodiaceae and Resedaceae.
- 3. THREE WAY INTERACTION. Mycorrhizal associationinvolves 3 way interactionbetween Host, Fungi and Soil. HOST PLANT FUNGI SOIL FACTORS
- 4. TYPES OF ASSOCIATION Mycorrhiza are commonly dividedinto endomycorrhiza and ectomycorrhiza. These two type are differentiated by- Ectomycorrhiza do not penetrate individual cells withinthe root. Endomycorrhiza penetrate the cell wall and invaginate the cell membrane.
- 5. ENDOMYCORRHIZA Endomycorrhiza’sare variable belonging to basidiomycetesand associated with root development which have been furtherclassifiedas :- Vesiculararbuscular mycorrhizae (VAM). Ericoid mycorrhizae. Arbutoid mycorrhizae. Monotropoid mycorrhizae. Orchid mycorrhizae.
- 6. VESICULAR ARBUSCULARMYCORRHIZA VAMare produced by aseptate mycelial fungi whichpenetrateroot forming vesicles and arbuscles. Vesicles are thin or thick walled structure which stores polyphosphateand other minerals. Arbuscles are dichotomously branched haustoria which lives for 4 days and then get lysed releasing storedfoodas oil droplets in the cortex.
- 7. ERICOIDMYCORRHIZA Slowgrowing, septate and mostly sterile . Rootlets are coveredby very loose, sparse, dark hyphae that penetrates the cortex forming intercellular coils. Thesecoils degenerate after 3-4 weeks likeVAM. They usually improve the uptake of P and N nutritionof plants.
- 8. MONOTROPOIDMYCORRHIZA Seen in Monotropaceae which are achlorophyllous. Uses their mycorrhizae not only to obtain minerals and nutrients, but also to tap the carbon supplies via the nearby plants or soil by breakdown of cellulose and lignin. Boletusa mycorrhizal fungus associatedwithroots of both pine and Monotropa. Fungal sheath present.
- 9. ORCHIDMYCORRHIZA All orchids are myco-heterotrophic at some stage and formorchid mycorrhizas with a range of basidiomycete fungi. Their hyphae penetrate into the root cells and formpelotons (coils) for nutrient exchange The fungus provides C-nutrition to the seeds.
- 10. ECTENDOMYCORRHIZA (ARBUTOID) They have mycorrhiza intermediate in formbetween ecto and endomycorrhiza types found in ericaceae. The root systemis differentiated in short and long roots. Short roots are swollen and covered by mantle. The formeractually penetrate the cortical cells and fill themwithcoils.
- 11. ECTOMYCORRHIZA Theseare association, where fungi forma mantlearound roots withno hyphal penetration in the cells. Fungal hypha is generally separate. Hartig’s net is present between the cells whichis 40µmthick. Most conspicuous and easily recognized.
- 12. DISTRIBUTIONOR OCCURRENCE OF ENDOMYCORRHIZA Ubiquitous in Artic, Temperateand Tropical regionsfound in almost all angiospermsincludinggymnosperms and liverworts. Distribution pattern weresurveyed in montane scrubgrassland, alpine steppe ad alpine meadow. Their altitudes are rangingfrom3500 to 5200mon Tibetan plateau. Their general occurrence is in Gramineae, Palmae, Rosaceae, Leguminosae and Papilionaceae. They are reported fromcarboniferousand Devonian periods.
- 13. DISTRIBUTION OR OCCURRENCE OF ECTOMYCORRHIZA Found in 3% of seeded plantsviz common in northern temperate forest especially in Fagaceae and Pinaceae where as in tropics Myrtacceae and Dipterocarpacae. Majoritycomes fromthe general Amanita, Boletus and Tricholoma. Its distribution is limited to the arid areas of south-central Asia and the northern hilly margin of the Tibetan Plateau.
- 14. SIGNIFICANCE WITHREFERENCE TO AGRICULTURE Increases nutrient uptake of plant fromsoil. Increase diversity of plants. Produce uniformseedling. Significant role in nutrient recycling. More tolerant to adverse soil chemical constraints which limit crop production. Inoculation of VAM as biofertiliser provides a distinct possibility for the uptake of P in phosphorus-deficient soil.
- 15. Increases plant resistance to diseases and drought. Improve soil structure. Protection of plants during stress condition. Uptake of sulphur and inorganic salts fromsoil. Obligatory for the germination of orchidseeds.
- 16. CONCLUSION Mycorrhizal association is very essential for the plants because it has several benefits like absorption of nutrients, increase drought resistance, enhance plant efficiency in absorbing water and nutrients fromsoil. AM fungi useful in agriculture because it serves as biofertilizers as it helps in the absorption of phosphorus and other nutrient uptake.
- 17. REFERENCE Introduction to mycology by R.S Mehrotra and R.K Aneja. Principles of microbiology.