Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Titre : Production of vesicular arbuscular mycorrhizal spores as inoculant for one of the leguminous seedlings in desert

Auteur : Faramawy، Fatma Mohamed

Etablissement de soutenance : Benha University .

Grade : Doctor of Philosophy (PhD) Microbiology 2003

Résumé
Vasicular- arbuscular mycorrhizae are commonly make asymbiotic association bet ween plant root and the mycelium of mycorrhizal fungi which mainly associate within plant root cortex.Today more than 90% of the higher plants especially the agricultural onces make mycorrhizal association. The benefits of the mycorrhizal association to plants have been attributed to improve nutrients absorption particularly phosphorus, nitrogen, sulphur and other microelements. It helps plants by producing enzymes which transfere soil organic compounds into simple for ms. These compounds transport inside plants via fungal hyphae VAM fungi produce also phytohormones which increase plant growth. It has an important role in plant protection against soil pathogens. It helps plants to over come against many environmental stress conditions like, drought and nutrient defficiency . The experimental results indicate that : A. Ecological studies : Of the 72 plant species collected from interesting areas of Egyptian soils. 64 showed VA-mycorrhizae and 8 plants were non-mycorrhizal. All agronomic plants were collected from the agricultural areas of El-Sharkya, El-Munofia, El-Behera, El-Gharbia, El-Kalubia, Esmaillia, El-suez, Alexandria, North Sinai, South Sinai. North Coast, Beny Swaf and Aswan, had VA my corrhizal colonization. The given data show that 1. Some field crops are heavy infected by VA mycorrhizal fungi e.g. Bean, onion, clover, cotton, eg. lettus, maize, wheat cotton, barely, clover and phaseolus bean however, a small number of plant species belonging mainly to the Juncaceae, Cyperaceae, Zygophyllaceae, Cruciferae and some species of Chenopodraceae are non-mycorrhizal. 2.There is no relationship between the number of spores isolated from the rhizoshere area and the rate of colonization within the root of the host plant, that is because spore production in the rhizosphere depends on many factors, eg. the infection of the plant by other pathogens, the age of the growing plant and the kind of the cultivated soil. 3.There is a clear relationship bet ween the number of the spores present in the rhizosphere and the physico-chemical properties of the cultivated soil, also the amount of the soluble phosphorus present in the soil. It is clear that when the amount of the soluble phosphorus increase the number of mycorrhizal spores decrease. In the sandy soil, where the available phosphorus is very low, the number of mycorrhizal spores are ranged bet ween high, slightly high or low. But in sandy clay and sandy loam soil, alhough the amount of available phosphorus is high, there are a moderatly high numbers of VAM spores. 4-The increase in organic matter in soil leads to better mycorrhizal development and spore production. 5-High soil salinity appears to be a determining effect on the endogonaceous spore number and percentage of mycorrhizal infection.

Présentation étendue (EULC)