MYCORHIZA INDUCED SALT TOLERANCE IN HELIANTHUS ANNUUS L. VAR. SUNCROSS

The project aims at finding a biological control of salinity by the introduction of appropriate mycorrhiza in plants under saline conditions. A umber of assays in pursuance of this goal were designed and performed:\ud \ud During the rhizospheric studies of native halophytic vegetation, 32 different non-mycorrhizal fungal species were isolated, whereas a total of 8 mycorrhizal species were identified among which Glomus fasciculatum , G. macrocarpum and G. mosseae were more prevalent,\ud \ud Salt tolerance assays of mycorrhizal isolates revealed maximum spore germination in basic culture medium. In comparative salt tolerance studies maximum spore germination was obtained in G. fasciculatum, minimum in G. mosseae and intermediate in G. macrocarpum,\ud \ud alt tolerance assays of non-mycorrhizal fungal species showed that the species of Aspergillus and Mucor were highly; Alternaria-alternata and Penicillium sp., were moderately; and Curvularia clavata and Fusarium solani were the least salt tolerant species,\ud \ud Interactions between mycorrhizal and non-mycorrhizal fungi under various salinity levels in pots indicated that the general response of the Glomus spp., was almost similar ;i.e there was a decrease in extent of VA mycorrhizal infection with an increase in salinity level. The plants inoculated with G. fasciculatum showed maximum, with G. macrocarpum intermediate and with G. mosseae least extent of VA mycorrhizal infection. Results of shoot dry weight and phosphorus content were also parallel to the results of extent of mycorrhizal infection. Sodium and chloride content of plants inoculated with G. fasciculatum and maximum number of non-mycorrhizal fungi was significantly lower as compared to rest of the treatments,\ud \ud Evaluation of the performance of selected mycorrhizal and non-mycorrhizal fungi, under saline field conditions indicated that the mycorrhizal status and shoot dry weight was significantly greater in plants inoculated with saline VA mycorrhizal inoculum as compared to the plants inoculated with normal field spores or non-inoculated controls. Moreover, the sporulation of saline mycorrhiza was much higher as compared to normal field mycorrhiza.\ud \ud Probable mechanisms involved in mycorrhiza induced salt tolerance and its economic feasibility are discussed