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Subject: Microbiology × Author: SHARMA, NIPUN × End date: 2009 × Start date: 2000 ×
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    ThesisItemOpen Access
    PHOSPHATE SOLUBILIZING POTENTIAL OF PLANT GROWTH PROMOTING RHIZOBACTERIA (PGPR) ISOLATED FROM TOMATO SEEDLINGS
    (DR. YASHWNAT SINGH PARMAR UNIVERSITY OF HORTICULTURE AND FORESTRY NAUNI SOLAN, 2009) SHARMA, NIPUN; SHIRKOT, C. K.
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    ThesisItemOpen Access
    PHOSPHATE SOLUBILIZING POTENTIAL OF PLANT GROWTH PROMOTING RHIZOBACTERIA (PGPR) ISOLATED FROM TOMATO SEEDLINGS
    (2009) SHARMA, NIPUN; SHIRKOT, C.K.
    ABSTRACT Phosphate solubilizing microorganism play an important role in supplementing phosphorus to the plants by several mechanisms like lowering of pH by acid production and ion chelation and thus benefit plant growth and development. Therefore, the aim of this study was to determine the phosphate solubilizing potential of plant growth promoting rhizobacteria (PGPR) isolated from tomato seedlings. Twenty three bacterial isolates were selected (by modified replica plating technique) as the representative of the total plated population from the rhizosphere soil and roots of the tomato seedlings grown in nursery at different locations of Hamirpur district. All the bacterial isolates were able to grow simultaneously on nutrient agar, Pikovskaya’s, nitrogen free media and selected for further screening for various plant growth promoting activities. Twelve phosphate solubilizing bacterial isolates exhibited concurrent IAA production and antifungal activity against Alternaria solani, Fusarium oxysporum and Pythium aphanidermatum. Seventeen isolates were found as good siderophore producers. After screening, four isolates were selected for ability to solubilize tricalcium phosphate (TCP) in PVK broth and for antifungal activity against A. solani. Isolate TE5 showed maximum P- solubilization (145.40 mg/l) and maximum per cent growth inhibition (75.33%) at pH 7.5, 0.5 per cent TCP concentration, after 72 h of incubation at 350C. In net house and growth chamber studies also, TE5 showed maximum germination (%), germination energy index (%), vigour index, shoot length, root length, shoot dry weight and root dry weight and was higher in the seedlings treated with bacterial isolates as compared to the untreated control. N, P and K content of soil and whole shoot system was found maximum in TE5 treated seedlings, closely followed by other bacterial strains and higher as compared to the untreated control. The present study, therefore, suggests that the use of phosphate solubilizing bacteria as inoculant biofertilizers might be beneficial for tomato cultivation and has significance to develop cost effective ecofriendly sustainable system in the management of environmental and agricultural problems.