EFFECT OF RHIZOBIUM LEGUMINOSARUM ON TOMATO PLANTS GROWING IN HEAVY METAL CONTAMINATED SOIL

A. YADAV¹*, K. YADAV², A. GOEL^3
1Department of Microbiology, College of Basic Science & Humanities, S.D. Agricultural University, S.K. Nagar, Dist. Banaskantha, 385506, Gujarat, India
²Department of Biochemistry, University of Lucknow, Lucknow, 226012, Uttar Pradesh, India
³Department of Microbiology, Division of Life Sciences, S.B.S. (PG) Institute of Biomedical Sciences & Research, Balawala, 248161, Dehradun, India
* Corresponding Author : anuragyadav123@gmail.com

Received : 10-09-2015     Accepted : 29-11-2015     Published : 14-12-2015
Volume : 7     Issue : 13       Pages : 848 - 853
Int J Agr Sci 7.13 (2015):848-853

Keywords : Bioinoculant, Heavy metals, Rhizobium leguminosarum, Tomato
Academic Editor : Sayar Mehmet Salih, K. V. Chaitanya, Sarma Aniruddha, Dr Aziz Mujtaba Aezum, Kant Rama, Jafari Ali Ashraf, Dr S. G. Savalia, Kumar Rakesh
Conflict of Interest : None declared
Acknowledgements/Funding : None declared
Author Contribution : None declared

An experiment was conducted to study the effect of R. leguminosarum biovar TF17 inoculation on tomato (Lycopersicon esculentum) plants treated with four different heavy metal salts. A pot experiment used complete randomized block design pattern with three replicates. Prior to pot study the rhizosphere of fenugreek (Trigonella foenum-graecum L.) plant was screened for efficient Rhizobium leguminosarum biovars. From the 152 bacterial isolates screened, 11 biovars of R. leguminosarum were identified and screened for PGPR traits. The isolated R. leguminosarum biovar TF17 with multi plant growth promoting traits was selected for pot study. Effect of heavy metals on tomato seed germination was also studied. Treatment of CoSO4, CuSO4, HgSO4 and ZnSO4 with or without R. leguminosarum TF17 inoculum was provided to tomato seeds at the dose of 20 mg Kg-1 soil. The final observation of 14 weeks showed highest (96.41 cm) and the lowest (50.47 cm) plant length (shoot and root length) from ZnSO4 and CuSO4 treatments, respectively. Similarly, the highest (0.947 g) and the lowest (0.401 g) plant dry weights were recorded with ZnSO4 and CuSO4 treatments, respectively. Application of R. leguminosarum TF17 along with heavy metal salts mitigated the plant growth retarding effect to some extent. In a separate experiment spectrophotometric analysis showed negative relation between heavy metal concentration and R. leguminosarum TF17 growth. The lowest bacterial growth, in the form of optical density (OD) drop, was observed with 40 mg L-1 CoSO4 treatment, followed by CuSO4 of same concentration.