Journal of Environmental Biology

Effects of saline tolerant Azospirillum species on the growth

parameters of mangrove seedlings

Author Details

S. Ravikumar

(Corresponding author)

School of Marine Science, Department of? Oceanography and Coastal? Area Studies,? Alagappa

University, Thondi- 623 409, India.

e-mail : ravibiotech201321@gmail.com

S. Thadedus Maria Ignatiammal

Department of Botany, Holy Cross College, Nagercoil-629 004, India

M. Gnanadesigan

Department of Microbiology, Selvamm Arts and Science College, Namakkal - 637 003, Tamil Nadu, ?

India

A. Kalaiarasi

School of Marine Science, Department of? Oceanography and Coastal? Area Studies, Alagappa

University, Thondi- 623 409, India

Publication Data

Paper received:

30? March 2011

Revised received:

20? August 2011

Accepted:

18 October 2011

Abstract

Five species of Azospirillum isolated from Manakkudi mangrove ecosystem were subjected for their efficiency to find out their growth parameters potential for the successful establishment of mangrove seedlings. Of the isolated five Azospirillum species, Azospirillum lipoferum (60%) was found to be the dominant one.? But the level of maximum indole acetic acid (IAA) production (19.8mg.ml^-1) and nitrogen fixation (5.9 C₂H₂hr^-1) was identified with A. brasilense. Further, A. brasilense showed significant (p<0.05) level of increased growth parameters [maximum root length (29.55%), average root length (7.39%), total Chl (55.36%), carrotenoids (28.57%), Chl b (37.50%), carbohydrates (90.91%) and total amino acids (78.95%)] in Avicennia officinals when compared with control group. ?Further, A. brasilense also showed significant (p<0.05) level of increased growth parameters [average number of primary roots (40%), average biomass (44.44%), average shoot biomass (55.56%), total Chl (20%), Chl b (77.78%) and carotenoid (1.54%)] in C. decandra seedlings when compared with control group. Similarly, the average number of primary roots (23.08%), average root biomass (15.52%), average shoot biomass (15.30%), carbohydrate (20%) and total amino acids (44.44%) were found significant (p<0.05) in A. irakense inoculated R. apiculata seedlings. In conclusion, Azospirillum brasilense was found better for the growth of Avicennia officinalis and Ceriops decandra seedlings, but Azospirillum irakense was found better for Rhizophora apiculata seedlings.

Key words

Azospirillum, Indole acetic acid, Mangroves, Nitrogen fixation????

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