Morphological and Biochemical Activities of Root Nodule Rhizobium Isolated From Five Multipurpose Forest Species of India

Abstract

Five leguminous tree species viz. Dalbergia sissoo Albizia procera, Albizia labbeck, Pongamia pinnata and Leucaena leucocephala were evaluated for their rhizobial activities in different growth medium through biochemical test and the Rhizobium strain isolated from different tree species were coded as Ds1(D. sissoo), Ap1(A. procera), Al1 (A. lebbeck), Pp1(P. pinnata) and Ll1(L. leucocephala) respectively. All strains of Rhizobium isolated showed variation in their morphology and biochemical test. The nodule in A. procera and P. pinnata mainly recovered from lateral roots while in D. sissoo, A. lebbeck, and L. leucocephala nodules were principally formed in tape roots. The isolated Rhizobia were rod shaped, gram negative, showed no growth in Hofer’s alkaline medium and glucose peptone agar. The Rhizobium strain Ds1 exhibited fastest growth in YEMA and CRYEMA followed by Al1 strain as both isolates attained 6 to 11 mm diameter size within 3-4 days compared to other species under present investigation. In a salt tolerance test all the isolates found tolerant in 1% NaCl, however Ds1 and Ap1 strains both were showed their ability to grow even in 2% salt medium. The Pp1 strain was found the most active strain among all other isolates of tree species as this isolate rendered highest positive results in citrate utilization, carbohydrate catabolism, catalase activities, methyl red test and urease production test.