Advances in Biology

Research Article

Plant Beneficial Endophytic Bacteria from the Ethnomedicinal Mussaenda roxburghii (Akshap) of Eastern Himalayan Province, India

Table 2

Results of siderophore, HCN production, salt (NaCl), pH, heavy metal (Al+3 and Mn+2) tolerance, growth on N-free media, and polysaccharide production by endophytic bacterial isolates.
Characters testedEndophytic bacterial isolates
PAK1PAK2PAK3PAK6PAK7PAK8PAK9
Siderophore production++ − − − − − ++
HCN production− ++ − − − − ++
Salt tolerance (NaCl)       
 2% +++ +++ +++ +++ +++ +++ +
 4% +++ +++ +++ ++ +++ +++ +
 6% +++ +++ +++ +++ +++ +++ +
 8% +++ +++ +++ +++ +++ +++ +
 10% +++ +++ ++ ++ ++ ++ +
pH tolerance       
 6.9 + + +++ +++ +++ ++ +
 6.0 − + ++ + +++ ++ −
 5.0 − − + + ++ + −
 4.0 − − − − − − −
 3.0 − − − − − − −
Heavy metal tolerance       
 Al+3 tolerance (400 μg/mL) − + + + + + +
 Al+3 tolerance (500 μg/mL) − + + + + + −
 Al+3 tolerance (600 μg/mL) − + − − + + −
 Mn+2 tolerance (500 μg/mL) + + + + + + +
 Mn+2 tolerance (600 μg/mL) − + + + + + +
Growth on N-free media       
 Jensen’s medium − + −−+ + −
 N-free mannitol agar − − − − + + +
Polysaccharide production       
 24 hours + ++ + ++ + + ++
 48 hours ++ ++ ++ ++ ++ ++ ++
−: no growth; +: slight growth; ++: moderate growth; +++: high growth.