Characterisation of plant growth

table 1: Location of sampling sites and soil pH.

Sites

Soil pH

Kanpur

6.8

Unnao

7.8

Lucknow

7.7

Hardoi

7.8

Jaunpur

7.6

Varanasi

7.5

Jhansi

7.3

In total, 152 endophytic bacteria were isolated from root nodules of Lens culinaris .

Most of isolates differed in phenotypic and biochemical characteristics (Table 2).

All the rhizobial isolates were Gram-negative, non-spore forming, and non-

capsulated rod and motile. The isolates formed red, semi-translucent, rounded,

smooth, mucoid colonies (2 to 4 mm diameter) on congo red yeast extract mannitol

agar (CrYEMA) after 48 h of incubation. All Pseudomonas isolates were Gram-

negative, non- spore forming, non-capsulated, motile and rod shaped structure.

The colonies were smooth, large, 2-4 mm in diameter with regular edge on nutrient

agar medium. Isolates (RT2, RT4, RT5, RT8, RT17 and RT18) produced greenish-

blue fluorescent pigment on Pseudomonas agar medium. All the Bacillus isolates

were Gram-positive, endospore forming, and motile rods. The isolates formed

translucent, large, white colonies (2 to 4 mm diameter) on nutrient agar medium

after 24 h of incubation. The Gram–negative isolates were more in number within

the root nodules of lentil. Earlier workers have reported a predominance of Gram-

negative bacteria in the tissues of various plants (Stoltzfus et al. , 1997; Elbeltagy

et al ., 2000; Stajković et al ., 2009). Zinniel et al ., 2002 reported an equal presence

of Gram-negative and Gram-positive bacteria inside the root nodule.

Effect of temperature on all isolates was noticed and optimum growth was observed

at 28 ° C. The maximum and minimum temperature tolerated by the isolates was

recorded as 4 and 50 ° C respectively. Bacterial growth also influenced by pH and

the optimum growth was observed at neutral pH. The pH value tolerated by the

isolates was recorded as 4 and 9 respectively. It was observed that at high alkaline

and acidic pH, growth was sharply affected. Effect of various salt concentrations

on the growth of isolates was assessed and optimum growth was observed at 2-3%

concentration of NaCl. Maximum and minimum concentration of salt tolerated by

isolates was recorded as 0.5% and 6% respectively.

Int. J. Bioinformatics and Biological Sci.: v.2 n.1&2, p. 95-109. March & June 2014

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