An efficient plant propagation system through nodal explants was established in Ocimum gratissimum L, a medicinally important herbaceous perennial herb belonging to the family Lamiaceae. Axillary shoot bud proliferation was initiated from nodal explants cultured on Murashige and Skoog (MS) medium supplemented with various concentrations of N 6 -benzyladenine (BA) (0.5 -3.0 mg/l), Kinetin (KN) (0.5 -3.0 mg/l) and 2-isoPentenyladenine (2-iP) (0.5 -3.0 mg/l). Maximum numbers of shoots (5.17 ± 0.04) with average length (2.50 ± 0.07) were induced on medium containing 1.0 mg/l BA. Shoot multiplication was maintained by repeated subculturing the original nodal explants on shoot multiplication medium after each harvest of newly formed shoots. Histological study shows that the organogenesis occurs directly, without callus formation on epidermal and sub epidermal layer of the explants. Rooting of shoots was achieved on half strength MS medium supplemented with 1.5 mg/1 Indole-3-butyric acid (IBA) and 2% sucrose. Well-developed complete plantlets were transferred to plastic pots containing a mixture of (1:1) soil and vermiculite showed 82.5% survival rate. Genetic fidelity was assessed by chromosome analysis and DNA fingerprinting using random amplified polymorphic DNA (RAPD) of in vitro and in vivo plants. Nine arbitrary decamers displayed same banding profile showed no genomic alterations, indicating homogeneity among the tissue culture regenerates and genetic uniformity with that of donor plants. The present study provides high fidelity micro-propagated system for efficient and rapid micro-propagation protocol of this important medicinal plant and great use in conserving without risk of genetic instability.

Saha S., Dhar T.N., Sengupta C., Ghosh P.D. (2013): Biological activities of essential oils and methanol extracts of five Ocimum species against pathogenic bacteria. Czech J. Food Sci., 31: 194-202.The essential oils and methanol extracts of Ocimum basilicum L., Ocimum kilimandscharicum Guerke, Ocimum gratissimum L, Ocimum canum Sims, and Ocimum tenuiflorum L. (green type) were examined for their potential antibacterial activities. The chemical composition of essential oils of Ocimum species was analysed by GC-MS. The inhibitory effects of essential oils and methanol extracts were studied on two Gram-positive (Bacillus subtilis, Micrococcus luteus) and five Gram-negative (pseudomonas aeruginosa, Shigella dysenteriae, escherichia coli, Vibrio cholera, and Shigella flexneri) bacteria using disc-diffusion method. Minimum inhibitory concentration (MIC) was assessed by micro broth dilution method. The antibacterial test results showed that the essential oils of Ocimum basilicum L., Ocimum kilimandscharicum Guerke, and Ocimum gratissimum L. strongly inhibited the growth of all of the microorganisms studied, especially of the Gram-negative strains, whereas other two essential oils showed moderate activities. The result may suggest that the essential oils of Ocimum possess compounds with antibacterial activities, and therefore could be used as natural preservative ingredients in food and/or pharmaceutical industries.

Elevated substrate salinity and anthropogenic impulse are the major threat to the mangrove ecosystem. In the Indian subcontinent, Sundarbans have the richest mangrove species diversity. Due to geomorphic characteristics and unplanned management, the elevated salinity prevails in the western part and that has direct impact on vegetation. Seven mangrove taxa were examined, of which four (Aegialitis rotundifolia, Heritiera fomes, Xylocarpus granatum, and X. mekongensis) were considered as degrading and three (Bruguiera gymnorrhiza, Excoecaria agallocha, and Phoenix paludosa) were considered as natural control. The targeted taxa were collected from five different islands and were selected on the basis of increasing salinity gradient. As salinity increased from site I to V (11.76-15.2 ppt), the amount of total leaf proteins decreased in all the targeted species and ranged between 5.67 and 25.23%. The percentage of protein depletion was less in Aegialitis, Heritiera, and Xylocarpus than the other three taxa in higher salinity that pointed out their less adaptability, as degradation of protein may be essential for efficient stress management. Two antioxidative (peroxidase and superoxide dismutase) and two hydrolyzing (acid phosphatase and esterase) enzymes showed a positive correlation with salinity. In four degrading taxa, the percentage of enzyme increment was less than those of their natural control taxa. Salinity imposed increment of antioxidant enzymes facilitate ROS scavenging, which is an inevitable elevated byproduct during photo-inhibition. Lower amount and number of isoforms in higher salinity indicated towards less suitability of Aegialitis rotundifolia, Heritiera fomes, Xylocarpus granatum, and X. mekongensis in increased salinity level of western Sundarbans.

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The root nodules of Phaseolus mungo (a herbaceous leguminous pulse) contained a high amount of 3-indolylacetic acid (IAA). A tryptophan pool present in the nodule might play the role of precursor for IAA production. From the root nodule a Rhizobium sp. was isolated. The symbiont produced a large amount of IAA (142 microg/mL) from L-tryptophan-supplemented basal medium. The production of IAA by the symbiont was much increased over the control when a L-tryptophan (2 mg/mL) supplemented C-free mineral medium was enriched with mannitol (1 %), L-asparagine (0.3 %) and thiamine hydrochloride (1 microg/mL). The possible role of the rhizobial production of IAA on the rhizobia-legume symbiosis is discussed.