Sujit Kumar Shah

An Overview on Orchid Endophytes

Orchids, one of the most beautiful and diverse plant species in the nature, are a bit of a mystery for their seeds lack endosperm and they must depend on endophytes for germination, growth and adaptation. Naturalists and even the general public are drawn to orchids for their ornamental, medicinal and food value. In their keenness to harvest them, collectors have rendered many orchid species threatened or even endangered. Recent research into orchids, which are mycohetetrophic plants, has focused on isolation and identification of the mycorrhizal and non-mycorrhizal endophytes that directly or indirectly contribute to the growth and development of orchids as well as the production of valuable secondary metabolites. This article considers both the role such endophytes play and explains how such symbiotic partner scan be used in the plant tissue culture technique to help conserve and even commercialize various species of orchid.

Effect of Methanol on Viscosity of Aqueous Solutions of Cationic Surfactants at 298.15 to 323.15 K

Viscosity measurements have been made to the solutions of dodecyltrimethylammonium bromide (DTAB) and cetyltrimethylammonium bromide (CTAB) in 0.10, 0.20, 0.30, and 0.40 volume fractions of methanol in methanol-water mixed solvent media at 298.15, 308.15, 318.15, and 323.25 K. Critical micelle concentration (CMC) values have been determined. From relative viscosity for surfactant solutions, related viscosity B coefficients are calculated and the values are interpreted in terms of solute-solvent interactions.