Selection and characterization of sodium chloride and mannitol tolerant callus lines of red pepper (Capsicum Annuum L.)

Callus cultures of Capsicum annuum cv. G₄ were selected on different concentrations of NaCl and mannitol containing media. Growth, viability and proline content of adapted and unadapted calluses were affected when treated with different osmotica like NaCl (ionic, penetrating) and mannitol (non-ionic, penetrating). The tissues adapted to a low concentration of NaCl (35mM) showed less growth with high proline content compared to the tissues adapted to a low concentration of mannitol (110mM). Proline content was similar in tissues adapted to high concentrations of NaCl (175mM) and mannitol (329mM) but growth in the latter case was relatively low. Growth and viability were subsequently correlated with proline content of the tissues after osmotic treatments. The loss of tissue viability of the adapted calluses was comparatively less than the unadapted callus even after osmotic treatments with 210 mM NaCl and 329 mM mannitol. The adapted calluses retained the capability of regrowth, though at a slow rate and also retained more proline. The results indicated that the effects of different osmotica on plant tissues varied depending upon the physio-chemical nature of the compounds used as stress inducing agents and that the retention and diffusion of proline was altered when the tissues were treated with high concentration of these compounds.