Effect of Salt Stress on Callus Cultures ofOryza sativaL.

Abstract

Kavi Kishor, P. B. 1988. Effect of salt stress on callus cultures of Oryza sativa L.—J. exp. Bot. 39: 235-240. Callus cultures of rice adapted to grow under increasing NaCl stress were found to accumulate considerable amounts of free proline, compared with unadapted cells. Salt-adapted cells grown for 10 passages (25 d each) on NaCl-free medium accumulated proline on re-exposure to salt as did cells which were grown continuously on NaCl. On replacing NaCl (100 mol m~3) with 100 mol m~3 of KC1, fresh and dry weights as well as free proline content of salt-adapted callus declined compared to that attained on 100 mol m 3 NaCl medium. However, equimolar concentrations of NaCl and KC1 (when added together) produced an increase in growth and free proline accumulation in salt adapted callus. Omission of Ca2+ from the growth medium inhibited the growth of salt-adapted cells in the presence of NaCl, while it had little effect on the growth of non-adapted cells in the presence of NaCl. ABA increased the fresh and dry weights of the non adapted callus only in the presence of 200 mol m~3 of NaCl but not in the absence of NaCl. ABA failed to evoke the same response in salt adapted cells in the presence of the salt. Tissues exhibited good growth under inhibitory levels of NaCl (500 mol m~3) only when glycine betaine, choline and proline were added to the medium but showed no growth in the presence of sarcosine, glycine and dimethylglycine.