CALLUS-CULTURE FROM HYPOCOTYLS OF KOSTELETZKYA-VIRGINICA (L) SEEDLINGS - ITS GROWTH, SALT TOLERANCE AND RESPONSE TO ABSCISIC-ACID

It was shown that callus established from Kosteletzkya virginica (L.) Presl. (Malvaceae) can grow in salinities higher than 200 mM NaCl if p reviously accomodated stepwise. Callus lines developed from seedlings of different harvests or of the same harvest at different times, all s howed the same pattern of growth and sensitiviy to salinity. The absor ption of Na+ into the callus increased with increasing external NaCl c oncentration. In the callus, Na+ was apparently distributed outside an d inside a cellular membrane (possibly the plasmalemma). This membrane was, apparently, capable of regulating the Na+ concentration in the p rotoplast. Outside this membrane Na+ accumulated to concentrations hig her than in the external growth medium. Exogenously supplied proline o r glycine-betaine did not affect the growth of the callus. Externally applied ABA stimulated growth under saline conditions and increased th e accumulation of proline. Growth and proline content were positively correlated in callus exposed to salinity, but in the presence of ABA t hey were negatively correlated. ABA was involved in both growth and pr oline accumulation, but there was no clear relationship between these two effects. Both ABA and proline, if added to the growth medium, impr oved the appearence of the callus.