Callus culture from hypocotyls of Kosteletzkya virginica (L.) seedlings

It was shown that callus established from Kosteletzkya virginica (L.) Presl. (Malvaceae) can grow in salinities higher than 200 mM NaCl if previously accomodated stepwise. Callus lines developed from seedlings of different harvests or of the same harvest at different times, all showed the same pattern of growth and sensitiviy to salinity. The absorption of Na⁺ into the callus increased with increasing external NaCl concentration. In the callus, Na⁺ was apparently distributed outside and inside a cellular membrane (possibly the plasmalemma). This membrane was, apparently, capable of regulating the Na⁺ concentration in the protoplast. Outside this membrane Na⁺ accumulated to concentrations higher than in the external growth medium. Exogenously supplied proline or glycine-betaine did not affect the growth of the callus. Externally applied ABA stimulated growth under saline conditions and increased the accumulation of proline. Growth and proline content were positively correlated in callus exposed to salinity, but in the presence of ABA they were negatively correlated. ABA was involved in both growth and proline accumulation, but there was no clear relationship between these two effects. Both ABA and proline, if added to the growth medium, improved the appearence of the callus.Abbreviations ABA abscisic acid - B₅ Gamborg's medium - BA benzylalanine - 2,4-d 2,4-dichlorophenoxy acetic acid - FW fresh weight - G B₅ medium without growth regulators - GH B₅ medium supplemented with growth regulators - NAA naphthalene acetic acid - PGR plant growth regulators - Q_T total amount of a certain ion in the tissue - Q_s amount of the ion that has leaked out - QAC Quaternarty Ammonium Compounds - RGR mean relative growth rate - W₁ and W₂ fresh weight at times t₁ and t₂