STIMULATORY EFFECTS OF JASMONIC ACID ON POTATO STEM NODE AND PROTOPLAST CULTURE

The effect of jasmonic acid (JA), in a wide range of concentrations (0 .01-100-mu-M), on the development of potato plantlets (Solanum tuberos um L.cv. Vesna) was investigated in order to discriminate between phys iological and supraoptimal effects of this growth regulator in vitro. Concentrations from 0.1-1-mu-M significantly increased the length of d eveloped plants. Application of JA in these concentrations resulted in a very well differentiated root system with many lateral branches. Wi th increasing JA concentrations, the main roots shortened and thickene d. Concentrations higher than 10-mu-M led to the compaction of the ste m, roots, and root hairs, giving a stunted appearance to the plants. T he effect of JA on cell wall regeneration and callus formation was obs erved in potato leaf protoplast culture. JA at concentrations from 0.0 1-1-mu-M stimulated cell division and microcalli development.