IMPROVEMENT OF IN VITRO PROPAGATION OF JOJOBA BY LOW CONCENTRATIONS OF NaCl OR MANNITOL

This work was done to improve our understanding about the effect of growth regulators on micropropagation and gene expression of stress tolerant jojoba plant and how they were influenced by the presence of different stress agents. Genetic variation of plants obtained from seeds of jojoba, was checked using RAPD technique. The registered genetic variation was too high and to avoid it, offspring one shoot was used in this study. A combination of 3 mg/l BAP and 0.1 mg/l NAA was the best for jojoba micropropagation, while changing the concentrations from that decreased shoot multiplication and growth. Application of GA3 is not recommended for in vitro multiplication of jojoba. In case of jojoba as stress tolerant plant species, the effect of the selected growth regulators combination (3 mg/l BAP + 0.1 mg/l NAA) on micropropagation was improved when high salt-MS medium containing low concentrations of NaCl or mannitol was used. The negative effect of NaCl or mannitol on in vitro shoot growth was only detected at concentration 4 g/l. On the other side, lead acetate abolished the effect of growth regulators on jojoba micropropagation even in low concentration. Isoenzymes and SDS-PAGEs indicated that the registered effects of growth regulators and stress agents on shoot multiplication and growth were associated with variation in gene expression.