Effects of culture medium strength and antioxidants on adventitious bud multiplication, hyperhydricity and tissue browning of date palm cv. Aziza Bouzid

The effects of medium strength as well as different antioxidant types and concentrations on adventitious shoot bud multiplication, hyperhydricity and tissue browning of date palm cv. Aziza Bouzid were evaluated. Organogenic cultures of date palm cv. Aziza Bouzid were cultured on semi-solid Murashige and Skoog medium at half-strength (MS/2) or one-third-strength (MS/3), supplemented with 0.5 mg/L 2-naphthoxyacetic acid (NOA), 0.5 mg/L kinetin, and different concentrations of activated charcoal and polyvinylpyrrolidone (PVP). The findings of the present study showed that the use MS/3 media resulted in lower hyperhydricity rates than MS/2 media. Besides, activated charcoal significantly reduced tissue browning. The lowest rates of hyperhydricity (35%) and tissue browning (20%) were observed in MS/3 medium supplemented with 1.5 g/L activated charcoal. Interestingly, this culture medium showed also the highest number of adventitious shoot buds per explant (35.20), with a significant difference with all the other media (25.55-30.15 adventitious shoot buds per explant). Increasing the concentration of activated charcoal to 2 g/L did not decreased the browning rate. The use of PVP alone showed tissue browning rates varying from 30 to 55% while combining PVP and activated charcoal showed browning percentages ranging from 20 to 30%. Shoot elongation and rooting were successfully achieved and plantlet were acclimatized and showed normal growth and development under the greenhouse conditions.