Optimization of the Media and Plant Growth Regulators for Clonal Propagation of Adansonia digitata L.: An Endangered Tree

Abstract

This research carried out to evaluate the influence of different nutrient media, specifically Murashige and Skoog (MS), Anderson medium (AM), and Woody Plant Medium (WPM), in both liquid and semisolid forms, on the in vitro growth of shoots and roots in Adansonia digitata (baobab) using nodal segments as the starting explants. These media were supplemented with varying concentrations of two plant growth regulators, NAA (0.1-1.0 mg/l) and BAP (0.2-2.0 mg/l).The results of the study demonstrated that Adansonia digitata explants exhibited the highest increase in both the number and length of shoots when cultured on MS medium with a combination of NAA (0.3 mg/l) and BAP (0.5 mg/l) in a semisolid state. The average number of shoots reached 3.8±2.33, and their average length was 2.3±2.00 cm. Plantlets grown on MS medium exhibited well-developed leaves and shoots.Further experiments were conducted with in vitro shoots, exploring various concentrations of the auxin NAA and cytokinins BAP, TDZ, and KN on MS medium. The findings indicated that BAP and NAA were more effective in promoting shoot proliferation compared to the other tested hormones. The combination of BAP (0.5 mg/l) and NAA (0.2 mg/l) significantly improved the shoot proliferation rate, with the highest percentage (60.4%) and the greatest number of regenerated shoots (4.8±2.33) observed on MS medium.In contrast, plantlets cultured in both AM and WPM media displayed lower averages for shoot and root numbers and lengths compared to those grown on MS medium. The maximum number of roots (3.1±1.66) was obtained when MS medium was augmented with IBA at a concentration of 1.0 mg/l.Subsequently, the produced plantlets were gradually transferred to pots filled with a mixture of perlite and cocopeat in a 1:3 ratio and placed in a greenhouse for further growth.