Exogenous application of 6-benzyladenine and spermine improves shoot bud induction of shoot apex of Terminalia bellerica Roxb.

Abstract

Shoot regeneration was optimized from shoot apex explants of mature tree species Terminalia bellerica using 6-benzyl adenine (BA) and spermine (Spm). The maximum shoot bud regeneration response (100%) was observed on BA supplemented Murashige and Skoog (MS) medium. However, MS medium with 2.22 μM BA and 9.90 μM Spm induced an average of 21 micro shoots per shoot apex and averaged 2.4 cm shoot length after 4 weeks of culture. Of four combinations tested, 2.22 μM BA + 1.50 μM gibberellic acid (GA3) was found to be most responsive for shoot bud proliferation, followed by intermediate response on BA (4.44 μM), BA (2.22 μM) and further lower on combination of 2.22 μM BA, 1.50 μM GA3 and 9.90 μM Spm. Micro shoots production reached to 100%, with maximum number of 32 micro shoot buds per explant cultured on MS medium with 2.22 μM BA and 1.50 μM GA3 after an interval of 8 weeks. Between auxin combinations as indole-3-acetic acid (IAA)/indole-3-butyric acid (IBA), IAA/naphthalene acetic acid (NAA) or IBA/NAA, the root induction was highest (94%) on the latter medium added with 2.46 μM IBA and 2.69 μM NAA producing 11.8 healthy roots per shoot with an averaged root length of 1.8 cm within 15–30 days of culture. Successful acclimatization of plantlets in the garden soil resulted to 90% healthy plants with no differences observed in the morphological characteristics of the growing shoots.