Regeneration of leaves of noni.
Using noni (Morinda citrifolia) leaves as explant for culture in vitro on 3% MS medium with different types and concentrations of plant hormones, two kinds of in vitro regeneration modes were built. Mode I: the callus was induced first, and then the adventitious roots and buds were induced; Mode II: the adventitious roots were induced, and then the buds were induced directly. The results showed that the optimal medium of generating callus by noni leaves in Mode I was MS+0.1 mg.L-1 6-BA+2.0 mg.L-1 2,4-D; the optimal medium that induced leaf callus to generate adventitious roots and buds was MS+1.0 mg.L-1 6-BA+0.4 mg.L-1 NAA or MS+2.0 mg.L-1 6-BA+0.4 mg.L-1 NAA, Thereinto, the solution of MS+1.0 mg.L-1 6-BA+0.4 mg.L-1 NAA made the rooting time earlier, about 10 d, and its root system was more developed. Instead, the solution of MS+2.0 mg.L-1 6-BA+0.4 mg.L-1 NAA made it 15 d. The optimal medium that induced leaves to generate roots and buds in mode II was MS+1.0 mg.L-1 6-BA+0.4 mg.L-1 NAA. Cutting and transplanting the seedlings regenerated in vitro from model I and Model II into MS+0.2 mg.L-1 NAA medium to induce rooting. Getting the differentiation of adventitious root about 15 d and complete plant 45 d. This study provides useful references for the breeding and the application of genetic transformation technique in noni.