In vitro pre-existing meristem proliferation and water culture cuttings propagation of pilea (Pilea trinervia Wight.)

Pilea (Pilea trinervia Wight.) is one of the indigenous vegetables in West Java, Indonesia. It has the potential for commercial cultivation because of its aromatic taste. Pilea's phytonutrients include steroid/triterpenoid, alkaloid, and flavonoid (quercetin, kaempferol, myricetin, luteolin, spigenin), and ascorbic acid, α- tokoferol, β-karoten, and high soluble dietary fiber. Pilea does not form seeds in the West Java climate, so it has to be propagated by vegetative means, however, the vegetative propagation has not been optimize yet. That plant can be propagated by hardwood and softwood cutting, but the percentage of rooted cutting is low. In this experiment we tried to propagate pilea by tissue culture, and water culture cuttings. The tissue culture experiment was to study the effect of benzyl adenine (BA) and gibberallic acid (GA3) on axillary buds induction and to determine the concentration of BA for shoot multiplication on pre-existing meristem micropropagation. The tissue culture study was divided into two experiments: 1) the experiments for optimizing BA concentration (0.0, 0.5, 1.0, 1.5 and 2 mg L-1) and GA3 (0.0, 0.5 and 1.0 mg L-1) on shoot induction, 2) shoot multiplication experiment by using BA (0.0, 0.25, 0.5, 0.75 and 1.0 mg L-1). The result showed that 0.0-2.0 mg L-1 BA at 0.0 mg L-1 GA3 had a linear pattern effect, whereas all BA concentrations at 0.5 and 1.0 mg L-1 GA3 had a quadratic pattern effect, at the time of the shoot emergence 0.0 to 1.0 mg L-1 BA showed the linear patterns effect on the number of shooted explant, the number of shoots per explant, number of leaves and the shoot height. The second experiment is to study the effect of IBA (0.0, 0.5, 1.0, and 2.0 mg L-1) and aeration (with and without aeration) of water culture on the root formation of pilea cuttings. IBA has a significant effect on improving pilea cuttings in terms of number of roots, root length and number of shoots, but no significant effect on the shoot length and number of leaves. Aeration treatment significantly reduced the number of roots and root length but had no significant effect on the shoot length and number of leaf.