GROWTH OF ‘PRATA-ANA’ BANANA’S MICROSHOOTS CLONE GORUTUBA FROM SYNTHETIC SEEDS:SUBSTRATES AND BAP CONCENTRATION

ABSTRACT The banana crop stands out as an activity of great social and economic importance in Brazil, which occupies the fifth place in world production. Synthetic seed production is becoming promising for a micropropagation and in vitro conservation. The aim of the study was to analyze the conversion and growth of ‘Prata-anã’ banana’s microshoots clone Gorutuba from synthetic seed in MS medium and vermiculite, different substrates and concentrations of BAP (6-benzylaminopurine) associated with ANA (acetic naphthalene acid) in the constitution of its capsule were tested. The microshoots were immersed in the sodium alginate matrix (3%) and dripped in a solution of CaCl2.2H2O (100 mM) for complexation and then in KNO3 solution (100 mM) to decomplex. The experimental design was completely randomized in a 2 x 5 factorial design (substrate x BAP concentrations), containing different substrates (MS culture medium and vermiculite) and BAP concentrations (2.22, 4.44, 6.66, 8.88 and 13.32 µmol L-1) associated with NAA (naphthalene acetic acid) 0.54 µmol L-1, totaling 10 treatments, with 4 replicates, and that each replicate containing 5 seeds. The evaluations of conversion, number of leaves, leaf length, leaf height, number of roots, root length and oxidation were performed at 30 and 60 days.The use of the MS medium provided better growth results in relation to vermiculite as substrate, in which the different BAP concentrations did not differ from each other. It was found that, in MS culture medium, BAP concentrations above 8.88 µmol L-1 in the capsule composition are not indicated for microshoots growth.摘要 香蕉产业在巴西具有重要的社会与经济价值，该国香蕉产量位居全球第五。人工种子生产在微繁殖与离体保存领域展现出良好应用前景。本研究旨在分析‘普拉塔-阿纳’（Prata-anã）香蕉戈鲁图巴（Gorutuba）无性系微芽经人工种子后的萌发与生长情况；试验设置不同基质（MS培养基（MS medium）与蛭石（vermiculite））以及添加于人工种皮的6-苄氨基腺嘌呤（BAP, 6-benzylaminopurine）浓度梯度，并搭配萘乙酸（NAA, naphthalene acetic acid）开展试验。将微芽浸入3%海藻酸钠基质中，随后滴入100 mM氯化钙二水合物（CaCl₂·2H₂O）溶液进行络合反应，再置于100 mM硝酸钾（KNO₃）溶液中完成解络合。试验采用完全随机设计，设置2×5因子组合（基质×BAP浓度）：基质分为MS培养基与蛭石2种，BAP浓度设置为2.22、4.44、6.66、8.88及13.32 µmol·L⁻¹，所有处理均搭配0.54 µmol·L⁻¹萘乙酸，共设10个处理组，每组4次重复，每次重复包含5粒人工种子。分别于接种后30天与60天，测定人工种子的萌发率、叶片数、叶长、株高、根数、根长以及褐化程度。结果表明，以MS培养基为基质时，微芽生长效果显著优于蛭石基质，且该基质下不同BAP浓度处理间生长指标无显著差异；研究同时发现，当人工种皮配方中BAP浓度超过8.88 µmol·L⁻¹时，不利于MS培养基基质上微芽的生长。