AGE OF STOCK PLANTS, SEASONS AND IBA EFFECT ON VEGETATIVE PROPAGATION OF ILEX PARAGUARIENSIS

ABSTRACT The low germination of Ilex paraguariensis seeds and their long reproductive cycle make cuttings propagation a good alternative for its reproduction all year round, enabling to obtain genetically superior clones. Thus, we evaluated the influence of stock plants age, plant growth regulator indole-3-butyric acid (IBA) application and plant material collection in different seasons related to rooting of cuttings. From 12 and over 80-years-old trees shoots cuttings were made in four seasons, treated with IBA hydroalcoholic solution at concentrations of 0, 1500, 3000, 4500 and 6000 mg L-1. The rooting was performed in plastic boxes filled with vermiculite and carbonized rice husk at a ratio of 1:1 (v/v) and, after 90 days in controlled greenhouse conditions were evaluated the rooting percentage, callus formation, survival, mortality, number of roots/cutting and length of three larger roots/cutting. Cuttings from 12-years-old stock plants have higher ability to form adventitious roots and the use of IBA did not increase rooting potential. Autumn proved to be the most favorable season for rooting, followed by spring and winter.

摘要 巴拉圭冬青（Ilex paraguariensis）种子发芽率低下且生殖周期漫长，因此扦插繁殖成为其全年无性繁殖的优质替代方案，可获得遗传性状优良的无性系。本研究探究了母株树龄、植物生长调节剂吲哚-3-丁酸（indole-3-butyric acid, IBA）施用方案，以及不同季节采集插穗材料对插穗生根效果的影响。实验分别从12年生和80年生以上的母株上采集枝条，分四个季节开展扦插处理，以浓度为0、1500、3000、4500及6000 mg·L⁻¹的IBA水醇溶液对插穗进行处理。扦插基质采用体积比1:1（v/v）的蛭石与碳化稻壳混合物，装填于塑料箱中；在可控温室条件下培养90天后，测定插穗的生根率、愈伤组织形成率、存活率、死亡率、单插穗生根数以及3条最长根的长度。结果表明，12年生母株的插穗不定根形成能力更强，施加IBA并未提升插穗的生根潜力；秋季被证实为最适宜的扦插季节，其次依次为春季与冬季。