SHADING LEVELS AND PLANT GROWTH REGULATOR FOR FORMATION OF SCHIZOLOBIUM AMAZONICUM COMPACT SEEDLINGS

ABSTRACT Paricá (Schizolobium amazonicum) can be used for rehabilitation of degraded lands, timber manufacturing markets. However, for its planting, high-quality seedlings should be used. Thus, this study aimed to evaluate the effect of different types of paclobutrazol (PBZ) application and two shading levels on high-quality seedling production. As there was no replication of cultivation environments, we considered each one of them as an experiment. For each environment (35 and 50% shading screen), a completely randomized design was adopted, testing combinations of two types of PBZ application (direct seed immersion in 0.005% PBZ solution; substrate hydration with 0.005% PBZ solution; and 50% seed hydration and 50% substrate hydration; plus, a control), with five replications and five seedlings per plot. The environments were evaluated by analysis of groups of experiments. Seedling growth was evaluated. Under 50% shading, Paricá seedlings had better growth conditions. Application of 100% PBZ in substrate provided compact seedlings with larger dry root phytomass, besides being more practical.摘要：Paricá（Schizolobium amazonicum）可用于退化土地生态修复及木材用材市场。但该树种的栽植需以优质壮苗为基础。为此，本研究旨在评估不同多效唑（paclobutrazol, PBZ）施用方式与两种遮光度水平对优质壮苗培育的影响。因栽培环境未设置重复，故将各环境视作独立试验。针对35%与50%遮光度的遮阴网环境，分别采用完全随机试验设计，设置4组多效唑施用处理：种子直接浸于0.005%多效唑溶液、基质浇灌0.005%多效唑溶液、50%种子浸种+50%基质浇灌，以及空白对照组，每组设置5次重复，每小区种植5株幼苗。采用分组试验分析法对两类遮阴环境开展评价，并测定幼苗生长性状。结果表明，50%遮光度条件下的Paricá幼苗生长状况更优；采用100%基质浇灌多效唑的处理方式可培育出株型紧凑、根系干物质生物量更高的壮苗，且操作更为简便。