Influence of shadowing in Sequoia sempervirens (D. Don) Endl. mini-stumps and mini-cuttings

ABSTRACT The aim of the work was to analyze the influence of variables such as shading, temperature and humidity in the production and rooting of mini-cuttings of Sequoia sempervirens (D. Dom) Endl. in a clonal mini-garden. The experiment was conducted at the Forest Nursery at the University of Santa Catarina State - CAV/UDESC, Lages - SC. The minicuttings were obtained by vegetative rescue of a single clone (A228). The original S. sempervirens individuals studied are located in the National Forest of São Francisco de Paula -RS (FLONA). Sprouts were collected 90 days after the application of girdling rescue techniques. Subsequently, mini-stumps were obtained, which were submitted to three different treatments: T1 - Mini-stumps without shading protection, T2 - Mini-stumps with single layer of shading and T3 - Mini-stumps with double layer of shading. There was no significant difference for humidity and temperature in relation to the production of mini-cuttings by the mini-stumps, while for shading the treatments T2 and T3 showed greater efficiency. It is possible that the shading treatments on S. sempervirens mini-stumps allows the vegetative tissue to be more juvenile, obtaining excellent results in cutting.

摘要 本研究旨在分析遮阴、温度、湿度等环境变量对无性系微型采穗圃中北美红杉（Sequoia sempervirens (D. Dom) Endl.）微型插穗的产出与生根的影响。本实验于巴西圣卡塔琳娜州拉热斯市的圣卡塔琳娜州立大学森林苗圃（CAV/UDESC）开展。微型插穗通过单克隆株系（A228）的营养复壮获取，其所源自的原始北美红杉个体种植于南里奥格兰德州圣弗朗西斯科德保拉国家森林公园（FLONA）。在施加环剥复壮技术90天后采集萌条，随后获得微型采穗桩，将其分为3组施以不同处理：T1组为无遮阴保护的采穗桩，T2组为单层遮阴采穗桩，T3组为双层遮阴采穗桩。结果显示，湿度与温度对采穗桩的微型插穗产量无显著影响；而遮阴处理中，T2与T3组表现出更优的繁育效率。对北美红杉微型采穗桩施加遮阴处理，或可使营养组织保持更强幼态，从而在扦插繁育中获得优异效果。