Application of hypergravity in Eucalyptus and Corymbia seeds

ABSTRACT: The aim of this study was to evaluate the growth responses of various Eucalyptus and Corymbia species subjected to different intensities of simulated hypergravity relative to the control. A centrifuge was used to simulate hypergravity. It was developed and built at the Centro de Microgravidade of the Pontifícia Universidade Católica do Rio Grande do Sul, Brazil. Seeds of five Eucalyptus and one Corymbia species (E. grandis, Eucalyptus globulus, Eucalyptus benthamii, Eucalyptus saligna, Eucalyptus dunnii, and C. maculata) were placed on moist germination paper in plastic containers and rotated at speeds simulating 5 Gz and 7 Gz for different lengths of time. Hypergravity technology significantly increased seedling production (diameter, height, and survival at 120 days) in nurseries. In E. globulus, the effects of hypergravity were significant at 7 Gz at all lengths of time (from 1 d to 9 days). Effects of hypergravity were significant in both E. benthamii and E. grandis at 7 Gz and 8 h exposure. Therefore, simulated hypergravity could be used in performance tests of Eucalyptus seedlings in early stages of development.摘要：本研究旨在评估不同桉树属（Eucalyptus）与伞房桉属（Corymbia）物种在不同强度模拟超重力（hypergravity）条件下相较于对照组的生长响应。本研究使用离心机模拟超重力，该设备由巴西南里奥格兰德天主教大学微重力中心研发搭建。本次试验选取5种桉树属植物及1种伞房桉属植物的种子，分别为巨桉（E. grandis）、蓝桉（Eucalyptus globulus）、本哈姆桉（Eucalyptus benthamii）、柳桉（Eucalyptus saligna）、邓恩桉（Eucalyptus dunnii）以及斑点伞房桉（C. maculata）。将种子放置于塑料容器内的湿润发芽纸上，以模拟5Gz与7Gz超重力环境的转速进行旋转处理，处理时长各不相同。试验结果表明，超重力技术可显著提升苗圃内桉树幼苗的培育效果，相关指标包括120日龄幼苗的地径、株高及存活率。针对蓝桉而言，7Gz的超重力处理在所有时长（1天至9天）下均产生了显著效果。本哈姆桉与巨桉在7Gz、8小时处理时长的条件下，超重力处理同样表现出显著效果。综上，模拟超重力技术可应用于桉树幼苗早期发育阶段的性能测试。