Abstract

The quality and quantity of light are important factors in controlling in vitro plant growth in photoautotrophic systems. The aim of this study was to evaluate the influence of light quality (fluorescent, white, red, blue, red/blue, and distant red) on microstumps of a Eucalyptus urophylla clone in an in vitro photoautotrophic system, as well as the intensity of fluorescent light (60, 85, 100, and 140 μmol m^–2 s^–1) in the growth and production of microcutting. The number of shoots and microcutting, the size of the largest shoot, the stomatal density, chlorophyll, and carotenoid content were analyzed. Light quality altered plant growth, and fluorescent light intensity did not affect the microstumps’ production during the evaluation period. In white light-emitting diode (LED) light, there was higher production of carotenoids, with a lower initial production of microcuttings. A smaller number of shoots were obtained in blue LED. In general, the different qualities and light intensities tested allowed for the growth of the Eucalyptus urophylla clone grown in vitro, making it possible to obtain microcuttings under photoautotrophic cultivation.

Study Implications

In vitro propagation is a stressful process for plants and has limitations for commercial-scale Eucalyptus production. Fluorescent lamps, closed containers, and high sucrose concentrations are traditionally used. To reduce costs and improve production, the use of efficient light sources and photoautotrophic cultivation systems become alternatives. This study investigated the influence of light on the in vitro growth of a Eucalyptus clone in a photoautotrophic system. The quality was more important than the intensity of light. Foresters will be able to indicate the use of LEDs (light-emitting diodes) as a replacement for fluorescent lamps. This approach is useful in enhancing micropropagation techniques.

中文翻译：

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光自养系统中尾叶桉微树桩体外发育中光的质量和强度

摘要

光的质量和数量是控制光合自养系统中体外植物生长的重要因素。这项研究的目的是评估光质量（荧光，白色，红色，蓝色，红色/蓝色和远处的红色）对体外光合养分系统中尾叶桉树无性系微树桩的影响以及其强度。荧光灯（60、85、100和140μmolm ^–2 s ^–1）在微切割的生长和生产中。分析了枝条的数量和微切，最大枝条的大小，气孔密度，叶绿素和类胡萝卜素含量。在评估期间，光质量改变了植物的生长，荧光强度没有影响微树桩的生产。在白色发光二极管（LED）灯中，类胡萝卜素的产量较高，而微切口的初始产量较低。在蓝色LED中获得较少的芽。通常，所测试的不同质量和光强度允许体外生长的尾叶桉（Eucalyptus urophylla）克隆的生长，从而有可能在光合养分条件下获得微切块。

研究意义

体外繁殖对植物来说是一个压力过程，并且对商业规模的桉树生产具有局限性。传统上使用荧光灯，密闭容器和高蔗糖浓度。为了降低成本和提高产量，使用高效光源和光合自养培养系统成为替代方案。这项研究调查了光对光养养系统中桉树克隆体外生长的影响。质量比光的强度更重要。森林人将能够指示使用LED（发光二极管）替代荧光灯。此方法可用于增强微传播技术。