Quality and Intensity of Light in the In Vitro Development of Microstumps of Eucalyptus urophylla in a Photoautotrophic System

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.

Spectral quality and temporary immersion bioreactor for in vitro multiplication of Eucalytpus grandis × Eucalyptus urophylla

“…6c) light. These results are similar to the ones reported by Miranda et al (2020) for Eucalyptus urophylla explants grown under a broad light spectrum. Each spectrum is capable of changing the expression levels of specific genes involved in the structural organization of plant cells, as well as of photosynthetic pathway genes (Fan et al 2013).…”

“…Studies focused on investigating the micropropagation of Eucalyptus grandis, Eucalyptus urophylla, and of their hybrids, have been important for the industrial forestry sector. These studies comprise in vitro establishment (Moura et al 2017;Keret et al 2018), bud multiplication (Businge et al 2017;Máximo et al 2018;Trueman et al 2018;Carvalho et al 2019), shoot elongation (Gallo et al 2017;Miranda et al 2020), as well as adventitious rooting and acclimatization phases (Nakhooda and Watt 2017;Brondani et al 2018).…”

Application of Light-Emitting Diodes for Improving the Nutritional Quality and Bioactive Compound Levels of Some Crops and Medicinal Plants

“…In addition to biomass, chlorophyll content was increased in different plant species cultured under LED irradiation [ 24 , 42 , 117 , 118 , 119 ]. In similar studies, increased total carotenoid level was reported in shoot cultures irradiated with different LEDs [ 119 , 120 , 121 ]. Tuan et al [ 120 ] observed elevated expression of carotenoid biosynthesis-associated PSY, ZDS, CHXB , and ZEP genes.…”

THE INFLUENCE OF LIGHT QUALITY IN THE in vitro CULTIVATION OF Cattleya crispata

“…LED light sources can be used separately, or in combination, for the optimization of morphophysiological processes (SHENGXIN et al, 2016). However, it is important to highlight that light wavelength has varying responses according to the genotype (MIRANDA et al, 2020); therefore, adjustments are necessary for each species and/or genotype.…”