In Vitro Development of Yellow Lapacho (Bignoniaceae) Using High-Power Light Emitting Diode

Abstract

Handroanthus ochraceus (yellow lapacho) is a medicinal, ornamental and timber tree which can be propagated by in vitro culture. Conventional methods use fluorescent lighting (FL), whereas light emitting diode (LED) has been used for this purpose only recently. The aim of this work was to evaluate the effects of FL and high-power LED (HP-LED) on the in vitro multiplication and rooting of yellow lapacho at different irradiances (15 to 60 µmol m-2s-1). Epicotyls obtained from half-siblings was multiplicated in WPM (Woody Plant Medium) supplemented with 20 µM benzilaminopurine and 1 mM IBA (indolebutiric acid). For rooting, shoots were cultured for 3 days in ½WPM supplemented with 50 µM IBA and for 42 days in auxin-free ½WPM under HP-LED or FL lighting. Under HP-LED, the multiplication rate of shoots increased significantly (61%) from 20 to 40 µmol m-2s-1 respect to FL. Differences in abaxial stomatal density and size were observed between light sources at 20 µmol m-2s-1. High HP-LED irradiance produced the highest rooting percentage. In the rooting stage, the marginal means of treatments without factors interaction showed that HP-LED irradiances significantly increased shoot length by 20%, shoot fresh weight by 77% and shoot dry weight by 30% in comparison to the values under FL. The maximum values calculated from the regression curves were around 50 µmol m-2 s-1 for HP-LED for all parameters except root lenght whereas were around 20 µmol m-2 s-1 for FL for all parameters except fresh and dry weigth of shoot. Here we show that HP-LED lighting improve in vitro culture of H. ochraceus, reduced 81% energy consumption respect to FL and uses only a multispectral LED instead of different single color LEDs. Therefore, HP-LED could be useful for the micropropagation of tree species contributing to sustainable agriculture and ecological restoration of degraded areas.

Testing Explant Sources, Culture Media, and Light Conditions for the Improvement of Organogenesis in Pinus ponderosa (P. Lawson and C. Lawson)

“…Regarding LLR, shoots under white LEDs and FL light showed longer primary roots. A similar pattern was reported in Handroanthus ochraceus where plants showed higher root length values when exposed to low FL irradiances [ 12 ]. In contrast, longer roots were obtained in plants of P. radiata and Vitis ficifolia growing under red LEDs [ 42 , 57 ].…”

“…Among these physico-chemical factors, light is one of the most important factors controlling plant growth and development [ 11 ]. In general, fluorescent light (FL) has been used as the main source of lighting, with irradiances between 25 and 150 mmol m −2 s −1 for a 16 h photoperiod [ 12 ]. However, the power consumption of this kind of lamp is high, making the process expensive, and culture rooms need to remove the heat emitted by them using air conditioners together with FL efficiency [ 10 ].…”

Influence of Physico-Chemical Factors on the Efficiency and Metabolite Profile of Adult Pinus radiata D. Don Bud Organogenesis

“…A similar pattern has been reported in Handroanthus ochraceus (Cham.) Mattos, Achilea millefolium L. and Alocasia amazonica, where higher values of root induction were obtained in plants growing under low FL irradiances [16,70,71].…”

“…Light also affects plant morphogenesis, and it may not only induce plant development but also induce photo-inhibition when leaves are exposed to more light than they can utilize [15]. Usually, fluorescent tubes (FL) are used for plant micropropagation in growth chambers, with irradiances between 25 and 150 mmol m −2 s −1 for a 16 h photoperiod [16]. However, this illumination method has some drawbacks, such as its short lifespan (10,000 h) and the fact that it produces heat, which leads to the need for an extensive cooling system and high maintenance costs [15,17].…”

Adult Trees Cryptomeria japonica (Thunb. ex L.f.) D. Don Micropropagation: Factors Involved in the Success of the Process

“…Plant growth and development are also influenced by different physical factors, with light being one of the most important [22]. The traditional light source used in in vitro culture in the growth chambers is fluorescent tubes (FL), with irradiances between 25 and 150 mmol m −2 s −1 for a 16 h photoperiod [23]. FL emit a broad light spectrum, and their physiological effects on plants are not specific [24].…”