Effects of LED light on Acacia melanoxylon bud proliferation in vitro and root growth ex vitro

Abstract

This study examines the effects of light emitting diodes (LEDs) on tissue culture proliferation of Acacia melanoxylon plantlets among five different clones (FM1, FM2, FM4, FM5, and FM10). Shoot bud apex cuttings were transplanted onto Murashige and Skoog basal medium containing 0.1 mg L-1 6-benzyladenine and 0.5 mg L-1 naphthalene acetic acid and cultured in vitro for 40 days. Root growth was studied under different light intensities and photoperiods ex vitro. The bud proliferation coefficient was greatest under a light intensity of 45 μmol m-2 s-1 photosynthetic photon flux and photoperiod of 16 h light, but decreased as the light intensity increased. However, the greatest light intensity was beneficial for the growth of robust plantlets. Plantlets exposed to red and blue LED combinations grew tall and green, with a small number of roots. Plantlets also grew taller and some roots expanded under the longer photoperiod. Increased light intensity had positive effects on root number and rooting rate, and prolonged light greatly increased root number. Therefore, lower light intensity and a short photoperiod were beneficial for bud proliferation, while red/blue LED combinations, increased light intensity, and longer light illumination were beneficial for plantlet growth and root growth of Acacia melanoxylon.

Effects of LED photoperiods and light qualities on in vitro growth and chlorophyll fluorescence of Cunninghamia lanceolata

“…In the present study, we found that plantlets during photoperiod 16 h showed higher height, dry weight, rooting rate, average root number, root length, root surface area, and volume at most light qualities compared to photoperiods 8, 24 h. And the best plantlets were harvested with more roots and leaves. Similar results were reported by Li et al [24], the plantlet growth and root growth of Acacia melanoxylon found to be the highest among in vitro culture under photoperiod 16 h. Plants mainly perceive light signals through photoreceptors such as red/far red light receptors, blue/near ultraviolet photoreceptors, and ultraviolet photoreceptors, to regulate plant growth and physiological metabolism [19,25]. Our results showed that plant height, rooting rate, root length, root surface area and root volume of R/B/P/G were higher than R/B, R/B/P and W under photoperiods 8 and 16 h, while they were lower in the R/B, R/B/P than W, suggesting that the red-blue-purple-green composite light could increase growth of C. lanceolata in vitro culture plantlets.…”

Morphological and Physiological Properties of Greenhouse-Grown Cucumber Seedlings as Influenced by Supplementary Light-Emitting Diodes with Same Daily Light Integral

“…Under equal DLI, higher root activity was observed in those cucumber seedlings exposed to supplementary light with a longer photoperiod at 10 h d -1 and 12 h d -1 (Figure 3D). Li et al [58] demonstrated that the average root number of Acacia melanoxylon increased significantly with a prolonged photoperiod, but this trend was not observed in the average root length. A large root absorption area with higher root activity promoted plant growth, which was consistent with other reports [59].…”

Colored LED Lights: Use One Color Alone or with Others for Growth in Hedyotis corymbosa In Vitro?

“…Monochromatic blue LEDs were more effective on the biomass compared with the red, B3R7 LEDs, and control light treatments. Most studies have demonstrated that BR-combined LED lights contribute to an enhanced overall plant biomass compared with other light treatments [ 14 , 18 , 19 , 32 , 33 ]; however, it was not applicable for H. corymbosa in vitro. There was no fresh and dry weight difference measured between all combinations of the BR combination LEDs and the control light ( Figure 1 C,D).…”