Root growth of Eleuthero (Eleutherococcus senticosus [Rupr. &amp; Maxim.] Maxim.) seedlings cultured with chitosan oligosaccharide addition under different light spectra

Shenglei Guo,Liwei Jia,Mingyuan Xu,Zhenyue Wang,Shuang Zhang

doi:10.15835/nbha48211634

Abstract

Eleuthero (Eleutherococcus senticosus [Ruprecht & Maximowicz] Maximowicz is an important understory species as well as a source of natural products in Asia. The natural source of Eleuthero has been over exploited for pharmacological use, but the manual restoration to rehabilitate its natural distribution has not yet been established. The root is one of the main underground organs in Eleuthero for the acquisition of pharmaceutical ingredients. Root growth also determines the seedling quality of this species for ecological restoration. In this study, Eleuthero seedlings were cultured for one growing cycle with chitosan oligosaccharide (CO) addition at rates of 0 and 25 ppm under artificial lightings by high-pressure sodium (HPS) lamps and two light-emitting diodes (LEDs) with photosynthetic photon flux density set to 94±5 μmol m-2. Light spectra of red (R): green (G): blue (B) ratios were measured to be 43.7:54.6:1.7, 43.8:47:9.2, and 72.7:13.3:14 for the HPS, LED-1, and LED-2 treatments, respectively. In autumn, no interactive effect was found between CO addition and light spectra treatments on any root parameters. Compared to the HPS treatment, the LED-1 treatment resulted in a greater root dry weight and morphology by over 30%. The CO addition caused an increase of root growth by 40-70%. Fine roots in diameter between 0-0.4 mm were the main root part that contributed to the length, surface area, and root tip number. Therefore, LED lighting with the R/G/B spectrum of 43.8:47:9.2 was suggested for the culture of Eleuthero seedlings with the purpose of promoting dry weight and morphology of fine roots.

Highlights

The Eleutherococcus Maxim. [Acanthopanax (Decne. et Planch) Witte] genus comprises about 40 species, most of which are naturally distributed in Eastern Asia and Far East Russia (Wan et al, 2016; Zaluski and Smolarz, 2016)
Eleuthero seedlings were cultured for one growing cycle with chitosan oligosaccharide (CO) addition at rates of 0 and 25 ppm under artificial lightings by high-pressure sodium (HPS) lamps and two light-emitting diodes (LEDs) with photosynthetic photon flux density set to 94±5 μmol m-2
Our results showed that the addition of Chitosan oligosaccharide (CO) can promote root dry weight and fine root morphology, which concur with former findings about plant root growth in response to CO addition (AleksandrowiczTrzcińska et al, 2015; Chamnanmanoontham et al, 2015; Zong et al, 2017)

Summary

Introduction

The Eleutherococcus Maxim. [Acanthopanax (Decne. et Planch) Witte] genus comprises about 40 species, most of which are naturally distributed in Eastern Asia and Far East Russia (Wan et al, 2016; Zaluski and Smolarz, 2016). Et Planch) Witte] genus comprises about 40 species, most of which are naturally distributed in Eastern Asia and Far East Russia (Wan et al, 2016; Zaluski and Smolarz, 2016). Eleutherococcus senticosus (Eleuthero) is the only species from the Eleutherococcus family that was documented by the European Pharmacopoea and American Herbal Pharmacopoeia monographs. Received in revised form: 20 May 2020.

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