Effects on Growth and Metabolism of Difference between Day and Night Temperatures (DIF) and Supplementation with Rare Earth Elements (REE) in Micropropagated Dendrobium aphyllum (Roxb.) C. E. Fischer

Boling Liu,Byoung Ryong Jeong,Bowen Gao,Lijun Tang,Shijun Deng,Hao Wei

doi:10.3390/horticulturae7110425

Boling Liu, Byoung Ryong Jeong + Show 4 more

Open Access

https://doi.org/10.3390/horticulturae7110425

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Abstract

Dendrobium aphyllum (Roxb.) C. E. Fischer is an ornamental plant with certain medicinal values from the Orchidaceae family. Currently, micropropagation is the main means through which it is propagated. In this research, the effects of different daytime and nighttime temperatures (DIF) and medium supplementation with rare earth elements (REE) on the growth and metabolism of D. aphyllum during a micropropagation period were investigated. Three kinds of REE nitrates, La(NO₃)₃, Ce(NO₃)₃ and Nd(NO₃)₃, at four concentrations, 50, 100, 150, and 200 μM, were added to the culture medium. Three DIFs, 0, 6 and 12 °C, with an identical mean daily temperature of 20 °C, were used with photoperiod/dark period temperatures of 20/20 °C, 23/17 °C and 26/14 °C, respectively. After four weeks of culture, both supplemental REE and DIF treatments promoted growth of the plant compared with the control group. With increased REE concentration and DIF, the growth of the plants was suppressed and symptoms of stress response occurred. At the same concentration, Ce(NO₃)₃ had a more significant promotional effect on plant growth. In general, the medium supplemented with 100 μM Ce(NO₃)₃ combined with a 6 °C DIF was the most optimal for the vegetative growth of the plant. A 12 °C DIF promoted synthesis of more primary metabolites such as total proteins and polysaccharides. From the perspective of improving the medicinal values of this plant, increasing the DIF for an optimal growth environment is a valuable reference. This study can provide a technical basis for the propagation and production of Dendrobium aphyllum in the future.

Highlights

Dendrobium (‘Shihu’ in Chinese) is the second largest genera in the Orchidaceae family, and is widely distributed throughout Asia, Europe and Australia
Through the F-test, it was found that the DIF and rare earth elements (REE) concentrations had significant effects on the new shoot length of D. aphyllum, while the REE type had no significant effects; there was no interaction among the three treatment factors
Through the F-test, it was found that the DIF and REE concentration had a significant effect on the diameter of new D. aphyllum shoots, while the REE type had no significant effects

Summary

Introduction

Dendrobium (‘Shihu’ in Chinese) is the second largest genera in the Orchidaceae family, and is widely distributed throughout Asia, Europe and Australia. In China, the fresh or dried stems of about thirty Dendrobium species are collectively regarded as a famous herbal medicine, and are used in tea or soups to improve health. Dendrobium aphyllum is used as a common source of ‘Shihu’, and is grown in large areas of Southwest China [4]. Due to its high medicinal values, the demand for D. aphyllum is increasing, which is leading to over-exploitation, which poses a threat to wild resources [7]. In order to simultaneously protect wild resources and meet the increasing market demand, Chinese producers have developed micro-propagation technology to induce D. aphyllum

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