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

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.

Stomata Profile Comparisons in Abaxial and Adaxial Zones of Dendrobium aphyllum and Arachnis flos-aeris Leaves

Stomata play an essential role in transpiration and metabolism. Orchids are Crassulacean Acid Metabolism (CAM) plants which are generally succulent leaf type. Orchids have several types of stomata, depending on habitat and environmental parameters that affect them. This study aimed to compare the stomata, including the anatomical structure, activity, and density of the orchids Dendrobium aphyllum and Arachnis flos-aeris. The method used was printing the surface of the leaves using glue and observed with a microscope. Data obtained were analyzed with the help of Image raster 3.0 and MS. Excel. In the present study, the stomata of D. aphyllum and A. flos-aeris are characterized by anomocytic type. The highest stomata density was obtained on the abaxial part of D. aphyllum 09.00 am 1177.78 um2. The adaxial leaves of both species are classified as low, or no stomata are found at all. The distance between the stomata on the abaxial leaves of D. aphyllum and A. flos-aeris is denser than the leaves' adaxial side. Stomata activity in orchids is related to orchids' adaptation process to the environmental parameters of their habitat. Stomata activity affects the transpiration process and CO2 fixation in orchid CAM metabolism.

Discovering active sites in peptide Ala–Val–Thr–Phe that counter 2,2-azobis(2-methylpropanimidamidine)dihydrochloride-induced oxidative stress in HepG2 cells

The potential mechanism underlying the cytoprotective effects of the Ala–Val–Thr–Phe (AVTF) peptide derived from edible Dendrobium aphyllum was co-incubated with Lactobacillus amylolyticus.

The genus Dendrobium Sw. (Orchidaceae) in Tripura, India

Tripura is a part of Indo-Burma biodiversity hotspot and is rich in orchid diversity. The present paper deals with 10 species of Dendrobium recorded from Tripura during the field survey in 2016-2018. This paper deals with three new additions of Dendrobium species i.e., Dendrobium aphyllum, Dendrobium capillipes and Dendrobium formosum to Tripura.