Shading effect on survival, growth, and contents of secondary metabolites in micropropagated Anoectochilus plantlets

Abstract

Many Anoectochilus plants are now facing extinction; hence, they are propagated mainly from tissue culture. However, growth performance and secondary metabolites have not been fully identified on tissue-cultured plantlets from multiple Anoectochilus species under shading. In the present study, five Anoectochilus species [A. roxburghii (Wall.) Lindl., Fu_1; A. koshuaensis Hayata, Fu_2; A. formosanus Hayata, Tai; unidentified species of Fu_New_1 and Fu_New_2] were generated from micropropagated plantlets and cultured under shade treatments of three levels (mean light intensities: mild, *2000 Lx; medium, *800 Lx; intensive, *440 Lx) for five months. Among the five Anoectochilus species, the Tai and Fu_New_1 species had the highest survival rate and the Tai species had the best performance of stem morphology and foliar kaempferol content in the medium shade treatment, but it had fewer leaves and lower ratio of quercetin/ kaempferol than the Fu_1 species. The Fu_New_2 species had the greatest biomass accumulation and highest content of total flavonoids, especially under the mild shade treatment. Therefore, among the Anoectochilus species tested in this study, A. formosanus is suggested to be used in continuous propagation, A. roxburghii is suggested to be planted in stressed environment, and the new species of Fu_New_2 is suggested to be planted for the production of flavonoids. Mild and medium levels of shading are suggested to be used when biomass production and fast growing are needed for Anoectochilus plantlets, respectively.

Effects of Light on Secondary Metabolite Biosynthesis in Medicinal Plants

“…According to their sunlight intensity requirements, medicinal plants are classified into three types: heliophytes, sciophytes, and intermediates. Similar to other physiological processes, the accumulation of SMs in medicinal plants is significantly affected by light intensity (Chen et al, 2017;Li et al, 2020). Generally, high light intensity promotes SM production in heliophytes, such as Ginkgo biloba (Xu et al, 2014), Lonicera japonica (Fang et al, 2020), Tabernaemontana pachysiphon (Hoft et al, 1996), and Andrographis paniculata (Saravanan et al, 2008), while low light intensity promotes SM production in sciophytes, such as Glechoma longituba (Zhang et al, 2015), Changium smyrnioides (Wang et al, 2017), Polygonum minus (Mohd Yusof et al, 2021), and Panax ginseng (Jung et al, 2020).…”

Natural Bioactive Substances in Fruits of Aronia melanocarpa (Michx.) Elliott Exposed to Combined Light-Type, Chitosan Oligosaccharide, and Spent Mushroom Residue Treatments

“…Transmittance of sunlight for NWFP populations can be adjusted by adjusting canopy gap [ 20 , 21 ], which matters for the yield of bioactive production [ 22 ]. Light quality can be determinative in medicinal or edible uses of NWFPs [ 23 , 24 , 25 ].…”

Response of total phenols, flavonoids, minerals, and amino acids of four edible fern species to four shading treatments

“…Light's influence on plant growth is well-known, and its intensity has an obvious impact on plant growth and physiology (Chen et al, 2017;Shao et al, 2014). But, more specifically, light intensity affects the accumulation of some secondary metabolites and nutrition.…”