Influences of Organic Additives on Asymbiotic Seed Germination of Dendrobium cruentum Rchb. f. for In Vitro Micropropagation

Abstract

Dendrobium cruentum Rchb. f., a commercial orchid in Thailand, faces the risk of extinction and should be conserved, and propagated for commercial. Therefore, the aim of this research was to identify a suitable VW medium supplemented with organic additives for the micropropagation of D. cruentum through asymbiotic seed germination. The VW media supplemented with separate organic additives (coconut water (CW) (100 mL/L), ‘Hom Thong’ banana homogenate (BH) (1000 mg/L), and potato homogenate (PH) (1000 mg/L) or its combination was determined, and the seed germination rate (%), protocorm formation, and plantlet development were observed. The results showed that a combination of BH and PH resulted in the highest seed germination (94.69 ± 1.55 %) when compared to basal VW (control). Protocorm formation was highest with CW alone (47.38 ± 7.17 %) and a combination of CW and PH (52.13 ± 6.20 %). Additionally, after 10 weeks of culture, supplementation with BH yielded the highest number of plantlets. However, after 24 weeks of culture, each organic additives gave the different developments of healthy plantlets. To investigate suitable potting media for acclimatization of well-grown plantlets in greenhouse conditions, 2 pieces of foam, dried coconut husk, and a combination of peat moss: Sphagnum moss: Pumice: Perlite (3:1:1:1) were investigated. The highest survival rate percentage was found in foam-planted plantlets (80 %). Ultimately, the effectively simple mediums containing organic additives and a one-step protocol were provided for the micropropagation of D. cruentum via seeds, and the derived information could be used for D. cruentum conservation and production. HIGHLIGHTS The effects of organic additives on asymbiotic seed germination for in vitro micropropagation of Dendrobium cruentum Rchb. f. was firstly reported The media supplemented with organic additives yield significantly the highest seed germination, protocorm formation, and plantlet formation and development of D. cruentum when compared to basal media In greenhouse conditions, 2 pieces of foam gave the highest survival rate percentage of plantlets (80 %) The practical and beneficial media supplemented with organic additives for micropropagation of D. cruentum was provided GRAPHICAL ABSTRACT

Effect of Organic Additives on the Micropropagation of Asparagus officinalis

“…According to De Stefano et al [39], BH at a concentration of 1% (w/v) promoted shoot and root proliferation in Epidendrum nocturnum. A recent study by Samala and Thipwong [22] also demonstrated that BH yielded the highest number of in vitro D. cruentum plantlets. Notably, the excess of some substances in BH, specifically sugars or some trace elements, such as calcium or sodium, may inhibit cell growth and development.…”

“…Apart from natural sources of carbon, mainly sugars, CW also contains some vitamins (thiamin, pyridoxine, ascorbic acid), amino acids, minerals (phosphorus, magnesium, potassium, calcium, iron, and manganese), and PGRs, such as cytokinins, zeatin, auxins (indoleacetic acid, IAA), gibberellic acid (GA), and abscisic acid (ABA), which are essential for plant cell division, differentiation, and development [18,20,24,26,27]. CW has been successfully used to promote shoot proliferation in several plants, such as Musa acuminata [24], Dendrobium chryseum [28], Dianthus caryophyllus [29], Hylocereus polyrhizus [30], Coelogyne pandurata [21], Echinacea purpurea [31], Cymbidium aloifolium [32], and D. cruentum [22]. According to DMRT analysis, means followed by distinct letters within a column are significantly different at p ≤ 0.05.…”

“…These organic additives provide not only natural sources of carbon, such as sucrose and fructose, but also natural vitamins, amino acids, lipids, minerals, and PGRs, specifically plant hormones, which are essential for plant growth and development [19,20]. However, based on a literature review, the effect of organic additives on the in vitro propagation of A. officinalis has never been documented; in most studies, organic additives were added to culture media for the in vitro propagation of orchids [20][21][22]. Therefore, to overcome the limitations of the conventional propagation of A. officinalis, which is generally based on plant seeds and rhizomes, and to minimize the in vitro propagation cost of plant tissue culture medium, this research aimed to employ an in vitro culture technique for the micropropagation of A. officinalis.…”