Dendrobium officinale Kimura et Migo is an orchid with both medicinal and edible values and a high economic value. The wild resources of D. officinale are in an endangered state. Compared with the wild D. officinale, cultivated D. officinale exhibits inferior quality and a low content of medicinal components. Polyploid induction is a conventional breeding tool for genome doubling of species, which can effectively increase the total amount of plant components to improve the medicinal efficacy of D. officinale. In this study, D. officinale tetraploids were generated by treating the protocorms with colchicine. Morphological observations showed that tetraploids exhibited decreased plant size and leaf shape index and increased stem diameter. Cytological observations showed that the polyploid plants had larger stomata and a lower number of stomata per unit area compared with normal plants. The highest stomata variation of 30.00% was observed when the plant was treated with 0.3% colchicine for 24 h. Chromosomal observations showed that treatment of plants with 0.2% colchicine for 48 h resulted in the highest tetraploid induction rate of 10.00%. A total of 10 tetraploids were successfully obtained by inducing plant protoplasts with colchicine. The number of diploid D. officinale chromosomes was 38 with a base number of 19, and the karyotype formula was 2n = 2x = 38 = 24m + 14sm with a karyotype asymmetry coefficient of 60.59%, belonging to type 2B. The number of tetraploid D. officinale chromosomes was 76 with a base number of 19, and the karyotype formula was 2n = 4x = 76 = 58m + 18sm with a karyotype asymmetry coefficient of 60.04%, belonging to type 2B. This study determined the optimal mutagenesis treatment based on the chromosome observation results, investigated the relationship between the phenotype and ploidy level, and generated the polyploid germplasm of D. officinale, thereby laying the foundation for the breeding of new D. officinale cultivars enriched with compounds of medicinal value.

Dendrobium officinale (DO) is a well-known medicinal and edible plant, yet its impact on the quality of noodles has been infrequently reported. In this study, DO was incorporated into multi-grain flour in varying proportions (0, 2, 4, 6, 8%) to prepare noodles, and their quality was assessed. The percentage increase in DO decreased the cooking loss, whiteness, appearance, and taste of the noodles while simultaneously enhancing their water absorption, adhesiveness, smoothness, and starch digestion resistance. Lower supplemental levels of DO (2–4%) facilitated the water absorption of protein and the formation of a dense and extensive protein network surrounding the partially gelatinized starch, which was characterized by higher relative crystallinity. The highest sensory score (77.4) and greatest content of slowly digestible starch content (38%) were observed in the noodles containing 4% DO. Conversely, higher percentages of DO (6–8%) diluted and compromised the protein network in the cooked noodles, leading to water migration from protein to starch. The excessive polysaccharides from DO tended to complex with fully gelatinized starch, promoting starch aggregation and interactions between starch and non-starch components. This ultimately resulted in the highest adhesiveness and resistant starch content (34%) in the cooked noodles with 8% DO. These findings provide a reference for enhancing noodle quality by regulating the amount of DO added, thereby promoting the application of DO in cereal-based food products.

The genus Dahlia has approximately 40 species; however, the complete chloroplast genome has been reported only for one species. Due to this lack of information on the chloroplast genomes, the phylogenetic relationships within the Dahlia genus remain unclear. Therefore, the present study sequenced the complete chloroplast genome of D. imperialis for the first time. This genome was 152,084 bp long with a typical quadripartite structure and a GC content of 38.45%. A total of 134 genes were annotated in the genome, including 86 protein-coding genes, 38 transfer RNA genes, 8 ribosomal RNA genes, and 2 pseudogenes. The detailed analysis identified UUA as the most frequently used codon and found 62 intergenic repeat sequences and 157 SSR loci in the D. imperialis genome. Phylogenetic analysis based on 49 chloroplast genomes showed that Dahlia was a monophyletic group, with D. imperialis positioned at the base of this clade. Network evolution and gene flow analysis unveiled extensive hybridization events within the Heliantheae alliance, especially in Dahlia. Thus, the comprehensive analysis of the complete chloroplast genome of D. imperialis enriches the information on the genetic resources of the Dahlia species, provides valuable information for reconstructing their phylogeny, and reveals the evolutionary dynamics of the Dahlia chloroplast genome.