Dendrobium officinale Kimura et Migo, a highly valued Chinese herbal medicine, is on the verge of extinction in the wild, and is not cultivated efficiently. In this study, we explored the possibility that orchid mycorrhizal fungi (OMF) might improve the growth and cultivation of D. officinale. Serendipita sp., Tulasnella calospora and Tulasnella asymmetrica isolated from three different orchids were co-cultured with sterile seedlings of D. officinale. The seedlings were found to stably coexist with fungi after 60 days of co-culture. The co-culture of T. calospora with plants upregulated the activity of antioxidant enzymes, stimulated the production of osmoregulatory substances and reduced electrical conductivity. Plants with T. calospora had longer roots (141.2%), thicker leaves (58.3%), increased root number (71.4%) and leaf number (11.1%), and increased weight (155.2%) and photosynthetic pigment content (99.6%), relative to controls. The content of total medicinal polysaccharides increased by 42.69 % due to the addition of T. calospora. T. asymmetrica was less effective, followed by Serendipita sp. When T. calospora established a symbiotic relationship with D. officinale, resistance indicators increased. The content of functional components was significantly increased. This study contributes to the protection and commercial reproduction of endangered orchid plants with mycorrhizal technology.

The simplex strategies of fertilizer management and problems caused by simultaneous precipitation and high-temperature (SPH) climate were the main factors that led to yield loss and quality decline in the continuous cropping of tea chrysanthemum (Dendranthema morifolium ‘Jinsi Huang’). In this study, with sustainable biofertilizers being proposed as a potential solution. However, their effects under such constraints are underexplored. In this study, we compared different proportions of a sustainable dark tea biofertilizer, made with two commonly used fertilizers, by their contributions to the morphological, photosynthetic, and flowering traits of D. morifolium ‘Jinsi Huang’. The results showed that increasing the dark tea biofertilizer application to 4.5 kg·m⁻² significantly enhanced the soil alkali hydrolyzed nitrogen (596.53% increase), available phosphorus (64.11%), and rapidly available potassium (75.56%) compared to the levels in yellow soil. This nutrient enrichment in soil caused D. morifolium ‘Jinsi Huang’ to produce more leaves (272.84% increase) and flower buds (1041.67%), along with a strengthened photosynthetic capacity (higher Fv/Fm values and light saturation point). These improvements alleviated the photoinhibition caused by SPH climate conditions, ultimately leading to significantly higher contents of chlorogenic acid (38.23% increase) and total flavonoids (80.28%) in the harvested flowers compared to the control group. Thus, dark tea biofertilizer is a cost-effective and efficient additive for growing tea chrysanthemum in SPH regions due to improving soil quality and causing nutritional and functional components to accumulate in harvest flowers, which greatly promotes the commercial value of rural revitalization industries centered around tea chrysanthemum.