Mycorrhizal Compatibility and Germination-Promoting Activity of Tulasnella Species in Two Species of Orchid (Cymbidium mannii and Epidendrum radicans)

Abstract

In nature, Orchidaceae seeds establish a relationship with orchid mycorrhizal fungi to obtain essential nutrients for germination. The orchids, Cymbidium mannii and Epidendrum radicans, have significant ornamental and economic value. We isolated and cultured mycorrhizal fungi from C. mannii, E. radicans, and C. goeringii roots. Three strains of fungi, Tulasnella calospora (Tca), T. asymmetrica (Tas), and T. bifrons (Tbi), were identified using ITS-rDNA sequencing. Their mycorrhizal compatibility, germination-promoting effects, and symbiosis with the seeds of C. mannii and E. radicans were studied in vitro using various concentrations of oatmeal agar (OA) medium. Tca exhibited significant seed-germination-promoting effects on C. mannii (92.1%) and E. radicans (84.7%) on 2.0 and 4.0 g/L OA, respectively. For Tbi and Tas, the highest germination percentages were observed on 4.0 g/L OA in E. radicans (73.60% and 76.49%, respectively). Seed germination in C. mannii was enhanced by high oatmeal concentrations (8.0 and 12.0 g/L) during symbiosis with Tas, whereas Tbi had no effect regardless of OA concentration. Tca exhibited high compatibility with C. mannii and E. radicans, and the oatmeal concentration of the medium affected this compatibility. The findings of this study will aid in the propagation of endangered orchid species for conservation and commercial purposes using mycorrhizal technology.

Medicinal Use, Flower Trade, Preservation and Mass Propagation Techniques of Cymbidium Orchids—An Overview

“…A study on the dependence of Cymbidiums on fungi during seed germination and seedling development provides a means of understanding the role of fungi in the developmental process [64]. Symbiotic seed germination is widely regarded as an effective tool for Cymbidium conservation and could be a cost-effective method to maintain the genetic diversity of reintroduced Cymbidium populations [65].…”

Study of morphology and orchid mycorrhizal associations in Malaxis rheedei

“…Orchids depend on these fungal partners, especially for nutrient acquisition, as they often grow in nutrient-poor soils [8]. The most prevalent orchid mycorrhizal fungus in temperate and tropical areas are particularly members of the Tulasnellaceae family [9]. As a member of the fungal family Tulasnellaceae, Tulasnella calospora is known for its specific associations with orchids and its ability to facilitate their growth and development [10].…”