Characterization of seed germination and protocorm development of Cyrtopodium glutiniferum (Orchidaceae) promoted by mycorrhizal fungi Epulorhiza spp.

Abstract

Cyrtopodium glutiniferum is an endemic orchid of Brazil with potential medicinal and ornamental applications. As mycorrhizal fungi are essential for the initiation of the orchid life cycle, the aim of this study was to determine the strains of mycorrhizal fungi suitable for seed germination and protocorm development of C. glutiniferum and to characterize the symbiotic development of protocorms. Seeds of C. glutiniferum were inoculated with nine mycorrhizal fungi, Epulorhiza spp., Ceratorhiza spp., Rhizoctonia sp., originally isolated from Brazilian neotropical orchids. Only Epulorhiza isolates promoted seed germination and protocorm development. Three Epulorhiza isolates (M1, M6 = E. epiphytica, M20 = Epulorhiza sp.) promoted protocorm development until leaf production at 63 days. The protocorms are comprised of parenchyma cells delimited by a unistratified epidermis; the parenchyma cells of the upper part of the protocorms are smaller than those located more towards the base. Intact and digested pelotons were observed inside of protocorms implying that the seedlings were capable of mycotrophy. Additionally, the development of a bud primordium only occurred after colonization by fungus. This study suggests that C. glutiniferum has a preference for strains of Epulorhiza and that fungus digestion is essential to protocorm development.

Cyrtopodium paludicolum germination with two Tulasnella isolates

“…These authors observed that the average percentage germination and development obtained by using their own isolated species were no different from the averages obtained by using another isolate from Eulophia spectabilis. Additionally, Pereira et al (2015) suggested that Cyrtopodium glutiniferum has a preference for strains of Tulasnella and that fungus digestion is essential to protocorm development. In contrast, these authors observed that the isolates of Ceratorhiza and Rhizoctonia did not promote germination in Cyrtopodium glutiniferum seeds.…”

Native Mycorrhizal Fungi in Land Contaminated Cr, Co and Cu

“…Germination and formation process of mycorrhizal fungi spore, through 3 stages, i.e, (1) germination of spores in the soil, (2) penetration of hyphae into root cells and (3) development of hyphae in the root cortex (Pereira et al 2015), and these third of stages possibility also be carried out by mycorrhizal fungi in the land contaminated heavy metals in to multiply themselves. The calculation results of the number of mycorrhizal fungi spores in 100 gr of heavy metals contaminated rhizosphere found in different amounts and dominated by the genus Acaulospora sp.…”

Root endophytic fungi promote in vitro seed germination in Pleurothallis coriacardia (Orchidaceae)

“…For instance, Tolumnia variegata in the presence of Ceratobasidium have a positive influence in seed germination (Otero et al 2005), Epulorhiza spp. promoted protocorm development until leaf production of Cyrtopodium glutiniferum (Pereira et al 2015). Besides, Fusarium spp.…”