The Role of Mycorrhizal Fungi in Orchids

In nature, orchid plants are obligate myco-heterotrophs, and rely on mycorrhizal nutrient resources to grow and sustain in the wild, until they become physiologically active photosynthetic plants. Their seeds lack nutrient reserves and receive the necessary carbon from symbiotic fungi during germination. A mycorrhizal fungus provides nutrients, especially sugars, as well as water to the corresponding host plant. The range and distribution of orchid mycorrhizal fungi influence the survivability of orchid populations in their natural habitats. Mycorrhizae form symbiotic connections with the parenchymatous tissues of the roots of orchid plants. That the symbiotic orchid mycorrhiza can invade through roots of orchid seedling, raised in vitro, has been patented.

The objective of this study was to examine the presence of mycorrhiza in the roots of Aerides multiflora during the vegetative phase.

Fresh roots were hand-sectioned, and thin sections were observed under the microscope to locate the presence of mycorrhiza. Simultaneously, to observe the expansion of mycorrhiza in the cortical region.

During the vegetative phase of plant growth, a peloton-like structure forms within the cortical region of the orchid roots. Mycorrhizae was observed to be distributed throughout the cortical layer of the root.

This communication reviews the role of mycorrhiza in orchid plants.