In situ seed sowing techniques for the recovery of endangered orchids(Scientific Evaluations)

Abstract

When a population needs to be increased for habitat restoration, seed propagation is preferred to vegetative grown because it increases genetic diversity. In orchidaceous plants, seed propagation under natural conditions is not always successful. Only seeds sown in the presence of appropriate fungi will germinate, because orchid seeds require nutrition from mycorrhizal fungi for germination in their natural habitat. It is difficult to find the appropriate fungi in the field, and many orchid fungi are not known. In situ seed sowing techniques, which observe germination by burying and retrieving seed packets, constitute a valuable tool for detecting suitable fungi in the natural habitat. In this report, we used in situ seed sowing to detect mycorrhizal fungus using the endangered orchids Cymbidium macrorhizon and Cymbidium nipponicum. As a result, seed germination was observed in several packets and the distribution of fungi was determined successfully. Moreover, the appropriate depth and period for seed germination in the natural habitats were estimated. This technique provided useful information, such as suitable environmental conditions and seed dormancy, for assisting orchid research and conservation.