Protocorm or rhizome? The morphology of seed germination in Cymbidium dayanum Reichb.

Seeds of Cymbidium dayanum Reichb. were sown in vitro and germinated to produce protocorms one month later. Protocorms elongated, and the unicellular cell absorbing hairs were initiated at the base. The anterior of the protocorm produced the sheath leaf primordium. After two months, the protocorms grew, with the structure similar to that of rhizomes with nodes and lateral buds. The terminal buds spontaneously developed into shoots. According to the morphological pattern in vitro, we inferred that the seed germination of C. dayanum involved a fast transition from protocorm to plantlet by rhizome.