protocorm

A protocorm is a specialized organ found in orchids and certain other plants, serving as a transitional structure between the seed and the seedling. It is essentially a thickened, fleshy, and often irregularly shaped mass of tissue that develops from the germinating orchid seed. Orchid seeds are typically minute and lack stored food reserves, relying on a symbiotic relationship with mycorrhizal fungi for germination and early growth. The protocorm represents the initial stage where this fungal association is established and the plant begins to develop.

Within the protocorm, the cells are densely packed and undifferentiated, allowing for rapid growth and the formation of both roots and shoots. It serves as a storage organ, accumulating nutrients obtained from the symbiotic fungi or from reserves within the seed coat itself. As the protocorm matures, it begins to produce lateral buds, which will eventually develop into the characteristic aerial roots and leafy shoots of the adult orchid plant. The protocorm stage is crucial for the survival of many orchid species, particularly those in challenging environments. Some orchids may remain in the protocorm stage for an extended period, and in some cases, the protocorm can reproduce asexually, producing new protocorms.