PHOTOSYNTHESIS IN PLATYCERIUM-CORONARIUM (KOENIG EX MUELLER) DESV

In the dimorphic stag's horn fern, Platycerium coronarium (Koenig ex M ueller) Desv., photosynthetic characters and chlorophyll (Chl) content s were determined in both nest and pendulous fronds at different stage s of ontogeny and at different positions along the longest length of e ach frond. Area-specific radiant energy-saturated net photosynthetic ( P-N) and dark respiration rates, dry mass-specific Chl content and qua ntum yield increased during frond development and decreased when senes cence set in. Radiant energy-saturated P-N and dry-mass specific Chl c ontent were greatest in the youngest tissues of each frond. in additio n to the functions ascribed to the nest (water and nutrient collection ) and pendulous (reproduction) fronds, the results indicate the import ant roles of both frond types in providing chemical energy to the grow th and survival of the plant.