![]() ![]() When plants grew under a photosynthetic photon flux of c. Under both natural conditions and in the screenhouse, partial shade enhanced growth and CAM activity. ![]() Its maximum net CO2 uptake rates were low under natural conditions (1.4 itmol m-2 S-1) but were comparable to tlhose of other CAM and C3 epiphytes under wet conditions in a screen- house. Vogel and Tabebiia guayacan (Seem.) Hemsl. It occurred most frequently in tree cavities with its roots in canopy soil and was especially abundant on two tree species: Platypodiuim elegai?s J. Overall, viviparity is an intrinsic, genetic event involving high metabolic costs favouring germination and dispersal of the fittest offspring regardless of substrate and environmental conditions.read more read lessĪbstract: In the tropical forest of Barro Colorado Island, habitat characteristics, diel acidity changes, CO2 uptake and growth were investigated for the epiphytic cactus EpipAlyllbm pkiyllanthlzs (L.) Haw. phyllanthus, seedling mortality during establishment rather than failure to germinate within the fruit is a limiting factor affecting local population density. Germination is not a limiting factor in the perpetuation of this viviparous species, but seedling establishment is. It is suggested that vivipary is associated with thermoregulation, parental care, conspecific nursing, and rapid seedling establishment. The number of survivors gradually stabilized, and the contribution to establishment was comparable in each of the treatments after the acclimation phase. Transplanting experiments showed that the first week is critical for seedling establishment, and high mortality occurred in the three treatments used: 69% on the phorophyte surface, 58.6% on the ground, and 44.8% under controlled conditions. The viviparous seedlings exhibited normal development and were no different from non-viviparous offspring. Seed number/fruit varied from 197 to 230 with percentage of viviparous germination from 97.5% to 99%. A low proportion (33.3%) of individuals produced viviparous fruits. ![]() This epiphytic cactus has no host-specific relationship. Information is provided regarding the biology of viviparous fruits, morphology, mortality, survival rates of viviparous offspring, and some eco-evolutionary implications of this reproductive strategy in the Cactaceae. A remarkable case of vivipary in Epiphyllum phyllanthus is described here. Pseudovivipary and cryptovivipary occur in approximately 30 (2%) species of the cactus family. Abstract: Vivipary, the germination of seeds before they are shed from the parent plant, is a rare event in angiosperms involving complex ecophysiological processes. ![]()
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