Two types of carbon fixation in tropical orchids

摘要

The isotopic composition of the carbon (δ13C values) of leaf tissue from 10 species and hybrids of orchids grown in Singapore fell into two groups, one having a mean value of-15.4‰, the other-26.6‰. The least negative of these values was associated with thick-leaved plants (0.2–0.4 mm). This is consistent with the view that some orchids are CAM plants and others possess a C3type of carbon fi