Pierce et al. 2002 (Article) Carbon isotope

Carbon isotope ratio and the extent of daily CAM use by Bromeliaceae

Author(s):—S. Pierce, K. Winter & H. Griffiths

Publication:—The New phytologist 156: 75–83. (2002) — DOI

Abstract:—• Use of carbon isotope ratio ( δ 13 C) to resolve photosynthetic pathways (C 3 , C 4 or CAM) has limitations imposed by the use of intermediate photosynthetic modes by certain plant taxa. • Diel gas-exchange patterns, leaf δ 13 C values and nocturnal tissue acidification were determined for 50 Bromeliaceae. • δ 13 C values for well watered plants reflected the proportion of daily CO 2 uptake occurring at night. Thirteen per cent of species with δ 13 C values typical of C 3 plants (i.e. from − 22.6 to − 31.5‰) showed nocturnal acidification and either a small proportion (< 10%) of daily CO 2 uptake occurring nocturnally or internal CO 2 recycling during part of the night. None altered CAM expression in response to short-term drought, but the contribution of CAM to daily carbon gain became proportionally more important as C 3 CO 2 uptake failed. • Surveys of plant communities using solely the carbon isotope technique underestimate the number of CAM-equipped plants.