Environmental and genetic control of crassulacean acid metabolism in two crassulacean species and an F1 hybrid with differing biomass δ13C values

Abstract

Abstract The growth, biomass δ13C values, and ability to accumulate titratable acidity at night were compared in eight environmental treatments for Cremnophila linguifolia, Sedum greggii, and their F1 hybrid. In the phytotron, differences in treatment daylength, day/night temperature and water availability were all found to have effects on total plant dry weight, nocturnal accumulation of titratable acidity and biomass δ13C value of at least some of the genotypes. However, there were differences between the genotypes both in the magnitude and direction of response of the phenotypic properties to the treatment variables. The phytotron δ13C values ranged from ‐12.9 to ‐19.2‰ for C. linguifolia, from ‐22.2 to ‐33.4‰ for S. greggii, and from ‐19.2 to ‐24.9‰ for the hybrid. After with‐holding water for 76 h both C. linguifolia and the hybrid had midday Ψleaf values of ‐0.23 MPa; however, S. greggii had a value of ‐1.05 MPa. In contrast to past observations of other species, the daily watered plants of C. linguifolia had less negative δ13C values than did the plants watered only weekly.