Properties of blood oxygen transport in the turtle Pseudemys scripta and the tortoise Testudo graeca: effects of temperature, CO2 and pH.
Properties of oxygen-haemoglobin binding have been investigated in the aquatic turtle Psuedemys scripta and the terrestrial tortoise Testudo graeca. Haematocrit (30-35%) and haemoglobin concentration (12-14 g/100 ml blood) were similar in both species. P50 at physiological levels of PCO2 (20-25 mm Hg) was 21 mm Hg in Pseudemys, compared with 23 mm Hg in Testudo. The Bohr shift of the blood of both the turtle and the tortoise was almost identical at -0.28. The heat of oxygenation, deltaH, reflecting the temperature sensitivity of O2-Hb affinity, was -10.55 in Pseudemys and -8.12 kcal/mol in Testudo. These data on whole blood do not support previous generalizations in the literature suggesting marked differences in oxygen-haemoglobin binding between aquatic and terrestrial chelonian reptiles.
D000818:Animals; D001692:Biological Transport; D006400:Hematocrit; D006454:Hemoglobins / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D010100:Oxygen / Q000097:blood*; D013045:Species Specificity; D013696:Temperature; D014426:Turtles / Q000097:blood*
D006454:Hemoglobins; D010100:Oxygen