Growth Responses to Sodium by Bryophyllum tubiflorum under Conditions Inducing Crassulacean Acid Metabolism

The dry weight yield of plants of Bryophyllum tubiflorum Harvey, a species with Crassulacean acid metabolism characteristics, increased significantly (P < 1%) in response to added sodium (0.1 milliequivalents per liter NaCl was supplied to the culture solution initially containing less than 0.08 microequivalents per liter of Na) when grown under short day (8 hours) conditions but not when grown under long day conditions (16 hours).From results of other work with Crassulacean acid metabolism species, it appears likely that under long day conditions, the plants assimilate CO(2) by the C(3) pathway but under short day conditions by the Crassulacean acid metabolism pathway in which metabolic processes common to those operating in the C(1) dicarboxylic pathway are active. It is suggested that sodium is involved in plants assimilating CO(2) with the C(4) and Crassulacean acid metabolism pathways.