The effects of carbon dioxide on the growth and development of amphibious plants

摘要

When grown in a stream of 5 CO2in air on a solid substrate, the heterophyllous amphibious speciesRanunculus flabellarisandMyriophyllum brasiliensedeveloped many characteristics of the water form. Plants of the same clones grown in 0.03 CO2exhibited the land form. Submerged plants grew rapidly when 5 CO2in air was bubbled through the nutrient medium, and exhibited the typical water form, while plants kept in 0.03 CO2grew poorly, and the small leaves which developed were intermediate in morphology between the land and water forms. These results are similar to those obtained previously withMarsilea. None of these species were able to utilize bicarbonate. The stream from which theRanunculusused in the experiments was collected contained high concentrations of dissolved free CO2during part of the growing season. Thus concentrations of free CO2higher than those in air may be essential for the normal growth and development of submerged amphibious plants.