EFFECTS OF CARBON DIOXIDE ON THE GROWTH AND MORPHOGENESIS OF MARSILEA

Abstract

Increased concentrations of CO2 in air (1–50%) cause young plants of Marsilea vestita to exhibit many characteristics of the water form when they are grown on a solid substrate under sterile conditions. Thus these plants have longer internodes, shorter petioles, more rectangular‐shaped epidermal cells and fewer stomata on the lower leaf epidermis than controls grown in 0.03% CO2. Over a 2‐week period, dry weight increase is considerably greater in 12.5% and 25% CO2 than in 0.03% CO2. Fifty percent CO2 is inhibitory to growth. CO2‐enriched air has the same morphogenetic effect when supplied in the light or the dark. Possible explanations for this effect are discussed.