CARBON-BASED SECONDARY COMPOUNDS AT ELEVATED CO2

From literature sources we compiled the data on carbon-based-secondary compounds CBSC (phenolics and terpenoids) and biomass of 17 plant spe cies grown at different CO2 concentrations under low and high nutrient availabilities. With a low nutrient availability a possible inverse c orrelation was found between the biomass and CBSC changes. On the cont rary, under a high nutrient availability, both the CBSC and biomass in creased with elevated CO2. The wide variation in the CBSC production a mong species and compounds (larger responses in phenolics than in terp enoids) indicates that the allocation to CBSC may not completely be go verned by changes in CO2 and nutrient availabilities per se. Yet the c omparison shows that elevated CO2 generally loads the carbon into CBSC [their leaf concentration increased an overall average of 14 % at 700 mu mol(CO2) mol(-1)] which may improve our understanding of the carbo n storage and cycling in ecosystems under the ''global change'' of cli mate.