EFFECTS OF ELEVATED CO2 ON ABOVEGROUND GROWTH IN SEEDLINGS OF FOUR DOMINANT QUERCUS SPECIES

Seedlings of four Quercus species dominant in Korea (Quercus mongolica, Quercus serrata, Quercus acutissima, and Quercus variabilis) were grown at different CO2 levels (ambient; 380 ppmv and enriched; 800 ppmv) to determine growth responses under elevated CO2. Three weeks after germination, seedlings were transplanted into chambers and grown over a period of 105 days. Aboveground plant parts were harvested at the end of the experiment to measure dry weight, leaf area, specific leaf area (SLA), leaf area ratio (LAR), leaf weight ratio (LWR), and leaf quality (carbon, nitrogen). Q. mongolica exhibited increased growth, Q. serrata and Q. acutissima did not respond to enrichment, and the growth of Q. variabilis was diminished with elevated CO2. Total aboveground biomass of each seedling increased by 31% for Q. mongolica, but for Q. variabilis, it decreased significantly by 39% under CO2-enriched conditions (p < 0.05). SLA and LAR decreased, and LWR was unchanged or decreased slightly in the elevated CO2 treatment for all species, with the exception of Q. acutissima. In addition, the elevated CO2 treatment was correlated with a decrease in total N concentrations, and an increase in the C/N ratio of the leaves of Q. mongolica and Q. acutissima. In conclusion, plant growth responses to elevated CO2 were species-specific, and they showed large interspecific variation.