상부 개방형 온실을 이용한 대기 중 이산화탄소 농도 증가가 우리나라 자생 수종에 미치는 형태적, 생리적 영향

Abstract

The physiological responses of three common temperate species, Pinus densiflora, Fraxinus rhynchophylla, Sorbus alnifolia to elevated CO2 was investigated using open top chambers with different CO2 concentrations. Morphological (stomatal size, density and area) and physiological characteristics (maximum rates of photosynthesis, carboxylation and electron transport) were compared among trees grown under ambient, ambient ×1.4 (~550 ppm) and ambient ×1.8 (~700 ppm) CO2 concentrations for last four years. Morphological responses were different among species. F. rhynchophyllar increased their stomatal size and S. alnifolia had higher stomatal density under elevated CO2 than ambient. Stomatal area decreased in P. densiflora, whereas it increased in S. alnifolia. However, the maximum photosynthesis rate increased in all species up to 43.5% by S. alnifolia under elevated CO2 and the enhancement increased with time. Even with four years of exposure to elevated CO2, there was no sign of acclimation in the maximum carboxylation rate and the maximum electron transport rates in all species. Especially, S. alnifolia even showed the temporary increase of photosynthetic capacities in spring, when leaf nitrogen concentration was high with new leaf development. There was no significant differences in diameter growth rate in any species due to high variation in their tree sizes, however accumulated diameter and biomass for four years showed significantly increment in all species under elevated CO2. For example, S. alnifolia showed 59% increase in diameter at the ambient ×1.8 (~700 ppm) compared to ambient.