Anatomical and physiological leaf characteristics and biomass production of Fatsiajaponica plants were studied. Plants were grown in a growth chamber at 300 umol m ? S-I (high light) and 50 umol m ? S-I (low light) photosynthetic photon flux density. Plants grown under high light showed a net maximum photosynthetic rate 44% higher than plants grown under low light; the light compensation point and the light saturation point were also higher in high-light plants. Photosynthetic oxygen evolution in isolated chloroplasts was about 40% higher in high-light plants. However, chlorophyll content on a dry weight basis, on a leaf area basis, and per chloroplast was greater in plants grown under low light. Leaf thickness in high-light plants was 13% higher than in low-light plants. The number of chloroplasts was 30% higher in high-light leaves, while chloroplast size was only slightly higher. Chloroplast ultrastructure was also affected by light. Leaf dry weight, leaf area, and biomass production per plant were drastically reduced under low light. Thus, F. japonica is a plant that is able to acclimate to different photosynthetic photon flux density by altering its anatomical and physiological characteristics. However, lowlight acclimation of this plant has a considerable limiting effect on biomass production.
1149