Lysimetric Analysis for Transpiration and Carbon Accumulation of Cnidium officinale Makino in Hot Weather Conditions

Background: Evaluation of transpiration is required for agricultural and environmental management applications, as crop yields and plant growth are primarily water limited. This study aimed to determine the transpiration and carbon accumulation of Cnidium officinale.BRMethods and Results: The transpiration of C. officinale was evaluated using weighing lysimeter. The relationship between transpiration and factors such as solar radiation, air temperature, and leaf area was assessed. Transpiration increased as the leaf area increased with the growth stage. Furthermore, daily transpiration per unit leaf area was 0.69 ± 0.16 g·㎝SUP−2/SUP·daySUP−1/SUP and there were no significant differences in daily transpiration during the cultivation period. The maximum transpiration was 620.6 g mSUP−2/SUP·hSUP−1/SUP and diurnal changes in transpiration were highly correlated with solar radiation although the maximum transpiration was observed at the air temperatures of 20℃ - 26℃. The ratio of carbon accumulation to transpiration was 0.12%.BRConclusions: Our results indicated that the transpiration of C. officinale is primarily regulated by solar radiation energy on clear days and that 97% of the water is discharged through transpiration for heat dissipation. Therefore, weighing lysimeters can measure transpiration accurately and may be useful in interpreting plant growth.