KOREASCHOLAR

Mathematically modeling photosynthesis helps to interpret gas exchange in a plant and estimate the photosynthetic rate as affected by environmental factors. Notably, the photosynthetic rate varies among leaf vertical positions within a single plant. The objective of this study was to measure the distinct photosynthetic rate of lily (Lilium Oriental Hybrid ‘Casa Blanca’) at the upper, medium, and basal leaf positions. Subsequently, the FvCB (Farquhar-von Caemmerer-Berry) photosynthesis model was employed to determine the parameters of the model and compared it with a rectangular hyperbola photosynthesis model. The photosynthetic rates were measured at different intracellular CO2 concentrations () and photosynthetic photon flux density (PPFD) levels. SPAD values significantly decreased with lowered leaf position. The photosynthetic rates at the medium and basal leaves were lower compared with the upper leaves. FvCB model parameters,  and   , showed no significant difference between the medium and basal leaves. Estimated photosynthetic rates from derived parameters by the FvCB model demonstrated over 0.86 of R2 compared with measured data. The rectangular hyperbola model tended to overestimate or underestimate photosynthetic rates at high  with high PPFD levels or low  with high PPFD levels, respectively, at each leaf position. These results indicated that the parameters of the FvCB model with different leaf positions can be used to estimate the photosynthetic rate of lily.

Introduction
Materials and Methods
    Plant materials and growth conditions
    Measurement of leaf photosynthetic rate andSPAD value
    Photosynthetic rate models and statistical analysis
Results
    Photosynthetic capacity in different leaf positions
    Parameter estimation of FvCB model
    Estimating photosynthetic rates by FvCB modelcompared to rectangular hyperbola model
Discussion
Acknowledgments
References

• Hoon Choi(Department of Agriculture, Forestry and Bioresources, Seoul National University, Seoul 08826, Korea)
• Won Jun Jo(Department of Agriculture, Forestry and Bioresources, Seoul National University, Seoul 08826, Korea)
• Hyo Beom Lee(Department of Agriculture, Forestry and Bioresources, Seoul National University, Seoul 08826, Korea, Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 08826, Korea) Corresponding author