TY - JOUR

T1 - Rethinking the potential productivity of crassulacean acid metabolism by integrating metabolic dynamics with shoot architecture, using the example of Agave tequilana

AU - Wang, Yu

AU - Smith, J. Andrew C.

AU - Zhu, Xin‐Guang

AU - Long, Stephen P.

PY - 2023/8/3

Y1 - 2023/8/3

N2 - Terrestrial CAM plants typically occur in hot semiarid regions, yet can show high crop productivity under favorable conditions. To achieve a more mechanistic understanding of CAM plant productivity, a biochemical model of diel metabolism was developed and integrated with 3-D shoot morphology to predict the energetics of light interception and photosynthetic carbon assimilation. Using Agave tequilana as an example, this biochemical model faithfully simulated the four diel phases of CO 2 and metabolite dynamics during the CAM rhythm. After capturing the 3-D form over an 8-yr production cycle, a ray-tracing method allowed the prediction of the light microclimate across all photosynthetic surfaces. Integration with the biochemical model thereby enabled the simulation of plant and stand carbon uptake over daily and annual courses. The theoretical maximum energy conversion efficiency of Agave spp. is calculated at 0.045–0.049, up to 7% higher than for C 3 photosynthesis. Actual light interception, and biochemical and anatomical limitations, reduced this to 0.0069, or 15.6 Mg ha −1 yr −1 dry mass annualized over an 8-yr cropping cycle, consistent with observation. This is comparable to the productivity of many C 3 crops, demonstrating the potential of CAM plants in climates where little else may be grown while indicating strategies that could raise their productivity.

AB - Terrestrial CAM plants typically occur in hot semiarid regions, yet can show high crop productivity under favorable conditions. To achieve a more mechanistic understanding of CAM plant productivity, a biochemical model of diel metabolism was developed and integrated with 3-D shoot morphology to predict the energetics of light interception and photosynthetic carbon assimilation. Using Agave tequilana as an example, this biochemical model faithfully simulated the four diel phases of CO 2 and metabolite dynamics during the CAM rhythm. After capturing the 3-D form over an 8-yr production cycle, a ray-tracing method allowed the prediction of the light microclimate across all photosynthetic surfaces. Integration with the biochemical model thereby enabled the simulation of plant and stand carbon uptake over daily and annual courses. The theoretical maximum energy conversion efficiency of Agave spp. is calculated at 0.045–0.049, up to 7% higher than for C 3 photosynthesis. Actual light interception, and biochemical and anatomical limitations, reduced this to 0.0069, or 15.6 Mg ha −1 yr −1 dry mass annualized over an 8-yr cropping cycle, consistent with observation. This is comparable to the productivity of many C 3 crops, demonstrating the potential of CAM plants in climates where little else may be grown while indicating strategies that could raise their productivity.

KW - 3‐D plant form

KW - crassulacean acid metabolism

KW - bioenergy

KW - metabolic model

KW - drought

KW - food security

KW - crassulacean acid metabolism (CAM) photosynthesis

KW - photosynthesis

U2 - 10.1111/nph.19128

DO - 10.1111/nph.19128

M3 - Journal article

VL - 239

SP - 2180

EP - 2196

JO - New Phytologist

JF - New Phytologist

SN - 0028-646X

IS - 6

ER -