Predicting biochemical acclimation of leaf photosynthesis in soybean under in‐field canopy warming using hyperspectral reflectance

Abstract

Traditional gas exchange measurements are cumbersome, which makes it difficult to capture variation in biochemical parameters, namely the maximum rate of carboxylation measured at a reference temperature (Vcmax25) and the maximum electron transport at a reference temperature (Jmax25), in response to growth temperature over time from days to weeks. Hyperspectral reflectance provides reliable measures of Vcmax25 and Jmax25; however, the capability of this method to capture biochemical acclimations of the two parameters to high growth temperature over time has not been demonstrated. In this study, Vcmax25 and Jmax25 were measured over multiple growth stages during two growing seasons for field‐grown soybeans using both gas exchange techniques and leaf spectral reflectance under ambient and four elevated canopy temperature treatments (ambient+1.5, +3, +4.5, and +6°C). Spectral vegetation indices and machine learning methods were used to build predictive models for Vcmax25 and Jmax25, based on the leaf reflectance. Results showed that these models yielded an R2 of 0.57–0.65 and 0.48–0.58 for Vcmax25 and Jmax25, respectively. Hyperspectral reflectance captured biochemical acclimation of leaf photosynthesis to high temperature in the field, improving spatial and temporal resolution in the ability to assess the impact of future warming on crop productivity.

Lower photosynthetic rate and photosynthetic nitrogen use efficiency in northern Japanese soybean cultivars than Midwestern U.S. cultivars

“…The maximum rate of carboxylation, a photosynthetic biochemical parameter, is strongly related to the content and activation state of Rubisco (Onoda et al., 2005). A linear plateau relationship was found between the maximum rate of carboxylation and N area in field‐grown soybeans under different growing temperatures (Kumagai et al., 2022). The nonlinear relationship was explained by the deactivation of Rubisco with increasing N area in apple (Cheng & Fuchigami, 2000).…”

Advances in field-based high-throughput photosynthetic phenotyping

“…light intensity, relative humidity, CO 2 concentration, and temperature) surrounding the leaf so that multiple genotypes can be measured and compared under the same environment. Variation in environmental conditions in nature can have a greater effect on photosynthesis than genotype ( Kumagai et al , 2022 ), so HTP techniques for testing genetic variation in photosynthesis need to minimize the influence of environmental variation. Even with these challenges, studies have estimated photosynthetic capacity in diverse populations using hyperspectral reflectance ( Yendrek et al , 2017 ; Silva-Perez et al , 2018 ).…”

“…Greater efforts are needed to make multiple repeated measurements of the same plot to demonstrate the limitations of different HTP techniques and methods. Variation in growing season conditions or differences in phenology within a season can also cause changes to photosynthetic capacity and are important to detect ( Kumagai et al , 2022 ). Year-to-year variation decreases the effectiveness of specific PLSR models to predict photosynthesis from reflectance ( Ge et al , 2019 ; Meacham-Hensold et al , 2019 ), and thus more research is needed to fully evaluate the transferability of models ( Grzybowski et al , 2021 ); that is, whether models developed based on data from one set of field plots/trials can be applied to another set of field plots/trials.…”

Improving the Photosynthetic Efficiency and Productivity of Cowpea in Sub Saharan Africa: A Review

“…The increase in yield is greatest when the Sun is directly overhead but as the Sun angle decreases, this benefit gradually diminishes. Kumagai et al [46] and studies by other authors Gitelson et al [47] investigated whether a drop in chlorophyll content would result in an increase in canopy photosynthesis in soybeans using several canopy photosynthesises models [92,95]. Correlation between leaf Chlorophyll content, leaf optical characteristics, and biochemical capacity in several soybean accessions, as well as a wild type and a Chlorophyll content -deficient mutant, using a variety of criteria was tested.…”