Leaf chlorophyll content as a proxy for leaf photosynthetic capacity

By H. Croft, J. Chen, Xiangzhong Luo, P. Bartlett, Bin Chen, R. Staebler. Global Change Biology, 2017

633 citations recorded by the source corpus.

Improving the accuracy of estimates of forest carbon exchange is a central priority for understanding ecosystem response to increased atmospheric CO2 levels and improving carbon cycle modelling. However, the spatially continuous parameterization of photosynthetic capacity (Vcmax) at global scales and appropriate temporal intervals within terrestrial biosphere models (TBMs) remains unresolved. This research investigates the use of biochemical parameters for modelling leaf photosynthetic capacity within a deciduous forest. Particular attention is given to the impacts of seasonality on both leaf biophysical variables and physiological processes, and their interdependent relationships. Four deciduous tree species were sampled across three growing seasons (2013–2015), approximately every 10 days for leaf chlorophyll content (ChlLeaf) and canopy structure. Leaf nitrogen (NArea) was also measured during 2014. Leaf photosynthesis was measured during 2014–2015 using a Li‐6400 gas‐exchange system, with A‐Ci curves to model Vcmax. Results showed that seasonality and variations between species resulted in weak relationships between Vcmax normalized to 25°C ( Vcmax25 ) and NArea (R2 = 0.62, P < 0.001), whereas ChlLeaf demonstrated a much stronger correlation with Vcmax25 (R2 = 0.78, P < 0.001). The relationship between ChlLeaf and NArea was also weak (R2 = 0.47, P < 0.001), possibly due to the dynamic partitioning of nitrogen, between and within photosynthetic and nonphotosynthetic fractions. The spatial and temporal variability of Vcmax25 was mapped using Landsat TM/ETM satellite data across the forest site, using physical models to derive ChlLeaf. TBMs largely treat photosynthetic parameters as either fixed constants or varying according to leaf nitrogen content. This research challenges assumptions that simple NArea– Vcmax25 relationships can reliably be used to constrain photosynthetic capacity in TBMs, even within the same plant functional type. It is suggested that ChlLeaf provides a more accurate, direct proxy for Vcmax25 and is also more easily retrievable from satellite data. These results have important implications for carbon modelling within deciduous ecosystems.

Subfields: Ecology, Global and Planetary Change, Plant Science

View Paper: https://www.semanticscholar.org/paper/75d7f9f9e06614869bd5619bb13304f94e5b0282

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Ecology

1. Nianpeng He

In Global and Planetary Change

1. Qiufeng Wang
2. Jiahui Zhang
3. L. Sack
4. Nianpeng He
5. U. Niinemets
6. F. Valladares
7. Sylvain Delzon

In Plant Science

1. L. Sack
2. U. Niinemets

Citations in the corpus

• Factors Influencing Leaf Chlorophyll Content in Natural Forests at the Biome Scale (2018, background): “The reliability of leaf Chl content represents the maximum rate of carboxylation (Vmax), and has the potential for use as a proxy in models in the future (Croft et al., 2017).”
• Variation in leaf chlorophyll concentration from tropical to cold-temperate forests: Association with gross primary productivity (2018, background): “Thus, leaf chlorophyll concentration (Chl) may directly influence the photosynthetic capacity of plants to some extent (Croft et al., 2017).”