Different Responses of Solar-Induced Chlorophyll Fluorescence at the Red and Far-Red Bands and Gross Primary Productivity to Air Temperature for Winter Wheat

Abstract

Solar-induced chlorophyll fluorescence (SIF) is closely related to the light-reaction process and has been recognized as a good indicator for tracking gross primary productivity (GPP). Nevertheless, it has not been widely examined how SIF and GPP respond to temperature. Here, we explored the linkage mechanisms between SIF and GPP in winter wheat based on continuous measurements of canopy SIF (cSIF), GPP, and meteorological data. To separately explore the structural and physiological mechanisms underlying the SIF–GPP relationship, we studied the temperature responses of the estimated light use efficiency (LUEp), canopy-level chlorophyll fluorescence yield (cSIFyield) and photosystem-level chlorophyll fluorescence yield (ΦF) estimated using canopy-scale remote sensing measurements. We found that GPP, red canopy SIF (cSIF688) and far-red canopy SIF (cSIF760) all exhibited a decreasing trend during overwintering periods. However, GPP and cSIF688 showed relatively more obvious changes in response to air temperature (Ta) than cSIF760 did. In addition, the LUEp responded sensitively to Ta (the correlation coefficient, r = 0.83, p-value < 0.01). The cSIFyield_688 and ΦF_688 (ΦF at 688 nm) also exhibited significantly positive correlations with Ta (r > 0.7, p-value < 0.05), while cSIFyield_760 and ΦF_760 (ΦF at 760 nm) were weakly correlated with Ta (r < 0.3, p-value > 0.05) during overwintering periods. The results also show that LUEp was more sensitive to Ta than ΦF, which caused changes in the LUEp/ΦF ratio in response to Ta. By considering the influence of Ta, the GPP estimation based on the total SIF emitted at the photosystem level (tSIF) was improved (with R2 increased by more than 0.12 for tSIF760 and more than 0.05 for tSIF688). Therefore, our results indicate that the LUEp/ΦF ratio is affected by temperature conditions and highlights that the SIF–GPP model should consider the influence of temperature.

Solar‐Induced Chlorophyll Fluorescence as a Potential Proxy for Gross Primary Production and Methane Emission in a Cool‐Temperate Bog in Northern Japan

“…The SIFs in the red and far‐red bands (SIF red and SIF far‐red ) significantly responded to GPP in the sparsely vegetated Bibai Mire wetland. This finding was consistent with previous studies of SIF far‐red in various ecosystems, such as temperate deciduous forest (Morozumi et al., 2023; X. Yang et al., 2015), paddy fields (Buareal et al., 2023; K. Yang et al., 2018), soybean (Miao et al., 2018), maize (Miao et al., 2020), winter wheat (J. Chen et al., 2022), and coastal salt marsh (Huang et al., 2022). A non‐linear relationship between SIF and GPP was observed from the combination of non‐linear APAR–GPP and linear APAR–SIF relationships, as shown in previous studies (K. Yang et al., 2018; X. Yang et al., 2015).…”

“…Air and soil temperatures, T a, and T s , were the dominant variables that affected ΦSIF, probably via vegetation growth, as reported for winter wheat as a similar herbaceous ecosystem (J. Chen et al, 2022). The current findings from this bog ecosystem reveal a significant relationship between ΦSIF and temperature (both T a, and T s ), while showing no significant correlation with VPD.…”

“…Yang et al, 2015), paddy fields (Buareal et al, 2023;, soybean (Miao et al, 2018), maize (Miao et al, 2020), winter wheat (J. Chen et al, 2022), and coastal salt marsh (Huang et al, 2022). A non-linear relationship between SIF and GPP was observed from the combination of non-linear APAR-GPP and linear APAR-SIF relationships, as shown in previous studies (K. Yang et al, 2018;X.…”

“…Yang et al, 2015) and croplands (J. Chen et al, 2022;Dechant et al, 2020;He et al, 2020;L. Liu et al, 2017;Miao et al, 2020;.…”

“…Another unique characteristic of wetlands is the effect of water inundation. However, a few ground‐based SIF studies have been conducted in wetlands, such as the coastal marsh (Huang et al., 2022), compared with the many studies undertaken in forests (Cheng et al., 2021; Lu et al., 2018; Magney, Bowling, et al., 2019; Nichol et al., 2019; H. Yang et al., 2017; X. Yang et al., 2015) and croplands (J. Chen et al., 2022; Dechant et al., 2020; He et al., 2020; L. Liu et al., 2017; L. Liu, Teng, et al., 2020; L. Liu, Zhao, et al., 2020; Miao et al., 2020; K. Yang et al., 2018). Therefore, it is important to evaluate the potential for SIF to represent photosynthesis and predict methane production, in conjunction with temperature and soil moisture, each of which can be remotely sensed from satellites.…”