## 5 Conclusions  
Using automated systems, this research effort assembled a set of corresponding leaf and canopy chlorophyll fluorescence and reflectance measurements, representative of the diurnal dynamics in the major growth stages for corn, which is supported by canopy GPP collected by an eddy co-variance tower. Statistical analyses of the observations demonstrated that: (1) Canopy SIF was able capture the dynamics in leaf level light-adapted YII and ETR, and SIF\({}_{\text{A+B}}\) exhibited the strongest correlation, (2) As compared to APAR and PRI, SIF metrics provided stronger relationships to GPP and LUE, which differed depending on PAR levels: strongest correlations to GPP under low PAR were provided by SIF\({}_{\text{A+B}}\) and SIF\({}_{\text{A}}\), under high PAR by SIF\({}_{\text{A+By}}\) and SIF\({}_{\text{Ay}}\); PRI had the strongest correlation to LUE under low PAR, while under high PAR, SIF\({}_{\text{A+By}}\) and SIF\({}_{\text{By}}\) provided stronger correlations. (3) The relationships of canopy SIF to leaf F and to canopy GPP differed during the day in association with the diurnal variation in PAR and GPP and with growth stage. This study demonstrated that canopy SIF metrics co-varied with leaf ETR and YII, both indicative of photosynthetic function at leaf level, and therefore show high potential for scaling photosynthetic processes from leaf to canopy level. Using diurnals from the different growth stages, single linear relationships between LUE and SIF\({}_{\text{A+By}}\), and LUE and SIF\({}_{\text{By}}\) described approximately seventy percent of the variation in data associated with both time of observation and growth stage. Diurnal observations of SIF (both SIF\({}_{\text{A}}\) and SIF\({}_{\text{B}}\)) and SIF yield (i.e., SIF\({}_{\text{Ay}}\), SIF\({}_{\text{By}}\), and SIF\({}_{\text{A+By}}\)), spanning the growing season can provide an important capability for remote sensing of canopy GPP and LUE, however, additional research and analysis are warranted to corroborate the applicability of these findings for other species. The change in the PRI diurnal pattern established with corn senescence requires further investigation using other species. Future research is needed to evaluate the driving factors for the established relationships between canopy GPP and the associated reflectance and fluorescence properties, in the context of varying climate and environmental conditions, and using independent field bio-physical measurements. The results contribute to enhancing the ability to relate the commonly measured leaf-level photosynthetic parameters to the canopy level, based on SIF\({}_{\text{A}}\), SIF\({}_{\text{B}}\), SIF\({}_{\text{A+B}}\), and their yields. SIF\({}_{\text{A}}\) is currently measured by satellites (e.g., GOME-2, GOSAT, OCO-2) and the measurement of SIF\({}_{\text{A}}\), and both SIF\({}_{\text{A}}\) and SIF\({}_{\text{B}}\) are targeted by the future NASA GeoCarb and ESA FLEX missions, respectively. The following are available online at [[http://www.mdpi.com/2072-4292/11/5/488/s1](http://www.mdpi.com/2072-4292/11/5/488/s1)]([http://www.mdpi.com/2072-4292/11/5/488/s1](http://www.mdpi.com/2072-4292/11/5/488/s1)), **Table S1:** Linear correlation coefficients (R\({}^{2}\)) between Gross Primary Production (GPP) and leaf-level active fluorescence metrics (PSII (YII) and electron transport rate (ETR), canopy-level optical indices (normalized difference vegetation index (NDVI), photochemical reflectance index (PRI), chlorophyll index (CI\({}_{\text{red}}\)), and photosynthetically active radiation (PAR) metrics. **Table S2:** Linear correlation coefficients (R\({}^{2}\)) between midday Gross Primary Production (GPP) and leaf-level active fluorescence metrics (PSII (YII) and electron transport rate (ETR), canopy-level optical indices (normalized difference vegetation index (NDVI), photochemical reflectance index (PRI), chlorophyll index (CI\({}_{\text{red}}\)), and absorbed photosynthetically active radiation (APAR).