## 5 Conclusions  
In this study, field campaigns were conducted over wheat and maize and continuous ground measurements of SIF (including F760, AF760, and Fy760) were collected based on an automated spectroscopy system. Growth parameters (including LAI, Chl, MTA, and RWC) and environmental parameters (including SWR, Ta, VPD, and SM) were also measured during the field campaigns. Based on this data set, the seasonal and diurnal patterns of SIF were described. Most importantly, we systematically assessed the impacts of both growth and environmental parameters on SIF variation at different time scales. Our results suggested that SIF was affected by both growth and environmental parameters.  
Specifically, F760 was mainly driven by SWR for environmental parameters and LAI, Chl, MTA, and RWC for growth parameters, while being less driven by Ta, VPD, and Rh due to their covariation with SWR. SM also affected seasonal and diurnal patterns of F760 when SM was at a deficit. With the removal of influence from SWR, both AF760 and Fy760 were likely to be less dependent on Ta, Rh, and VPD, while an enhanced relationship of AF760 and Fy760 with SM was particularly observed under water stress. Wheat AF760 was more related to LAI and RWC than F760, as expected, while maize AF760 did not show an enhanced relationship with all growth parameters compared with F760, mostly due to its complicated canopy structure. Compared with AF760, the relationship of Fy760 with canopy structure parameters were further reduced, except for maize measurements. SM-induced water stress could lower the SIF radiance not only by limiting photosynthesis but also by inhibiting plant growth (e.g., LAI in our study); thus, much more attention should be paid when the relationship of SIF with each parameter is interpreted. The impacts of phenological stages on SIF were always present over both seasonal and diurnal scales. This suggests that SIF might be used as a potential indicator for exploring the phenological variation with the global climate change.  
**Supplementary Materials:** The following are available online at [[http://www.mdpi.com/2072-4292/11/17/2002/s1](http://www.mdpi.com/2072-4292/11/17/2002/s1)]([http://www.mdpi.com/2072-4292/11/17/2002/s1](http://www.mdpi.com/2072-4292/11/17/2002/s1)), Figure S1: Seasonal patterns of daily F760, AF760 and Fy760 from four plots of maize compared with daily solar radiation (SWR), Figure S2: Relationships of daily environmental parameters with daily F760, AF760 and Fy760, Figure S3: Comparison of average values of seasonal F760 and concurrent SWR, AF760, Fy760 and growth parameters, including LAI, MTA, Chl (SPAD) and RWC from wheat and maize, Figure S4: Comparison of canopy radiance at 685 nm at four plots of wheat.  
**Author Contributions:** [PERSON] collected data, conducted data analysis, and wrote the manuscript text, guided by [PERSON] [PERSON] and [PERSON] proposed many insightful suggestions on several versions of the manuscript. [PERSON], [PERSON], and [PERSON] provided help with the filed work. All authors contributed to organization and writing of the manuscript.  
**Funding:** This research was funded by the National Natural Science Foundation of China (41671424) to [PERSON] and China Postdoctoral Science Foundation to [PERSON] (2019M650521).  
**Acknowledgments:** We thank [PERSON] for the help with the design of the spectral collecting system and [PERSON] for insightful suggestions on several versions of the manuscript. We also thank the editor and the anonymous reviewers for the constructive comments.  
**Conflicts of Interest:** The authors declare no conflict of interest.