## 2 Materials and Methods
### Leaf Measurements  
Measurements were performed on attached leaves fixed in a vertical position by taping the leaf tip to a wooden stake (avocado), or by fixing multiple leaves onto a black foam board target to produce a flat surface (orange jasmine). Leaf targets faced east at a distance of one meter from the LIFT fore optic. Measurements of active fluorescence and reflected solar radiance were performed in a semi-continuous fashion. Each cycle began with a white reference measurement (Spectralon,Labsphere Inc., North Sutton, NH, USA), followed by a leaf measurement before returning to the white reference (Figure 1; see supplementary material; Video S1).  
Each measurement consisted of a QE Pro reflected radiance measurement consisting of six 160 ms scans (440-870 nm), followed by a LIFT non-invasive Q\({}_{\mathrm{A}}\) flash measurement (500 ms; time for Q\({}_{\mathrm{A}}\) flash and transient fitting). Sequential leaf and white reference measurements resulted in a measurement resolution of approximately 3 min per leaf. These semi-continuous and sequential leaf measurements were repeated from dawn to dusk on cloud free and full sun days, with the set of six leaves changed daily over a total of 18 days. Six leaf replicates were chosen due to geometrical constraints of the tripod panning movements and to maximise the measurement frequency for each leaf. At UOW the 5 d of avocado and 8 d of orange jasmine measurements started 1 h before sunrise and concluded 2 h after sunset. Due to field power limitations the 5 d of avocado measurements at SHF had to be halted 2 h before sunset. Following diurnal measurements, dark-adapted Fm reference values were collected 30 min post sunset using the PQ flash protocol.  
Simultaneously with LIFT/QE Pro measurements, leaf-level PAR was recorded at the surface of each leaf every 5 s using six LS-C micro quantum light sensors (Walz, Effeltrich, Germany) connected to two custom built data loggers (TriplePAR, Gademann Instruments, Wurzburg, Germany). In addition, global PAR was recorded every 10 s using a sky facing MQS-B mini quantum sensor (Walz, Effeltrich, Germany) connected to a Universal Light Meter (ULM-500, Walz, Effeltrich, Germany). Following diurnal measurements, leaf thickness and Chl content measurements were collected at three inter-vein locations per leaf using Vernier calliper and a Soil-Plant Analyses Development 502 chlorophyll meter (SPAD, Spectrum Technologies Inc, Aurora, IL, USA), respectively. Leaf discs (1.5 cm\({}^{2}\) in diameter) were collected from adjacent non-monitored areas of avocado leaves for laboratory leaf pigment determination. Leaf discs were collected from each leaf pre-dawn at UOW. At SHF they were sampled  
Figure 1: Nadir perspective of the diurnal measurement set-up with the Light Induced Fluorescence Transient instrument (LIFT) and QE Pro mounted on a motorized tripod and successively panned between two white reference panels (WR) and six different leaves on two trees (T1 and T2). The solid arc indicates the movement range of the tripod mounted LIFT and QE Pro. Broken arcs indicate the movements for successive measurements, where each arc indicates a single panning movement from WR to leaf and back to WR. The number labels on the broken lines indicate the sequence of panning movements, with those proceeded with an “L” indicating panning motions where leaf measurements occurred.  
four times during each measurement day: pre-dawn, 1 h and 2 h after direct sunlight exposure, and post-sunset (\(n\) = 36 different leaves). Leaf discs were immediately frozen in liquid N\({}_{2}\) and stored at \(-\)80 \({}^{\circ}\)C pending pigment analysis.