Amir Mayo1, Menachem
Moshelion1, Oded Liran2
1 Institute of Plant Sciences and
Genetics in Agriculture. The Robert H. Smith Faculty of Agriculture,
Food and Environment. The Hebrew University of Jerusalem,
Rehovot, Israel
2 Kineret Limnological Laboratory, Horvat
Kur, Israel
ORCiD: [0000-0003-0156-2884]
Keywords: SIF, Whole-canopy stomatal conductance, Photosynthesis, Functional phenotyping, High-throughput, Plant water relations, Drought stress
High-throughput measurements of photosynthesis across various
cultivars/genomes and environmental conditions are crucial for
understanding plant photosynthetic adaptability. Advanced remote sensing
techniques, such as solar-induced chlorophyll fluorescence (SIF),
facilitate field-based, high-throughput photosynthesis assessments. Our
research explored whether combining SIF measurements with whole-plant
water relation data during standardized drought experiments could
effectively quantify photosynthetic activity and early-stage water
stress detection. We employed the functional-phenotyping PlantArray
system for controlled drought treatment and simultaneous monitoring of
growth and water balance in 72 tomato plants from four different
introgression lines (ILs).
We introduced a SIF-derived index, electron transport rate (RS-ETRi),
and found it negatively correlated with whole-plant stomatal conductance
(Gsc) under normal conditions, and positively during drought.
Surprisingly, no substantial links were found between SIF and either
plant biomass or Gsc. Among various vegetation indices (VIs), SIF 687
was the earliest drought indicator but presented detection challenges
due to its weak signal. Interestingly, while SIF parameters failed to
differentiate between ILs, significant differences were observed through
gravimetric water-relation measurements.
Our findings suggest that while SIF is a valuable tool in photosynthesis
studies, its correlation with photosynthetic activity is complex. Thus,
using SIF alone to quantify photosynthetic activity might be an
oversimplification. We concluded that SIF does not offer advantages over
traditional methods in detecting physiological variations among ILs,
highlighting the complexity and limitations of SIF in plant
physiological research.