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Table 2 Response of non-photochemical quenching to step-decreases (relaxation) and increases (induction) in PPFD

From: High throughput procedure utilising chlorophyll fluorescence imaging to phenotype dynamic photosynthesis and photoprotection in leaves under controlled gaseous conditions

Cultivar

Relaxation

500 to 100 umol m − 2 s − 1 PPFD

Induction

100 to 1000 umol m − 2 s − 1 PPFD

Min. NPQ

R50 (s)

Decrease in NPQ (%)

Max. NPQ

I50 (s)

Fold increase

Paragon W07/08

0.37 ± 0.018

124.5 ± 6.6

81.3 ± 0.7*

2.2 ± 0.0*

5 ± 1.4

6.2 ± 0.3*

CS94

0.43 ± 0.058

108.6 ± 5.8

64.8 ± 3.2

1.5 ± 0.3

4.1 ± 1.3

3.7 ± 0.5

Pavon76

0.26 ± 0.012

67.9 ± 1.0

71.9 ± 1.8

1.2 ± 0.0

9 ± 1.5

4.5 ± 0.2

  1. Example parameters extracted from the response of non-photochemical quenching (NPQ) in leaf sections of T. aestivum ‘Paragon W07/08’, ‘CS94’ and ‘Pavon76’ shown in Fig. 5. Measurements were taken every minute under step-wise changes in Photosynthetic Photon Flux Density (PPFD) from 500 (15 min), 100 (10 min) to 1000 umol m−2 s−1 (10 min). The minimum and maximum NPQ values were determined under 100 and 1000 umol m−2 s−1 PPFD respectively. In addition, the percentage decrease (500 to 100 umol m−2 s−1 PPFD) and fold-increase (100–1000 umol m−2 s−1) in NPQ were calculated. Lastly, a 2-factor exponential decay function was used to determine the time taken to achieve half the minimum (relaxation—R50) or maximum (induction—I50) NPQ (see’Determining the rates of relaxation and induction in NPQ′). Data are the mean ± SE (n = 3–4). Asterisks indicate significant differences where ‘***’ P < 0.001 ‘**’ P < 0.01 ‘*’ P < 0.05