• Why to study light absorption?

Extracted electrons = f(Reaching photons)

– Emission spectrum (LED, solar, any combination)– Absorption spectrum in vivo

– Photoadaption (NPQ, state transitions)– Fluorescence

– Energy efficiency– Energy Photosystem balance

• Emission spectrum

– LED

– Fluorescent lamp

– Solar irradiance

• Absorption spectrum (WT) - Spectrophotometer

• Absorption spectrum (Olive) - Spectrophotometer

Lamp emission spectrum

• Absorption spectrum (WT) – White LED

Absorption spectrum (total)

Absorptium spectrum (components)

• Absorption spectrum (WT) – Orange LED, 590 nm

Chl a Photoprotective C. Photosynth. C. Phycocyanin Allophycocyanin

WT Spectrophotometer 25,5 8,4 10,8 17,8 7,3 37%   12%   15%   26% 10% 71%   29%WT lamp 1,9 0,4 0,5 3,6 0,9 26% 6% 7% 49% 12% 81% 19%WT solar light 2,9 1,1 1,1 1,4 0,5 42% 15% 15% 20% 7% 73% 27%WT blue light 0,1 0,0 0,0 0,0 0,0N(440 nm, 10nm) 63% 20% 13% 3% 1% 76% 24%WT orange light 0,0 0,0 0,0 0,0 0,0N(440 nm, 10nm) 10% 0% 2% 74% 14% 84% 16%

Olive Spectrophotometer 33,2 21,8 28,0 0,0 14,2 34%   22%   29%   0% 15% 0% 100%Olive solar light 5,9 5,4 5,7 0,0 1,0 33% 30% 32% 0% 6% 0% 100%

• Light absorption results

• Blue light absorption

PSII PSI

90-95% Chl aLimiting step: Fb- + Fd (μs)

5-10% Chl aLimiting step: Qa- + Qb- (ms)

PQ

Fluorescence?Heat? Blue = State 1Cyclic flow (10-50%)

0 μE (dark) PQred 60%100 μE (LL) PQred 10%1000 μE (HL) PQred 0%

Cyclic flow

• Light affects cell behaviour– Electron flow affected

• Equations

𝑣 𝑃𝐶∗=𝑘𝑃𝐶 𝑓 ∗𝜎 (𝜆)𝑃𝐶 (𝑆𝑡𝑎𝑡𝑒1)∗𝑃𝐵𝑆 :𝑃𝑆𝐼𝐼∗ 𝐼 (J/s)

𝑣𝐴𝑃𝐶∗=𝑘𝐴𝑃𝐶 𝑓 ∗ [𝑅𝑜𝑑∗]∗ [𝐴𝑃𝐶 ]−𝑘𝐴𝑃𝐶𝑟 ∗ [ 𝐴𝑃𝐶∗ ]∗ [𝑅𝑜𝑑 ]

Rod* + APC ↔ Rod + APC*

Rod + hv → Rod*

• Energy costs– Growth associated (building blocks, polymerisation…)– Basal (osmotic pressure)

– Olive (saving prophycobilin costs)– Photoinhibition spilling