C e n t e r f o r L i g h t i n g E n a b l e d S y s t e m s & A p p l i c a t i o n s Copyright 2017 Rensselaer Polytechnic Institute

Action Spectrum and Beyond

Tessa Pocock Ph.D.

Pocock 2011 Heliospectra AB.

C e n t e r f o r L i g h t i n g E n a b l e d S y s t e m s & A p p l i c a t i o n s 2 Copyright 2017 Rensselaer Polytechnic Institute

Action spectrum - Photosynthesis

Hogewoning et al. 2012

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Action Spectrum: PSII Photodamage

Takahashi et al. 2010

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Photoreceptor Control

(Kami et al. 2010)

Developmental • Flowering • Photoperiodism • Circadian rhythm • Height • Leaf expansion • Branching • Stomatal opening

• Pigments • Immunity • Defense

(Pocock 2016)

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Photosynthetic control – Chloroplast as signal

Organic Compounds

H2O PSII P680

PSI P700

NADPH

PQH2

PQ

Electron flow

ATP

High light

> 700 nm > 680 nm

Chemical energy

Operational • Light capture • PSN efficiency • CO2 assimilation • Stomatal opening • Pigments • Protection • Defense • Height (Pocock 2015)

Light

abso

rptio

n

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Photochemical time constants: More control

PSN control through Pulse Width Modulation of LEDs Ruban 2015

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Chlorophyll fluorescence - 1-3% absorbed light

P680

Pheo

QA QB

2 H2O O2 + 4H+

YZ

e-

http://plantsinaction.science.uq.edu.au

Can increase to 15% under stress

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13 cm

LESA Plant Sensing Project

40 cm

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Day 16h

Night 8h

Seven Days of Sensing: Lettuce

24h

Death

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Continuous light

24h

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Whole CEA Ecosystem

Pollinators

Arikawa et al. 2013

Integrated pest management

Tokushoma et al. 2016

C e n t e r f o r L i g h t i n g E n a b l e d S y s t e m s & A p p l i c a t i o n s 12 Copyright 2017 Rensselaer Polytechnic Institute

Future: Energy Savings through Biological Efficacy

1. Incorporate Biological Efficacies

• Biomass efficacy (g/kWh) • Nutrient density efficacy (μ/mg FW) • Water use efficiency • Photosynthetic efficiency • Photochemical efficiency

CROP

Tuneable LED

Biological Feedback

2. Self-regulated light control

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Thank You!

Funding provided by the National Science Foundation and NYSERDA

(New Scientist 2015)