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Bringing Research indoors


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By Paul Davis from Hansatech about measuring the health of trees and plants via their photosynthesis activity.

Published in: Data & Analytics
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Bringing Research indoors

  1. 1. Bringing Research Indoors The Applied Use of Chlorophyll Fluorescence Analysis for Monitoring Indoor Landscapes Paul Davis Research & Development Officer
  2. 2. • How can current plant science research trends be applied to indoor landscaping? • Used widely in precision agriculture for many years • Principles are the same but different timescales
  3. 3. What is Photosynthesis? The process by which green plants use sunlight to synthesize nutrients from carbon dioxide and water
  4. 4. What do Plants Need to Photosynthesize? • Light • CO2 • Water CO2 + Water O2 + Sugars Light = Chlorophyll
  5. 5. Light energy from the sun Photosynthesis • Plant draws water from the roots • Leaves take in CO2 • Chlorophyll harvests energy from sunlight • Light energy splits H2O molecule into O2 and 2 hydrogen ions • O2 released into the atmosphere • CO2 and Hydrogen ions converted to sugars • Sugars used for plant growth. CO2 O2 Water Sugars
  6. 6. Light energy from the sun Photosynthesis • No system is entirely perfect • Leaf absorbs more energy that it can use • Energy that is surplus to requirement must be dissipated to avoid damaging the leaf structure. CO2 O2 Water Sugars
  7. 7. Light energy from the sun Photosynthesis Chlorophyll Fluorescence Chlorophyll Fluorescence • Biological process that exists in all photosynthetic organisms • Used to dissipate excess energy that cannot be used for photosynthesis • A re-emission of far-red light energy from within the leaf • It is NOT reflected light.
  8. 8. Light energy from the sun Photosynthesis Chlorophyll Fluorescence • Biotic or abiotic stress factors may inhibit photosynthesis • Results in a reduction in photosynthetic output • Inversely proportional rise in chlorophyll fluorescence. STRESS Chlorophyll Fluorescence
  9. 9. • Far-red light energy • Just outside of the spectral response of our eyes. Chlorophyll Fluorescence
  10. 10. How do we Measure Chlorophyll Fluorescence? • Not a new technique • First discovered in 1931 by Dr. Hans W. Kautsky at the University of Heidelberg in Germany Advances in technology have allowed increasingly advanced instrumentation to be developed from this in the 1970’s....
  11. 11. Through to the Handy PEA and Pocket PEA; the current crop of research fluorescence systems. Each system consists of: • Leaf dark-adaptation clips • High-intensity LED light source • Fast-response chlorophyll fluorescence detector. How do we Measure Chlorophyll Fluorescence?
  12. 12. Arborcheck system for arboricultural professionals • Takes 20 readings from a single tree (10 x fluorescence, 10 x chlorophyll content) • Compares data to species-specific benchmark values for trees in optimum condition • Presents results in a easy to interpret visual format. How do we Measure Chlorophyll Fluorescence?
  13. 13. From a Healthy Leaf: • Signal starts at a base level of fluorescence where all light energy receptors in the leaf are open • Rises rapidly (approx. 0.5s) through a series of phases representing energy moving through electron transport chains • Reaches a maximum level when all light receptors are closed i.e. no further light energy can be used and maximum energy dissipation occurs When a dark-adapted leaf is suddenly illuminated with a bright light:
  14. 14. From a Healthy Leaf: • Leaf in the dark • all light acceptors open
  15. 15. From a Healthy Leaf: • Leaf illuminated • Some light acceptors closed • Baseline chlorophyll fluorescence
  16. 16. From a Healthy Leaf: • Illumination continues • More light acceptors closed • Fluorescence intensity rises
  17. 17. From a Healthy Leaf: • Illumination continues • More light acceptors closed • Fluorescence intensity rises
  18. 18. From a Healthy Leaf: • Illumination continues • All light acceptors closed • Fluorescence intensity reaches maximum
  19. 19. From a Healthy Leaf: During this poly-phasic rise, various measured and calculated parameters are defined: • Fo : Base level fluorescence • Fm: Maximum level fluorescence • Fv: Variable fluorescence (Fm – Fo) • Area over the fluorescence trace • OJIP – inflection points where energy moves between electron transport chains • Fv/Fm: Maximum light use efficiency • Over 50 individual measured and calculated parameters offered in research devices.
  20. 20. How is this Helpful? • Measurements taken from 2 different samples • Red trace – Mature English Oak • Blue Trace - Elysia viridis
  21. 21. How is this Helpful? • All healthy photosynthetic material exhibits same characteristic traits during measurement • Allows chlorophyll fluorescence to be used as an indicator of plant health regardless of species. O J I P
  22. 22. Visual Changes in the Signal
  23. 23. Visual Changes in the Signal
  24. 24. Visual Changes in the Signal Heat stress
  25. 25. Changes in Measured/Calculated Parameters Correlation of chlorophyll fluorescence Vs survival of young trees (>2.0m)
  26. 26. Changes in Measured/Calculated Parameters Increases in plant vitality following appropriate fertilisation
  27. 27. Early Detection of Stress Chlorophyll fluorescence can detect stress BEFORE any visible symptoms are apparent.
  28. 28. photosynthesis <> > cell growth > wall/protein synthesis > protochlorophyll formation > nitrate reductase > ABA accumulation > respiration > proline & sugar accumulation > cell leakage > > death. What Happens to a Plant Under Stress? leaf stomatal closure necrosis
  29. 29. Stress Type Chlorophyll Fluorescence Leaf Necrosis Waterlogging 4-8d 10-28d Drought 8h 4d Chilling 6-12h 6-18d Salinity 2h 3-4d Freezing 0h 1-3d h =hours, d =days Chlorophyll Fluorescence vs. Visible Symptoms in Young Trees
  30. 30. Early Detection of Stress: Brief Case Study • Avenue of 18 Lime trees • Visually in good health… however… • Fluorescence results showed that the Fv/Fm for all trees was between 2 and 10 standard deviations below the value expected for a healthy Lime tree • The cause…
  31. 31. Early Detection of Stress: Brief Case Study • Poor nursery practice (tree too deep in root ball) • Poor planting • Too deep • Root ball wire not cut • Compacted soil • Herbicide overspray by gardener.
  32. 32. Early Detection of Stress: Brief Case Study • Chlorophyll fluorescence was effective in detecting a significant decline in vitality prior to any visible symptoms • Allowed remedial work to be prescribed • Clear grass to drip line • Airspade decompaction of soil • Soil amendments (biochar) • Mulch • Repeat fluorescence test following year…
  33. 33. Early Detection of Stress: Brief Case Study
  34. 34. Having a Plan • A newly project requires a certain degree of flexibility in the plans throughout all stages of development/construction • Important when/if unforeseen circumstances occur • What if the selected plants are already in poor health prior to planting? • What if the people trusted to follow the plan make mistakes? • Once the development is finished, can we simply hand responsibility of the welfare of the plants to the customer? • Could fluorescence analysis help to avoid problems associated with plant health?
  35. 35. “Everyone has a plan until they get punched in the face” - Mike Tyson Having a Plan
  36. 36. The Plan • King’s Cross Square, London • Part of a £550 million regeneration of the King’s Cross area.
  37. 37. The Launch – September 2013
  38. 38. The Punch in the Face 2019
  39. 39. Hindsight – a Wonderful Thing! • Chlorophyll fluorescence analysis is demonstrably effective in detecting pre-visual loss of vitality • As part of routine monitoring, fluorescence analysis could have identified problems soon after planting • Simple remedial action to prevent further decline could have been prescribed • Public perception? • Financial implications? • Legal cases to answer? • Should routine, post-planting monitoring have been part of the original plan?
  40. 40. • Routine monitoring as part of an ongoing maintenance plan • Selection of quality planting stock • QC/biosecurity monitoring for nurseries • Early detection of problems caused by pests and diseases • Monitoring effects of maintenance/pruning • Checking vitality following damage • Tracking changes following remedial action How else can Fluorescence be Used?
  41. 41. Which Tree is Under Stress?
  42. 42. Which Tree is Under Stress?
  43. 43. Final Thoughts… A very simple, cost-effective method of getting detailed “under-the-hood” information Can provide early warnings for decline in vitality and presence of stress in plants Can validate visual assessment with empirical data Directs your line of questioning Helps you to understand that……
  44. 44. Thank You for Listening!! Things aren’t always what they seem!