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The utility of light induced fluorescence transients for remote monitoring of canopy photosynthesis at high time resolutions, with special reference to sun-flecks

Conference Paper


Abstract


  • The canopy environment of plants presents a challenging system for understanding photosynthetic dynamics and regulation. This is principally due to the highly variable patchwork of light intensities and qualities, known as sunflecks, that occur as light interacts with canopy elements. Sunflecks commonly vary over the order of seconds to minutes and when combined with difficult to access leaves they make photosynthetic measurements difficult. For sunfleck measurements, the PAM approach is limited by how often saturating flashes can be applied without causing photosystem damage. However, an alternative approach, known as LIFT, has been demonstrated to provide remote (1 to 5 m) PAM comparable measurements, with high time resolutions (<1 second) without disturbing photosynthetic yields. In this study we assess the utility of LIFT for canopy sunfleck measurements. We examine the effect of leaf angularity on LIFT measurements; examine the utility of 685 nm reflectance (R685) for approximating leaf irradiance and preform in vivo measurements of sunflecks using the LIFT approach. We found that LIFT measurements are strongly leaf angle independent (> 40° and < -40° degrees from perpendicular) and that estimates of leaf irradiance can potentially be made from R685 when leaf chlorophyll content is controlled. ¬In vivo measurements of sunflecks revealed novel intra-sunfleck dynamics, in ETR and NPQ engagement, while generalized additive modelling revealed a dependency of PSII yield, NPQ and ETR on sunfleck length and a dependency of ETR and YNO on time since last sunfleck. Our results demonstrate that the LIFT approach is capable of providing high time resolved canopy measurements of photosynthesis with low dependence on leaf angle with the potential to provide remote estimates of ETRs when combined with measurements of R685.

Authors


  •   Wyber, Rhys (external author)
  •   Osmond, Barry B. (external author)
  •   Ashcroft, Michael B. (external author)
  •   Malenovky, Zbynek (external author)
  •   Robinson, Sharon

Publication Date


  • 2017

Citation


  • Wyber, R., Osmond, B., Ashcroft, M. B., Malenovky, Z. & Robinson, S. A. (2017). The utility of light induced fluorescence transients for remote monitoring of canopy photosynthesis at high time resolutions, with special reference to sun-flecks. Photosynthetic Plasticity: From the Environment to Synthetic Systems (pp. 1-1).

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End Page


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Abstract


  • The canopy environment of plants presents a challenging system for understanding photosynthetic dynamics and regulation. This is principally due to the highly variable patchwork of light intensities and qualities, known as sunflecks, that occur as light interacts with canopy elements. Sunflecks commonly vary over the order of seconds to minutes and when combined with difficult to access leaves they make photosynthetic measurements difficult. For sunfleck measurements, the PAM approach is limited by how often saturating flashes can be applied without causing photosystem damage. However, an alternative approach, known as LIFT, has been demonstrated to provide remote (1 to 5 m) PAM comparable measurements, with high time resolutions (<1 second) without disturbing photosynthetic yields. In this study we assess the utility of LIFT for canopy sunfleck measurements. We examine the effect of leaf angularity on LIFT measurements; examine the utility of 685 nm reflectance (R685) for approximating leaf irradiance and preform in vivo measurements of sunflecks using the LIFT approach. We found that LIFT measurements are strongly leaf angle independent (> 40° and < -40° degrees from perpendicular) and that estimates of leaf irradiance can potentially be made from R685 when leaf chlorophyll content is controlled. ¬In vivo measurements of sunflecks revealed novel intra-sunfleck dynamics, in ETR and NPQ engagement, while generalized additive modelling revealed a dependency of PSII yield, NPQ and ETR on sunfleck length and a dependency of ETR and YNO on time since last sunfleck. Our results demonstrate that the LIFT approach is capable of providing high time resolved canopy measurements of photosynthesis with low dependence on leaf angle with the potential to provide remote estimates of ETRs when combined with measurements of R685.

Authors


  •   Wyber, Rhys (external author)
  •   Osmond, Barry B. (external author)
  •   Ashcroft, Michael B. (external author)
  •   Malenovky, Zbynek (external author)
  •   Robinson, Sharon

Publication Date


  • 2017

Citation


  • Wyber, R., Osmond, B., Ashcroft, M. B., Malenovky, Z. & Robinson, S. A. (2017). The utility of light induced fluorescence transients for remote monitoring of canopy photosynthesis at high time resolutions, with special reference to sun-flecks. Photosynthetic Plasticity: From the Environment to Synthetic Systems (pp. 1-1).

Start Page


  • 1

End Page


  • 1