Monitoring of cold and light stress impact on photosynthesis by using the laser induced fluorescence transient (LIFT) approach

Abstract

Chlorophyll fluorescence measurements have been widely applied to quantify the photosynthetic efficiency of plants non-destructively. The most commonly used pulse amplitude modulated (PAM) technique provides a saturating light pulse, which is not practical at the canopy scale. We report here on a recently developed technique, laser induced fluorescence transient (LIFT), which is capable of remotely measuring the photosynthetic efficiency of selected leaves at a distance of up to 50 m. The LIFT approach correlated well with gas exchange measurements under laboratory conditions and was tested in a field experiment monitoring the combined effect of low temperatures and high light intensity on a variety of plants during the early winter in California. We observed a reduction in maximum and effective quantum yield in electron transport for Capsicum annuum L., Lycopersicon esculentum L. and Persea americana Mill. as the temperatures fell, while a grass community was not affected by combined low temperature and high light stress. The ability to make continuous, automatic and remote measurements of the photosynthetic efficiency of leaves with the LIFT system provides a new approach for studying and monitoring of stress effects on the canopy scale.

Integrating Solar Induced Fluorescence and the Photochemical Reflectance Index for Estimating Gross Primary Production in a Cornfield

“…These findings suggest a future approach to significantly improve the performance of current LUE models, by combining these two optical signals. NPQ and chlorophyll fluorescence emission are considered as direct indicators of photosynthetic activities and physiological stress when plants are under sub-optimal environmental conditions [28,53,59,80,[90][91][92][93] such as low water availability [81,[93][94][95], unfavorable temperatures [96,97], nutrients [98][99][100][101], and salinity [102,103]. Consequently, many studies have utilized the spectral indices, PRI and SIF retrievals, as indicators of stress and down-regulation of LUE and GPP [29,50,51,65,82,92,[104][105][106][107].…”

Canopy conundrums: building on the Biosphere 2 experience to scale measurements of inner and outer canopy photoprotection from the leaf to the landscape

“…When calibrated against the 'gold standard' of PAM and gas-exchange measurements, LIFT clearly identified different photosynthetic responses to high light and low night temperatures in cold sensitive tomato and pepper plants, in avocado and in native grassland (Pieruschka et al 2010). The potential of raster-LIFT for monitoring spatial heterogeneity of photosynthesis in the outer canopy was demonstrated using a potted avocado plant (Pieruschka et al 2009) and our preliminary efforts to exploit this capability are shown in Fig.…”

“…7c). Empirically determined corrections against the 'gold-standard' of PAM can be used to accommodate the lower DF/F m 0 of LIFT at high PFD (Pieruschka et al 2010). Much further laboratory evaluation of this instrument is needed to establish its suitability for evaluation of sun flecks within the inner canopy.…”

“…For some, research has ranged from pioneering airborne measurements of the transition from winter photoprotection to spring rejuvenation of light use efficiency (LUE) in the boreal forest of Siberia using remote sensing of spectral reflectance and Eddy covariance flux tower data (Nichol et al 2002), to lead roles in current European projects that provide simultaneous airborne measurements of solar induced fluorescence and CO 2 fluxes , to monitoring of stress in Antarctic moss beds using unmanned aerial vehicles (Lucieer et al 2010). Others invented new techniques for remote sensing of chlorophyll fluorescence and the sensitivity of photosynthesis to stress in the canopy of the model rainforest of B2 L , in Arabidopsis mutants and in the field (Pieruschka et al 2010). Successful combination of infrared thermal imaging and chlorophyll fluorescence imaging to assess consequences of stomatal closure at the leaf level (Omasa and Takayama 2003) is now driving the design of robotic systems to monitor greenhouse crops (K. Takayama, unpubl.…”

Leaf optical properties and dynamics of photosynthetic activity

“…10), can be estimated by simply multiplying a general value for photochemical yield by the light intensity (Maxwell and Johnson 2000). However, this study suggests that efforts to estimate individual leaf light absorption are worthwhile, especially in studies comparing parameters related to the photochemical activity of various species (Pieruschka et al 2010;Magney et al 2017), or between the leaves of a particular species that differ in age, canopy position or season. This is true because PAR absorption can greatly differ from the commonly assumed 0.84, and thus obscure the actual dynamics of photosynthesis.…”