Li 190r quantum sensor

Lactuca sativa L. plants were grown in a greenhouse at the State University of Maringá in Maringá, Paraná, Brazil, as described in [3 (link)]. For the study, 11 lettuce varieties were selected, including Rainha de Maio (V01), Vitória (V02), Maravilha de Inverno (V03), Grandes Lagos Americana (V04), Mimosa Prado (V05), Quatro Estações (V06), Batávia Joaquina (V07), Mimosa Vermelha (V08), Batávia Cacimba (V09), Pipa (V10), and Mimosa Rubi (V11) (Figure 1). Fertilization was applied with N-P-K (10-10-10) as recommended for lettuce plants. The intensity of the light was monitored and reached 1200 µmol m⁻² s⁻¹ irradiance, measured by an LI-190R quantum sensor (Li-Cor Inc., Lincoln, NE, USA) under a natural photoperiod (approx. 12/12; light/dark) at 30 °C (±5 °C) with 45–85% relative humidity. The cultivation was conducted through a completely randomized design with 11 treatments and 6 biological repetitions (Figure 1).

Lettuce seeds (Lactuca sativa L.) were germinated on Germitest^® paper immersed in 4 mL of Hoagland’s solution (pH 5.4) in a dish. After 15 days of growth, seedlings were transplanted to MecPlant^® (MecPrec Ind., Telêmaco Borba, Paraná, Brazil), a commercial substrate, and then transported to grow in a greenhouse.
Experiments were conducted in the greenhouse at the State University of Maringá, Maringá, Paraná, Brazil. Eleven lettuce varieties (V_X) were grown (V01—Rainha de Maio, V02—Vitória, V03—Maravilha de Inverno, V04—Grandes Lagos Americana, V05—Mimosa Prado, V06—Quatro Estações, V07—Batávia Joaquina, V08—Mimosa Vermelha, V09—Batávia Cacimba, V10—Pipa and V11—Mimosa Rubi) in pots with a capacity of 3 L containing substrate (soil:sand:organic compounds, in a proportion of 3:2:2). Fertilization was applied with N-P-K (10-10-10) as recommended for lettuce plants. Light was monitored and reached 1200 µmol m⁻² s⁻¹ irradiance, measured by a LI-190R quantum sensor (Li-Cor Inc., Lincoln, NE, USA) under a natural photoperiod (approx. 12/12; light/dark) at 30 °C (±5 °C) with 50–80% relative humidity. The varieties were visually chosen by color (green to purple colors) due to the classes and content of different pigments (Figure 1). The cultivation was conducted through a completely randomized design with 11 treatments and 12 biological repetitions.

LED light tubes were provided by the LED Agri-Bio Fusion Technology Research Center (LAFTRC) at Chonbuk National University in the Republic of Korea. The experiments were conducted in three treatments: monochromatic red LED 660 nm (R), blue LED 450 nm (B), and a fluorescent lamp (FL) (Philips, The Netherlands) as a control. The emission spectra from light sources were measured with an MK-350S (UPRtek, Taipei, Taiwan) (Figure 1).
The in vitro and ex vitro plant materials were incubated for four weeks under light treatment with a 12/12 photoperiod, and a light intensity was controlled at 100 μmol·m⁻²·s⁻¹ and measured by a LI-250A with a LI-190R Quantum Sensor (LI-COR Inc., Lincoln, NE, USA) above the plant canopy.

To determine the greenhouse transmissivity, PPFD at plant level was measured on a cloudy day with a quantum sensor (LI-191SA, LI-COR Biosciences, Lincoln, NE, USA) while concomitantly measuring global radiation (W m⁻²) outside the greenhouse using a solarimeter (Kipp en Zonen, Delft, The Netherlands). The fraction of photosynthetic photon flux (PPF; 400–700 nm) in the total global radiation was assumed to be 47% (Britton and Dodd (1976)), and the conversion factor from energy flux to quantum flux in the PPF region of sunlight 4.57 µmol J⁻¹ [49 (link)]. Greenhouse transmissivity (%) was calculated as:

Global radiation outside the greenhouse was measured every five minutes. When the shading screen was closed, greenhouse transmissivity decreased by ~42%. To calculate PPFD supplied from supplemental light (SL), the number of hours during which SL was switched on was multiplied by its intensity. Light quality of a HPS and LED lamp was measured at 1 m distance with a field spectroradiometer (SS-110, Apogee instruments, Logan, UT, United States). Light intensity at plant level was measured with a quantum sensor (LI-COR, LI-190R Quantum Sensor).

To develop a disease scoring method, the cuticle permeable and Botrytis-resistant long-chain acyl-coa synthase 2 (lacs2-3) mutant and camalexin and indole glucosinolate deficient and Botrytis-susceptible cytochrome p450 79-b2 and -b3 (cyp79 b2/b3) double mutant were used as controls (Bessire et al., 2007 and Buxdorf et al., 2013). The wild type Columbia-0 (Col-0) accession was used as a reference control. Seeds were sown in water saturated vermiculite-peat (Type B2 peat, Kekkilä, Vantaa, Finland, www.kekkila.fi) substrate (1:1 ratio) in 8 × 8 cm pots at high density (~100 seeds per pot). Then, pots were put in mini greenhouses and stratified at 4 °C for 72 h, in darkness, to ensure even germination. Mini greenhouses were placed in a growth room (PhytoScope, PSI, Drasov, Czech Republic) and kept covered to maintain humidity during germination. On day four, the lid was removed, and seedlings were manually thinned using forceps leaving 30 seedlings per pot. Growth conditions in the Arabidopsis growth chamber were 12 h light/12 h darkness and 22 °C and 60% relative air humidity. White LED was used as light source with a photosynthetically active radiation (PAR) of 130 µmol·m⁻²·s⁻¹, controlled using an LI-190R Quantum Sensor coupled to an LI-250A light meter (LI-COR, Bad Homburg, Germany, www.licor.com).

At each sampling, photosynthetically active radiation (PAR; 400–700 nm) was measured with a LI-193 spherical underwater quantum sensor (LI-COR Biosciences, NE, USA) at 0.5 m depth intervals. Measurements were corrected for variance in incident irradiance using a LI-190R quantum sensor (LI-COR Biosciences, NE, USA), and euphotic zone depth calculated (i.e., <1% sub-surface irradiance). A YSI multi-parameter sonde (Xylem Inc., New York, NY, USA) was used to obtain depth profiles of temperature, dissolved oxygen, pH, specific conductivity, redox, and turbidity at each site, while a FluoroProbe (FP) (bbe Moldaenke GmbH, Schwentinental, Germany) was used to measure depth profiles of in situ, fluorescence-based, phytoplankton pigment class-specific chlorophyll (‘green algae’, ‘cyanobacteria’, ’brown’ algae’ (diatoms, chrysophytes and dinoflagellates), and ‘cryptophytes’).

6-fluoroindole (6FI, Fluorochem) was prepared as a 250 mM stock solution in deuterated dimethylsulfoxide (99.8% DMSO-d6, Eurisotop), and diluted as required with H₂O and 10% ²H₂O (Sigma-Aldrich). Riboflavin 5’-monophosphate sodium salt hydrate (FMN, Sigma-Aldrich) was prepared as concentrated 10 mM stock, and added to the final samples immediately before experiments. No attempts were made to degas samples, or remove oxygen. The samples were placed in NMRtorch tubes and sealed with the transparent caps. The photo-CIDNP enhancement factor α has been calculated as: $\alpha =\frac{∣I_L∣}{I_D}$ where I_L and I_D is the signal intensities in the illuminated and in the dark state, respectively. Light intensity (photosynthetic photon flux density, PPFD) at the exterior surface of the tube just outside the sample volume was measured with a calibrated Li-250A photometer and Li-190R quantum sensor (both Li-Cor).