Lcp narrow lamp

The photosynthetic activity of dark-acclimated plants was assessed using the LCpro-SD Gas Exchange Measurement System (ADC BioScientific Ltd., UK), based on the following parameters:–A—CO₂ assimilation level (μmol m^-2s^-1),–E—transpiration (mmol m^-2s^-1),–s—stomatal conductance (mol m^-2s^-1),–i—intercellular CO₂ concentration (vpm). Measurements were carried out in the phytotron at a constant air temperature of 298.15 K and ambient humidity of 70±5%. The measurement sequence was the same, and the drought-stressed and non-stressed plants under the same fertilizer regimes were alternately measured. For measurements in each plant, the same, youngest, fully developed leaf was selected. The gas exchange measuring settings were set up according to the methods described earlier [36 (link)]. The concentration of CO₂ supplied to the measuring chamber (reference CO₂) was kept at 360 vpm. The flow of air supplied to the measuring chamber (u) was maintained at 200 μmol s^-1. The concentration of H₂O (reference H₂O) was set to ambient, i.e., the actual concentration in the environment. The intensity of the light emitted in the measuring chamber (PPFD) by the red and blue (in the proportion of 10:1) LEDs of the spectrum was set to 400 μmol m^-2s^-1 (LCP Narrow Lamp, ADC BioScientific Ltd., UK). Gas exchange measurements were performed in 3 biological replications.

Net CO₂ assimilation rate (photosynthetic rate: A) and leaf transpiration rate (E) were measured on the same fully mature leaf with a portable photosynthesis system (LCpro-SD, ADC BioScientific Ltd., Hoddesdon, UK) with a narrow leaf chamber (area: 5.8 cm²). During the period of measurements, CO₂ concentration (reference CO₂) in the leaf chamber was kept at 360 ppm, leaf chamber temperature was maintained at 25 ± 1 °C, the flow rate of air was kept at 200 µmol s⁻¹ and ambient H₂O concentration (Reference H₂O) and PAR were adjusted automatically by a red-blue light-emitting diode (LED) light source (LCP Narrow Lamp, ADC BioScientific Ltd., UK). Water use efficiency (WUE) (4) was calculated according to the following equation: $WUE=\frac{A}{E}$