*2.5. Photosynthesis and Transpiration*

Plant leaf photosynthetic rate and transpiration analyses were carried out using an LI-6400XT Portable Photosynthesis System (LI-COR Biosciences, NE, USA) with a standard leaf chamber of 2 × 3 cm. During the measurements, CO<sup>2</sup> concentration was maintained at <sup>400</sup> <sup>±</sup> 12.0 <sup>µ</sup>mol mol−<sup>1</sup> , air temperature 21–23 ◦C, and air humidity 60 ± 4.0%.

Photosynthesis and transpiration were measured at the same light intensity as the growth light. Photosynthetic water use efficiency was calculated as the ratio of the rate of carbon assimilation (photosynthesis) to the rate of transpiration.

The light response curve, i.e., the photosynthetic rate as a function of incident light intensity, was measured for four different leaves using an infrared gas analyzer (IRGA) with an LI-6400XT standard lighting chamber; the internal LED lamp in the IRGA machine was used as a light source.
