Light Quality Affects Water Use of Sweet Basil by Changing Its Stomatal Development

Abstract

Different light qualities affect plant growth and physiological responses, including stomatal openings. However, most researchers have focused on stomatal responses to red and blue light only, and the direct measurement of evapotranspiration has not been examined. Therefore, we quantified the evapotranspiration of sweet basil under various red (R), green (G), and blue (B) combinations using light-emitting diodes (LEDs) and investigated its stomatal responses. Seedlings were subjected to five different spectral treatments for two weeks at a photosynthetic photon flux density of 200 µmol m−2 s−1. The ratios of the RGB light intensities were as follows: R 100% (R100), R:G = 75:25 (R75G25), R:B = 75:25 (R75B25), R:G:B = 60:20:20 (R60G20B20), and R:G:B = 31:42:27 (R31G42B27). During the experiment, the evapotranspiration of the plants was measured using load cells. Although there were no significant differences in growth parameters among the treatments, the photosynthetic rate and stomatal conductance were higher in plants grown under blue LEDs (R75B25, R60G20B20, and R31G42B27) than in the R100 treatment. The amount of water used was different among the treatments (663.5, 726.5, 728.7, 778.0, and 782.1 mL for the R100, R75G25, R60G20B20, R75B25, and R31G42B27 treatments, respectively). The stomatal density was correlated with the blue light intensity (p = 0.0024) and with the combined intensity of green and blue light (p = 0.0029); therefore, green light was considered to promote the stomatal development of plants together with blue light. Overall, different light qualities affected the water use of plants by regulating stomatal conductance, including changes in stomatal density.

Light regulation of quality and growth of basil

“…with 37 % blue light) to be optimal. However, Lim and Kim (2021) did not find a clear effect of solely red and of R:B ratio ranging from 1.1 to 3 (from 20 to 27 % blue light) on basil growth or morphology. The spectrum of supplemental light under greenhouse conditions did not affect the fresh or dry weight of basil but the dry matter percentage was increased with a R:B ratio of 4 (i.e.…”

Space Flight Cultivation for Radish (Raphanus sativus) in the Advanced Plant Habitat

“…During stage 2 (day 13-28), the water consumption increases exponentially. Both stages are approximations, as the evapotranspiration rates are known to be affected by humidity and temperature (Nonnecke et al, 1971), plant size (Kim et al, 2011), and light quality (Lim and Kim, 2021). Under constant temperature and humidity levels in our tests, the major driving factor for water usage was leaf size and plant density (Table 4).…”

Not All Light Spectra Were Created Equal: Can We Harvest Light for Optimum Food‐Energy Co‐Generation?

“…To assess the capabilities of the model to reproduce the plant response to different light treatments, we simulated photosynthesis and transpiration with the conditions of four studies carried out in controlled laboratory experiments. In these four studies (Clavijo‐Herrera et al., 2018; Lim & Kim, 2021; Mochizuki et al., 2019; Pennisi et al., 2019), various crops (lettuce, basil, and strawberry) were subjected to different light treatments (Figure S1 in Supporting Information S1) based on several combinations of LED lights and other artificial lighting systems. The stomatal conductance was measured in all these experiments, while water use and photosynthetic rate were either measured or assessed with different approaches, as reported in Table S1 in Supporting Information S1.…”

“…More recently, many experimental studies have been conducted to investigate how crops (especially herbal crops such as lettuce, basil, soybean, etc.) react to different light treatments in laboratory controlled conditions (Ahmed et al., 2020; Chen et al., 2021; Clavijo‐Herrera et al., 2018; Danziger & Bernstein, 2021; Fang et al., 2021; Kang et al., 2021; Kim et al., 2004; Lim & Kim, 2021; Liu et al., 2017; Mochizuki et al., 2019; Muneer et al., 2014; Nguyen & Oh, 2021; Pennisi et al., 2019; Pennisi, Pistillo, Orsini, Cellini, et al., 2020; Pennisi, Pistillo, Orsini, Gianquinto, et al., 2020; Pundir et al., 2020; Samuolienė et al., 2020). The majority of these studies, although sometimes with contrasting results, suggest that some parts of the light spectrum are less efficient in terms of carbon assimilation and water use and could be more effectively used to produce solar energy.…”

“…FigureS3in Supporting Information S1 shows the model capabilities to reproduce photosynthetic rate, A n , stomatal conductance, g S , and water use (either in terms of transpiration, T, or water use efficiency, WUE = A n /T) in three different experimental studies, where lettuce(Clavijo-Herrera et al, 2018) and basil(Lim & Kim, 2021;Pennisi et al, 2019) were subjected to different light treatments (FigureS1in Supporting Information S1). The color of the data points indicates the dominant part of the spectrum in the different treatments.…”