Acclimations to light quality on plant and leaf level affect the vulnerability of pepper (Capsicum annuum L.) to water deficit

Abstract

We investigated the influence of light quality on the vulnerability of pepper plants to water deficit. For this purpose plants were cultivated either under compact fluorescence lamps (CFL) or light-emitting diodes (LED) providing similar photon fluence rates (95 µmol m(-2) s(-1)) but distinct light quality. CFL emit a wide-band spectrum with dominant peaks in the green and red spectral region, whereas LEDs offer narrow band spectra with dominant peaks at blue (445 nm) and red (665 nm) regions. After one-week acclimation to light conditions plants were exposed to water deficit by withholding irrigation; this period was followed by a one-week regeneration period and a second water deficit cycle. In general, plants grown under CFL suffered more from water deficit than plants grown under LED modules, as indicated by the impairment of the photosynthetic efficiency of PSII, resulting in less biomass accumulation compared to respective control plants. As affected by water shortage, plants grown under CFL had a stronger decrease in the electron transport rate (ETR) and more pronounced increase in heat dissipation (NPQ). The higher amount of blue light suppressed plant growth and biomass formation, and consequently reduced the water demand of plants grown under LEDs. Moreover, pepper plants exposed to high blue light underwent adjustments at chloroplast level (e.g., higher Chl a/Chl b ratio), increasing the photosynthetic performance under the LED spectrum. Differently than expected, stomatal conductance was comparable for water-deficit and control plants in both light conditions during the stress and recovery phases, indicating only minor adjustments at the stomatal level. Our results highlight the potential of the target-use of light quality to induce structural and functional acclimations improving plant performance under stress situations.

Blue light is more essential than red light for maintaining the activities of photosystem II and I and photosynthetic electron transport capacity in cucumber leaves

“…Although effects of light quality on photosynthetic characteristics has been studied in various species of plants, effects of blue and red lights on photosynthetic electron transport capacity has rarely been further investigated (Hoffmann et al 2015;Li et al 2013;Matsuda et al 2007). In this study, red light severely injured electron transport from Table 3), accompanied by lower connectivity (positive L-band; Fig.…”

Effects of Light Quality on the Chlorophyll Degradation Pathway in Rice Seedling Leaves

“…Meanwhile, both Chls and Cars have low light absorption at 530-610 nm. Previous studies (Nhut et al, 2003;Lee et al, 2007;Johkan et al, 2010;Guo et al, 2011;Lin et al, 2011;Liu et al, 2011;Fan et al, 2013, Hoffmann et al, 2015Hoffmann et al, 2016) have demonstrated that blue light induced the synthesis of Chl and Car. In our study, the concentrations of Chl and Car were greater under FL, B, and RB treatments, with the exception of (Table 1).…”

“…Light induces the Chl biosynthesis pathway, and different spectrums influence the formation of photosynthetic pigments (Jilani et al, 1996;Hoober et al, 1999;Su et al, 2014). Blue light induces higher Chl a/b ratios (Rivkin, 1989;Demarsac et al, 1993;Chen et al, 2014;Hoffmann et al, 2015) and greater accumulations of Chl (Kurilčik et al, 2008;Poudel et al, 2008;Hoffmann et al, 2016). Red light inhibits Chl synthesis at lower concentrations of Chl and precursors like 5-aminolevulinic acid (Tanaka et al, 1998;Sood et al, 2005), protoporphyrin IX (PPIX), magnesium protoporphyrin IX (MGPP), and protochlorophyllide (Pchlide) (Fan et al, 2013).…”

Method and device for measuring stability of plant development by fluctuating asymmetry of optical density of leaves

“…Moreover, blue light causes changes in the composition of chloroplasts providing a higher Chl a / Chl b ratio [19]. Green radiation has a generally positive effect on the plant development [20].…”