Spectral effects of LEDs on chlorophyll fluorescence and pigmentation in Phalaenopsis ‘Vivien’ and ‘Purple Star’

Abstract

We examined the effect of light emitting diode (LED) lighting in greenhouse facilities on growth, chlorophyll fluorescence and pigmentation in Phalaenopsis 'Vivien' and 'Purple Star' under purpose-built LED arrays yielding c. 200 µmol m(-2) s(-1) at plant height for 14 h per day and 24/18°C day/night temperature, respectively, from January to April 2013. The light treatments were (1) 40% blue in 60% red (40% B/R), (2) 0% blue in 100% red (0% B/R) and (3) white LEDs with 32% blue in white (32% B/W, control), with background daylight under shade screens. The plants were harvested twice for leaf growth and pigmentation. There was no clear pattern in the spectral effect on growth since the order of leaf size differed between harvests in March and April. Fv /Fm was in the range of 0.52-0.72, but overall slightly higher in the control, which indicated a permanent downregulation of PSII in the colored treatments. The fluorescence quenching showed no acclimation to color in 'Purple Star', while 'Vivien' had lower ETR and higher NPQ in the 40% B/R, resembling low light acclimation. The pigmentation showed corresponding spectral response with increasing concentration of lutein while increasing the fraction of blue light, which increased the light absorption in the green/yellow part of the spectrum. The permanent downregulation of PSII moved a substantial part of the thermal dissipation from the light regulated NPQ to non-regulated energy losses estimated by ΦNPQ and ΦNO and the difference found in the balance between ΦPSII and ΦNPQ in 'Vivien' disappeared when ΦNO was included in the thermal dissipation.

Morphological and Physiological Responses of <i>Morus alba</i> Seedlings under Different Light Qualities

“…Light is an important factor for the production of pigments and exposure to different light qualities triggers different physiological responses (Ouzounis et al, 2015). In this study, we found that light quality affected the chlorophyll a/b ratio and carbohydrate content ( Table 2).…”

“…Hogewoning et al (2010b) found that Fv/Fm and ΦPSII of plants grown under blue light and combinations of red and blue light were significantly higher than those grown under red light, yet Fv/Fm and ΦPSII of plants had no significant difference between blue light and combinations of red and blue light, and in addition, monochromatic red light resulted in dysfunctional photosynthetic machinery. Ouzounis et al (2015) also reported that the Fv/Fm of phalaenopsis sp. grown under red light alone was significantly lower than the Fv/Fm of plants grown under a mixture of red and blue light.…”

Morphology, development, and transplant potential of Prunus aviumand Cornus sanguinea seedlings growing under different LED lights

“…In Phalaenopsis, it has been reported that reddish leaves formed under increasing B light (Ouzounis et al, 2014). Leaf coloration is affected by many factors with varying effects (Sims and Gamon, 2002).…”

“…The effect of LEDs on a great deal of horticultural [lettuce (Shen et al, 2014), cucumber (Hernández and Kubota, 2016), basil (Bantis et al, 2016)] and ornamental [Phalaenopsis (Ouzounis et al, 2014)] plants has already been studied. However, only a few studies have been conducted using forest tree species as test material (Astolfi et al, 2012;Riikonen, 2016;Smirnakou et al, 2016).…”

Predawn and high intensity application of supplemental blue light decreases the quantum yield of PSII and enhances the amount of phenolic acids, flavonoids, and pigments in Lactuca sativa

“…In spite of the fact that red lighting has been proved to influence the photosynthetic ability, plant biomass, and plant growth (Kim et al, 2004), it was not applied together with blue lighting. The whole premise behind using pure blue LED light in combination with natural or supplemental light is based on our previous studies (Ouzounis et al, 2014a,b), which have shown that additional blue light increases the amount of SMs; however, those studies were performed almost solely with LEDs as supplemental light.…”