In the light of new greenhouse technologies: 1. Plant‐mediated effects of artificial lighting on arthropods and tritrophic interactions

Abstract

This review describes the effects of the current and emerging lighting technologies on plants, and the plant‐mediated effects on herbivorous and beneficial arthropods in high‐technology year‐round greenhouse production, where light quality, quantity and photoperiod differ from the natural environment. The spectrum provided by the current lighting technology, high‐pressure sodium lamp (HPSL), differs considerably from that of solar radiation. The major plant‐mediated effects on arthropods were predicted to result from (a) extended photoperiods and lower light integrals, (b) the attenuation of ultraviolet (UV) wavelengths, particularly UV‐B, (c) the high red: far‐red (R : FR) ratio and lower blue : red (B : R) in comparison with solar radiation and (d) the high proportion of yellow wavelengths during winter months. Of these light factors (a–d) (ceteris paribus), (a) and (b) were hypothesised to result in increased performance of herbivores in winter months, whereas the high R : FR ratio decreased herbivore performance or not affected it, at least when interlights are used. The predictions obtained on the basis of this review are also discussed in relation to the modifying factors prevailing in these production environments: enriched CO2 levels, high nutrient amounts, optimised irrigation and temperatures optimal for plants' needs. Based on the carbon/nitrogen and growth/differentiation balance theories, these modifying factors tend to produce plants that allocate most resources to growth at the expense of defensive secondary metabolism and physicochemical defensive structures. At the end, this review discusses knowledge gaps and future research prospects, in which light‐emitting diodes, the emerging lighting technology, play an important role by enabling the targeted manipulation of plant responses to different wavelengths.

Influence of Yellow Light-Emitting Diodes at 590 nm on Storage of Apple, Tomato and Bell Pepper Fruit

“…There are nevertheless some promising reports that irradiation with light in the range of 500-600 nm results in an increase of ascorbic acid and anthocyanin content (29) and that yellow light with wavelengths in the range of 580-600 nm may infl uence gene expression in plants during growth (30). However, there are no literature data available about the infl uence of irradiation with yellow LED light during storage on secondary metabolites of fruits and vegetables.…”

Light Spectrum Affects Growth and Gas Exchange of Common Dandelion and Purple Coneflower Seedlings

“…It is possible to enhance photosynthetic performance modifying the spectral energy distribution (light quality) of lamps. 14 The imbalance in excitation of the photosystem I and II leads to a loss of quantum yield for CO 2 fixation. 6 In this research, common dandelion and purple coneflower showed different gas exchange dynamics under LED and FLUORA treatments, respectively.…”

“…This result is of key importance, as plant blue light photoreceptors influence phototropism, stomata opening, leaf growth and chlorophyll production, while phytochromes absorb red light wavelengths, that initiate flowering, seed germination and root development. 14,15 LEDs are used in numerous applications, including shelf-style lighting in growth rooms and in fullcycle plant production in greenhouses. 2 These lights are also used to determine the better combinations of bulbs, usually of blue and red wavebands, able to produce optimal growth for different species.…”

Seasonal climatic variations influence the efficacy of predatory mites used for control of western flower thrips in greenhouse ornamental crops

“…Although it is known that predatory mites perform differently under varying light intensities and day lengths (Auger et al, 1999;Kazak et al, 2004;Weintraub et al, 2005), only a few studies have investigated possible interactions between these factors, and the impacts this may have on greenhouse BCAs (Johansen et al, 2011;Weintraub et al, 2005;Zilahi-Balogh et al, 2007). The actions of phytoseiids can be impacted directly by light reception and photophase (Gerson et al, 2003), or indirectly, through such effects as altered nutritional quality of the plant, plant defense mechanisms, volatile compound emission levels (Shipp et al, 2009;Vanninen et al, 2010) and behaviours associated with activity and movement when dehydrated (Gerson et al, 2003). Some strains of N. cucumeris enter a reproductive diapause or inactive state when they are exposed to short day lengths of less than 12-14h of light per day (Heinz et al, 2004), thus, a non-diapausing strain of N. cucumeris has been selected for use in greenhouses (Zilahi-Balogh et al, 2007).…”