UV-B Radiations and Secondary Metabolites

Abstract

Ultraviolet-B (UV-B: 280 to 320 nm) radiations have appeared to be detrimental to plants, due to their damaging effects on proteins, lipids, membranes and DNA. UV-B radiations are a significant regulator of plants’ secondary metabolites. High intensity of ultraviolet radiations may interfere with growth and productivity of crops. But low levels of UV-B radiations give rise to changes in the plants’ secondary metabolites such as phenolic compounds, carotenoids and glucoseinolates. Therefore, low intensity of UV-B radiations may be used to generate plants, enriched with secondary metabolites, having improved reproductive ability, early ripening and tolerance against fungi, bacteria and herbivores.

Full text

Turkish Journal of Agriculture - Food Science and Technology, 8(1): 147-157, 2020
DOI: https://doi.org/10.24925/turjaf.v8i1.147-157.2878
Turkish Journal of Agriculture - Food Science and Technology
Available online, ISSN: 2148-127X | www.agrifoodscience.com | Turkish Science and Technology
UV-B Radiations and Secondary Metabolites
İlkay Yavaş1,a,* Aydın Ünay2,b, Shafaqat Ali3,c, Zohaib Abbas3,d
1Department of Plant and Animal Production, Koçarlı Vocational School, Adnan Menderes University, 09100 Aydın, Turkey
2Department of Field Crops, Faculty of Agriculture, Adnan Menderes University, 09100 Aydın, Turkey
3Department of Environmental Sciences and Engineering, Government College University, Allama Iqbal Road, Faisalabad, 38000 Pakistan
*Corresponding author
A R T I C L E I N F O
A B S T R A C T
Review Article
Received : 11/08/2019
Accepted : 17/12/2019
Ultraviolet-B (UV-B: 280 to 320 nm) radiations have appeared to be detrimental to plants, due to
their damaging effects on proteins, lipids, membranes and DNA. UV-B radiations are a significant
regulator of plants’ secondary metabolites. High intensity of ultraviolet radiations may interfere with
growth and productivity of crops. But low levels of UV-B radiations give rise to changes in the
plants’ secondary metabolites such as phenolic compounds, carotenoids and glucoseinolates.
Therefore, low intensity of UV-B radiations may be used to generate plants, enriched with secondary
metabolites, having improved reproductive ability, early ripening and tolerance against fungi,
bacteria and herbivores.
Keywords:
Carotenoids
Glucosinolates
Phenolic compounds
Secondary metabolites
Ultraviolet-B
a
iyavas@adu.edu.tr
https://orcid.org/ 0000-0002-6863-9631
b
aunay@adu.edu.tr
https://orcid.org/0000-0002-7278-4428
c
shafaqataligill@yahoo.com
https://orcid.org/0000-0003-0272-7097
d
shafaqataligill@yahoo.com
https://orcid.org/0000-0003-0711-680X
This work is licensed under Creative Commons Attribution 4.0 International License
Introduction
Ultraviolet-B (UV-B: 280 to 320 nm) radiations are
absorbed by stratospheric ozone (O3) and a very small
percentage is transmitted to the Earth’s surface which is
harmful to plants (Ravindran et al., 2010; Kumari and
Prasad, 2013; Frohnmeyer and Staiger, 2003; Gupta, 2017;
Klein et al., 2018). Secondary metabolites, like flavonoids,
alkaloids, and lignin are UV-B absorbing compounds,
which can preserve the genetic material of plants (Gu et al.,
2010; Katerova et al., 2012). Exposure of plants to UV-B
radiations may cause changes in the production of
secondary metabolites (Klein et al., 2018) and pigment
composition (Delgado-Vargas et al., 2000). Kakani et al.
(2003 b) stated that although the amount of UV-B
radiations changed from 2 to 12 kJ m−2 per day, most of the
UV-B studies were conducted under fairly high UV-B
radiation levels (>15 kJ m −2 per day), that are likely to be
unusual in the future climates.
Ultraviolet wavelength (400–200 nm) refers to
electromagnetic radiations between visible light and X-
rays, with significant influence on the living organisms,
including plants (Katerova et al., 2012; Mao et al., 2017).
Climate change refers to seasonal variations, defined as
increased atmospheric temperatures, carbon dioxide
concentrations and intensity of Ultraviolet-B radiations,
having significant influences on plants (Teramura et al.,
1990; Torres et al., 2016). UV-B (280–315 nm) radiations
reach the Earth as a result of stratospheric ozone depletion
due to pollutants.
The aim of this review is to evaluate the effects of
elevated UV-B radiations on the secondary metabolites of
plants. Moreover, yield and yield components, leaf
morphology and anatomy, flowering and pollination of
some important crops under elevated UV-B condition were
also reviewed.

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Crop Yield and Morphological Characters
It is emphasized in the important crops such as pea,
soybean and cotton that the most commonly observed
morphological changes, due to UV-B radiations, include
decreased leaf area or increased leaf thickness (Figure 1).
Decrease in leaf area is attributed to reduction in size,
number, division and expansion of cells. Together with the
reduced leaf area, heliotropism reduced the amount of UV-
B radiations absorbed by the soybean leaves. (Gao et al.,
2003; Gupta et al., 2017). Epicuticular wax content of
cotton leaves was increased by elevated UV-B radiations
but leaf thickness was reduced due to decrease in thickness
of palisade and mesophyll tissue (Kakani et al., 2003 a).
Shorter internodes are observed in UV-B treated pea plants
as a consequence of reduction in number rather than cell
length (Gonzalez et al. 1998). The tolerance to UV-B
radiations has been considered as an important selection
criterion by pea and rice breeders (Brosché and Strid, 2000;
Hidema and Kumagai, 2006; Sharma, 2001). Besides Mao
et al. (2017) have reported that elevated UV radiations
significantly decreased soybean yield.
Figure 1 Changed from Verdaguer et al., 2017 and
Neugart and Schreiner, 2018
Some researchers have emphasized that the reduction
in root elongation, caused by UV-B radiations, was due to
changes in photo hormones such as IAA (Mark and Tevini,
1996). Ultraviolet-B radiations can affect pollination
directly or indirectly. Higher intensity of UV-B radiations
delays the onset of flowering in annual plants with
consequent reduction in fruit and/or seed production.
Flower morphology, pollen production, pollen
germination, pollen tube length and pollen morphology are
adversely affected by elevated UV-B radiations. In
addition, UV-B radiations in soybeans are associated with
the effect of temperature, CO2 and other stressors (Koti et
al., 2005). Plants on higher latitudes and longitudes, where
UV levels are higher, show greater tolerance to UV
radiation than those grown on plains.
UV-B radiation penetration is affected by photo
chromes / crypto chromes, aromatic amino acids, DNA and
phospholipids because they absorb UV-B to some degree.
The content of chlorophyll a, b and total chlorophyll
decreases with increasing UV radiation level (Figure 1). As
a result of decrease in photosynthetic pigments in plants,
due to structural damage, a decrease in the rate of
photosynthesis is observed. Besides, prolonged exposure
of plants to UV-B radiations results in reduced yields.
Quan et al. (2018) stated that the UV-B induced a decline
in photosynthesis with consequent loss in leaf and stem
biomass in Scutellaria baicalensis. High doses of UV-B
radiations impede plant growth and development by
limiting photosynthesis, overproduction of reactive oxygen
species (ROS) and development of oxidative stress, which
may decrease cell viability and ultimately can death of
plants (Katerova et al., 2012; Mao et al., 2017). On the
other hand, low UV-B doses may trigger acclimation
responses in plants. Frohnmeyer and Staiger (2003)
pointed out that low doses of UV-B induce photo
morphogenesis in etiolated seedlings. Similarly, Katerova
et al. (2012) observed enhanced production of secondary
compounds in plants, exposed to low UV-B doses.
Signalling and Perception of Uv-B Radiation
Plants have the extensive ability to respond to the UV-
B exposure. Such kind of plant responses can be measured
by (1) specific physiological and morphological changes
(2) alternations in gene expression and (3) accumulation of
definite secondary metabolites (Lake et al., 2009; Mewis et
al., 2012). Plants possess five different kinds of sensory
photoreceptors which help the plants precisely perceive the
ambient light and generate the responses that prevent the
damage and improve photosynthesis. These photoreceptors
include UVB (UVR8) photoreceptor, phototropism, blue
light-sensing crypto chromes, red/far-red light-sensing
phytochromes and Zeitlupe (Heijde and Ulm, 2012).
UVR8 is the most widely reported UV-B photoreceptor as
stated by different researchers (Yin and Ulm, 2017; Yang
et al., 2018).
UVR8 signalling considerably promotes the UV-B
acclimation and establishment of UV-B tolerance (Gonzalez
et al., 2012). UV-B acclimation is significantly linked with
expression of UVR8-activated gene associated with the
biosynthesis of flavonoids, protection against oxidative
stress, photo inhibition and DNA repair (Favory et al., 2009;
Stracke et al., 2010). Different physiological responses have
been associated with the activity of UVR8 photoreceptor,
including phototropism (Vandenbussche et al., 2014),
stomatal opening (Tossi et al., 2014), leaf development
(Wargent et al., 2009) downward leaf curling (Fierro et al.,
2015), salt stress tolerance (Fasano et al., 2014), shade
avoidance responses (Hayes et al., 2014; Mazza and Ballare,
2015), thermos morphogenesis (Hayes et al., 2017), auxin
signalling (Hayes et al., 2014) and UV-B signalling
influencing defence responses (Demkura et al., 2012).
UVR8 photoreceptor exists as active homodimer in cytosol
which is quickly monomerized during UV-B absorption,
where tryptophan residue act as chromophores UV-B.
Monomer of the UVR8 receptor, induced by UV-B, then
straightaway react with E3 ubiquitin ligase
CONSTITUTIVELY PHOTOMORPHOGENIC 1 (COP1),
thereby starting signal pathways that transduce changes in
gene expression (Favory et al., 2009; Christie et al., 2012;
Wu et al., 2012). Downstream of COP 1 and UVR8, the

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bZIP transcription factors HY5 HOMOLOG (HYH) and
ELONGATED HYPOCOTYL 5 (HY5) are needed for the
obvious regulation of UV-B regulated genes (Stracke et al.,
2013; Binkert et al., 2014). WD40 repeat gene protein
REPRESSOR OF UV-B PHOTOMORPHOGENESIS 1
(RUP1) and REPRESSOR OF UV-B
PHOTOMORPHOGENESIS 2 (RUP2) are quickly and
briefly encourage by UV-B irradiation in COP1, UVR8 and
HY5-Dependent Way (Gruber et al., 2010). Both RUP1 and
RUP2 perfectly interact with UVR8 to enable the reversion
of UVR8 monomers to homodimers in order to stabilize the
signal pathways (Gruber et al., 2010; Heijde et al., 2013).
Uv-B Radiation Stress and Plant Response
Upon continuous UV-B exposure, plants usually
display weakened metabolic stress response due to
governing feedback loops. This exposure subsequently
increases the accumulation of stress-induced metabolites
(Höll et al., 2019). Response of plants to stresses creates
considerable metabolic cost. Subsequently, adaption in
metabolic processes are usually accompanied by deceptive
growth penalties (Herms & Mattson, 1992). Exposure to
UV-B radiations is one of the most destructive factors due
to their subsequent interaction with biological molecules
such as proteins, nucleic acid, photo hormones and lipids,
with subsequent decline in overall performance of plants
(Kataria et al., 2014). Exposure to UV-B radiations affects
the growth of plants, yield, physiological processes,
morphology, DNA and denaturation of proteins. Dose and
proportion of UV-B radiations are critical factors regarding
the plant responses. Spectral balance between UV-B and
photo synthetically active radiations (PAR) is also an
important factor in determining plants’ sensitivity (Sharma
et al.,2017). Particularly, PAR can alleviate negative
effects of enhanced exposure of plants to UV-B radiation
(Nithia et al. 2005).
Plants have developed protective mechanisms to
combat the heightened UV-B irradiance by safeguarding
the sensitive targets (Rizzini et al.,2011). UV-B radiations
provoke the generation of reactive oxygen species (ROS)
through nicotinamide adenine dinucleotide phosphate
(NADPH) oxidase in different cellular components like
mitochondria (Huang et al., 2016) and chloroplasts (Dietz
et al., 2016). Over-generation of ROS in plants, as a
consequence of excessive exposure to UV-B radiations,
results in oxidative damage and cell death (Sharma et al.,
2012). Plants counterbalance the oxidative stress via
accumulation and synthesis of various antioxidant
enzymes and secondary metabolites like ascorbic acid, β-
carotene, flavonoids and some alkaloids which assist in
neutralizing the impact of oxidative stress (Kasote et al.,
2015). Secondary metabolites like flavonoids, free
phenolic acids, tannins and anthocyanin’s have shown
tremendous potential in ROS scavenging and oxidative
stress amelioration in plants (Dyduch-Siemińska et al.,
2015; Pandeya et al., 2018). Flavonoids act as sunscreen to
protect the inner cells of epidermis from harmful
radiations, thus forming a common protective mechanism
in plants (Morales et al., 2010; Petersen et al., 2010).
Biosynthesis of these secondary metabolites is noticeably
controlled by phenylalanine ammonia lease (PAL), and it
is extensively studied enzymes in plants’ responses to
abiotic stress (Kim and Hwang, 2014). Increase in UV-B
irradiance significantly enhances the activity of PAL
which, in turn, promotes the accumulation of secondary
metabolites which either directly or indirectly protect the
plants from UV-B radiation (Hideg et al., 2013).
Metabolic Changes Induced by Uv-B Radiations
Plants specifically sense and precisely react to the UV-B
radiations which can be observed as a modification in
different morpho-physiological attributes including gene
expression and secondary metabolites (Schreiner et al.,
2009; Schmidt et al., 2011; Robson et al., 2015). High levels
of UV-B radiations have been widely established to harm
macromolecules, such as proteins, lipids and DNA, initiating
with the impairment of DNA replication, photosynthesis and
gene transcription (Gill et al. 2015; Liu et al. 2015;
Khudyakova et al. 2019). UV-B radiations of 80–320 nm
wavelength are potentially much more damaging to proteins,
RNA, DNA, with increased generation of free radicals and
reactive oxygen species (ROS) (Kusano et al. 2011). These
harmful effects are partially aggravated by the reactive
oxygen species (ROS). Plants over the years has developed
different strategies to improve their growth under UV-B
Stress. Secondary metabolites act as growth regulators,
enzyme inhibitor, chemical signals, antioxidants and UV-B
screens (Takshak and Agrawal, 2015). UV-B irradiance
significantly controls the biosynthesis of secondary
metabolites such as flavonoid, glucosinolate and carotenoids
(Schreiner et al. 2012).
Generally, the effects of UV-B radiations on secondary
metabolites are greatly dose dependent. Detrimental level
of irradiance depends upon the morphological structure of
the plant organs. Spherical shaped vegetables and fruits,
with comparatively small surface area, require higher UV-
B irradiance to induce metabolic alterations. This effect has
been demonstrated in apple (Hilal et al., 2008), lemon
(Interdonato et al., 2010) and tomato (Liu et al., 2011).
Physiologically young plants respond differently in
contrast to the fully developed plant organs. Similarly,
receptivity of plant organs against UV-B application
appears to be enhanced with the increase in the surface area
(Huyskens-Keil et al., 2010) along with radical
physiological development (Ma et al. 2018). Dose of UV-
B application further regulates the dynamics of metabolite
accumulation in plants. Secondary metabolites such as
glucosinolates and carotenoids are induced at lower dose
of UV-B radiations, as compared with flavonols, which are
triggered by higher UV-B levels (Hagen et al., 2007;
Schmidt et al. 2011). Some metabolites are rapidly
unregulated, subsequent to the UV-B radiations, and other
display a late response. Polyamines seem to increase
quickly, while accumulation of flavonoids is
comparatively slow (Jansen et al., 2008).
Uv-B Radiations Induce Changes in Secondary
Metabolites
Ultraviolet radiations cause accumulation of secondary
metabolites such as flavonoids, glucosinolat, terpen,
alkaloid and phenolic acids which impact several
physiological processes in plants. Tolerance to UV-B is
associated with the induction of different signal

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transduction pathways, secondary metabolite production
and DNA repair mechanisms. Besides, Mao et al. (2017)
stated that the rutin, queretin and total flavonoids contents
were significantly increased under the enhanced UV
radiation at flowering and podding stages of soybean.
Some research reports indicate that UV radiations are used
to prepare plant products enriched with phytochemicals
(Schreiner et al. 2009). Menghini et al. (1993) summarized
that after exposure to UV-B radiations, the amount of
quercetin glycosides in Brassica napus was increased.
One of the mechanisms of adaptation to UV-B radiation
is the accumulation of secondary metabolites in leaf
tissues. Some studies have shown that UV-B radiations
induced 10 to 300% increase in some secondary
metabolites of plants. One of the most effective defence
mechanisms against UV-B radiations in plants is the
accumulation of phenolic compounds. The epidermal layer
accumulates many of the secondary metabolites such as
phenolic compounds and flavonoids which protect the
tissues against harmful effects of UV-B radiations.
Isoprenoids are a large group of C5 - isoprene units
containing compounds accumulated in plants, including
carotene, xanthophylls, terpenes and others. Terpene
provides protection against the deleterious effects of UV-
B radiations through absorbent compounds in plants. The
accumulation of tannin, salicylate and flavonoids in the
leaf, induced by UV-B radiations, was more pronounced in
male, as compared with female plants. Exposure to UV-B
radiation changed the composition of sterols and fatty acids
and increased the abundance of antioxidants in Stereum
hirsutum (Torres et al. 2016). In a study on aquatic plants
such as Alternanthera sessilis (Klein et al., 2018) the
highest estimated flavonoid levels were noted UV-B
exposure for 8 h, followed by a 24 h recovery period.
Hao et al. (2009) exhibited that UV-B in Ginkgo biloba
callus enhanced nitric oxide production, activities of nitric
oxide synthase and phenylalanine ammonia lyase and
flavonoid content. Glycyrrhizin, a biologically active
glycosidic triterpenoid of Glycyrrhiza uralensis, is
accumulated in response to UV-B exposure.
Glucosinolates are a sulphur-rich amino acid-derived
metabolite group found only in plants against biotic and
abiotic stresses. Some researchers have emphasized that
the effects of UV-B on glucosinolate metabolism and the
biosynthesis of genes are regulated in a different way by
UV-B. An increase in the concentration of glucotropeolin
of Tropaeolum majus with UV - B was observed (Gupta et
al., 2017). It was found that UV-B exposure significantly
increased flavonoids in Betula pendula (de la Rosa et al.
2001) and Pinus sylvestris (Lavola et al. 2003). UV-B
exposure increased the flavonoid, quercitrin, the minor
flavonoid, myricetin-3-galactoside chlorogenic acid
contents in birch seedlings (Lavola et al. 1998). Similarly,
Wulff et al. (1999) also observed an increased amount of
quercetin 3-glycoside in European silver birch seedlings,
exposed to high UV-B radiation. UV-B influences
carotenoid contents in plants.
The flavones, flavonols, isoflavonoids, anthocyanins
and phenolic acids play a protective role against prolonged
exposure to high intensity solar radiations (Schreiner et al.,
2012.). UV-B radiations improve the quality of medicinal
plants by increasing the content of secondary metabolites
(Kumari and Prasad, 2013; Pandey and Pandey-Rai, 2014).
Similarly, Ramani and Chelliah (2007) observed that mild
dose of UV-B radiation is effective to increase the
biosynthesis of catharanthine from Catharanthus roseus.
UV-B exposure induces negative effects on tea plant
growth but significantly increases the soluble phenolics
and flavans (Zagoskina et al. 2003). The amount of
carnosic acid, a ROS-retaining terpene, in rosemary
(Rosmarinus officinalis) leaves, was doubled on exposure
to UV-B radiations. UV-B exposure caused a significant
increase in phenylpropanoids and terpenoids levels of
Ocimum basilicum plants (Johnson et al. 1999).
UV-B radiation changed the content of amino acids,
proteins and total sugars of wheat grain. These changes are
indirect effects of alterations in plant vigour or
reproductive capacity. No significant difference was
observed in terms of coarse starch values between
varieties. It has been observed that UV-B radiations
decreased RNA activity and changed the expression of
defence genes, leading to a change in leaf chemistry
including protein, starch and soluble sugars in wheat,
barley, corn, beans, tomatoes and radish leaves.
Ultraviolet-B radiations can influence amino acids
metabolism protein synthesis in both chloroplasts and
cytoplasm. UV-B radiations are affected by the
microclimate and environmental factors including
temperature, precipitation, photosynthetic photon fluence,
UV-A, CO2, soil fertility (Zu et al., 2004). Janetta Nithia
and Shanthi (2017) investigated the effect of enhanced UV-
B radiations under field conditions and suggested that the
synthesis of secondary pigments like flavonoids and
anthocyanin varied among species. The accumulation of
UV-B absorbent pigments is one of the effective methods
of reducing the harmful effects of UV-B radiations in
plants. Flavonoids can accumulate in the leaf epidermis
either in the cuticle, cell wall or in the vacuole. These
absorbent compounds may not be effective against UV-B
radiations if contained within the mesophyll (Ravindran et
al., 2010; Katerova et al., 2012). The largest UV-B
absorbing compounds were observed in barley plants (Liu
et al. 1995). Flavonoid content of wheat plants, exposed to
UV-B and irrigation deficiency, increased with
synergistically effects of both stress factors (Feng et al.,
2007). Under UV-B exposure, saponarin (a flavonoid
found in young green barley leaves possessing potent
antioxidant activities) content was significantly increased
(Kaspar et al. 2010). In a study on soybean by Mao et al.
(2017), it was found that enhanced UV-B with elevated O3
damaged soybean growth mediated by changes in
secondary metabolites and endogenous hormones. The
duration and intensity of UV-B radiations disturb
glucosinolate biosynthesis. It also influences the
phenylpropanoid and flavonoid pathways, leading to
changes in glucosinolate and phenolic compound
concentrations (Schreiner et al., 2009).
Ultraviolet radiation has the capacity to affect a very
wide array of plant metabolites including a range of
antioxidants like xanthophyll’s, ascorbate, tocopherol and
glutathione (Topcu et al., 2015). Various polyamines such
as supermini, spermidine and putrescine are known to be
up regulated by the Ultraviolet radiations (Radyukina et al
2017). Soluble phenolic compounds in plants act as UV
screening pigments and antioxidants as well (Nascimento
et al. 2105; Wang et al.2017). Various phenolic compounds

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are favourable antioxidants and anticancer agents (Roleira
et al. 2015). Similarly, synthesis of carotenoids is
encouraged by the UV-B radiations via rise in phytoene
synthase expression (Shen et al. 2017). Carotenogenesis is
mainly managed by quality of light and controlled by UV-
B receptors and phytochrome (Becatti et al. 2009).
Uv-B Radiation Induces Change in Phenolic
Compounds
Phenolic compounds, predominantly flavonoids are
commonly known as secondary metabolites in plants that
holds aromatic ring having no less than one hydroxyl
groups. Approximately 800 phenolic compounds have
been reported from the plants as naturally occurring
substances (Tungmunnithum et al. 2018). Half of phenolic
compounds are flavonoids such as glycosides, aglycone
and methylated derivatives (Kumar and Pandey, 2013;
Ahmed et al., 2016). Bio-synthesis and accumulation of
flavonoids in chloroplasts, vacuoles and cell wall of the
plants are extensively controlled by the intensity and
exposure of UV-B radiations ((Tilbrook et al., 2013).
Flavonoids have gain considerable attention due to its
prospective health promoting advantage for humans, as
they are reported as effective cardio protective
(Mozaffarian et al., 2018), antioxidants (Tatullo et al.,
2016), anticancer (Madunić et al., 2018), anti-
inflammatory (Nile et al., 2018) and anti-bacterial agent
(Xie et al., 2015).
Increase in Ultraviolet-B light extensively affects the
flavonoids pathways and transforms the flavonoids profile
of various plants (Nascimento et al., 2015; Heinze et al.,
2018; Henry-Kirk et al., 2018). Effect of Ultraviolet-B
light is modified by the dose of UV-B (Xie et al., 2015),
flavonoids structure along with other environmental
aspects such as temperature (Virjamo et al., 2014), light
quality and intensity (Fu et al., 2016) and photosynthetic
photon flux density (Bilodeau et al., 2018). Idris et al.
(2018) also reported that intensity, duration and
wavelength of UV-B affects the accumulation of
flavonoids. Generally, higher UV-B radiations tend to
enhance the flavonoids accumulation in plants. UV-B
improved leaf quercetin (plant flavonol) content and
boosted up the total antioxidant capacity in Coriandrum
sativum (Fraser et al., 2017). Noticeable accumulation of
anthocyanin was observed at high light (HL) as compared
to Low light (LL) in leaves tissues of P. coleoides after 4th
day of UV-B exposure (Vidovic et al., 2015). Climate
change is a driving force behind the change in land and air
temperature (Hannah et al., 2013). Slight change from mild
to moderate temperature showed phenological
modification in grapevine (Jones et al., 2005). It was
reported that low temperature (LT) administration delayed
the ripening phase of the grape and showed a remarkable
impact on the activities of some enzymes which were
involved in the bio-synthesis of flavonoids, resulting in
enhanced accumulation of flavonols and anthocyanins.
Contrarily, berries grown-up under high temperature (HT)
displayed a great boost up in activity of peroxide, which
could ultimately restrict the accumulation of flavonoids
originated under these conditions (Pastore et al., 2017).
Photo synthetically active radiations (PAR) and UV-B
application significantly regulates the accumulation of
flavonoids and net photosynthesis of plants as given in
Figure 2. Much higher generation of flavonoids was detected
under PAR and UV-B application in old and young leaves
(Klem et al., 2012; Morales et al., 2013). Similarly, synthesis
of flavonoids, induced by the UV-B, can further be regulated
by other abiotic factors such as temperature and water stress
as well (Escobar-Bravo et al., 2017). Biosynthesis of
flavonoid in plants is closely linked with the light intensity,
histone deacetylase-6 and photoreceptor phytochrome-B.
Red/far-red (R/FR) ration and intensity of ultraviolet light
are most studied aspects with respect to the effect of light
quality on flavonoids concentration (Tessadori et al., 2009).
Flavonoid methyltransferases and flavonoid glycoside
transferases were significantly regulated through light
quality via series of regulation mechanisms. flavonoid
methyl derivatives showed positive correlation with far-red
(FR) and near infrared (NIR) while negatively correlated
with fraction of R/FR ratio and UV-A radiations. However,
flavonoids and glycoside contents exhibited opposite
correlation (Fu et al., 2016).
Figure 2. Interactive effects of UV-B light with other
abiotic factors on plant growth and production of plant
secondary metabolites
(Source: Escobar-Bravo et al., 2017).
Different studies have demonstrated that repetitive
application of UV-B also regulates the plants’ phenolic
contents. Repeated doses of UV-B considerably increases
the phenolic contents in Lactuca sativa (Lee et al., 2014).
Bio synthesis of important flavonoids and phenolic
compounds depends upon the threshold dose of UV-B
irradiation. Strawberries (Fragaria × ananassa) under high
dose of UV-B level demonstrated the much higher
concentrations of anthocyanins, phenolic acids and total
phenols (Ordidge er al., 2010). It is extensively studied that
quercetin, along with ortho-dihydroxylated flavonoids,
was significantly enhanced, whereas, kaempferol and Vitol
ortho-monohydroxylated flavonoids usually remained

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unaffected by the higher doses of solar radiation especially
UV-B (Winter and Rostas, 2008; Jansen and Bornman,
2012). Modest temperature and moderate dose of UV-B
irradiation were also found helpful in improving phenolic
contents in plants. modeate UV-B radiations (0.25 kJ m-2
d-1 – 0.75 kJ m-2 d-1 ) successfully enhanced the level of
structurally different hydroxycinnamic acid derivatives
and flavonol glycosides in in kale (Brassica oleracea var.
sabellica) under successive doses of UV-B radiation
(Neugart et al., 2014).
Uv-B Radiation Induces Change in Carotenoids
Carotenoids, as tetraterpenoid pigments, ar a bunch of
natural compounds widely found in photosynthesizing
organisms like green plants, fungi, algae and bacteria as
well (Sun et al., 2018). There are around 750 naturally
existing carotenoids. Among them, main carotenoids such
as α-carotene, β-carotene, lutein, β-cryptoxanthin,
astaxanthin, lycopene, fucoxanthin and zeaxanthin are well
documented. Carotenoids play exceptional role in photo
protection and photosynthesis of plants (Hashimoto et al.,
2016). Carotenoids works as necessary pigment in process
of light harvesting. Carotenoid plays a Vitol role in
scavenging of reactive oxygen species (ROS) produced
under UV-B radiation stress and also safeguard the
chlorophyll contents from photo oxidation (Shen et al.,
2018). Excessive production of ROS may otherwise
irreversibly damage the DNA, proteins and lipids
eventually leading to cell death. White and Jahnke (2002)
reported that β-carotene successfully protected the cells of
Dunaliella sp by scavenging the free radicals and ROS
produced as a result of oxidative stress induced by UV-A
and UV-B radiations. Polyene backbone is the core
structural component in carotenoids as it contains sequence
of conjugated bonds (C=C bonds). This special feature is
predominantly accountable for pigmentation properties
and potential of these compounds to effectively interact
with ROS and other free radicals, thus act as active
antioxidants (Andrew and Lowe, 2018). Increased UV-B
irradiance (+9.75 mW cm-2 +20.76 mW cm-2) encourages
the enhanced accumulation of lutein (carotenoid), which
further improves the total antioxidant capacity (TAC) of
antioxidant system to prevent the photo oxidative damage
in tobacco plant (Shen et al., 2017).
Temperature and light intensity are the main
environmental aspects affecting the growth and
development of plants. Slight change in intensity, duration
and range of light can cause cellular damage and eventually
leads to the death of plant. Different plants have adapted
numerous protective mechanisms that make help them
survive under unfavourable conditions of light and
temperature stress (Szymańska e t al. 2017). Crucial part of
antioxidant system usually operates in chloroplast where
carotenoids exist (Sun et al., 2018). Carotenoids pathways at
transcript level appear to be associated with stress response
e.g. light stress. High intensity of light increases the steady
state of carcinogenic enzymes such as phytoene desaturase
(PDS) and phytoene synthase (PSY). Maximum steady-state
of β-LCY at mRNA levels was observed when exposed to
maximum light intensity of 500 lmol m-2 s-1. Similarly, b-
carotene content accumulation at cellular level was twice at
maximum light intensity of (500 lmol m-2 s-1) as compared
to the value attained at low light (45 lmol m-2 s-1) conditions
in Dunaliella salina (Ramos et al.,2008). Improved
accumulation of antheraxanthin and zeaxanthin was
observed under high intensity light in Chlamydomonas
reinhardtii (Couso et al. 2012). Zeaxanthin fractions were
also enhanced in cells of Dunaliella salina with the increase
in the light irradiance (Fu et al., 2013). Light intensity
significantly affects the biomass and lutein productivity in
Chlamydomonas sp. The highest lutein productivity of
5.08 mg/L/d was attained at high light irradiation of
625 μmol/m2/s (Ma., 2019).
Temperature affects the quality and yield of the crops
by altering their important biochemical and physiological
processes (Wang et al. 2016; Sunoj et al. 2016; Yang et al.
2016; Xu et al. 2016). Environmental temperature
significantly affects the carotenogenesis as well.
Accumulation of carotenoids increases with the increase in
the temperature. Threefold increase in the astaxanthin was
observed in Haematococcus pluvialis with increase in
temperature from 20 to 30°C. High temperature induces
higher accumulation of carotenoids contents (Juneja et al.
2013). Significant reduction in carotenoids contents was
observed in Pisum sativum L. (Juozaitytė et al., 2008),
Phyllanthus amarus L (Indrajith and Ravindran, 2009) and
Dolichos lablab (Singh et al., 2011) as a result of UV-B
stress. Oxidative stress destroys the carotenoids contents at
much higher pace than their capability of scavenging the
ROS, which results in reduced ability to mitigate the UV-
B stress. Therefore, a complex relationship exists between
carotenoids and ROS under UV-B stress.
Uv-B Radiation Induces Change in Glucosinolates
Glucosinolates (GSL) are well known secondary
metabolites having sulfur- and nitrogen-compounds. They
are well known for keeping auxin homeostasis in plants, and
preventing cancer in human. Glucosinolates are classified in
three categories; (1) aliphatic glucosinolate derived from
leucine, alanine and valine, (2) indolic glucosinolate derived
from tryptophan and (3) benzoic glucosinolate derived from
tyrosine and phenylalanine (Kliebenstein et al., 2005).
Around 130 Glucosinolates are identified so far, and they
belong to family Brassicaceae (Baskar et al., 2012).
Production and accumulation of phenolic compounds and
flavanoids against exposure to UV-B radiation is well
documented. Whereas, effects of UV-B irradiance on
production and accumulation of glucosinolates has gained
little and no consideration in past. Reports on the outcomes
of UV-B radiations on preharvest and postharvest
lucosinolate contents are scarce in the previous literature.
UV-B irradiance (5.5 kJ m-2) significantly affected the
expression of gene responsible for the synthesis of indolyl
GLS in A. thaliana (Demkura and Ballaré, 2012). UV-B
irradiation (20 kJ m-2 d-1) also influenced the indolyl GLS,
total aliphatic and total GLS in Brassica oleracea L. var.
italic (Rybarczyk-Plonska et al., 2016). An increase in total
GLS was observed in mustard, nasturtium (Reifenrath and
Mueller, 2007) and canola (Moghadam et al., 2012) under
UV-B treatment. Even low level exposure of UV-B (0.3 to
0.6 kJ m-2 d-1) considerably enhanced the total glucosinolate
contents in broccoli sprouts (Pérez-Balibrea et al., 2010).
Recently, Moreira-Rodríguez et al. (2017) also reported an
extensive increase in total glucosinolate content (~148%) of

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153
young broccoli sprouts under UV-B (7.16 W/m-2) treatment.
While in contrast, Wang et al. (2012) reported a significant
decline in total glucosinolate in A. thaliana on continuous
exposure to UV-B for 12 hours.
Future outlook
This review revealed that UV-B radiations affected the
morphologic and anatomic characteristics of leaf. It is a
fact that the most important mechanisms of adaptation to
UV-B radiation are the accumulation of secondary
metabolites in leaf tissues. Especially, flavonoids protected
DNA from UV-induced DNA damage can accumulate in
the leaf epidermis, either in the cuticle, cell wall or in the
vacuole as a clear example of this mechanism. External
moderate dose of UV-B irradiation together with modest
temperature were also found helpful in improving phenolic
contents in plants. Moreover, carotenoid plays a vital role
in scavenging of reactive oxygen species (ROS) produced
under UV-B radiations stress and also safeguard the
chlorophyll contents from photooxidation. Similarly,
increased UV-B irradiance stimulated the accumulation of
carotenoid such as lutein, which further improves the total
antioxidant capacity (TAC) of antioxidant system to
prevent the photooxidative damage in plant. As a result,
review explained that UV radiations altered many aspects
of plant growth and metabolism, including the
development of defence compounds and structures.
References
Ahmed SI, Hayat MQ, Tahir M, Mansoor Q, Ismail M, Keck K,
Bates RB. 2016. Pharmacologically active flavonoids from
the anticancer, antioxidant and antimicrobial extracts of
Cassia angustifolia Vahl. BMC Complement. Altern. Med.
16: 460.
Baskar V, Gururani MA, Yu JW, Park SW. 2012. Engineering
glucosinolates in plants: Current Knowledge and potential
uses. Appl. Bioch. Biotech. 168: 1694-1717.
Becatti E, Petroni K, Giuntini D, Castagna A, Calvenzani V, Serra
G, Mensuali-Sodi A, Tonelli C, Ranieri A. 2009. Solar UV-B
radiation influences carotenoid accumulation of tomato fruit
through both ethylene-dependent and -independent
mechanisms. J. Agric. Food Chem. 57: 10979-10989.
Bilodeau SE, Wu B-S, Rufyikiri A-S, MacPherson S, Lefsrud M.
2019. An Update on Plant Photobiology and Implications for
Cannabis Production. Front. Plant Sci. 29 March 2019
https://doi.org/10.3389/fpls.2019.00296.
Binkert M, Kozma-Bognar L, Terecskei K, De Veylder L, Nagy
F, Ulm R. 2014. UV-B-responsive association of the
Arabidopsis bZIP transcription factor ELONGATED
HYPOCOTYL5 with target genes, including its own
promoter. Plant Cell. 26:4200- 4213.
Brosché M, Strid A. 2000. Ultraviolet‐B radiation causes tendril
coiling in Pisum sativum. Plant and Cell Physiology. 41:
1077-1079.
Christie JM, Arvai AS, Baxter KJ, Heilmann M, Pratt AJ, O’Hara
A, Kelly SM, Hothorn M, Smith BO, Hitomi K, Jenkins KI,
Getzoff ED. 2012. Plant UVR8 photoreceptor senses UV-B
by tryptophan-mediated disruption of cross-dimer salt
bridges. Science 335: 1492–1496.
Couso I, Vila M, Vigara J, Cordero B, Vargas M, Rodríguez H,
León R. 2012. Synthesis of carotenoids and regulation of the
carotenoid biosynthesis pathway in response to high light
stress in the unicellular microalga Chlamydomonas
reinhardtii. Europ J Phycol., 47:223–232.
de la Rosa TM, Julkunen-Tiitto R, Lehto T, Aphalo PJ. 2001.
Secondary metabolites and nutrient concentrations in silver
birch seedlings under five levels of daily UV-B exposure and
two relative nutrient addition rates. New Phytologist. 150:
121–131.
Delgardo-Vargas F, Jime´nez AR, Paredes-Lo´pez O. 2000.
Natural pigments: carotenoids, anthocyanins and betalains.
Characteristics, biosynthesis, processing, and stability.
Critical Reviews in Food Science and Nutrition. 40: 173–289.
Demkura PV, Ballare CL. 2012. UVR8 mediates UV-B-induced
Arabidopsis defense responses against Botrytis cinerea by
controlling sinapate accumulation. Mol. Plant. 5:116-126.
Dietz KJ, Turkan I, Krieger-Liszkay A. 2016. Redox- and
reactive oxygen species-dependent signaling into and out of
the photosynthesizing chloroplast. Plant Physiol. 171: 1541-
1550.
Dyduch-Siemińska M, Najda A, Dyduch J, Gantner M, Klimek
K. 2015. The Content of Secondary Metabolites and
Antioxidant Activity of Wild Strawberry Fruit (Fragaria
vesca L.). J Anal Methods Chem., 831238.
Escobar-Bravo R, Klinkhamer PGL, Leiss KA. 2017. Interactive
effects of UV-B light with abiotic factors on plant growth and
chemistry, and their consequences for defense against
arthropod herbivores. Front Plant Sci. 8:14
Fasano R, Gonzalez N, Tosco A, Dal Piaz F, Docimo T, Serrano
R, Grillo S, Leone A. 2014. Inze D: Role of Arabidopsis UV
RESISTANCE LOCUS 8 in plant growth reduction under
osmotic stress and low levels of UV-B. Mol. Plant. 7:773-
791.
Favory JJ, Stec A, Gruber H, Rizzini L, Oravecz A, Funk M,
Albert A, Cloix C, Jenkins GI, Oakeley EJ, Seidlitz HK,
Nagy F, Ulm R. 2009. Interaction of COP1 and UVR8
regulates UV-B-induced photomorphogenesis and stress
acclimation in Arabidopsis. EMBO J. 28:591-601.
Favory JJ, Stec A, Gruber H, Rizzini L, Oravecz A, Funk M,
Albert A, Cloix C, Jenkins GI, Oakeley EJ, Seidlitz HK, Nagy
F, Ulm R. 2009. Interaction of COP1 and UVR8 regulates
UV-B-induced photomorphogenesis and stress acclimation in
Arabidopsis. EMBO J. 28: 591-601.
Feng H, Li S, Xue L, An L, Wang X. 2007. The interactive effects
of enhanced UVB radiation and soil drought on spring wheat,
South Afr. J. Bot. 73: 429-434
Fierro AC, Leroux O, De Coninck B, Cammue BP, Marchal K,
Prinsen E, Van Der Straeten D, Vandenbussche F. 2015.
Ultraviolet-B radiation stimulates downward leaf curling in
Arabidopsis thaliana. Plant Physiol. Biochem. 93:9-17.
Fraser DP, Sharma A, Fletcher T, Budge S, Moncrieff C, Dodd
AN, Franklin KA. 2017. UV-B antagonises shade avoidance
and increases levels of the flavonoid quercetin in coriander
(Coriandrum sativum). Sci Rep. 7: 17758.
Frohnmeyer H, Staiger D. 2003. Ultraviolet-B radiation-mediated
responses in plants. Balancing damage and protection. Plant
Physiol. 133:1420–28
Fu W, Guðmundsson Ó, Paglia G, Herjólfsson G, Andrésson ÓS,
Palsson BØ, Brynjólfsson S. 2013. Enhancement of
carotenoid biosynthesis in the green microalga Dunaliella
salina with light-emitting diodes and adaptive laboratory
evolution. Appl. Microbiol. Biotechnol. 97(6):2395-2403.
Gao W, Zheng Y, Slusser JR, Heisler GM. 2003. Impact of
enhanced ultravioletB irradiance on cotton growth,
development, yield and qualities under field conditions.
Agric. For. Meteor. 120: 241–248.
Gill SS, Anjum NA, Gill R, Tuteja N. 2015. DNA damage and
repair in plants under ultraviolet and ionizing radiations. Sci.
World J. 250158. doi: 10.1155/2015/250158.
Gonzalez Besteiro MA, Bartels S, Albert A, Ulm R. 2011.
Arabidopsis MAP kinase phosphatase 1 and its target MAP
kinases 3 and 6 antagonistically determine UV-B stress
tolerance, independent of the UVR8 photoreceptor pathway.
Plant J. 68:727-737.

Yavaş et al. / Turkish Journal of Agriculture - Food Science and Technology, 8(1): 147-157, 2020
154
Gonzalez R, Mepsted R, Wellburn AR, Paul ND. 1998. Non‐
photosynthetic mechanisms of growth reduction in pea
(Pisum sativum L.) exposed to UV‐B radiation. Plant, Cell &
Environment 21: 23-32.
Gruber H, Heijde M, Heller W, Albert A, Seidlitz HK, Ulm R.
2010. Negative feedback regulation of UV-B-induced
photomorphogenesis and stress acclimation in Arabidopsis.
Proc. Natl. Acad. Sci. U.S.A. 107:20132-20137.
Gu XD, Sun MY, Zhang L, Fu HW, Cui L, Chen RZ, Zhang DW,
Tian JK. 2010. UV-B induced changes in the secondary
metabolites of Morus alba L. Leaves. Molecules. 15: 2980-
2993.
Gupta SK, Sharma M, Deeba F, Pandey V. 2017. Plant response:
UV-B avoidance mechanisms. In Singh VP, Singh S, Prasad
SM, Pariha P. (eds). UV-B Radiation: From Environmental
Stressor to Regulator of Plant Growth. New York: John Wiley
& Sons Ltd., 217–58.
Hagen SF, Borge GIA, Bengtsson GB, Bilger W, Berge A,
Haffner K, Solhaug KA. 2007. Phenolic contents and other
health and sensory related properties of apple fruit (Malus
domestica Borkh., cv. Aroma): Effect of postharvest UV-B
irradiation. Postharvest Biol. Technol. 45: 1–10.
Hannah L, Roehrdanz PR, Ikegami M, Shepard AV, Shaw MR,
Tabor G, Zhi L, Marquet PA, Hijmans RJ. 2013. Climate
change, wine, and conservation. Proc. Natl. Acad. Sci. U.S.A.
110, 6907–6912.
Hao G, Du X, Zhao F, Shi R, Wang J. 2009. Role of nitric oxide
in UV-B-induced activation of PAL and stimulation of
flavonoid biosynthesis in Ginkgo biloba callus. Plant Cell
Tiss Organ Cult. 97: 175–185.
Hashimoto H, Uragami C, Cogdell RJ. 2016. Carotenoids and
photosynthesis. Subcell. Biochem. 79:111–139.
Hayes S, Sharma A, Fraser DP, Trevisan M, Cragg-Barber CK,
Tavridou E, Fankhauser C, Jenkins GI, Franklin KA. 2017.
UV-B perceived by the UVR8 photoreceptor inhibits plant
thermomorphogenesis. Curr. Biol. 27:120-127.
Hayes S, Velanis CN, Jenkins GI, Franklin KA. 2014. UV-B
detected by the UVR8 photoreceptor antagonizes auxin
signaling and plant shade avoidance. Proc. Natl. Acad. Sci.
111 :11894-11899.
Heijde M, Ulm R. 2012. UV-B photoreceptor-mediated
signalling in plants. Trends Plant Sci. 17:230–37.
Heijde M, Ulm R. 2013. Reversion of the Arabidopsis UV-B
photoreceptor UVR8 to the homodimeric ground state. Proc.
Natl. Acad. Sci. 110:1113-1118.
Heinze M, Hanschen FS, Wiesner-Reinhold M, Baldermann S,
Grafe J, Schreiner M, Neugart S. 2018. Effects of
developmental stages and reduced uvb and low uv conditions
on plant secondary metabolite profiles in Pak Choi (Brassica
rapa subsp chinensis). J. Agric. Food Chem. 66: 1678–1692.
Henry-Kirk RA, Plunkett B, Hall M, McGhie T, Allan AC,
Wargent JJ, Espley RV. 2018. Solar UV light regulates
flavonoid metabolism in apple (Malus × domestica). Plant
Cell Environ. 41(3):675–688
Herms DA, Mattson WJ. 1992. The dilemma of plants: to grow
or defend. Quarterly Review of Biology. 67: 283-335.
Hideg É, Jansen MAK, Strid Å. 2013. UVB exposure, ROS, and
stress: inseparable companions or loosely linked associates?
Trends Plant Sci. 18: 107–115.
Hidema J, Kumagai T. 2006. Sensitivity of rice to ultraviolet-B
radiation. Annal Bot. 97:933–42.
Hilal M, Rodríguez-Montelongo L, Rosa M, Gallardo M,
González JA, Interdonato R, Rapisarda VA, Prado FE. 2008.
Solar and supplemental UV-B radiation effects in lemon peel
UV-B-absorbing compound content-seasonal variations.
Photochem. Photobiol. 84:1480–1486.
Höll J, Lindner S, Walter H, Joshi D, Poschet G, Pfleger S, Ziegler
T, Hell R, Bogs J, Rausch T. 2019. Impact of pulsed UV-B
stress exposure on plant performance: How recovery periods
stimulate secondary metabolism while reducing adaptive
growth attenuation. Plant Cell Environ. 42(3):801-814.
Huang S, Van Aken O, Schwarzlander M, Belt K, Millar AH.
2016. The roles of mitochondrial reactive oxygen species in
cellular signaling and stress response in plants. Plant Physiol.
171:1551–1559.
Huyskens-Keil S, Schreiner M, Krumbein A, Reichmuth C,
Janata E, Ulrichs C. 2010. UV-B and gamma irradiation as
physical elicitors to promote phytochemicals in Brassica
sprouts. Acta Hort. 858: 37–41.
Indrajith A, Ravindran KC. 2009. Antioxidant potential of Indian
medicinal plant on Phyllanthus amarus L. under
supplementary UV-B radiation. Recent Res. Sci. Technol. 1:
34-42.
Interdonato R, Rosa M, Nieva CB, Gonzalez JA, Hilal M, Prado
F.E. 2010. Effects of low UV-B doses on the accumulation of
UV-B absorbing compounds and total phenolics and
carbohydrate metabolism in the peel of harvested lemons.
Environ. Exp. Bot. 70: 204–211.
Janetta Nithia SM, Shanthi N. 2017. Effect of enhanced solar
UVB (280-320nm) radiation on secondary pigment synthesis
in some plants. International Journal of Environmental &
Agriculture Research. 3 (1):111-115
Jansen MAK, Bornman JF. 2012. UV-B radiation: from generic
stressor to specific regulator. Physiol. Plantarum. 145: 501-
504.
Jansen MAK, Hectors K, O’Brien NM, Guisez Y, Potters G.
2008. Plant stress and human health: Do human consumer
benefit from UV-B acclimated crops? Plant Sci. 175: 449–
458.
Johnson CB, Kirby J, Naxakis G, Pearson S. 1999. Substantial
UV-B-mediated induction of essential oils in sweet basil
(Ocimum basilicum L.). Phytochemistry, 51: 507–510.
Jones GV, White MA, Cooper OR, Storchmann K. 2005. Climate
change and global wine quality. Clim. Change 73: 319–343.
Juozaitytė R, Ramaškevičienė A, Sliesaravičius A, Burbulis N,
Kuprienė R, Liakas V, Blinstrubienė A. 2008. Effects of UVB
radiation on photosynthesis pigment system and growth of
pea (Pisum sativum L.). Sci Works Lithuanian Inst. Hortic.
Lithuanian Univ. Agric. 27: 179-186.
Kakani VG, Reddy KR, Zhao D, Mohammed AR. 2003 b.
Ultraviolet-B radiation effects on cotton (Gossypium
hirsutum L.) morphology and anatomy. Ann. Bot. 817–826.
Kakani VG, Reddy KR, Zhao D, Sailaja K. 2003 a. Field crop
response to ultraviolet-B radiation: a review. Agric Forest
Meteorol. 120:191–218
Kasote DM, Katyare SS, Hegde MV, Bae H. 2015. Significance
of antioxidant potential of plants and its relevance to
therapeutic applications. Int. J. Biol. Sci. 11:982–991.
Kaspar S, Matros A, Mock H-P. 2010. Proteome and flavonoid
analysis reveals distinct responses of epidermal tissue and
whole leaves upon UV-B radiation of barley (Hordeum
vulgare L.) seedlings. Journal of Proteome Research. 9(5):
2402–2411.
Kataria S, Jajoo A, Guruprasad KN. 2014. Impact of increasing
ultraviolet-B (UV-B) radiation on photosynthetic processes. J
Photochem Photobiol B Bio.l 137:55–66.
Katerova Z, Todorova D, Tasheva K, Sergiev I. 2012. Influence
of ultraviolet radiation on plant secondary metabolite
production. Genetics and Plant Physiology. 2(3–4): 113–144.
Khudyakova AY, Kreslavski VD, Shmarev AN, Lyubimov VY,
Shirshikova GN, Pashkovskiy PP, Kuznetsov VV,
Allakhverdiev SI. 2019 Impact of UV-B radiation on the
photosystem II activity, pro-/antioxidant balance and
expression of light-activated genes in Arabidopsis thaliana
hy4 mutants grown under light of different spectral
composition. Journal of Photochemistry and Photobiology B:
Biology. 194: 14-20.
Kim DS, Hwang BK. 2014. An important role of the pepper
phenylalanine ammonia-lyase gene (PAL1) in salicylic acid-
dependent signalling of the defence response to microbial
pathogens. J Exp Bot. 65(9): 2295–2306.

Yavaş et al. / Turkish Journal of Agriculture - Food Science and Technology, 8(1): 147-157, 2020
155
Klein FRS, Reis A, Kleinowski AM, Telles RT, do Amarante L,
Peters JA, Braga EJB. 2018. UV-B radiation as an elicitor of
secondary metabolite production in plants of the genus
Alternanthera. Acta Bot. Bras. 32 (4): 615-623.
Klem K, Ač A, Holub P, Kováč D, Špunda V, Robson TM, Urban
O. 2012. Interactive effects of PAR and UV radiation on the
physiology, morphology and leaf optical properties of two
barley varieties. Environ. Exp. Bot. 75:52–64.
Kliebenstein DJ, Kroymann J, Mitchell-Olds T. 2005. Current
Opinion in Plant Biology. 8: 264–271.
Koti S, Reddy KR, Reddy VR, Kakani VG, Zhao D. 2005.
Interactive effects of carbon dioxide, temperature, and
ultraviolet‐B radiation on soybean (Glycine max L.) flower
251 and pollen morphology, pollen production, germination,
and tube lengths. Journal of Experimental Botany. 56: 725–
736
Kumar S, Pandey AK. 2013. Chemistry and biological activities
of flavonoids: An overview. Sci. World J. 162750.
Kumari R, Prasad MNV. 2013. Medicinal Plant Active
Compounds Produced by UV-B Exposure. Sustainable
Agriculture Reviews. 12:225–254. doi: 10.1007/978-94-007-
5961-9_8
Kusano M, Tohge T, Fukushima A, Kobayashi M, Hayashi N,
Otsuki H, Kondou Y, Goto H, Kawashima M, Matsuda F,
Niida R, Matsui M, Saito K, Fernie AR. 2011. Metabolomics
reveals comprehensive reprogramming involving two
independent metabolic responses of Arabidopsis to UV-B
light. Plant J. 67:354–369.
Lake, JA, Field KJ, Davey MP, Beerling DJ, Lomax BH. 2009.
Metabolomic and physiological responses reveal multi-
phasic acclimation of Arabidopsis thaliana to chronic UV
radiation. Plant, Cell Environ. 32: 1377–1389.
Lavola A, Aphalo PJ, Lahti M, Julkunen- Tiitto R. 2003. Nutrient
availability and the effect of increasing UV-B radiation on
secondary plant compounds in Scots .pine. Environm Exp
Botany, 49: 49–60.
Lavola A, Julkunen-Tııtto R, Aphalo P, De La Rosa T, Lehto T.
1998. The effect of UV-B radiation on UV-absorbing
secondary metabolites in birch seedlings grown under
simulated forest soil. New Phytol.137:617-621.
Lee MJ, Son JE, Oh MM. 2014. Growth and phenolic compounds
of Lactuca sativa L. grown in a closed-type plant production
system with UV-A, -B, or -C lamp. Journal of the Science of
Food and Agriculture. 94, 197-204.
Liu C, Han X, Cai L, Lu X, Ying T, Jiang Z. 2011. Postharvest
UV-B irradiation maintains sensory qualities and enhances
antioxidant capacity in tomato fruit during storage.
Postharvest Biol. Technol. 59: 232–237.
Liu L, Dennis C, Gitz III, McClure JW. 1995. Effects of UV-B
on flavonoids, ferulic acid, growth and photosynthesis in
barley primary leaves. Physiol Plant. 93:734-8
Liu L, Gregan S, Jordan WC. 2015. From UVR8 to flavonol
synthase: UV- induced gene expression in Sauvignon blanc
grape berry. Plant Cell Environment. 38: 905-919.
Ma M, Wang P, Yang R, Gu Z. 2018. Effects of UV-B Radiation
on the Isoflavone Accumulation and Physiological-
biochemical Changes of Soybean during Germination. Food
Chemistry. 250:259-267.
Madunić J, Madunić IV, Gajski G, Popić J, Garaj-Vrhovac V.
2018. Apigenin: A dietary flavonoid with diverse anticancer
properties. Cancer Letters. 413:11-22.
Mao B, Yin H, Wang Y, Zhao TH, Tian RR, Wang W, Jia-Shu
Y. 2017. Combined effects of O3 and UV radiation on
secondary metabolites and endogenous hormones of soybean
leaves. PLoS ONE 12(8): e0183147.
https://doi.org/10.1371/journal.pone.0183147
Mark U, Tevini M. 1996. Combination effects of UV‐B radiation
and temperature on sunflower (Helianthus annuus L., cv.
Polstar) and maize (Zea mays L., cv. Zenit 2000) seedlings.
Journal of Plant Physiology. 148: 49-56
Matthew Robson T, Klem K, Urban O, Jansen MAK. 2015. Re-
interpreting plant morphological responses to UV-B
radiation. Plant, Cell and Environment. 38: 856-866.
Mazza CA, Ballare CL. 2015. Photoreceptors UVR8 and
phytochrome B cooperate to optimize plant growth and
defense in patchy canopies. New Phytol. 207:4-9.
Menghini A, Capuccella M, Mercati V, Mancini L, Burata M.
1993. Flavonoids contents in Passiflora spp. Pharmacol. Res.
Commun. 27:13-14
Mewis M, Schreiner N, Nhi C, Krumbein A, Ulrichs C, Lohse M,
Zrenner R.2012. UV-B irradiation changes specifically the
secondary metabolite Profile in Broccoli sprouts: Induced
signaling overlaps with defense response to biotic stressors.
Plant Cell Physiol. 53:1546-1560
Morales LO, Brosché M, Vainonen J, Jenkins GI, Wargent JJ,
Sipari N, Strid Å, Lindfords AV, Tegelberg R, Aphalo PJ.
2013. Multiple roles for UV RESISTANCE LOCUS8 in
regulating gene expression and metabolite accumulation in
Arabidopsis under solar ultraviolet radiation. Plant Physiol.
161: 744-759.
Morales LO, Tegelberg R, Brosché M, Keinänen M, Lindfors A,
Aphalo PJ. 2010. Effects of solar UV-A and UV-B radiation
on gene expression and phenolic accumulation in Betula
pendula leaves. Tree Physiol. 30:923–934.
Moreira-Rodríguez M, Nair V, Benavides J, Cisneros-Zevallos L,
Jacobo-Velázquez DA. 2017. UVA, UVB Light, and Methyl
Jasmonate, Alone or Combined, Redirect the Biosynthesis of
Glucosinolates, Phenolics, Carotenoids, and Chlorophylls in
Broccoli Sprouts. Int J Mol Sci. 4:18(11).
Mozaffarian D, Wu JHY. 2018. Flavonoids, dairy foods, and
cardiovascular and metabolic health: a review of emerging
biologic pathways. Circ Res. 122(2):369-84.
Nascimento LBDS, Leal-Costa MV, Menezes EA, Lopes VR,
Muzitano MF, Costa SS, Tavares ES. 2015. Ultraviolet-B
radiation effects on phenolic profile and flavonoid content of
Kalanchoe pinnata. J Photochem Photobiol B Biol. 148:73-
81.
Neugart S, Fiol M, Schreiner M, Rohn S, Zrenner R, Kroh LW,
Krumbein A. 2014. Interaction of moderate UV-B exposure
and temperature on the formation of structurally different
flvonol glycosides and hydroxycinnamic acid derivatives in
kale (Brassica oleracea var. sabellica). Journal of
Agricultural and Food Chemistry. 62: 4054-4062.
Neugart S, Schreiner M. 2018. UVB and UVA as eustressors in
horticultural and agricultural crops, Sci. Hortic. 234: 370–381
Nile SH, Keum YS, Nile AS, Jalde SS, Patel RV. 2018.
Antioxidant, anti-inflammatory, and enzyme inhibitory
activity of natural plant flavonoids and their synthesized
derivatives. J Biochem Mol Toxicol. 32(1):e22002.
Nithia SMJ, Shanthi N, Kulandaivelu G. 2005. Different
responses to UV-B enhanced solar radiation in radish and
carrot. Photosynthetica. 43:307-311.
Ordidge M, Garcia-Macias P, Battey NH, Gordon MH, Hadley P,
John P, Lovegrove JA, Vysini E, Wagstaffe A. 2010.
Phenolic contents of lettuce, strawberry, raspberry, and
blueberry crops cultivated under plastic films varying in
ultraviolet transparency. Food Chem. 119:1224–1227
Pandey N, Pandey-Rai S. 2014. Short-term UV-B radiation-
mediated transcriptional responses and altered secondary
metabolism of in vitro propagated plantlets of Artemisia
annua L. Plant Cell Tiss Organ Cult.116:371-385
Pandeya A, Rayamajhi S, Pokhrel P, Giri B. 2018. Evaluation of
secondary metabolites, antioxidant activity, and color
parameters of Nepali wines. Food and nutrition. 6 (8): 2252-
2263.
Pastore C, Allegro G, Valentini G, Muzzi E, Filippetti I. 2017.
Anthocyanin and favonol composition response to veraison
leaf removal on Cabernet Sauvignon, Nero d’Avola, Raboso
Piave and Sangiovese Vitis vinifera L. cultivars. Sci. Hortic.
218: 147-155.

Yavaş et al. / Turkish Journal of Agriculture - Food Science and Technology, 8(1): 147-157, 2020
156
Pérez-Balibrea S, Moreno DA, García-Viguera C. 2010.
Glucosinolates in broccoli sprouts (Brassica oleracea var.
italica) as conditioned by sulphate supply during germination.
J. Food Sci. 75: 673-677.
Petersen M, Hans J, Matern U. 2010. “Biosynthesis of
phenylpropanoids and related compounds,” in Annual Plant
Reviews: Biochemistry of Plant Secondary Metabolism, Vol.
40, ed. M. Wink (Hoboken, NJ: Wiley-Blackwell). 182–257.
Quan J, Song S, Abdulrashid K, Chai Y, Yue M, Liu X. 2018.
Separate and combined response to UV-B radiation and
jasmonic acid on photosynthesis and growth characteristics of
Scutellaria baicalensis. Int. J. Mol. Sci. 19:1194
Radyukina YV, Mapelli IS, Mikheeva LE, Karbysheva EA. 2017.
Vestnik Moskovskogo Universiteta, Seriya 16: Biologiya.
72(3): 179–183.
Ramani S, Chelliah J. 2007. UV-B-induced signalling events
leading to enhanced-production of catharanthine in
Catharanthus roseus cell suspension cultures. BMC Plant
Biol. 7:61–77. doi:10.1186/1471-2229-7-61
Ramani S, Chelliah J. 2008. Enhanced catharanthine and
vindoline production in suspension cultures of Catharanthus
roseus by ultraviolet-B light. J Mol Signal. 3: 9–14.
Ravindran KC, Indrajith A, Pratheesh PV, Sanjiviraja K,
Balakrishnan V. 2010. Effect of ultraviolet-B radiation on
biochemical and antioxidant defence system in Indigofera
tinctoria L. seedlings. Int. J. Eng. Tech. 2 (5): 226-232.
Reifenrath K, Mueller C. 2007. Species-specifi and leaf-age
dependent effects of ultraviolet radiation on two
Brassicaceae. Phytochemistry. 68: 875-885.
Rizzini L, Favory JJ, Cloix C, Faggionato D, O’Hara A, Kaiserli
E, Baumeister R, Schafer E, Nagy F, Jenkins GI, Ulm R.
2011. Perception of UV-B by the Arabidopsis UVR8 protein.
Science. 332:103–106.
Roleira FMF, Tavares-da-Silva EJ, Varela CL, Costa SC, Silva
T, Garrido J, Borges F. 2015. Plant derived and dietary
phenolic antioxidants: anticancer properties, Food Chemistry.
183: 235-258.
Ruijuan Ma, Xurui Zhao, Youping Xie, Shih-Hsin Hoa, Jianfeng
Che. 2019. Enhancing lutein productivity of Chlamydomonas
sp. via high-intensity light exposure with corresponding
carotenogenic genes expression profiles. Bioresource
Technology. 275:416-420.
Rybarczyk-Plonskaa A, Hagen SF, Borge GIA, Bengtsson GB,
Hansena MK, Wold AB. 2016. Glucosinolates in broccoli
(Brassica oleracea L. var. italica) as affected by postharvest
temperature and radiation treatments. Postharvest Biology
and Technology 116:16-25.
Schmidt S, Zietz M, Schreiner M, Rohn S, Kroh LW, Krumbein
A. 2011. Influence of UV-B on flavonol aglycones and main
flavonol glycosides in kale (Brassica oleracea var. sabellica).
In: Proceedings UV4growth, COST Action FA0906, 7–9
February, Szeged, Hungary, p. 27.
Schreiner M, Krumbein A, Mewis I, Ulrichs C, HuyskensKeil S.
2009. Short-term and moderate UV-B radiation efects on
secondary plant metabolism in different organs of nasturtium
(Tropaeolum majus L.). Innovative Food Science &
Emerging Technologies. 10: 93-96.
Schreiner M, Mewis I, Huyskens-Keil S, Jansen MAK, Zrenner
R, Winkler JB, O’Brien N, Krumbein A. 2012. UV-B-
Induced Secondary Plant Metabolites - Potential Benefits for
Plant and Human Health, Critical Reviews in Plant Sciences.
31:3: 229-240.
Schreiner M, Mewis I, Huyskens-Keil S, Jansen MAK, Zrenner
R, Winkler J.B. O’Brien N, Krumbein A. 2012. UV-B-
Induced Secondary Plant Metabolites Potential Benefits for
Plant and Human Health, Critical Reviews in Plant Sciences.
31(3): 229-240
Schreiner M. 2009. Die Rolle des Verbrauchers in der
Wertschopfungskette.¨ In: Status quo und Perspektiven des
deutschen Gartenbaus, pp. 99–109. Dirksmeyer, W., Ed.,
Landbauforschung vti, Sonderheft 330, Braunschweig,
Germany.
Sharma P, Jha AB, Dubey RS, Pessarakli M. 2012. Reactive
oxygen species, oxidative damage, and antioxidative defense
mechanism in plants under stressful conditions. J. Bot.
2012:217037.
Sharma R. 2001. Impact of solar UV-B on tropical ecosystems
and agriculture. Case study: effect of UV-B on rice. Proc.
SEAWIT98 SEAWPIT2000. 1: 92–101.
Sharma S, Chatterjee S, Kataria S, Joshi J, Datta S, Vairale MG,
Veer V. 2017. A review of stress and responses of plants to
UV-B radiation. In: Singh VP, Singh S, Prasad MS, Parihar P
(eds) UV-B radiation: from environmental stressor to
regulator of plant growth. Wiley-Blackwell, New York, pp
75–99.
Shen J, Jiang C, Yan Y, Liu B, Zu C. 2017. Effect of increased
UV-B radiation on carotenoid accumulation and total
antioxidant capacity in tobacco (Nicotiana tabacum L.)
leaves. Genet Mol Res. 8:16(1).
Shen Y, Li J, Gu R, Yue L, Wang H, Zhan X, Xing B. 2018.
Carotenoid and superoxide dismutase are the most effective
antioxidants participating in ROS scavenging in
phenanthrene accumulated wheat leaf. Chemosphere.
197:513-525.
Singh R, Singh S, Tripathi R, Agrawal SB. 2011. Supplemental
UV-B radiation induced changes in growth, pigments and
antioxidant pool of bean (Dolichos lablab) under field
conditions. J. Environ. Biol. 32: 139-145.
Stracke R, Favory JJ, Gruber H, Bartelniewoehner L, Bartels S,
Binkert M, Funk M, Weisshaar B, Ulm R. 2010. The
Arabidopsis bZIP transcription factor HY5 regulates
expression of the PFG1/ MYB12 gene in response to light and
ultraviolet-B radiation. Plant Cell Environ. 33:88-103.
Sun T, Yuan H, Cao H, Yazdani M, Tadmor Y, Li L. 2018.
Carotenoid Metabolism in Plants: The Role ofPlastids. Mol.
Plant.11: 58–74.
Sunoj VSJ, Shroyer KJ, Jagadish SVK, Prasad PV. 2016. Diurnal
temperature amplitude alters physiological and growth
response of maize (Zea mays L.) during the vegetative stage.
Environ Exp Bot. 130:113-121.
Szymańska R, Ślesak I, Orzechowska A, Kruk J. 2017.
Physiological and biochemical responses to high light and
temperature stress in plants. Environmental and Experimental
Botany. 139:165-177.
Takshak S, Agrawal SB. 2015. Defence strategies adopted by the
medicinal plant Coleus forskohlii against supplemental
ultraviolet-B radiation: augmentation of secondary
metabolites and antioxidants. Plant Physiology and
Biochemistry. 97:124-138.
Tatullo M, Simone GM, Tarullo F, Irlandese G, De Vito D,
Marrelli M, Santacroce L, Cocco T, Ballini A, Scacco S.
2016. Antioxidant and Antitumor Activity of a Bioactive
Polyphenolic Fraction Isolated from the Brewing Process.
Sci. Rep. 6: 36042.
Teramura AH, Sullivan JH, Lydon J. 1990. Effects of UV-B
radiation in altering soybean yield: a 6-year field study.
Physiol. Plant. 80: 5-11
Tessadori F, van Zanten M, Pavlova P, Clifton R, Pontvianne F,
Snoek LB, Millenaar FF, Schulkes RK, van Driel R,
Voesenek LA. 2009. Phytochrome B and histone deacetylase
6 control light-induced chromatin compaction in Arabidopsis
thaliana, PLoS Genet. 5, e1000638.
Tohidi-Moghadam HR, Ghooshchi F, Jamshidpour F, Zahedi H.
2012. Effect of UV radiation and elevated CO2 on
physiological attributes of canola (Brassica napus L.) grown
under water defiit stress. Polish Journal of Environmental
Studies. 21: 1417–1427.
Topcu Y, Dogan A, Kasimoglu Z, Nadeem HS, Polat E, Erkan M.
2015. The effects of UV radiation during the vegetative
period on antioxidant compounds and postharvest quality of
broccoli (Brassica oleracea L.). Plant Physiology and
Biochemistry. 93:56-65.

Yavaş et al. / Turkish Journal of Agriculture - Food Science and Technology, 8(1): 147-157, 2020
157
Torres S, Cabrera-Pardo JR, Alonso F, Bustos E, Perez C, Palfner
G, Hernandez V, Uriarte E, Becerra J. 2016. Changes in
secondary metabolites profiles and biological activity of the
fresh fruiting bodies of Stereum hirsutum exposed to high-
dose UV-B radiation. J. Chil. Chem. Soc. 61(4): 3224-3227
Tossi V, Lamattina L, Jenkins GI, Cassia RO. 2014. Ultraviolet-
Binduced stomatal closure in Arabidopsis is regulated by the
UV RESISTANCE LOCUS8 photoreceptor in a nitric
oxidedependent mechanism. Plant Physiol. 164:2220-2230.
Vandenbussche F, Tilbrook K, Fierro AC, Marchal K, Poelman
D, Van Der Straeten D, Ulm R. 2014. Photoreceptor-
mediated bending towards UV-B in Arabidopsis. Mol. Plant.
7:1041-1052.
Verdaguer D, Jansen MAK, Llorens L, Morales LO, Neugart S.
2017. UV-A radiation effects on higher plants: Exploring the
known unknown. Plant Sci. 255: 72–81
Vidovic´ M, Morina F, Milic´ S, Zechmann B, Albert A, Winkler
JB, Jovanovic SV. 2015. Ultraviolet-B component of sunlight
stimulates photosynthesis and flavonoid accumulation in
variegated Plectranthus coleoides leaves depending on
background light. Plant, Cell and Environment. 38: 968–979.
Virjamo V, Sutinen S, Julkunen-Tiitto R. 2014. Combined effect
of elevated UVB, elevated temperature and fertilization on
growth, needle structure and phytochemistry of young
Norway spruce (Picea abies) seedlings. Glob. Change Biol.
20: 2252–2260.
Wang H, Gui M, Tian X, Xin X, Wang T, Li J. 2017. Effects of
UV‐B on vitamin C, phenolics, flavonoids and their related
enzyme activities in mung bean sprouts (Vigna radiata).
International Journal of Food Science and Technology. 52
(3): 827-833.
Wang PC, Mo BT, Long ZF, Fan SQ, Wang HH. 2016. Factors
afecting seed germination and emergence of Sophora davidii.
Ind Crop Prod. 87:261–265.
Wang Y, Xu WJ, Yan XF, Wang Y. 2011. Glucosinolate content
and related gene expression in response to enhanced UV-B
radiation in Arabidopsis. African Journal of Biotechnology.
10: 6481–6491.
Wargent JJ, Gegas VC, Jenkins GI, Doonan JH, Paul ND. 2009.
UVR8 in Arabidopsis thaliana regulates multiple aspects of
cellular differentiation during leaf development in response
to ultraviolet B radiation. New Phytol. 183:315-326.
White AL, Jahnke LS. 2002. Contrasting efects of UV-A and UV-
B on photosynthesis and photoprotection of β-carotene in two
Dunaliella spp. Plant & Cell Physiology (PCP). 43 (8): 877-
884.
Winter TR, Rostas M. 2008. Ambient ultraviolet radiation
induces protective responses insoybean but does not attenuate
indirect defense. Environ. Pollut. 155: 290-297.
Wu D, Hu Q, Yan, Z, Chen W, Yan CY, Huang, X, Zhang J, Yang
PY, Deng HT, Wang JW, Deng, XW, Shi YG. 2012.
Structural basis of ultraviolet-B perception by UVR8. Nature
484: U214–U296.
Wulff A, Anttonen S, Pellinen R, Savonen EM, Sutinen ML,
Heller W, Sandermann Jr H, Kangasjärvi J. 1999. Birch
(Betula pendula Roth.) responses to high UV-B radiation.
Boreal Environment Research. 4: 77–88
Xie Y, Zhang W, Duan X, Dai C, Zhang Y, Cui W, Wang R, Shen
W. 2015. Hydrogen-rich water-alleviated ultraviolet-B-
triggered oxidative damage is partially associated with the
manipulation of the metabolism of (iso) flavonoids and
antioxidant defence in Medicago sativa. Functional Plant
Biology. 42: 1141–1157.
Xie Y, Yang W, Tang F, Chen X, Ren L. 2015. Antibacterial
activities of flavonoids: structure-activity relationship and
mechanism. Curr Med Chem. 22 (1):132-49.
Xu GL, Singh SK, Reddy VR, Barnaby JY. 2016 Soybean grown
under elevated CO2 benefts more under low temperature than
high temperature stress: varying response of photosynthetic
limitations, leaf metabolites, growth, and seed yield. J Plant
Physiol. 205:20–32.
Yang DL, Sun P, Li MF. 2016. Chilling temperature stimulates
growth, gene over-expression and podophyllotoxin
biosynthesis in Podophyllum hexandrum royle. Plant Physiol
Biochem. 107:197–203.
Yang Y, Yang X, Jang Z, Chen Z, Ruo X, Jin W, Wu Y, Shi X,
Xu M. 2018. UV RESISTANCE LOCUS 8 From
Chrysanthemum morifolium Ramat (CmUVR8) Plays
Important Roles in UV-B Signal Transduction and UV-B-
Induced Accumulation of Flavonoids. Front Plant Sci. 9: 955.
Yin R, Ulm R. 2017. How plants cope with UV-B: from
perception to response. Curr Opin Plant Biol. 37:42-48.
Young AJ, Lowe GL. 2018. Carotenoids-antioxidant properties.
Antioxidants 7:28-31.
Zagoskina NV, Dubravina GA, Alyavina AK, Goncharuk EA.
2003. Effect of ultraviolet (UV-B) radiation on the formation
and localization of phenolic compounds in tea plant callus
cultures. Russian Journal of Plant Physiology. 50(2): 270–
275.
Zu Y, Li Y, Chen J, Chen H. 2004. Intraspecific responses in
grain quality of 10 wheat cultivars to enhanced UV-B
radiation under field conditions. J. Photochem. Photobiol. B
Biol. 74: 95-100.