Effects of Enhanced UV‐B Radiation on Biochemical Traits in Postharvest Flowers of Medicinal Chrysanthemum

This article reported UV‐B radiation effects on biochemical traits in postharvest flowers of chrysanthemum. The experiment included six levels of UV‐B radiation (UV0, 0 μW cm^?2; UV50, 50 μW cm^?2; UV200, 200 μW cm^?2; UV400, 400 μW cm^?2; UV600, 600 μW cm^?2 and UV800, 800 μW cm^?2). Enhanced UV‐B radiation significantly increased hydrogen peroxide content (except for UV50), but did not evidently affect malondialdehyde content in flowers. Chlorophyll b and total chlorophyll content were significantly increased by UV600 and UV800. UV400 and UV600 significantly increased anthocyanins, carotenoids and UV‐B absorbing compounds content, and the activities of phenylalanine ammonia lyase (PAL) and cinnamic acid‐4‐hydroxylase (C4H) over the control. 4‐coumarate CoA ligase (4CL) activity was significantly decreased by enhanced UV‐B radiation (except for UV50). The relationships between UV‐B radiation intensities and the activities of secondary metabolism enzymes were best described by a second‐order polynomial. The R² values for UV‐B radiation intensities and the activities of PAL, C4H and 4CL were 0.8361, 0.5437 and 0.8025, respectively. The results indicated that enhanced UV‐B radiation could promote secondary metabolism processes in postharvest flowers, which might be beneficial for the accumulation of medically active ingredients in medicinal plants. The optimal UV‐B radiation intensities in the study were between UV400‐UV600.     

The Injury and Cumulative Effects on Human Skin by UV Exposure from Artificial Fluorescence Emission

The injury and cumulative effects of UV emission from fluorescence lamp were studied. UV intensity from fluorescence lamp was measured, and human skin samples (hips, 10 volunteers) were exposed to low‐dose UV irradiation (three times per week for 13 consecutive weeks). Three groups were examined: control group without UV radiation; low‐dose group with a cumulative dose of 50 J cm^?2 which was equivalent to irradiation of the face during indoor work for 1.5 years; and high‐dose group with 1000 J cm^?2 cumulative dose equivalent to irradiation of the face during outdoor activities for 1 year. Specific indicators were measured before and after UVA irradiation. The findings showed that extending the low‐dose UVA exposure decreased the skin moisture content and increased the transepidermal water loss as well as induced skin color changes (decreased L* value, increased M index). Furthermore, irradiated skin showed an increased thickness of cuticle and epidermis, skin edema, light color and unclear staining collagen fibers in the dermis, and elastic fiber fragmentation. In addition, MMP‐1, p53 and SIRT1 expression was also increased. Long‐term exposure of low‐dose UVA radiation enhanced skin photoaging. The safety of the fluorescent lamp needs our attention.     

Effects of Suplementary Ultraviolet‐B Irradiance on Maize Yield and Qualities: A Field Experiment¶

Stratospheric ozone depletion has caused an increase in the amount of ultraviolet‐B (UV‐B) radiation reaching the earth's surface. Numerous investigations have demonstrated that the effect of UV‐B enhancements on plants includes reduction in grain yield, alteration in species competition, susceptibility to disease and changes in plant structure and pigmentation. Many experiments examining UV‐B radiation effects on plants have been conducted in growth chambers or greenhouses. It has been questioned whether the effect of UV‐B radiation on plants can be extrapolated to field responses from indoor studies because of the unnaturally high ratios of UV‐B/ ultraviolet‐A radiation (320–400 nm) and UV‐B/photosynthetically active radiation (PAR) in many indoor studies. Field studies on UV‐B radiation effect on plants have been recommended to use the UV and PAR irradiance provided by natural light. This study reports the growth and yield responses of a maize crop exposed to enhanced UV‐B radiation and the UV‐B effects on aize seed qualities under field conditions. Enhanced UV‐B radiation caused a significant reduction in the dry matter accumulation and the maize yield in turn was affected. With increased UV‐B radiation the flavonoid accumulation in maize leaves increased and the contents of chlorophyll a, b and (a+b) of maize leaves were reduced. The levels of protein, sugar and starch of maize seed decreased with enhanced UV‐B radiation, whereas the level of lysine increased with enhanced UV‐B radiation.     

Synthesis and Herbicidal Activities of 3‐(4‐Chloro‐2‐fluoro‐5‐substituted phenyl)benzo[d][1,2,3]triazin‐4(3H)‐one Derivatives

A series of 3‐phenyl benzo[d][1,2,3]triazin‐4(3H)‐one derivatives were synthesized through the condensation of phenol E and alkyl (alkenyl, alkynyl) chlorides (bromides, iodide) or alkyl chloroacetates or N‐alkyl chloroacetamides using K₂CO₃ as the acid acceptor in N,N‐dimethylformamide. Phenol E was prepared from starting material, 5‐amino‐2‐chloro‐4‐fluorophenyl ethyl carbonate, in four steps involving in amidation, reduction, diazotization, and deprotecting‐group reaction. The herbicidal activities of the title compounds were tested against two dicotyledonous plants and two monocotyledonous plants, in which some of them exhibited high herbicidal activities against two dicotyledonous plants in preemergence and postemergence treatments. Moreover, when the dosage was decreased to 180 and 90 g/ha, compounds F1 , F8 , and F9 showed highly selective inhibitory activities against amaranth pigweed, alfalfa, asteraceae, field sowthistle, morning glory, purslane, and velvetleaf in postemergence treatment but had no herbicidal efficacy on rape except F1 , suggesting that it be possible to find a kind of herbicides to inhibit dicotyledonous weeds in the field of dicotyledonous crops with the same genus as aforementioned weeds.     

Assessment of Fatty Acid Profile and Seed Mineral Nutrients of Two Soybean (Glycine max L.) Cultivars Under Elevated Ultraviolet‐B: Role of ROS,Pigments and Antioxidants

Current scenarios under global climate change envisage a considerable increase in ultraviolet B (UV‐B) radiation in near future which may affect the productivity and yield quality of major agricultural crops. Present investigation was conducted to examine various defense strategies adopted against elevated UV‐B (ambient + 7.2 kJ mˉ² dayˉ¹) and their impact on seed nutrients, content and quality of oil including fatty acid profile of two soybean cultivars (JS‐335 and PS‐1042). Elevated UV‐B (eUV‐B) exposure leads toward higher unsaturation of fatty acids and changes in other oil quality parameters (acid, iodine and saponification value) indicated that eUV‐B favored the synthesis of long‐chain fatty acids with fewer carboxylic acid groups, making the oil rancid, with undesirable flavor and low nutritional value. The effect was more severe in JS‐335 as compared to PS‐1042. Negative effects were also seen on nutrients of soybean seeds. Adverse effects resulted due to insufficient quenching of ROS (superoxide radical and hydrogen peroxide) by the defense system and thus unable to overcome the imposed oxidative stress. Credit of better performance by PS‐1042 against eUV‐B may be given to the adoption of efficient defense strategies like higher wax deposition, increase in lignin and flavonoids (quercetin and kaempferol) contents.     

Simultaneous Determination of Glyphosate,Glufosinate, and Aminomethylphosphonic Acid by Capillary Electrophoresis After 9‐Fluorenylmethyl Chloroformate Derivatization

A capillary electrophoresis (CE) with UV absorption detection method is described for the simultaneous determination of glufosinate, glyphosate, and aminomethylphosphoric acid. The 9‐fluorenylmethyl chloroformate (FMOC‐Cl) was used for precolumn derivatization of the non‐absorbing herbicides. The three analytes were separated by CE in 9 min with 25 mM borate buffer at pH 9, followed by detection with a UV detector at 260 nm. We demonstrate how the detection limit can be enhanced by using acetonitrile‐salt mixtures. With acetonitrile‐salt mixtures, the limit of detection (LOD) was in the 10^?7 M range. Linearity of more than two orders of magnitude was generally obtained. Precisions of migration times and peak areas were less than 0.9% and 7.5%, respectively. The applicabilities of the method for the analysis of ground water and lake water were examined.     

Effects of PAR and UV‐B Radiation on Herbal Yield,Bioactive Compounds and Their Antioxidant Capacity of Some Medicinal Plants Under Controlled Environmental Conditions

Photosynthetically active radiation (PAR) and Ultraviolet B (UV‐B) radiation are among the main environmental factors acting on herbal yield and biosynthesis of bioactive compounds in medicinal plants. The objective of this study was to evaluate the influence of biologically effective UV‐B light (280–315 nm) and PAR (400–700 nm) on herbal yield, content and composition, as well as antioxidant capacity of essential oils and polyphenols of lemon catmint (Nepeta cataria L. f. citriodora), lemon balm (Melissa officinalis L.) and sage (Salvia officinalis L.) under controlled greenhouse cultivation. Intensive UV‐B radiation (2.5 kJ m^?2 d^?1) influenced positively the herbal yield. The essential oil content and composition of studied herbs were mainly affected by PAR and UV‐B radiation. In general, additional low‐dose UV‐B radiation (1 kJ m^?2d^?1) was most effective for biosynthesis of polyphenols in herbs. Analysis of major polyphenolic compounds provided differences in sensitivity of main polyphenols to PAR and UV‐B radiation. Essential oils and polyphenol‐rich extracts of radiated herbs showed essential differences in antioxidant capacity by the ABTS system. Information from this study can be useful for herbal biomass and secondary metabolite production with superior quality under controlled environment conditions.     

UV‐B and Drought Stress Influenced Growth and Cellular Compounds of Two Cultivars of Phaseolus vulgaris L. (Fabaceae)

Combined enhanced UV‐B radiation and drought may induce different morphological and physiological alterations in plants than either abiotic stress alone. We evaluated morphology, biomass, and primary and secondary metabolism changes in seedlings of two common bean cultivars, IAC Imperador (drought‐resistant) and IAC Milênio. To test the hypothesis that cultivars responded differently to combined stresses in a controlled environment, seedlings of the examined been cultivars were exposed to UV‐B and/or drought treatments for three weeks. The cultivars behaved differently, especially to the drought treatment, suggesting that they use different mechanisms to cope with unfavorable environmental conditions. IAC Imperador showed a stronger protective response, modifying wax composition and primary metabolism, and improving its resistance to UV‐B radiation. For IAC Imperador, the accumulation of cuticular wax and alkane was higher under combined stress but production of primary alcohols was reduced, suggesting a possible fatty acyl switch. Root/shoot length and biomass ratios increased in both cultivars, particularly for the combined stress, indicating a common plant response. We show that these two bean cultivars responded more strongly to UV‐B and combined stress than drought alone as evident in changes to their chemistry and biology. This shows the importance of investigating plant morphological and physiological responses to combined stress.     

The Effects of Ambient Solar UV Radiation on Alkaloid Production by Erythroxylum novogranatense var. novogranatense†

Truxillines are alkaloids produced by Erythroxylum species and are thought to be derived from the UV‐driven dimerization of cinnamoylcocaines. This study was conducted to determine the effects of ambient UV radiation on the production of truxillines in Erythroxylum novogranatense var. novogranatense. Field plants were grown under shelters covered with plastic filters that were transparent to UV radiation, filtered UV‐B, or both filtered UV‐B and UV‐A radiation. The treatments had no significant effect on plant biomass or specific leaf weight. Absorption values in the UV‐C and UV‐A region of acidified‐methanol leaf extracts were higher for plants exposed to UV radiation compared to the no UV radiation treatment. There was a trend in decreasing levels of trans‐cinnamoylcocaine and a statistically significant decrease in levels of cis‐cinnamoylcocaine in the leaves of plants exposed to UV radiation compared to the no UV radiation treatment. Truxilline levels increased in leaves from plants exposed to UV radiation compared to the no UV radiation treatment. Most significantly, the ratio of truxillines to total cinnamoylcocaines in the leaves was affected by UV, increasing with increased UV exposure. The results support the hypothesis that UV radiation is involved in the formation of truxillines from cinnamoylcocaines.     

Effects of Ultraviolet Radiation (UVA+UVB) and Copper on the Morphology,Ultrastructural Organization and Physiological Responses of the Red Alga Pterocladiella capillacea

The effect of ultraviolet (UV) radiation and copper (Cu) on apical segments of Pterocladiella capillacea was examined under two different conditions of radiation, PAR (control) and PAR+UVA+UVB (PAR+UVAB), and three copper concentrations, ranging from 0 (control) to 0.62, 1.25 and 2.50 μm . Algae were exposed in vitro to photosynthetically active radiation (PAR) at 70 μmol photons m^?2 s^?1, PAR + UVB at 0.35 W m^?2 and PAR +UVA at 0.70 W m^?2 during a 12‐h photocycle for 3 h each day for 7 days. The effects of radiation and copper on growth rates, content of photosynthetic pigments and photosynthetic performance were analyzed. In addition, samples were processed for light and transmission electron microscopy. The content of photosynthetic pigments decreased after exposure to radiation and Cu. Compared with PAR radiation and copper treatments modified the kinetics patterns of the photosynthesis/irradiance curve. The treatments also caused changes in the ultrastructure of cortical and subcortical cells, including increased cell wall thickness and accumulation of plastoglobuli, as well as changes in the organization of chloroplasts. The results indicate that the synergistic interaction between UV radiation and Cu in P. capillacea, led to the failure of protective mechanisms and causing more drastic changes and cellular imbalances.     

Inactivation of Bacteriophage Infecting Bacteroides Strain GB124 Using UV‐B Radiation

Ultraviolet‐B radiation (280–320 nm) has long been associated with the inactivation of microorganisms in the natural environment. Determination of the environmental inactivation kinetics of specific indicator organisms [used as tools in the field of microbial source tracking (MST)] is fundamental to their successful deployment, particularly in geographic regions subject to high levels of solar radiation. Phage infecting Bacteroides fragilis host strain GB124 (B124 phage) have been demonstrated to be highly specific indicators of human fecal contamination, but to date, little is known about their susceptibility to UV‐B radiation. Therefore, B124 phage (n = 7) isolated from municipal wastewater effluent, were irradiated in a controlled laboratory environment using UV‐B collimated beam experiments. All B124 phage suspensions possessed highly similar first order log‐linear inactivation profiles and the mean fluence required to inactivate phage by 4 ? log¹⁰ was 320 mJ cm^?2. These findings suggest that phage infecting GB124 are likely to be inactivated when exposed to the levels of UV‐B solar radiation experienced in a variety of environmental settings. As such, this may limit the utility of such methods for determining more remote inputs of fecal contamination in areas subject to high levels of solar radiation.     

Effects of PAR and UV Radiation on the Structural and Functional Integrity of Phycocyanin,Phycoerythrin and Allophycocyanin Isolated from the Marine Cyanobacterium Lyngbya sp. A09DM

An in vitro analysis of the effects of photosynthetically active and ultraviolet radiations was executed to assess the photostability of biologically relevant pigments phycocyanin (PC), phycoerythrin (PE) and allophycocyanin (APC) isolated from Lyngbya sp. A09DM. Ultraviolet (UV) irradiances significantly affected the integrity of PC, PE and APC; however, PAR showed least effect. UV radiation affected the bilin chromophores covalently attached to phycobiliproteins (PBPs). Almost complete elimination of the chromophore bands associated with α‐ and β‐subunit of PE and APC occurred after 4 h of UV‐B exposure. After 5 h of UV‐B exposure, the content of PC, PE and APC decreased by 51.65%, 96.8% and 96.53%, respectively. Contrary to PAR and UV‐A radiation, a severe decrease in fluorescence of all PBPs was observed under UV‐B irradiation. The fluorescence activity of extracted PBP was gradually inhibited immediately after 15–30 min of UV‐B exposure. In comparison to the PC, the fluorescence properties of PE and APC were severely lost under UV‐B radiation. Moreover, the present study indicates that UV‐B radiation can damage the structural and functional integrity of phycobiliproteins leading to the loss of their ecological and biological functions.     

Incident Ultraviolet Irradiances Influence Physiology,Development and Settlement of Larva in the Coral Pocillopora damicornis

Ultraviolet radiation (UVR, 280–400 nm) is one of the potential factors involved in the induction of coral bleaching, loss of the endosymbiotic dinoflagellate Symbiodinium or their photosynthetic pigments. However, little has been documented on its effects on the behavior and recruitment of coral larvae, which sustains coral reef ecosystems. Here, we analyzed physiological changes in larvae of the scleractinian coral Pocillopora damicornis and examined the photophysiological performance of the symbiont algae, following exposure to incident levels of UVR and subsequently observed the development of coral larvae. The endosymbiotic algae exhibited a high sensitivity to UV‐B (295–320 nm) during a 6 h exposure, showing lowered photosynthetic performance per larva and per algal cell, whereas the presence of UV‐A (320–395 nm) significantly stimulated photosynthesis. UVR decreased chlorophyll a concentration only at higher surface temperature or at the higher doses or intensities of UVR. Correlations between UV‐absorbing compound (UVAC) contents or UVR sensitivity and temperature were identified, implying that UVACs might act as a screen or antioxidants in Pocillopora damicornis larvae. Larvae reared under UVR exposures showed lower levels of survivorship, metamorphosis and settlement, with inhibition by UV‐A being much greater than that caused by UV‐B.     

The Effects of UV‐B Radiation Intensity on Biochemical Parameters and Active Ingredients in Flowers of Qi Chrysanthemum and Huai Chrysanthemum

The article studied UV‐B effects on biochemical parameters and active ingredients in flowers of Qi chrysanthemum and Huai chrysanthemum during the bud stage. The experiment included four UV‐B radiation levels (CK, ambient UV‐B; T1, T2 and T3 indicated a 5%, 10% and 15% increase in ambient UV‐B_BE, respectively) to determine the optimal UV‐B radiation intensity in regulating active ingredients level in flowers of two chrysanthemum varieties. Flower dry weight of two cultivars was not affected by UV‐B radiation under experimental conditions reported here. UV‐B treatments significantly increased the rate of superoxide radical production, hydrogen peroxide (H₂O₂) (except for T1) and malondialdehyde concentration in flowers of Huai chrysanthemum and H₂O₂ concentration in flowers of Qi chrysanthemum. T2 and T3 treatments induced a significant increase in phenylalanine ammonia lyase enzyme (PAL) activity, anthocyanins, proline, ascorbic acid, chlorogenic acid and flavone content in flowers of two chrysanthemum varieties, and there were no significant differences in PAL activity, ascorbic acid, flavone and chlorogenic acid content between the two treatments. These results indicated that appropriate UV‐B radiation intensity did not result in the decrease in flower yield, and could regulate PAL activity and increase active ingredients content in flowers of two chrysanthemum varieties.     

Controllable Effect of Structural Modification of Sulfonylurea Herbicides on Soil Degradation

The study of soil degradation behaviors of sulfonylurea herbicides in relation to their different structural attributes is utmost important for us to comprehend the development of new eco‐friendly herbicides. It is postulated that the structural modification of the chemical structures could influence their degradation rates in soil. Nine devised structures were synthesized to study their herbicidal activity as well as their soil degradation behaviors respectively. The novel compounds I‐3 – I‐7 were characterized by UV, ¹H NMR and ¹³C NMR, MS and EA. Bioassays indicated that most of target compounds displayed superior herbicidal activities in comparison with Chlorsulfuron. Soil degradation results further confirmed our previous assumption that the introduction of electron‐donating substituents at 5^th position of the benzene ring distinctly increased their degradation rates, among which dimethylamino and diethylamino groups can adjust the degradation rate to a more favorable status.     

Differential Photosynthetic Response of a Green Tide Alga Ulva linza to Ultraviolet Radiation,Under Short‐ and Long‐term Ocean Acidification Regimes

Both ocean acidification (OA) and solar ultraviolet (UV) radiation can bring about changes in macroalgal physiological performance. However, macroalgal responses to UV radiation when acclimatized to OA under different time scales are rare. Here, we investigate the response of Ulva linza, a green tide alga, to UV radiation in the form of photosynthetically active radiation (PAR) or PAB (PAR+UVA+UVB) radiation. Radiation exposures were assessed following long‐term (from spore to adult stage, 1 month) and short‐term (adult stage, 1 week) OA treatments. Results showed that increased CO₂ decreased the damage rate (k) and repair rate (r) of thalli grown under short‐term OA conditions with PAB treatment, the ratio of r:k was not altered. Following long‐term OA conditions, r was not affected, although k was increased in thalli following PAB treatment, resulting in a reduced ratio of r:k. The relative level of UV inhibition increased and UV‐absorbing compounds decreased when algae were cultured under long‐term OA conditions. The recovery rate of thalli was enhanced when grown under long‐term OA after UV radiation treatment. These results show that blooming algae may be more sensitive to UV radiation in marine environments, but it can develop effective mechanisms to offset the negative effects, reflecting acclimation to long‐term OA conditions.     

Environmental UV‐A and UV‐B Threshold Doses for Apoptosis and Necrosis in Humans Fibroblasts¶

Apoptosis involves a highly organized and programmed series of events aimed at maintaining genomic stability by eliminating defective host cells. The purpose of this study was to determine the threshold doses and environmental UV‐A and UV‐B exposure times necessary to produce apoptosis and necrosis in the normal cells of a human fibroblast cell line. Enviromental UV‐A and UV‐B doses were measured over a 6 year period with a four‐channel UV radiometer. The fibroblasts were irradiated once using an Oriel UV Solar Simulator with six doses of environmentally‐based UV. Doses corresponded to 0,11,19,23 and 45 min of average environmental UV‐A and UV‐B radiation at solar noon in Puerto Rico. The Annexin‐V binding method was used to differentiate between normal fibroblasts and apoptotic or necrotic fibroblasts. The threshold dose from apoptosis to necrosis was found between 24–28 kJ/m², which corresponded to 19 and 23 min of environmental UV‐A and UV‐B exposure. This study provides the first data that specify the environmental threshold doses of UV‐A and UV‐B at which human fibroblasts undergo apoptosis and necrosis. These results may provide valuable dose‐response thresholds for apoptosis and necrosis for future mechanistic studies and baseline data for skin cancer prevention programs.     

Photoprotective and Antigenotoxic Effects of the Flavonoids Apigenin,Naringenin and Pinocembrin

This work evaluated the photoprotective and antigenotoxic effects against ultraviolet B (UVB) radiation of flavonoid compounds apigenin, naringenin and pinocembrin. The photoprotective efficacy of these compounds was estimated using in vitro photoprotection indices, and the antigenotoxicity against UVB radiation was evaluated using the SOS chromotest and an enzymatic (proteinase K/T4 endonuclease V enzyme) comet assay in UV‐treated Escherichia coli and human (HEK‐293) cells, respectively. Naringenin and pinocembrin showed maximum UV‐absorption peak in UVC and UVB zones, while apigenin showed UV‐absorption capability from UVC to UVA range. These compounds acted as UV filters reducing UV‐induced genotoxicity, both in bacteria and in human cells. The enzymatic comet assay resulted highly sensitive for detection of UVB‐induced DNA damage in HEK‐293 cells. In this work, the photoprotective potential of these flavonoids was widely discussed.     

Photosynthetic Performance of the Red Alga Pyropia haitanensis During Emersion,With Special Reference to Effects of Solar UV Radiation,Dehydration and Elevated CO2 Concentration

Macroalgae distributed in intertidal zones experience a series of environmental changes, such as periodical desiccation associated with tidal cycles, increasing CO₂ concentration and solar UVB (280–315 nm) irradiance in the context of climate change. We investigated how the economic red macroalga, Pyropia haitanensis, perform its photosynthesis under elevated atmospheric CO₂ concentration and in the presence of solar UV radiation (280–400 nm) during emersion. Our results showed that the elevated CO₂ (800 ppmv) significantly increased the photosynthetic carbon fixation rate of P. haitanensis by about 100% when the alga was dehydrated. Solar UV radiation had insignificant effects on the net photosynthesis without desiccation stress and under low levels of sunlight, but significantly inhibited it with increased levels of desiccation and sunlight intensity, to the highest extent at the highest levels of water loss and solar radiation. Presence of UV radiation and the elevated CO₂ acted synergistically to cause higher inhibition of the photosynthetic carbon fixation, which exacerbated at higher levels of desiccation and sunlight. While P. haitanensis can benefit from increasing atmospheric CO₂ concentration during emersion under low and moderate levels of solar radiation, combined effects of elevated CO₂ and UV radiation acted synergistically to reduce its photosynthesis under high solar radiation levels during noon periods.