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1.
The aim of this study was to investigate the modifying influence of moderate ultraviolet-B (UV-B) radiation exposure on structurally different flavonol glycosides and hydroxycinnamic acid derivatives during pre-harvest using kale, a leafy Brassica species with a wide spectrum of different non-acylated and acylated flavonol glycosides. Juvenile kale plants were treated with short-term (1 day), moderate UV-B radiation [0.22-0.88 kJ m?2 day?1 biologically effective UV-B (UV-B(BE))]. Twenty compounds were quantified, revealing a structure-specific response of flavonol glycosides and hydroxycinnamic acid derivatives to UV-B radiation. A dose- and structure-dependent response of the investigated phenolic compounds to additional UV-B radiation was found. The investigated quercetin glycosides decreased under UV-B; for kaempferol glycosides, however, the amount of sugar moieties and the flavonol glycoside hydoxycinnamic acid residue influenced the response to UV-B. Monoacylated kaempferol tetraglucosides decreased in the investigated UV-B range, whereas the monoacylated kaempferol diglucosides increased strongly with doses of 0.88 kJ m?2 day?1 UV-B(BE) . The UV-B-induced increase in monoacylated kaempferol triglucosides was dependent on the acylation pattern. Furthermore, the hydroxycinnamic acid glycosides disinapoyl-gentiobiose and sinapoyl-feruloyl-gentiobiose were enhanced in a dose-dependent manner under UV-B. While UV-B radiation treatments often focus on flavonol aglycones or total flavonols, our investigations were extended to structurally different non-acylated and acylated glycosides of quercetin and kaempferol. 相似文献
2.
Hofmann Rainer W.; Swinny Ewald E.; Bloor Stephen J.; Markham Kenneth R.; Ryan Ken G.; Campbell Bruce D.; Jordan Brian R.; Fountain David W. 《Annals of botany》2000,86(3):527-537
This study aimed to quantify and identify flavonoids involvedin the response of nine populations of white clover (Trifoliumrepens L.) to ultraviolet-B radiation (UV-B). Plants were grownfor 12 weeks in controlled environment rooms with or withoutsupplemental UV-B radiation of 13.3 kJ m-2d-1. Methanolwaterextractable flavonoids were quantified using high performanceliquid chromatography (HPLC). Two major peaks showed significantenhancement in the HPLC chromatogram in response to supplementalUV-B. The structures of the compounds responsible were identifiedby1H and13C nuclear magnetic resonance (NMR) spectroscopy tobe the flavonols quercetin-3-O-ß- D -xylopyranosyl-(1 2)-ß- D -galactopyranoside and kaempferol-3-O-ß-D -xylopyranosyl-(1 2)-ß- D -galactopyranoside. Withsupplemental UV-B, quercetin glycoside levels increased on averageby 200% while the kaempferol glycoside response was much smaller.Significant differences in flavonol accumulation were foundamong T. repens populations, both constitutively and in responseto UV-B. Stress-adapted populations displayed particularly highflavonol levels under UV-B. There was an inverse correlationbetween plant productivity and quercetin accumulation. Furthermore,higher quercetin accumulation under UV-B was correlated withtolerance against UV-B-induced growth reduction. In conclusion,within-species comparisons in T. repens lend support to a distinctrole for ortho -dihydroxylated flavonoids in the adaptationto UV-B stress and suggest particular advantages in this UV-B-inducedbiochemical adaptation for populations characterized by lowhabitat and plant productivity. Copyright 2000 Annals of BotanyCompany Ultraviolet-B, Trifolium repens, white clover, HPLC, NMR, flavonoids, flavonols, quercetin, kaempferol, biomass, genetic variation, intraspecific 相似文献
3.
Michael Götz Andreas Albert Susanne Stich Werner Heller Hagen Scherb Andreas Krins Christian Langebartels Harald K. Seidlitz Dieter Ernst 《Protoplasma》2010,243(1-4):95-103
Long-term effects of ultraviolet (UV) radiation on flavonoid biosynthesis were investigated in Arabidopsis thaliana using the sun simulators of the Helmholtz Zentrum München. The plants, which are widely used as a model system, were grown (1) at high photosynthetically active radiation (PAR; 1,310 µmol m?2?s?1) and high biologically effective UV irradiation (UV-BBE 180 mW m?2) during a whole vegetative growth period. Under this irradiation regime, the levels of quercetin products were distinctively elevated with increasing UV-B irradiance. (2) Cultivation at high PAR (1,270 µmol m?2?s?1) and low UV-B (UV-BBE 25 mW m?2) resulted in somewhat lower levels of quercetin products compared to the high-UV-BBE conditions, and only a slight increase with increasing UV-B irradiance was observed. On the other hand, when the plants were grown (3) at low PAR (540 µmol m?2?s?1) and high UV-B (UV-BBE 180 mW m?2), the accumulation of quercetin products strongly increased from very low levels with increasing amounts of UV-B but the accumulation of kaempferol derivatives and sinapoyl glucose was less pronounced. We conclude (4) that the accumulation of quercetin products triggered by PAR leads to a basic UV protection that is further increased by UV-B radiation. Based on our data, (5) a combined effect of PAR and different spectral sections of UV radiation is satisfactorily described by a biological weighting function, which again emphasizes the additional role of UV-A (315–400 nm) in UV action on A. thaliana. 相似文献
4.
FEDERICO J. BERLI DANIELA MORENO PATRICIA PICCOLI LEANDRO HESPANHOL-VIANA M. FERNANDA SILVA RICARDO BRESSAN-SMITH J. BRUNO CAVAGNARO & RUBÉN BOTTINI 《Plant, cell & environment》2010,33(1):1-10
We investigated the interactions of abscisic acid (ABA) in the responses of grape leaf tissues to contrasting ultraviolet (UV)-B treatments. One-year-old field-grown plants of Vitis vinifera L. were exposed to photosynthetically active radiation (PAR) where solar UV-B was eliminated by using polyester filters, or where PAR was supplemented with UV-B irradiation. Treatments combinations included weekly foliar sprays of ABA or a water control. The levels of UV-B absorbing flavonols, quercetin and kaempferol were significantly decreased by filtering out UV-B, while applied ABA increased their content. Concentration of two hydroxycinnamic acids, caffeic and ferulic acids, were also increased by ABA, but not affected by plus UV-B (+UV-B) treatments. Levels of carotenoids and activities of the antioxidant enzymes, catalase, ascorbate peroxidase and peroxidase were elevated by +ABA treatments, but only if +UV-B was given. Cell membrane β -sitosterol was enhanced by ABA independently of +UV-B. Changes in photoprotective compounds, antioxidant enzymatic activities and sterols were correlated with lessened membrane harm by UV-B, as assessed by ion leakage. Oxidative damage expressed as malondialdehyde content was increased under +UV-B treatments. Our results suggest that the defence system of grape leaf tissues against UV-B is activated by UV-B irradiation with ABA acting downstream in the signalling pathway. 相似文献
5.
Rami Alkhatib Nour Abdo Laith AL-Eitan Rafeef Kafesha Akram Rousan 《Physiology and Molecular Biology of Plants》2020,26(5):1047-1054
Magnetism is one of the physical methods affecting water properties. It is considered as an environmental factor that plays a role in the physiological and biochemical reactions. A hydroponic experiment was conducted using four types of treated water (distilled water, magnetically treated distilled water, magnetically treated tap water, and tap water). Tobacco plants (Nicotiana tabacum var. Turkish) were placed in a growth chamber for three weeks. Plants irrigated with magnetically treated distilled water had a significant increase in the physiological parameters including shoot height and root length (P < 0.0001). The same pattern was seen in the photosynthetic rate and protein content, but no significant differences in the stomatal conductance and transpiration rate (P < 0.5601). In contrast, a significant increase of total carbohydrate content was exhibited in plant irrigated with tap water (P < 0.0064). Electron micrographs showed deformed chloroplasts with damaged thylakoid membranes associated with plastoglobules in plants irrigated with tap water and magnetically treated tap water. Lastly, this study suggests that magnetically treated water is an excellent option to improve irrigation methods and thus obtains agricultural production with high efficiency. 相似文献
6.
Andreas Albert Vipaporn Sareedenchai Werner Heller Harald K. Seidlitz Christian Zidorn 《Oecologia》2009,160(1):1-8
Plants in alpine habitats are exposed to many environmental stresses, in particular temperature and radiation extremes. Recent
field experiments on Arnica montana L. cv. ARBO indicated pronounced altitudinal variation in plant phenolics. Ortho-diphenolics increased with altitude compared to other phenolic compounds, resulting in an increase in antioxidative capacity
of the tissues involved. Factors causing these variations were investigated by climate chamber (CC) experiments focusing on
temperature and ultraviolet (UV)-B radiation. Plants of A. montana L. cv. ARBO were grown in CCs under realistic climatic and radiation regimes. Key factors temperature and UV-B radiation
were altered between different groups of plants. Subsequently, flowering heads were analyzed by HPLC for their contents of
flavonoids and caffeic acid derivatives. Surprisingly, increased UV-B radiation did not trigger any change in phenolic metabolites
in Arnica. In contrast, a pronounced increase in the ratio of B-ring ortho-diphenolic (quercetin) compared to B-ring monophenolic (kaempferol) flavonols resulted from a decrease in temperature by
5°C in the applied climate regime. In conclusion, enhanced UV-B radiation is probably not the key factor triggering shifts
in the phenolic composition in Arnica grown at higher altitudes but rather temperature, which decreases with altitude. 相似文献
7.
We studied the contents of flavonols (kaempferol and quercetin) in the meristem of vegetative and generative apices of the main plant shoot in floral Papaver somniferum L. mutants, as well as in the normal plants at successive stages of flower development. Five stages of flower development were distinguished. Flavonols (kaempferol and quercetin) were present in all flower organs at all stages of floral morphogenesis we studied. However, their contents and distribution in different organs and at different stages of flower development markedly varied. No significant differences were found in the contents of flavonols in the meristems of vegetative and generative apices of the main shoot in the lines of floral mutants, as well as between the lines with different amounts of vegetative phytomeres. In the plants with normal flower structure, the contents of flavonols (kaempferol + quercetin) sharply increased with the beginning of differentiation of flower organs, i.e. from stage 3, to reach a maximum in the open flower, when gametogenesis is terminated and fertilization takes place. The level of flavonol contents in the petals (upper part) and stamen was at a maximum at all stages of flower development, while that in the gynaecium was at a minimum. The kaempferol : quercetin ratio was shifted towards quercetin at successive stages of flower development, most significantly in the stamens. The involvement of flavonols in the regulation of floral morphogenesis at stages of flower organs differentiation and functioning is discussed. 相似文献
8.
The possible ameliorative effects of quercetin on soybean [Glycine max (L.) Merr.] leaves exposed to UV-B radiation were conducted in greenhouse. The symmetrical leaves supplied with quercetin
solution (0.2%, 1%) were exposed to UV-B radiation (0, 3.5, 6.5 kJ m−2 d−1). 0.2% quercetin ameliorated leaf photosynthesis, improved leaf water content (LWC), and decreased lipid oxidation. The unfavorable
effect on photosynthetic parameter was displayed in 1% quercetin treatment. The effect of quercetin on phenylalanine ammonia
lyase (PAL) activity varied with the quercetin concentration, UV-B radiation intensity and leaf development. In the later
development polyphenol oxidase (PPO) activity was increased significantly by quercetin treatments. We suggested that quercetin
with suitable concentration could serve as UV-B protective agent partly due to its antioxidant capacity. 相似文献
9.
We studied the contents of flavonols (kaempferol and quercetin) in the meristem of vegetative and generative apices of the main plant shoot in floral Papaver somniferum mutants, as well as in the normal plants at successive stages of flower development. Five stages of flower development were distinguished. Flavonols (kaempferol and quercetin) were present in all flower organs at all stages of floral morphogenesis we studied. However, their contents and distribution in different organs and at different stages of flower development markedly varied. No significant differences were found in the contents of flavonols in the meristems of vegetative and generative apices of the main shoot in the lines of floral mutants, as well as between the lines with different amounts of vegetative phytomeres. In the plants with normal flower structure, the contents of flavonols (kaempferol + quercetin) sharply increased with the beginning of differentiation of flower organs, i.e. from stage 3, to reach a maximum in the open flower, when gametogenesis is terminated and fertilization takes place. The level of flavonol contents in the petals (upper part) and stamen was at a maximum at all stages of flower development, while that in the gynaecium was at a minimum. The kaempferol: quercetin ratio shifted towards quercetin at successive stages of flower development, most significantly in the stamens. The involvement of flavonols in the regulation of floral morphogenesis at stages of flower organs differentiation and functioning is discussed. 相似文献
10.
Experiments were conducted on the atrazine-tolerant mutant Stallion and the atrazine-sensitive cv. Paroll of Brassica napus L., which were grown under either visible light or with the addition of UV-B radiation (280–320 nm) for 15 days. The mutant has been shown to be sensitive to high levels of visible light as compared to the atrazine-sensitive cultivar and therefore we wished to determine plant response to UV-B radiation with respect to potential pigment changes, certain anatomical features, radiation penetration and partial photosynthesis. With regard to pigment changes, we were particularly interested in whether the compositional shift in flavonol pigments under enhanced UV-B radiation, previously suggested to favour increased antioxidant activity, is confined to the adaxial epidermis, which generally receives most UV-B radiation or whether the pigment shift is also inducible in the abaxial epidermis.As was to be expected, the penetration of UV-B radiation (310 nm) was lower in the UV-B-exposed plants, which was correlated with an increased amount of UV-screening pigments in the adaxial and abaxial epidermal layers. The main flavonoid glycosides showed the largest shift from kaempferol to quercetin as aglycone moiety in the adaxial epidermal layer. However, in the abaxial epidermal layer the hydroxycinnamic acid (HCA) derivatives and kaempferol glycosides were predominant. Penetration of 430 nm light was higher after UV-B exposure, and probably contributed to the fact that photosynthetic efficiency of photosystem II was unchanged or higher after UV-B exposure. UV-B radiation decreased leaf area in the atrazine-tolerant mutant only. Both cultivars showed an increased leaf thickness after UV-B exposure due to cell elongation mainly of the palisade tissue. This was especially evident in the mutant. 相似文献
11.
Pratyusa Das Sunil Kumar Chaudhari Asmita Das Somashree Kundu 《Journal of biomolecular structure & dynamics》2019,37(6):1414-1426
Binding affinities of flavonols namely quercetin, myricetin, and kaempferol to human serum albumin (HSA) were determined fluorimetrically and the order was observed to be myricetin > quercetin > kaempferol demonstrating structure–activity relationship. Quercetin-coated silver nanoparticles (AgNPs) show higher binding affinity to HSA compared to free quercetin with binding constants 6.04 × 107 M?1 and 4.2 × 106 M?1, respectively. Using site-specific markers it is concluded that free quercetin and that coated on AgNPs bind at different sites. Significant structural changes in circular dichroism (CD) spectra of HSA were recorded with quercetin-coated AgNPs compared to free quercetin. These results were further substantiated by time-resolved fluorescence spectroscopy where fluorescence life time of the tryptophan residue in HSA–quercetin-coated AgNPs complex decreased to 3.63 ns from 4.22 ns in HSA–quercetin complex. Isothermal calorimetric studies reveal two binding modes for quercetin-coated AgNPs and also higher binding constants compared to free quercetin. These higher binding affinities are attributed to altered properties of quercetin when coated on AgNPs enabling it to reach the binding sites other than site II where free quercetin mainly binds. 相似文献
12.
Purification of the Trehalase GMTRE1 from Soybean Nodules
and Cloning of Its cDNA. GMTRE1 Is
Expressed at a Low Level in Multiple Tissues 总被引:17,自引:1,他引:16
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Roger A. Aeschbacher Joachim Müller Thomas Boller Andres Wiemken 《Plant physiology》1999,119(2):489-496
The effects of ultraviolet-B (UV-B) radiation on stomatal conductance (gs) in pea (Pisum sativum L.), commelina (Commelina communis L.), and oilseed rape (Brassica napus L.) plants were investigated. Plants were grown in a greenhouse either with three different high ratios of UV-B to photosynthetically active radiation or with no UV-B radiation. Pea plants grown in the highest UV-B radiation (0.63 W m−2) exhibited a substantial decrease of adaxial and abaxial gs (approximately 80% and 40%, respectively). With growth in 0.30 W m−2 of UV-B adaxial gs was decreased by 23%, with no effect on abaxial gs, and lower UV-B irradiance of 0.21 W m−2 had no effect on either surface. Although abaxial gs increased when leaves were turned over in control plants, it did not in plants grown with the highest UV-B. Adaxial gs in commelina and oilseed rape also decreased on exposure to high UV-B (0.63 W m−2). For previously unexposed pea plants the time course of the effect of UV-B on gs was slow, with a lag of approximately 4 h, and a time constant of approximately 3 h. We conclude that there is a direct effect of UV-B on stomata in addition to that caused by changes in mesophyll photosynthesis. 相似文献
13.
Effect of Cerium on Photosynthetic Pigments and Photochemical Reaction Activity in Soybean Seedling Under Ultraviolet-B Radiation Stress 总被引:1,自引:0,他引:1
Effects of cerium (Ce) on photosynthetic pigments and photochemical reaction activity in soybean (Glycine max L.) under ultraviolet-B (UV-B) radiation stress were studied under laboratory conditions. UV-B radiation caused the decrease
in chlorophyll content, net photosynthetic rate, Hill reaction activity, photophosphorylation rate and Mg2+-ATPase activity. Ce (III) (20 mg L−1) could alleviate UV-B-induced inhibition to these photosynthetic parameters because values of these photosynthetic parameters
in Ce (III) + UV-B treatment were obviously higher than those with UV-B treatment alone. Dynamic changes of the above photosynthetic
parameters show that Ce (III) could slow down the decrease rate of these photosynthetic parameters during a 5-day UV-B radiation
and quicken the restoration during recovery period. The final restoration degree of five parameters mentioned above in leaves
exposed to low level of UV-B radiation (0.15 W m2) was higher than that exposed to high level (0.45 W m2). Correlating net photosynthetic rate with other four parameters, we found that the regulating mechanisms Ce (ΠΙ) on photosynthesis
under various level of UV-B radiation were not the same. The protective effects of Ce (III) on photosynthesis in plants were
influenced by the intensity of UV-B radiation. 相似文献
14.
Hanna Bandurska Ma?gorzata Pietrowska-Borek Ma?gorzata Cie?lak 《Acta Physiologiae Plantarum》2012,34(1):161-171
Responses of barley seedlings to water deficit (WD) induced by polyethylene glycol (PEG 6000) and ultraviolet (UV-B; 280–320 nm)
radiation and their interaction (UV-B + WD) were examined. A decrease in dry matter yield and water content of leaves and
roots was observed following application of WD and UV-B + WD, while no changes were found after treating barley plants with
UV-B. Proline content was increased in leaves under WD conditions and UV-B + WD. In contrast, UV-B treatment had no effect
on the accumulation of proline in leaves of barley plants. Changes in root proline content showed a varied response: WD induced
an increase in the level of this amino acid, while UV-B as well as UV-B + WD suppressed root proline content. The lipid peroxidation
product malondialdehyde (MDA) was increased in leaves under WD and UV-B + WD stresses. Root MDA content increased in WD-stressed
plants, but it decreased in the case of combined application of both stresses. The applied stress factors operated in a variable
manner on phenylpropanoid metabolism. Phenylalanine ammonia-lyase (PAL) activity in leaves and roots was stimulated after
exposure to WD and application of UV-B + WD stresses, while UV-B stress did not affect its activity. On the other hand, UV-B
treatment enhanced the activity of 4:coumarate-CoA ligase (4CL) in leaves and this enhancement was positively correlated with
the accumulation of anthocyanins and flavonols. However, the combined application of WD and UV-B reduced the positive effect
of UV-B on the accumulation of these compounds and the activity of 4CL. Surprisingly, anthocyanins and flavonols were not
detected in roots of examined barley seedlings despite increased 4CL activity. The results suggest that UV-B-induced activation
of 4CL as well as accumulation of anthocyanin and flavonols in leaves is beneficial for the response to this stress factor.
On the other hand, WD-induced reduction of the effect of UV-B on 4CL activity and the contents of anthocyanin and flavonol
might be a cause of membrane damage in UV-B- and WD-stressed plants. In addition, conversely to what could be expected, the
UV-B effect was perceived by the water-stressed roots, which exhibited reduced lipid peroxidation (MDA) and proline accumulation
in WD-stressed plants exposed to UV-B. 相似文献
15.
The effects of different wavebands of UV radiation on photosynthesis and the expression and abundance of photosynthetic proteins
in oilseed rape (Brassica napus L. cv. Rebel) were investigated. Plants were grown outdoors under natural radiation (52° N, 0° E) supplemented with six wavebands
of UV radiation (0.4 Wm−2) between 313 nm and 356 nm. A control treatment was centred at 343 nm. Exposure to supplementary UV-A radiation (320–400
nm) had no significant effects, however UV-B radiation, centred at 313 nm, caused a marked reduction in photosynthesis. This
decrease was related to a reduction in the initial carboxylation velocity of Rubisco which was further correlated with a large
reduction in the expression and abundance of both large and small subunits of Rubisco. These results indicate a molecular
mechanism behind UV-B induced reductions in photosynthesis per unit area in plants grown under field conditions.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
16.
Seasonal accumulation of ultraviolet-B screening pigments in needles of Norway spruce (Picea abies (L.) Karst.) 总被引:4,自引:1,他引:3
R. J. FISCHBACH B. KOSSMANN H. PANTEN R. STEINBRECHER W. HELLER H. K. SEIDLITZ H. SANDERMANN N. HERTKORN & J.-P. SCHNITZLER 《Plant, cell & environment》1999,22(1):27-37
Conifer needles are highly effective in screening ultraviolet-B radiation (280–320 nm). This ability is mainly attributed to the presence of flavonoids and hydroxycinnamic acids in the epidermal tissue. In two field cabinet experiments with two different clones of Norway spruce we assessed the seasonal accumulation of UV-B screening pigments under near-ambient, and close-to-zero UV-B irradiation. At the beginning of needle development, i.e. in June, kaempferol 3- O -glucoside was the dominant UV-B screening pigment. It was replaced during needle differentiation by the more effective diacylated flavonol glucosides, particulary kaempferol 3- O -(3",6"- O -di- p -coumaroyl)-glucoside, which reached highest concentrations in July. In addition to the soluble pool of diacylated flavonol glucoside derivatives, a cell wall-bound UV-B screen in the epidermal cell walls was formed during needle differentiation, consisting mainly of p -coumaric acid and kaempferol 3- O -glucoside. An effect of UV-B radiation on the accumulation of diacylated flavonol glucosides was only observed in 1996 with clone 2, when the concentrations of kaempferol 3- O -(3",6"- O -di- p -coumaroyl)-glucoside were significantly higher in July and August under field, and near-ambient than under close-to-zero UV-B irradiance. For wall-bound p -coumaric acid and kaempferol 3- O -glucoside UV-B radiation enhanced the concentrations of these compounds by approximately 20% in relation to the concentrations in close-to-zero UV-B-treated plants in both field cabinet experiments. 相似文献
17.
We studied flavonol-degrading activity of cell-free extracts from petals of the flower color and structure mutants. The relationship between degradation of flavonols (kaempferol, quercetin, and myricetin) and biosynthesis of anthocyanins has been revealed. The white-flower mutant proved to have the highest flavonol-degrading activity toward all substrates, particularly quercetin. The mutations inhibiting synthesis of pelargonidin, an anthocyanin, provide for synthesis of various amounts of cyanidin in the petals. The flavonol-degrading activity considerably increases proportionally to the content of cyanidin. A similar relationship has been revealed in the mutants synthesizing both cyanidin and pelargonidin. The plants accumulating considerable amounts of pelargonidin in their petals have accordingly higher flavonol-degrading activity and predominantly hydrolyze kaempferol. The plants forming additional pods in their flower (pistillody) have higher flavonol-degrading activity as compared to the anther-in-petal and doubleness mutants 相似文献
18.
The Response of Bean Plants to UV-B Radiation Under Different Irradiances of Background Visible Light 总被引:14,自引:1,他引:13
Plants of Phaseolus vulgaris L. (cv. Stella) were grown in controlledconditions under three different irradiances of visible lightwith or without UV-B (280320nm) radiation. The biologicallyeffective UV-B radiation (UV-BBE) was 6.17 kJ m2 d1,and simulated a c. 5% decrease in stratospheric ozone at 55.7?N,13.4?E. The photon flux densities of the photosyntheticallyactive radiation (PAR, 400700 nm) were either 700 µmolm21 (HL), 500, µmol m2 s1(ML) or 230 µmol m2 s1 PAR (LL). Under highlight (HL) conditions plus UV-B radiation, bean plants appearedmost resistant to the enhanced levels of UV-B radiation, andresponded only by increasing leaf thickness by c. 18%. A smallincrease in UV screening pigments was also observed. Both thelower irradiances (ML and LL) increased the sensitivity of theplants to UV-B radiation. Changes in leaf structure were alsoobserved. Photosystem II was inhibited under ML and LL togetherwith UV-B radiation, as determined by Chi fluorescence inductionand calculation of the fluorescence half-rise times. Leaf reflectivitymeasurements showed that the amount of PAR able to penetrateleaves of UV-B treated plants was reduced, and that a possiblecorrelation may exist between the reduced PAR levels, loss ofChi and lowered photosynthetic activity, especially for LL +UV-Bgrown plants, where surface reflection from leaves was highest.Changes in leaf chlorophyll content were mostly confined toplants grown under LL + UV-B, where a decrease of c. 20% wasfound. With regard to protective pigments (the carotenoids andUV screening pigments) plants subjected to different visiblelight conditions responded differently. Among the growth parametersmeasured, there was a substantial decrease in leaf area, particularlyunder LL + UV-B (c. 47% relative to controls), where leaf dryweight was also reduced by c. 25%. Key words: Chlorophyll fluorescence induction, bean, flavonoids, Phaseolus vulgaris, reflectance, UV-B radiation 相似文献
19.
Ulla Anttila Riitta Julkunen-Tiitto Matti Rousi Shiyong Yang Markus J. Rantala Teija Ruuhola 《Oecologia》2010,164(1):163-175
Enhanced ultraviolet-B (UV-B) radiation may have multiple effects on both plants and animals and affect plant–herbivore interactions
directly and indirectly by inducing changes in host plant quality. In this study, we examined combined effects of UV-B and
herbivory on the defence of the mountain birch (Betula pubescens ssp. czerepanovii) and also the effects of enhanced UV-B radiation on a geometrid with an outbreak cycle: the autumnal moth (Epirrita autumnata). We established an experiment mimicking ozone depletion of 30% (a relevant level when simulating ozone depletion above Northern
Lapland). Both arctic species responded only slightly to the enhanced level of UV-B radiation, which may indicate that these
species are already adapted to a broader range of UV-B radiation. UV-B exposure slightly induced the accumulation of myricetin
glycosides but had no significant effect on the contents of quercetin or kaempferol derivatives. Mountain birch seedlings
responded more efficiently to herbivory wounding than to enhanced UV-B exposure. Herbivory induced the activities of foliar
oxidases that had earlier been shown to impair both feeding and growth of moth larvae. In contrast, the contents of foliar
phenolics did not show the same response in different clones, except for a decrease in the contents of tannin precursors.
The induction of foliar phenoloxidase activities is a specific defence response of mountain birches against insect herbivory.
To conclude, our results do not support the hypothesis that the outbreak cycle of the autumnal moth can be explained by the
cycles of solar activity and UV-B. 相似文献
20.
Hydrogen Peroxide-dependent Synthesis of Flavonols in Mesophyll Cells of Vicia faba L. 总被引:2,自引:0,他引:2
Mesophyll cells of Vicia faba contain kaempferol and quercetinglycosides. When isolated mesophyll cells were treated with0.1 mM H2O2 for 2 h, the levels of these flavonols increasedby 1070% of the control values (mean values, 19.6% and34.4% for kaempferol and quercetin glycosides, respectively).Such increases in levels of flavonols were also observed inisolated vacuoles of mesophyll cells. However, when mesophyllcells and vacuoles were treated with 10 mM H2O2)degradationof flavonols was observed. These data suggest that H2O2 hastwo effects on the metabolism of flavonols: induction of theirsynthesis and stimulation of their oxidation. (Received March 6, 1989; Accepted July 10, 1989) 相似文献