增强UV-B辐射和NaCl复合胁迫下绿豆光合作用的气孔和非气孔限制

研究了0.35 W/m2的UV-B辐射、0.4%NACl及其复合胁迫下绿豆(Phaseolus radiatus L.)幼苗光合作用的气孔和非气孔限制.发现各胁迫处理下,幼苗净光合速率、气孔导度、光合能力、羧化效率和Rubisco含量均明显降低;细胞间隙CO2浓度在各胁迫处理前期低于对照,后期高于对照;气孔限制值除复合处理第5天外,其余均高于对照;复合处理下上述指标的变化程度均大于两胁迫因子单独处理.表明各胁迫下光合速率的降低既有气孔因素也有非气孔因素,但前期以气孔限制为主,后期以非气孔限制为主;Rubisco含量的降低是各胁迫下光合速率降低的非气孔因素.     

The effects of long-term elevated UV-B on the growth and phenolics of field-grown silver birch (Betula pendula)

The effects of long‐term elevated UV‐B radiation on silver birch (Betula pendula Roth) seedlings were studied over three growing seasons in an outdoor experiment in Finland started 64 days after germination. One group of seedlings was exposed to a constant 50% increase in UV‐B_CIE radiation, which corresponds to 20–25% of ozone depletion; another group received a small increase in UV‐A radiation and a third (the control group) received ambient solar radiation. Changes in growth appeared during the third growing season; the stems of the UV‐B treated seedlings were thinner and their height tended to be shorter compared with that of the control seedlings. In contrast, there were no UV‐B effects on biomass, bud burst, bud dry weights, leaf area, rust frequency index or chlorophyll concentrations in any of the summers. During the three‐year study, the flavonols were significantly increased by the elevated UV‐B only in the first growing season. The responses varied greatly among individual compounds; the most induced were the quercetin glycosides, while the main flavonols, myricetins, were reduced by the UV‐A control treatment. In the second summer phenolic acids, such as 3,4′‐dihydroxypropiophenone‐3‐glucoside, neochlorogenic acid and 5‐coumarylquinic acid, were increased by the UV‐B treatment. In the third year, the constitutive concentrations of phenolics were not affected by the UV‐B treatment.     

Leaf thickness and UV-B absorbing pigments of plants in relation to an elevational gradient along the Blue Mountains,Jamaica

Terrestrial plant species vary widely in their adaptation to (increasing) solar UV-B radiation. Among the various responses of higher plants to enhanced UV-B are increasing leaf thickness and increasing concentrations of UV-B absorbing compounds. In some (UV-B resistant) plant species increased leaf thickness and UV-B absorbance may form part of mechanisms protecting plants from UV-B damage. However, in UV-B sensitive plant species leaf thickness and UV-B absorbance may increase as well with enhanced UV-B radiation. In the latter case however, this response cannot prevent plant damage and disturbance. In the present field study the relationship between these plant parameters and a natural elevational UV-B gradient on the tropical island of Jamaica was described. Four plant species of the Blue Mountain Tropical Montane Forest, occurring on open forest sites along the roadside and paths were studied along an elevational gradient. Plant species studied are Redbush (Polygonum chinense), Wild ginger (Hedychium gardneranum), John Crow Bush (Bocconia frutescens) and White clover (Trifolium repens). The elevational sites were at 800, 1000, 1200, 1400 and 1600 m above sea level. Leaf thickness was measured of leaves of intact plants around midday in the field. Leaf disks (5 mm) were sampled and extracted with a methanol/HCl mixture. UV-B absorption of these leaf extracts was measured spectrophotometrically. For all species leaves from higher elevations were thicker than those from lower elevations. In addition, the absorption of UV-B of leaf extracts increased with increasing elevations. It is assumed that the calculated gradient of the UV-B_BE from 800 m above sea level: 9.45 kJ m^-2 day^-1 to 9.75 kJ m^-2 day^-1 at 1600 m is related to the measured increase of leaf thickness and UV-B absorbing compounds. The responsiveness of these plant parameters to the elevational gradient does not necessarily imply that the plant species are UV-B resistant. One possibility is that the species studied, which are growing on open, disturbed sites on the forest floor and along mountain-roads, are relatively sensitive to UV-B. In addition to clear sky conditions, mist and clouds occur frequently in this tropical mountane forest at Jamaica. Also, the low nutrient status of the soil (low pH, nutrient deficiency) and the high content of polyphenols in leaves of many plant species of the tropical montane rain forest may relate to the marked response of the species studied with increasing elevation. Abbreviations: asl – above sealevel, UV-B – ultraviolet-B radiation (280–320 nm), TMCF – Tropical Montane Cloud Forest.     

UV-B辐射对南亚热带森林木本植物幼苗生长的影响

研究了UV -B辐射对广东省南亚热带森林木本植物九节、鸭脚木、猴耳环、半枫荷、山乌桕和绿化树种大叶合欢幼苗生长的影响。实验结果表明 ,UV -B辐射降低叶片光合色素的含量 ;显著降低幼苗的净光合速率、蒸腾速率和气孔导度 ;降低干物质的增长 ;抑制大叶合欢幼苗根瘤的形成     

CO_2加富对UV-B辐射胁迫下亚心形扁藻光合作用和膜脂过氧化以及抗氧化酶活性的影响(英文)

在CO2浓度分别为当今CO2浓度(360 mL/L)和加富浓度(5 000 mL/L)条件下,研究了UV-B胁迫对亚心形扁藻(Platymonas subcordiformis (Wille) Hazen)的光合作用、膜脂过氧化和抗氧化酶活性的影响。实验结果表明:(1) UV-B单独作用下,亚心形扁藻的干重、光合速率、叶绿素a (Chl a)和类胡萝卜素(Car.)含量显著降低,CO2加富单独作用下,亚心形扁藻的干重和光合速率显著升高,叶绿素a和类胡萝卜素含量与对照相比没有显著变化,而UV-B与CO2共同作用则使亚心形扁藻的干重和光合速率与对照相比没有显著变化,叶绿素a和类胡萝卜素含量显著降低。(2) UV-B单独作用和CO2加富单独作用都使可溶性蛋白含量显著降低,UV-B与CO2共同作用下的可溶性蛋白含量比UV-B单独作用的要高。高CO2对藻的可溶性蛋白含量的变化在很大程度上归因于Rubisco蛋白的降低。(3)UV-B单独作用下,O2-. 产生速率、H2O2 含量和MDA含量显著升高,而CO2加富单独作用下,O2-. 产生速率、H2O2 含量和MDA含量显著降低,与UV-B单独作用相比,UV-B与CO2共同作用使O2-. 产生速率、H2O2 含量和MDA含量显著降低。说明CO2加富可以减少活性氧对亚心形扁藻的氧化胁迫,同时减少UV-B对亚心形扁藻的膜脂过氧化伤害。(4) UV-B单独作用下,SOD、POD、CAT、GR和GPX活性显著升高,高CO2     

增强UV-B辐射和干旱对春小麦光合作用及其生长的影响

在室外盆栽条件下研究了UV-B辐射和土壤干旱对春小麦 '和尚头'生长和光合作用的影响.结果显示:(1)干旱、UV-B辐射、干旱+UV-B(复合)处理均可使叶片类黄酮含量增加,且干旱+UV-B处理增加显著高于其他处理(P<0.05).UV-B辐射和干旱单独处理均能显著降低叶片光合色素含量,但UV-B辐射的副作用大于干旱,复合处理对光合色素的影响介于UV-B和干旱之间.(2)各处理间的光合速率日均值大小次序为:对照>UV-B+干旱>UV-B>干旱;增强UV-B对净光合速率的抑制作用大于干旱,而UV-B+干旱处理的抑制作用较二者单独处理有所减轻.(3)UV-B辐射和干旱单独处理后总生物量比对照减少15%,且抑制作用为:干旱>UV-B>复合处理; UV-B辐射和干旱胁迫不但影响春小麦的生物量,而且影响小穗特征和产量.研究表明,UV-B辐射和干旱之间存在交互作用,说明一种胁迫可以减缓(轻)另外一种胁迫对春小麦的抑制作用.     

Effect of Ultraviolet (UV-B) Radiation on the Formation and Localization of Phenolic Compounds in Tea Plant Callus Cultures

The effect of ultraviolet (UV-B) radiation on the accumulation and tissue localization of phenolic compounds in two strains of callus cultures of tea plant (Camellia sinensisL.) were investigated. The strains differed in their morphological and physiological characteristics and biosynthetic capacity. UV-B radiation hampered culture growth, decreased the size of callus-forming cells and promoted the accumulation of soluble and, to a lesser extent, polymeric forms of phenolic compounds, such as lignin. This accumulation was accompanied by an increase in the phenolic compound deposition in cell walls and intercellular space and by deposition of a lignin-like material on the surface of callus cultures. The strain characterized by an increased formation of phenolic compounds was more resistant to UV-B radiation as compared to that with lower phenolic productivity.     

增强UV-B辐射和氮素互作对植物生长代谢影响的研究进展

不同氮源条件下,UV-B辐射增强能改变植株对氮的吸收利用以及植株叶片的碳氢比和碳氮比,增加氨基酸的生物合成.缺氮条件下, UV-B辐射增强使植物叶片中SOD、POD活性增强,MDA含量增加;氮素过量时,UV-B辐射增强会降低植物对UV-B辐射的耐性.UV-B辐射增强和氮缺乏相互作用会降低叶片的光合速率、叶绿素含量、可溶性糖及淀粉含量,从而抑制植物的生长,降低生物量.该文对近年来国内外有关UV-B辐射增强与氮素相互作用对植物抗氧化系统、氮代谢、光合作用、生物量和形态结构的影响进行综述.     

Heat Shock Increases the Tolerance of Plants to UV-B Radiation: 1. Growth,Development, and Water Supply to Tissues

The effects of heat shock (HS); UV-B irradiation; and the consecutive action of these factors on the growth, development, and water supply of seven-day-old melon (Melo sativusSager., cv. Torpeda) seedlings were investigated. Depending on the HS severity, we observed growth stimulation (after treatment at 45°C for 1 h), growth retardation (after treatment at 45°C for 2 h or at 48°C for 1 h), or complete growth inhibition and cell death (after treatment at 45°C for 3 h or at 55°C for 1 h). UV-B irradiation (18.3 kJ/(m²h)), depending on its duration, stimulated (5–10 min), retarded (60 min), or resulted in complete growth inhibition and plant death (90 min). HS treatment (at 45°C for 1 h) prior to UV-B irradiation (for 1 h) favorably affected both the growth and water balance of seedlings. Apparently, the HS pretreatment increases the tolerance of seedlings to high doses of UV-B radiation.     

补增UV—B辐射对香蕉叶片光合作用和叶氮在光合碳循环组分中分配 …

补增UV -B辐射的香蕉叶片光下呼吸速率 (Rd)和不包括光下呼吸的CO2 补偿点 (г ) ,分别为0 .33μmol·m- 2 ·s- 1 和 46.5μl·L- 1 ,较对照植株分别高 5.6%和 1 0 .0 %。在较高CO2 浓度 (>340 μl·L- 1 )条件下的An/θp关系最初直线部分斜率 ,即表观量子产率 (αA)为 0 .0 2 3± 0 .0 0 7,而补增UV B辐射处理的植株则降低 1 3.0 % ,光能转换效率 (δ)亦降低 2 8.6% ,表明UV B辐射明显降低αA 和δ。在高θp(1 1 0 0 μmol·m- 2 ·s- 1 )和Ci<2 0 0 μl·L- 1 条件下 ,对照植株的An/Ci关系为An =0 .0 2 8Ci 1 .44,补增UV B辐射处理的植株则为An =0 .0 2 1Ci 1 .0 1 ,UV B辐射降低羧化限制速率。最大羧化速率 (Vcmax)和电子传导速率的光饱和值 (Jmax)亦较低 ,补增UV B辐射的叶片 ,叶氮在Rubisco的分配系数 (PR)和叶氮在生物力能学组分的分配系数 (PB)分别较对照低 8.1 %和 3.0 % ,叶氮分配到类囊体膜捕光色素蛋白组分的则略见增高 ,UV B辐射降低叶氮在光合循环组分的分配     

外源NO对增补UV-B辐射下兴安落叶松幼苗叶片光合色素和叶绿素荧光特性的影响

在增强UV-B辐射下,以3年生兴安落叶松幼苗为实验材料,研究了外源NO供体硝普钠(Sodium nitroprusside,SNP)对幼苗的光合色素（Chla、Chlb和Car）和叶绿素荧光参数的影响。方差分析结果表明0.5 mmol·L^-1的SNP对增补UV B胁迫下的兴安落叶松幼苗产生显著影响。0.5 mmol·L^-1的SNP能够显著抑制增补UV-B辐射后光合色素、F_v/F_m、Φ_PSⅡ、F_v′/F_m′和qP的明显下降以及Chla /Chlb、F_o和NPQ的升高。表明了外源NO能够减轻UV-B辐射胁迫下兴安落叶松幼苗光合反应中心的生理损伤,从而增强兴安落叶松幼苗对增补UV-B辐射胁迫环境的适应能力。     

UV-B辐射对番茄花粉生活力的影响与内源激素和多胺的关系

以成熟期不同的两个番茄品种同辉(早熟型)和霞光(晚熟型)为试材,模拟兰州地区12％和20％臭氧层减薄时增强的UV- B辐射(分别为T1=2．54 KJ·m-2·d-1和T2=4．25 KJ·m-2·d-1),研究了大田条件下增强UV-B辐射对其花粉生活力的影响以及雄蕊中4种内源激素(IAA、GAs、ZR和ABA)和多胺(Put、Spm和Spd)及脯氨酸的变化。结果表明:辐射抑制了同辉的花粉萌发和花粉管伸长,但只降低了霞光的花粉萌发率;两种辐射明显降低了两品种番茄雄蕊中的GAs含量,同时造成同辉雄蕊中Put和Spd含量明显增加,Spm和Put／Spd+Spm比值显著降低;霞光中3种多胺含量都显著减少,导致高辐射时Put／Spd+Spm比值上升;同辉番茄雄蕊的脯氨酸含量不受影响,但高辐射使霞光番茄雄蕊的脯氨酸含量降低。实验表明,两品种番茄花粉生活力的变化与增强UV-B辐射下雄蕊中GAs水平、Spm含量以及脯氨酸含量的减少有关。雄蕊中多胺和脯氨酸含量变化对UV- B辐射的响应说明霞光品种对UV-B辐射更敏感。     

The effect of exposure to enhanced UV-B radiation on the penetration of monochromatic and polychromatic UV-B radiation in leaves of Brassica napus

Using quartz optical fibres, penetration of both monochromatic (310 nm) and polychromatic UV-B (280–320 nm) radiation in leaves of Brassica napus L. (cv. Ceres) was measured. Plants were grown under either visible light (750 μmol m⁻² s⁻¹ photosynthetically active radiation) or with the addition of 8. 9 KJ m⁻² day⁻¹ biologically effective UV-B (UV-B_BE) radiation. Results showed that of the 310 nm radiation that penetreated the leaf, 90% was within the intial one third of the leaf with high attenuation in the leaf epidermis, especially in UV-treated plants. Polychromatic UV-B radiation, relative to incident radiation, showed a relatively uniform spectral distribution within the leaf, except for collimated radiation. Over 30% of the UV-screening pigments in the leaf, including flavonoids, were found in the adaxial epidermal layer, making this layer less transparent to UV-B radiation than the abaxial epidermis, which contained less than 12% of the UV-screening pigments. UV-screening pigments increased by 20% in UV-treated leaves relative to control leaves. Densely arranged epicuticular wax on the adaxial leaf surface of UV-treated plants may have further decreased penetration of UV-B radiation by reflectance. An increased leaf thickness, and decreases in leaf area and leaf dry weight were also found for UV-treated plants.     

Changes in morphological, photosynthetic and physiological responses of Mono Maple seedlings to enhanced UV-B and to nitrogen addition

In the southeast of the Qinghai-Tibetan Plateau of China, Mono Maple is a common species in reforestation processes. The paper mainly investigated the changes in morphological, photosynthetic and physiological responses of Mono Maple seedlings to UV-B radiation, nitrogen supply and their combination. The experimental design included two levels of UV-B treatments (ambient UV-B, 11.02 KJ m⁻² day⁻¹; enhanced UV-B, 14.33 KJ m⁻² day⁻¹) and two nitrogen levels (0; 20 g N m⁻² a⁻¹)—to determine whether the adverse effects of UV-B on plants are eased by nitrogen supply. Enhanced UV-B caused a marked decline in growth parameters, net photosynthetic rate, and photosynthetic pigments, whereas it induced an increase in reaction oxygen species (hydrogen peroxide accumulation and the rate of superoxide radical production) and malondialdehyde content. Enhance UV-B also induced an increase in antioxidant compounds of Mono Maple, such as UV-B absorbing compounds, proline content, and activities of antioxidant enzymes (peroxidase, superoxide dimutase and catalase). On the other hand, nitrogen supply caused an increase in some growth parameters, net photosynthetic rate, photosynthetic pigments and antioxidant compounds (peroxidase, proline content and UV-B absorbing compounds), and reduced the content of reaction oxygen species (H₂O₂ accumulation, the rate of O₂⁻ production) and malondialdehyde content under ambient UV-B. However, under enhanced UV-B, nitrogen supply inhibited some growth parameters, and increased H₂O₂ accumulation, the rate of O₂⁻ production and MDA content, though proline content, UV-B absorbing compounds and activities of POD and SOD increased. These results implied that enhanced UV-B brought harmful effects on Mono Maple seedlings and nitrogen supply made plants more sensitive to enhanced UV-B, though increased some antioxidant activity.     

Changes in leaf expansion and epidermal screening effectiveness in Liquidambar styraciflua and Pinus taeda in response to UV-B radiation

Absorption or screening of ultraviolet-B (UV-B) radiation by the epidermis may be an important protective method by which plants avoid damage upon exposure to potentially harmful UV-B radiation. In the present study we examined the relationships among epidermal screening effectiveness, concentration of UV-absorbing compounds, epidermal anatomy and growth responses in seedlings of loblolly pine (Pinus taeda L.) and sweetgum (Liquidambar styraciflua L.). Seedlings of each species were grown in a greenhouse at the University of Maryland under either no UV-B radiation or daily supplemental UV-B radiation levels of 4, 8 or 11 kJ m^?2 of biologically effective UV-B (UV-B_BE) radiation. Loblolly pine seedlings were subsequently grown in the field under either ambient or supplemental levels of UV-B radiation. At the conclusion of the growing season, measurements of epidermal UV-B screening effectiveness were made with a fiber-optic microprobe. In loblolly pine, less than 0.5% of incident UV-B radiation was transmitted through the epidermis of fascicle needles and about 1% was transmitted in primary needles. In contrast, epidermal transmittance in sweetgum ranged from about 20% in leaves not preconditioned to UV-B exposure, to about 10% in leaves grown under UV-B radiation. The concentration of UV-absorbing compounds was unaffected by UV-B exposure, but generally increased with leaf age. Increases in epidermal thickness were observed in response to UV-B treatment in loblolly pine, and this accounted for over half of the variability in UV-B screening effectiveness. In spite of the low levels of UV-B penetration into the mesophyll, delays in leaf development (both species) and final needle size (loblolly pine) were observed. Seedling biomass was reduced by supplemental UV-B radiation in loblolly pine. We hypothesize that the UV-induced growth reductions were manifested by changes in either epidermal anatomy or epidermal secondary chemistry that might negatively impact cell elongation.     

Effect of enhanced UV-B radiation on pollen quantity,quality, and seed yield in Brassica rapa (Brassicaceae)

We conducted three experiments to examine the influence of ultraviolet-B radiation (UV-B; 280–320 nm) exposure on reproduction in Brassica rapa (Brassicaceae). Plants were grown in a greenhouse under three biologically effective UV-B levels that simulated either an ambient stratospheric ozone level (control), 16% (“low enhanced”), or 32% (“high enhanced”) ozone depletion levels at Morgantown, WV, USA in mid-March. In the first experiment, we examined whether UV-B level during plant growth influenced in vivo pollen production and viability, and flower production. Pollen production and viability per flower were reduced by ≈50% under both enhanced UV-B levels relative to ambient controls. While plants under high-enhanced UV-B produced over 40% more flowers than plants under the two lower UV-B treatments, whole-plant production of viable pollen was reduced under high-enhanced UV-B to 17% of that of ambient controls. Whole-plant production of viable pollen was reduced under low-enhanced UV-B to 34% of ambient controls. In the second experiment, we collected pollen from plants under the three UV-B levels and examined whether source-plant UV-B exposure influenced in vitro pollen germination and viability. Pollen from plants under both enhanced-UV-B treatments had initially lower germination and viability than pollen from the ambient level. After in vitro exposure to the high-enhanced UV-B levels for 6 h, viability of the pollen from plants grown under ambient UV-B was reduced from 65 to 18%. In contrast, viability of the pollen from plants grown under both enhanced UV-B treatments was reduced to a much lesser extent: only from ≈43 to 22%. Thus, ambient source-plant pollen was more sensitive to enhanced UV-B exposure. In the third experiment, we used pollen collected from source plants under the three UV-B levels to fertilize plants growing under ambient-UV-B levels, and assessed subsequent seed production and germination. Seed abortion rates were higher in plants pollinated with pollen from the enhanced UV-B treatments, than from ambient UV-B. Despite this, seed yield (number and mass) per plant was similar, regardless of the UV-B exposure of their pollen source. Our findings demonstrate that enhanced UV-B levels associated with springtime ozone depletion events have the capacity to substantially reduce viable pollen production, and could ultimately reduce reproductive success of B. rapa.     

UV-B Radiation Suppresses the Growth and Antioxidant Systems of Two Marine Microalgae, Platymonas subcordiformis (Wille) Hazen and Nitzschia closterium (Ehrenb.) W. Sm

This study investigated whether increased solar UV-B radiation (280-315 nm) could suppress the growth of marine microalgae through effects on their antioxidant systems. Two marine microalgae species, Platymonas subcordiformis (Wille) Hazen and Nitzschia closterium (Ehrenb.) W. Sm, were exposed to a range of UV-B radiation and both showed reductions in their growth rates, and the chlorophyll a (Chl a) and carotenoid (Car) contents when UV-B radiation dose increased. Superoxide anion radical (O2)production and the concentration of hydrogen peroxide (H2O2) and malodiadehyde (MDA) also increased with the increasing of UV-B radiation. Antioxidant systems, non-enzymic components (Car and glutathione content) and enzymic components (superoxide dismutase (SOD) and catalase (CAT) activity), decreased as a result of enhanced UV-B radiation. When the exogenous glutathione (GSH) was added, the effects of UVB radiation on the growth of the two species were alleviated. These results suggest that enhanced UV-B radiation suppressed the antioxidant systems and caused some active oxygen species to accumulate, which in turns retarded the development of the marine microalgae.     

Growth enhancement of soybean (Glycine max) upon exclusion of UV-B and UV-B/A components of solar radiation: characterization of photosynthetic parameters in leaves

Exclusion of UV (280–380 nm) radiation from the solar spectrum can be an important tool to assess the impact of ambient UV radiation on plant growth and performance of crop plants. The effect of exclusion of UV-B and UV-A from solar radiation on the growth and photosynthetic components in soybean (Glycine max) leaves were investigated. Exclusion of solar UV-B and UV-B/A radiation, enhanced the fresh weight, dry weight, leaf area as well as induced a dramatic increase in plant height, which reflected a net increase in biomass. Dry weight increase per unit leaf area was quite significant upon both UV-B and UV-B/A exclusion from the solar spectrum. However, no changes in chlorophyll a and b contents were observed by exclusion of solar UV radiation but the content of carotenoids was significantly (34–46%) lowered. Analysis of chlorophyll (Chl) fluorescence transient parameters of leaf segments suggested no change in the F _v/F _m value due to UV-B or UV-B/A exclusion. Only a small reduction in photo-oxidized signal I (P700⁺)/unit Chl was noted. Interestingly the total soluble protein content per unit leaf area increased by 18% in UV-B/A and 40% in UV-B excluded samples, suggesting a unique upregulation of biosynthesis and accumulation of biomass. Solar UV radiation thus seems to primarily affect the photomorphogenic regulatory system that leads to an enhanced growth of leaves and an enhanced rate of net photosynthesis in soybean, a crop plant of economic importance. The presence of ultra-violet components in sunlight seems to arrest carbon sequestration in plants. An erratum to this article can be found at