紫外线(UV-B)辐射对不同色型豌豆蚜生物学特性的影响

为了明确紫外线(UV-B)辐射对红色型和绿色型豌豆蚜生物学特性的影响,本研究将2种不同色型豌豆蚜的初生若蚜经过40 W UV-B波段紫外线每日照射30 min,在3种温度梯度(16℃、20℃、24℃)和2种苜蓿品种"甘农3号"和"甘农5号"条件下,在人工气候箱中单头饲养,测定各个处理豌豆蚜的发育历期、体质量差和相对日均体质量增长率等生物学参数。结果显示:在"甘农3号"上,16℃时,在UV-B辐射对2种色型豌豆蚜的发育历期、体质量差和日均体质量增长率均无显著影响(P>0.05);在20℃时,UV-B辐射下红色型豌豆蚜的发育历期显著延长(P<0.05),相对日均体质量增长率也显著减少(P<0.05),体质量差无显著变化(P>0.05);而在24℃时,UV-B辐射下绿色型豌豆蚜的发育历期显著延长(P<0.05),体质量差和相对日均体质量增长率也显著减少(P<0.05)。在"甘农5号"上,在16℃时,UV-B辐射下红色型豌豆蚜的发育历期显著延长(P<0.05),体质量差和相对日均体质量增长率也显著减少(P<0.05);在20℃和24℃时,UV-B辐射绿色型豌豆蚜的发育历期显著延长(P<0.05),体质量差和相对日均体质量增长率也显著减少(P<0.05)。由此可知,UV-B辐射对豌豆蚜的影响与温度和苜蓿品种均密切相关。

UV-B辐射对植物生长发育的影响及其应用价值

紫外线-B(UV-B)是影响植物生长发育的重要环境压力因子。UV-B辐射强度变化对植物生态系统造成的影响,已成为国内外研究热点。本文从UV-B辐射对植物形态发育、光合作用、次生代谢和抗氧化系统以及遗传物质的影响等方面,对国内外研究现状进行了简要述评。对UV-B辐照调节植物形态发育、改善植物品质、提高果实保鲜能力、增强植物抵抗生物胁迫能力和诱变育种的机制及其应用前景进行了深入探讨与展望。

UV-B辐射对颠茄氮代谢及次生代谢产物含量的影响

有害的中波紫外线(ultraviolet B,UV-B;280~320 nm)辐射影响植物的生长与发育。但也有研究证明,UV-B辐射可诱导生物碱合成。然而,UV-B辐射能否提高颠茄(Atropa belladonna L.)中托品烷类生物碱(tropane alkaloids,TAs)的含量尚未见报道。本研究以颠茄实生苗为材料,研究UV-B不同照射度强、时间(d数)对颠茄的氮代谢、生物碱含量及TAs代谢途径中的几个关键酶基因表达量的影响。结果表明,随着辐射天数的增加(5~30 d),低强度(LU,5μW/cm^2)UV-B处理与对照(无辐射)比较,硝态氮、莨菪碱、东莨菪碱含量无显著差异。然而,中等强度(MU,10μW/cm^2)和高强度(HU,15μW/cm^2)UV-B辐射,明显增加硝态氮含量,谷氨酰胺合成酶(glutamine synthetase,GS)、谷氨酸脱氢酶(glutamine dehydrogenase,GDH)活性明显高于对照。重要的是,中、高强度UV-B辐射显著降低了颠茄的叶片与茎中莨菪碱和东莨菪碱含量。荧光定量PCR揭示,莨菪碱合成的关键酶腐胺N-甲基转移酶(putrescine N-methyltransferase,PMT)编码基因、莨菪碱-6-β-羟化酶(hyoscyamine-6-β-hydroxylase,H6H)基因表达呈高度组织特异性,主要是在根部表达。与对照比较,低强度照射25 d引起pmt在根部的表达量显著上调,而中、高强度照射导致其下调;h6h在根部的相对表达量随着处理强度的增加逐渐降低;托品酮还原酶Ⅰ(tropinone reductaseⅠ,TRⅠ)编码基因在叶片中的表达量较高,随照射强度的增加而升高。上述结果表明,低强度UV-B辐射促进氮代谢,有利于莨菪碱合成;而长期中、高强度UV-B辐射,尽管促进了谷氨酸代谢,但却使pmt和h6h表达降低,不利于莨菪碱和东莨菪碱的积累。总之,本研究结果显示,不同UV-B辐射强度和时间,对颠茄合成TAs的影响不同,可为大田试验生产莨菪碱提供有益的参考。

Influences of Different UV-B Radiation Treatments in Short Time on Some Physiological Characteristics of Winter Wheat Seedlings

[Objective] studying the influences of different UV-B radiation treatments in short time on some physiological characteristics of winter wheat seedlings was to provide reference for the mechanism of plant response to ultraviolet irradiation in short time. [Method] The winter wheat taken as materials were treated with 15 and 30 pW/cm^2 UV-B radiation, then the physiological indexes such as pigment content and photosynthetic rate were determined. [ Results] The UV-B treatment caused the declines of chlorophyll content, soluble protein content and water content of leaves, besides, dose-effect was existed. The decline of 30 pW/cm^2 treatment was bigger than that of 15 μW/cm^2 treatment. The influences of UV-B radiation on carotenoid content and anthocyanidin content were similar; the change trends were declined firstly then increased. The UVB treatment with two doses restrained the electron transport of PSⅡ, particularly; the inhibitory effect was biggest after treated 2 h, and then this effect was declined in 4, 6 and 8 h, so the dose-effect was existed. The UV-B radiation with two doses restricted photosynthetic rate and the inhibitory effect increased with the increase of treatment time. The high dose treatment caused huge damage to membrane system, while the result of low dose treatment was not obvious. [ Conclusion] UV-B radiation treatment had dose-effect on winter wheat seedlings in short time and the influence of high dose was bigger than that of low dose. With the increase of treatment time, the damage was alleviated; besides, the result was not similar to that of UV-B radiation in long time.

Responses of Membrane Lipid Peroxidation and Endogenous Hormones of Soybean Seedlings to UV-B Radiation and Rare Earth

[ Objective] The aim was to provide strategies for development of rare earth and control of environmental pollution. [ Method] Responses of membrane lipid peroxidation and endogenous hormones of soybean seedlings to UV-B radiation and rare earth were studied through hydroponics in laboratory. [ Result] The results showed that under irradiation of UV-B（ T1-0.15 W/m^2 and T2-0.45 W/m^2）, chlorophyll and indole-3-acetic acid（IAA） contents firstly decreased during the stress phase （1 -5 d） and then increased during the restoration phase （6 -9 d） while contents of malonadialdehyde（MDA） and abscisic acid（ABA） gradually increased during the imposition of UV-B radiation （1 -5 d） and subsequently decreased during recovery from UV-B stress （6 -9 d） . With adding of La （III） with the concentration of 20 mg · L^-1 , the decline/dse trend of chlorophyll, IAA, MDA and ABA contents was slowed down during the stress period while the rise/decline speed was accelerated during the recovery period. [ Conclusion] It suggests that the regulation of La （ III ） on membrane lipid peroxidation and endogenous hormones could increase chlorophyll and IAA contents, improve the metabolism of reactive oxygen species （ ROS）, inhibit membrane lipid peroxidation, decrease the accumulation amount of ABA and alleviate injury of UV-B radiation to soybean seedlings. Further, the protective potential of La （ III ） was better under low UV-B radiation than under high one.

The Effects of UV-B Radiation on Maize at the Seedling Stage

In this study, maize plant seedlings were grown in soilless cultures, with and without ^-B radiation at a close of 5.4 kJt（m2-d）. Three clays later, it was found that the treatment of UV-B radiation significantly reduced such characteristics as biomass, plant height, leaf area, and so on. Also, the photosynthesis of the maize was inhabited, the anti-oxid activity decreased, and the MDA concentration increased with the UV-B radiation exposure. The maize presented visible hybrid vigor under the control condition, while the hybrid vigor under UV-B radiation barely emerged in biomass, plant height, leaf area, and physiological metabolic index.

Effect of Enhanced UV-B Radiation on Seed Setting Rate and 1 000-grain Weight of Indica Hybrid Rice Restorer Lines

[Objective] This study was to investigate the effect of enhanced UV-B radiation on seed setting rate and 1 000-grain weight of hybrid rice combinations. [Method] The seed setting rate and 1 000-grain weight of 10 new sterile indica restorer lines planted in pots under enhanced UV-B radiation and fluorescent lamps （control） were respectively measured, and the differences were compared. [Result] The enhanced UV-B radiation significantly reduced the seed setting rate of indica restorer lines, and the differences between that UV-B radiation treatment and control all reached extremely significant level. In addition, the enhanced UV-B radiation reduced the 1 000-grain weight of most indica restorer lines, and compared with that of control the difference achieved significant or very significant level. However, the effect of enhanced UV-B radiation on seed setting rate and 1 000-grain weight differed to different indica restorer lines, and the differences among restorer lines tested were significant or very significant, which indicated the possibility to screen antiUV-B radiation rice materials and combinations. Finally, the indica restorer lines 09R-14, Luhui 37 and 10R-7703 which were strongly resistant to UV-B radiation were screened out. [Conclusion] This study laid foundation for breeding hybrid rice varieties resistance to UV-B radiation.

Effects of UV-B radiation on tetraspores of Chondrus ocellatus Holm(Rhodophyta),and effects of red and blue light on repair of UV-B-induced damage

We evaluated the effects of red and blue light on the repair of UV-B radiation-induced damage in tetraspores of Chondrus ocellatus Holm. Tetraspores of C. ocellatus were treated with different UV-B radiation levels(0,36,72,108,144 and 180 J/m2),and thereafter subjected to PAR,darkness,or red or blue light during a 2-h repair stage,each day for 48 days. The diameters and cellular contents of cyclobutane pyrimidine dimmers(CPDs),chlorophyll a(Chl a),phycoerythrin,and UV-B-absorbing mycosporinelike amino acids(MAAs) contents of the tetraspores were determined. Our results show that low doses of UV-B radiation(36 and 72 J/m 2) promoted the growth of C. ocellatus; however,increased UV-B radiation gradually reduced the C. ocellatus growth(greater than 72 J/m2). The MAAs(palythine and asterina-330) in C. ocellatus were detected and analyzed by LC/MS. Our results suggest that moderate red light could induce the growth of this alga in aquaculture. In addition,photorepair was inhibited by red light,so there may be some other DNA repair mechanism activated by red light. Blue light promoted the activity of DNA photolyase,greatly improving remediation efficiency. Red and blue lights were found to reduce the capacity of C. ocellatus to form MAAs. Therefore,PAR,red light,and blue light play different roles during the repair processes for damage induced by UV-B radiation.

Effects of UV-B irradiation on isoforms of antioxidant enzymes and their activities in red alga Grateloupia filicina(Rhodophyta)

Macroalgae in a littoral zone are inevitably exposed to UV-B irradiance. We analyzed the effects of UV-B on isoenzyme patterns and activities of superoxide dismutase （SOD）, peroxidase （POX）, catalase （CAT）, and ascorbate peroxidase （APX） of red algae Grateloupia filicina （Lamour.） C. Agardh. The activities of SOD, CAT, and APX changed in response to UV-B in a time- and dose-dependent manner. POX activity increased significantly under all three UV-B treatments. The enzymatic assay showed three distinct bands of SODI （Mn-SOD）, SODII （Fe-SOD）, and SODIII （CuZn-SOD） under a low （Luv） and medium （Muv） dose of UV-B irradiation, while SODI and SODIII activities decreased significantly when exposed to a high dose of UV-B irradiation （Huv）. The activity of POX isoenzymes increased significantly after exposure to UV-B, which is consistent with the total activity. In addition, a clear decrease in activity of CATIV was detected in response to all the three doses of UV treatments. Some bands ofAPX isoenzyme were also clearly influenced by UV-B irradiation. Correspondingly, the daily growth rate declined under all the three exposure doses, and was especially significant under Muv and Huv treatments. These data suggest that, although the protection mechanisms of antioxidant defense system are partly inducible by UV-B to prevent the damage, G.filicina has incomplete tolerance to higher UV-B irradiation stress.

Physiological responses of macroalga Gracilaria lemaneiformis(Rhodophyta) to UV-B radiation exposure

This paper aims to evaluate the effects of ultraviolet-Bradiation(UVBR) on Gracilaria lemaneiformis,a commercial red macroalga and an important source of agar. To study the in-vitro effect of UVBR on G. lemaneiformis,this plant was cultivated and exposed to photosynthetically active radiation(PAR) at 40 μmol photons/(m2 ·s) and enhanced UVBR(0,0.36,0.72,1.08,1.44,and 1.80 k J/(m 2 ·d)) for 13 days. The samples were processed for histochemical analysis,and the growth rate,photosynthetic pigment contents,photosynthetic performance,reactive oxygen species levels,membrane permeability,malonyl dialdehyde contents and antioxidant capacity of G. lemaneiformis were investigated. After 13 days of exposure to PAR+UVBR,G. lemaneiformis showed photodamage and photoinhibition of photosynthetic pigments(chlorophylla and phycoerythrin),leading to a decreased photosynthetic efficiency. Further,there was a corresponding decrease in the relative growth rates and depigmentation and partial necrosis of the apical segments were noted after exposure to PAR+UVBR. Additionally,UVBR induced excess production of superoxide radicals and hydrogen peroxide,eliciting a marked cellular membrane damage and antioxidative response.

Effects of Elevated Solar UV-B Radiation from Ozone Depletion on Terrestrial Ecosystems

In the last three decades much researchhas been carried out to investigate the biologicaleffects of a thinning stratospheric ozone layeraccompanied by an enhanced level of solarultraviolet-B radiation at the Earth’s surface.Enhanced UV-B radiation affects ecosystems in manyways directly and indirectly. The responses can bebiochemical, physiological, morphological oranatomical, and the direction of the response can varybetween different species, communities andecosystems. In this paper we firstly introduce generalconcepts, and methods for measuring the ecologicaleffects of UV-B radiation. Secondly, we provide anoverview interpretation of the effects of enhancedUV-B on terrestrial ecosystems from recent studies.These studies include effects of UV-B on growth andreproduction, composition of communities,competitive balance, decomposition of litter, andinteractions with other factors etc. Finally, werecommend future research directions to identify theeffects of elevated UV-B radiation on ecosystems inChina.

Effects of different light conditions on repair of UV-B-induced damage in carpospores of Chondrus ocellatus Holm

We evaluated the effects of ultraviolet-B （UV-B） radiation and different light conditions on the repair of UV-B-induced damage in carpospores of Chondrus ocellatus Holm （Rhodophyta） in laboratory experiments. Carpospores were treated daily with different doses of UV-B radiation for 48 days, when vertical branches had formed in all treatments; after each daily treatment, the carpospores were subjected to photosynthetically active radiation （PAR）, darkness, red light, or blue light during a 2-h repair stage. Carpospore diameters were measured every 4 days. We measured the growth and cellular contents of cyclobutane pyrimidine dimers （CPDs）, chlorophyll a, phycoerythrin, and UV-B-absorbing mycosporine-like amino acids （MAAs） in carpospores on Day 48. Low doses of UV-B radiation （36 and 72 J/m2） accelerated the growth of C. ocellatus. However, as the amount of UV-B radiation increased, the growth rate decreased and morphological changes occurred. UV-B radiation significant damaged DNA and photosynthetic pigments and induced three kind of MAAs, palythine, asterina-330, and shinorine. PAR conditions were best for repairing UV-B-induced damage. Darkness promoted the activity of the DNA dark- repair mechanism. Red light enhanced phycoerythrin synthesis but inhibited light repair of DNA. Although blue light, increased the activity of DNA photolyase, greatly improving remediation efficiency, the growth and development of C. ocellatus earpospores were slower than in other light treatments.

Effect of UV-B Radiation on Nitrate, Phosphate and Ammonium Uptake in Chlorella vulgaris

UV-B exposure （312 nm and 2.5 W.m^-2） caused 50 percent killing m Chlorella at lO mln and complete Killing at oo ram. Nitrate and phosphate uptakes were faster under UV-B irradiation than in fluorescent light. Short exposure of UV-B stimulated nitrate and phosphate uptakes but inhibited ammonium uptake. Ammonium uptake was inhibited upto 30 min and thereafter increased and become constant after 60 min UV-B exposure. UV-B stimulated the nitrate uptake in deficient cells. Interestingly, there was rapid stimulation of nitrate uptake in deficient medium after 30 min UV-B treatment. Darkness inhibited the uptake mechanism but the fluorescent light enhanced the rate of nitrate uptake stimulation in deficient cells of Chlorella vulgaris.

Effect of Enhanced Ultraviolet-B Radiation on Photosynthetic Pigments and Flavonoids in the Leaves of Grapevine

[Objective] The study aimed at investigating the influence of enhanced UV-B radiation on photosynthesis of grapevine.[Method] The seedlings of Cabernet sauvignon were treated with different intensities of UV-B radiation under outdoor conditions,and then the contents of photosynthetic pigments and flavonoids in leaves were determined by measuring the absorbance of leaves extracts at 663,645,470 and 300 nm,respectively.[Result] The content of photosynthetic pigments in the leaves of grapevine obviously increased with time under the treatments of different enhanced UV-B radiation.Compared with the control,the chlorophyll a,chlorophyll b,total chlorophyll and carotenoid were obviously increased by 5%,2%,4% and 3% in the enhanced UV-B radiation treatment of 10.8 μW/cm2（T1）,and in the treatment of 25.6 μW/cm2（T2） the corresponding levels were subsequently increased by 11%,9%,10% and 7% with a significant increase in the content of chlorophyll a.On the other hand,the flavonoids content in the leaves of grapevine were obviously increased by 13%,9% in T1 and T2.[Conclusion] The grapevine has strong adaptability to UV-B radiation,and appropriate enhanced UV-B radiation couldn＇t decrease the photosynthesis of grapevine leaves.

植物光诱导延迟荧光的紫外辐射环境胁迫监测

以科丰1号大豆品种为测试模式,利用自制的便携式延迟荧光(DF)检测系统,研究了紫外(UV-B)辐射对其DF特征的影响。结果发现,绿色植物叶片光诱导DF强度的变化可以准确地反应叶绿素含量以及光合作用能力的变化。因此,DF强度可以用来表征UV-B辐射对植物的伤害程度。