不同海拔地区紫外线B辐射状况及植物叶片紫外线吸收物质含量的分析

对不同海拔地区的太阳ＵＶ－Ｂ辐射和植物叶片的光学特性进行了比较研究。结果表明：位于高海拔地区的海北高寒草甸生态系统定位站，太阳ＵＶ－Ｂ辐射明显高于相近纬度的西宁、兰州和南京地区。ＵＶ－Ｂ辐射与总辐射和ＰＡＲ的日变化规律相似，都受太阳高度角的直接影响，在当地太阳正午时最高。ＵＶ－Ｂ／Ｑ的日变化也为单峰曲线，海北部地区的ＵＶ－Ｂ／Ｑ高于西宁的同期测定结果。对蛛芽蓼等植物的研究表明，生长于海北部地区的蛛     

增强的UV-B辐射和其它因子的相互作用对植物的影响

全球变化中的平流层臭氧层耗损引起到达地球表面的紫外线-B(280～320 nm)辐射的增强,给人类健康,动物、植物、微生物的生命活动,生物地化循环,材料及大气质量等带来重大影响[1]。因此,近30年来,平流层臭氧层减薄和UV-B辐射增强对植物影响的问题引起人们的关注,并进行了大量的研究[1～4]。我国在这方面的研究刚刚起步[5]。但是,针对UV-B辐射增强和其它非生物因子如CO2浓度升高、全球变暖、干旱、矿质营养亏缺和空气污染物等的复合作用对植物生长、发育、繁殖及生态系统影响的研究较少[1～3]。在自然界,各种环境因子常常是相互作用共同影响植物及生态系统,因此,仅研究单因子的作用很难正确评估由于全球变化而产生的种种生物学和生态学效应[1,2]。本文就近年来关于UV-B辐射增强和其它非生物因子的复合作用对植物影响的研究进展作一介绍,并对其发展前景作了展望。1 UV-B辐射与矿质营养     

田间增强UV—B辐射对麦田生态系统K营养和累积的影响

研究大田栽培和自然光条件下,模拟UV－B辐射（UV－B,280－315nm)增强对麦田生态系统K营养和累积的影响,UV－B辐射显著影响春小麦不同生育期各部位K含量和群体K累积,并显著降低群体K总累积,在5．31kJ.m^-2UV-B辐射下,春小麦群体K总累积的降低最显著,UV－B辐射降低春小麦群体K输出,标志着麦田生态系统K产投比降低,K循环功能下降,麦田土壤速效K含量增加是春小麦群体K输出降低的结果,并将导致土壤库中K储量的增加。     

紫外线—B辐射与3种植物幼苗的光合作用：光合作用对紫外线—B敏 …

紫外线－Ｂ辐射降低豌豆、大豆和黄瓜３种植物幼苗的净光合作用速率（Ｐｎ）和表观量子效率（ＡＱＥ）,Ｐｎ和ＡＱＥ的减少幅度随紫外线－Ｂ辐射时间的延长逐渐增大。３种植物的光合作用对此外线－Ｂ辐射的敏感性依为：豌豆〉黄瓜〉大豆,光合作用光抑制的发生程度与光合作用对ＵＶ－Ｂ辐射敏感性有内在联系。定量分析显示,光合作用光抑制的发生程度随ＵＶ－Ｂ辐射时间增加,是ＵＶ－Ｂ辐射剂量的累积效应。     

增强的ＵＶ—Ｂ辐射对麦田生态系统中杂草、大型土壤动物和麦蚜种群数量动态

研究了大田栽培和自然光条件下,模拟ＵＶ－Ｂ辐射（ＵＶ－Ｂ,２８０－３１５nm)增强对麦田生态系统杂草、大型土壤动物和麦蚜种群数量动态的影响,在ＵＶ－Ｂ辐射下,杂草和大型土壤动物的种类和数量降低,种物多样性改变,杂草总生物量也降低。ＵＶ－Ｂ辐射降低牙复合种群数量,并与麦叶粗纤维、可溶性蛋白、可溶性糖、Ｍg和Ｚn含量有显著的相关性。ＵＶ－Ｂ辐射还导致麦蚜与麦叶Ｍg、Fe和Ｚn含量均显著增加。     

ＵＶ—Ｂ辐射对８个大豆品种种子萌发率和幼苗生长的影响

在生长房５种（暗处、可见光、低、中、高强度紫外线－Ｂ）处理下,研究了８个大豆品种的种子萌发率和萌发后幼苗的生长状况。结果表明,暗处种子萌发率高于自然当和ＵＶ－Ｂ辐射的种子。ＵＶ－Ｂ辐射增强对大豆种子的萌发率没有显著影响,仅使部分 品种的最大萌发率降低和导致部分品种达到最大萌发率的时间延长。幼苗的生长对增强的ＵＶ－Ｂ辐射非常敏感,使大部分品种的胚根变短增粗,这可能是植物激素作用的结果,大豆的叶绿素a、叶绿素b和总叶绿素含量明显受到ＵＶ－Ｂ辐射的抑制。ＵＶ－Ｂ作用能促进类黄酮在幼苗中的积累,紫外吸收色素的增设有利于提高对ＵＶ－Ｂ的抵抗力,ＵＶ－Ｂ辐射的这种效应及大豆种间的差异在自然情况下会产生深远的生物学和生态学意义。     

紫外线辐射增加对大豆光合作用和生长的影响

通过模拟南京地区自然光中有效紫外线Ｂ和紫外线Ａ辐射,增大辐射剂量对大豆光合作用,生长及生物量形成的影响迸行了研究。３个加强的ＵＶ辐射（０．１５,０．３５,０．７０Ｗ·ｍ－２）处理均使大豆植株矮化,抑制根、茎、叶的生长及干物质的积累。在３个ＵＶ处理中,生物效应以０．７０Ｗ·ｍ－２处理力最大,０．１５Ｗ·ｍ－２处理影响最小。ＵＶ辐射匀能使大豆叶片光合作用下降。下降幅度随ＵＶ辐射强度的增大而增大,本文还对ＵＶ影响大豆生长的可能机制进行了探讨。     

增强UV—B辐射对菜豆蛋白质代谢的影响

模拟研究了温室条件下兰州地区臭氧层减薄２５ ％ 时增强的ＵＶＢ（２８０ ～３２０ ｎｍ） 辐射对菜豆（ Ｐｈａｓｅｏｌｕｓｖｕｌｇａｒｉｓ Ｌ．） 蛋白质代谢的影响。菜豆幼苗期,ＵＶＢ辐射（ＵＶＢＢＥ：１６ ｋＪ·ｍ －２·ｄ－１） 促进菜豆叶片中蛋白质的合成;菜豆生长后期,ＵＶＢ辐射则抑制蛋白质的合成,降低叶片中可溶性蛋白质的含量,促进蛋白水解酶活性的上升和总游离氨基酸的积累。ＳＤＳＰＡＧＥ分析表明,ＵＶＢ辐射使幼苗期菜豆叶片中８８ ｋＤ、７６ ｋＤ、４２ ｋＤ、３５ ｋＤ、３３ ｋＤ 多肽的含量上升;而在菜豆生长后期,ＵＶＢ辐射使大分子量多肽（７６ ｋＤ 以上） 的含量迅速下降,１０～１４ ｋＤ、２９ ｋＤ、３３ ｋＤ、３５ｋＤ的多肽含量上升。蛋白质代谢的这种变化可能是植物的一种适应性反应     

增强UV-B辐射对小麦叶片内源ABA和游离脯氨酸的影响

研究温室种植的小麦在０（ＣＫ）、８．８２ＫＪ／ｍ＾２（Ｔ１）和１２．６ＫＪ／ｍ＾２（Ｔ２）３种剂量的ＵＶ－Ｂ辐射下其内源ＡＢＡ和游离脯氨酸含量的变化。ＵＶ－Ｂ辐射导致叶绿体膜脂脂肪酸配比改变和ＩＵＦＡ降低,叶片ＭＤＡ含量升高及ＡＢＡ和游离脯脯氨酸积累。分析表明,ＵＶ－Ｂ辐射对膜系统的损坏也许是内源ＡＢＡ和游离脯氨酸含量增加的原因之一,而后者也是植物抵抗ＵＶ－Ｂ胁迫所做出的适应性反应。     

我国热带亚热带几种人工林体内营养结构特征

营养是植物的一种资源 ,植物如何在体内分配这一资源影响到它对环境的适应性。植物体内的营养含量在某种程度上还反映了环境中营养供应的丰缺 ,同时 ,它又是生态系统营养循环的一个组成部分。国外曾对植物的营养含量特征进行过大量的研究 ,积累了相当多的资料 ,代表性工作如Ｊｏｒｄａｎ[12 ](亚马逊雨林 ) ,Ｗｈｉｔｔａｋｅｒ[13 ] (ＨｕｂｂａｒｋＢｒｏｏｋ生态站森林 ) ,Ｗｏｏｄｗｅｌｌ[14 ] (Ｂｒｏｏｋｈａｖｅｎ森林 )等 ,随着计算机模拟技术的发展 ,这些资料成了进行生态模拟不可缺少的珍贵资料。我国尽管在 2 0世纪 5 0年代就开…     

Effects of enhanced ultraviolet-B radiation on plant nutrients and decomposition of spring wheat under field conditions

Spring wheat (Triticum aestivum) was grown in the field under ambient and supplemental levels of ultraviolet-B (UV-B, 280–315 nm) radiation to determine the potential for alteration in plant nutrients, decomposition, leaf quality and dry matter yield. Supplemental UV-B radiation simulating a 12, 20 and 25% stratospheric ozone depletion significantly decreased dry matter yield, but had no significant impact on harvest index. UV-B radiation resulted in an increase of the concentrations of N and K in all plant parts; changes of the concentrations of P, Mg, Fe and Zn varied in a tissue-dependent manner, as the decrease of P in leaves and stems, and its increase in spikes and grains. The mass of N, P, K, Mg, Fe and Zn in various plant parts and whole plant was generally decreased except leaf N mass was increased by enhanced UV-B radiation. Enhanced UV-B radiation decreased the concentrations of soluble carbohydrates in leaves and increased that of holocellulose and soluble proteins. After 60 and 100 days of decomposition of leaves and stems in the field, enhanced UV-B radiation stimulated the loss of organic C. As a consequence, the nutrient content of soils might be less diminished under enhanced UV-B radiation.     

增强的UV-B辐射对麦田生态系统中种群数量动态的影响

研究了大田栽培和自然光条件下,模拟UV-B辐射(UV-B,280～315nm)增强对麦田生态系统杂草、大型土壤动物和麦蚜种群数量动态的影响。在UV-B辐射下,杂草和大型土壤动物的种类和数量降低,物种多样性改变,杂草总生物量也降低。UV-B辐射降低麦蚜复合种群数量,并与麦叶粗纤维、可溶性蛋白、可溶性糖、Mg和Zn含量有显著的相关性。UV-B辐射还导致麦蚜与麦叶Mg、Fe和Zn含量均显著增加。     

增强的UV—B辐射对春小麦植株化学成分、真菌定殖和分解的影响

在UV－B辐射下,叶可溶性糖含量显著降低,叶可溶性蛋白含量和粗纤维含量以及茎粗纤维含量显著增加,而根粗纤维含量没有显著变化,在生长期接受UV－B辐射的叶和茎上,赭绿青霉和黑曲霉的定殖率显著增加,康宁木霉和出芽短梗霉的定殖率明显降低,而土曲霉的定殖率未受明显影响,这些叶和茎经过60d和100d的分解,分解率均显著增加,叶分解率与粗纤维含量和可溶性蛋白含量呈显著正相关,而与可溶性糖含量呈显著负相关,茎分解率与粗纤维含量呈显著正相关,在增强的UV－B辐射下,春小麦植株化学成分的变化,真菌定殖率的改变,分解率的增加,可能会导致麦田生态系统营养周转加快,土壤库中营养贮量增加。     

Solar UV-B radiation affects below-ground parameters in a fen ecosystem in Tierra del Fuego, Argentina: implications of stratospheric ozone depletion

Stratospheric ozone depletion caused by the release of chlorofluorocarbons is most pronounced at high latitudes, especially in the Southern Hemisphere (including the so‐called ‘ozone hole’). The consequent increase in solar ultraviolet‐B radiation (UV‐B, 280–315 nm) reaching the earth's surface may cause a variety of alterations in terrestrial ecosystems. Most effects might be expected to occur above‐ground since sunlight does not penetrate effectively below‐ground. Here, we demonstrate that solar UV‐B radiation in a fen in Tierra del Fuego (Argentina), where the ozone hole passes overhead several times during the Austral spring, is causing large changes of below‐ground processes of this ecosystem. During the third and fourth year of a manipulative field experiment, we investigated root systems in these plots and found that when the ambient solar UV‐B radiation was substantially reduced, there was a 30% increase in summer root length production and as much as a threefold decrease in already low symbiotic mycorrhizal colonization frequency of the roots compared with plots receiving near‐ambient solar UV‐B. There was also an apparent shift toward older age classes of roots under reduced solar UV‐B. Such large changes in root system behaviour may have decided effects on competition and other ecological interactions in this ecosystem.     

增强的UV-B辐射对春小麦植株化学成分、真菌定殖和分解的影响

在UVB辐射下,叶可溶性糖含量显著降低,叶可溶性蛋白含量和粗纤维含量以及茎粗纤维含量显著增加,而根粗纤维含量没有显著变化.在生长期接受UVB辐射的叶和茎上,赭绿青霉和黑曲霉的定殖率显著增加,康宁木霉和出芽短梗霉的定殖率明显降低,而土曲霉的定殖率未受明显影响.这些叶和茎经过60d和100d的分解,分解率均显著增加.叶分解率与粗纤维含量和可溶性蛋白含量呈显著正相关,而与可溶性糖含量呈显著负相关.茎分解率与粗纤维含量呈显著正相关.在增强的UVB辐射下,春小麦植株化学成分的变化,真菌定殖率的改变,分解率的增加,可能会导致麦田生态系统营养周转加快,土壤库中营养贮量增加.     

Zinc Accumulation and Tolerance in Solanum nigrum are Plant Growth Dependent

Zinc tolerance, accumulation, and organic acid production by Solanum nigrum, a known Zn accumulator, was studied during pre- and post-flowering stages of development. The plants, when challenged with Zn concentrations lethal to plantlets, showed an increase in tolerance from pre-flowering to post-flowering, which was accompanied by a reduction of Zn translocation to the aerial plant parts. Treatment with Zn induced a differential response in organic acids according to the plant organ and developmental stage. In the roots, where Zn concentrations were similar in pre- and post-flowering plants, a general decrease in organic acid in pre-flowering roots contrasted with the increase observed in post-flowering plants. In the stems, Zn induced a generalized increase in organic acids at both growth stages while in the leaves, a slight increase in malic and shikimic was observed in pre-flowering plants and only shikimic acid levels were significantly increased in post-flowering plants. This work shows that Zn accumulation and tolerance in S. nigrum vary during plant development – an observation that may be important to improve the efficiency of phytoremediation approaches. Furthermore, the data suggest the involvement of specific organic acids in this response.     

UV-B and UV-C induction of NADP-malic enzyme in tissues of different cultivars of Phaseolus vulgaris (bean)

The effects of the treatment of different tissues of three bean cultivars (Pinto, Vilmorin and Arroz) with ultra‐violet (UV) UV‐B and UV‐C radiation and red light on the activity, quantity and RNA levels of NADP‐malic enzyme (NADP‐ME) were determined. Exposure to UV‐B radiation for 8 h caused a marked increase of NADP‐ME from leaves, stems and roots in the three cultivars studied. A similar induction was observed in the leaves and stems after 8 h of exposure under UV‐C, but not in the roots, suggesting that a different signal might be acting to induce the expression of NADP‐ME after UV‐B and UV‐C exposure. In contrast, red light was ineffective in inducing NADP‐ME in either tissue, so the regulation of the expression of this enzyme is phytocrome‐independent. The activity of superoxide dismutase, ascorbate peroxidase, catalase and peroxidase was also different in plants treated with UV‐B, UV‐C and photosynthetically active radiation, suggesting that various pathways may be acting in the regulation of these enzymes by UV‐B and UV‐C. Reactive oxygen species (ROS) were also required for UV‐B induction of NADP‐ME, as the addition of ascorbic acid before UV‐B treatment prevented NADP‐ME induction, whereas salicylic acid was not effective in inducing the enzyme, showing that NADP‐ME induction by UV‐B is ROS dependent but salicylic acid independent.     

Evaluation of Populus and Salix continuously irrigated with landfill leachate I. Genotype-specific elemental phytoremediation

There is a need for the identification and selection of specific tree genotypes that can sequester elements from contaminated soils, with elevated rates of uptake. We irrigated Populus (DN17, DN182, DN34, NM2, NM6) and Salix (94003, 94012, S287, S566, SX61) genotypes planted in large soil-filled containers with landfill leachate or municipal water and tested for differences in inorganic element concentrations (P, K, Ca, Mg, S, Zn, B, Mn, Fe, Cu, Al, Na, and Cl) in the leaves, stems, and roots. Trees were irrigated with leachate or water during the final 12 wk of the 18-wk study. Genotype-specific uptake existed. For genera, tissue concentrations exhibited four responses. First, Populus had the greatest uptake of P, K, S, Cu, and Cl. Second, Salix exhibited the greatest uptake of Zn, B, Fe, and Al. Third, Salix had greater concentrations of Ca and Mg in leaves, while Populus had greater concentrations in stems and roots. Fourth, Populus had greater concentrations of Mn and Na in leaves and stems, while Salix had greater concentrations in roots. Populus deltoides x P. nigra clones exhibited better overall phytoremediation than the P. nigra x P. maximowiczii genotypes tested. Phytoremediation for S. purpurea clones 94003 and 94012 was generally less than for other Salix genotypes. Overall, concentrations of elements in the leaves, stems, and roots corroborated those in the plant-sciences literature. Uptake was dependent upon the specific genotype for most elements. Our results corroborated the need for further testing and selecting of specific clones for various phytoremediation needs, while providing a baseline for future researchers developing additional studies and resource managers conducting on-site remediation.     

金华市郊10种杂草的热值和灰分含量及其适应意义

在金华市郊,选择了婆婆纳(Veronica didyma)、水蓼(Polygonum hydropiper)、车前(Plantago asiatica)、北美车前(Plantago virginica)、毛茛(Ranunculus japonicus)、商陆(Phytolacca acinosa)、鹅观草(Roegneria kamoji)、早熟禾(Poa annua)、北美独行菜(Lepidium virginicum)、窃衣(Torilis japonica)等10种常见杂草,测定了生殖生长时期这些杂草不同器官的热值和灰分含量。研究结果表明, 10种杂草花穗、叶、茎和根的干重热值的平均值分别为15.942、14.293、13.344和13.463 kJ/g,去灰分热值平均为16.983、16.219、14.480和15.233 kJ/g,整体上表现出花穗 > 叶 > 根 > 茎的趋势;10种杂草的花穗、叶、茎和根中的平均灰分含量为6.127%、11.899%、8.071%、11.383%,叶片和根中的灰分含量较高,花穗与茎中的较低。对于北美车前来讲,随着生长时间的推移,北美车前的营养器官热值下降,随着种群密度的上升,北美车前的繁殖器官干重热值上升。采取低热值策略可能是杂草适应严酷环境的选择方式,具有进化上的积极意义。