模拟增温与UV-B 辐射增强对云杉种子萌发和幼苗生长的影响

臭氧层损耗导致的地球表面UV-B辐射增强以及温室气体增多引起的气候变暖是当今两大全球环境问题。UV-B辐射增强和气候变暖对陆地植物和生态系统产生深远影响，并已成为全球变化研究的重要议题。作为世界第三极的青藏高原，UV-B 辐射增强以及气候变暖现象尤为突出。本试验所在林区是青藏高原东缘的主要林区，具有大面积的亚高山人工针叶成熟林，在全球变化背景下该森林的天然更新潜力如何是急待回答的重要问题。基于此，本研究围绕森林树种的种子和幼苗这一更新的重要阶段，开展了气候变暖、UV-B辐射增强和联合胁迫对云杉种子萌发及幼苗定居影响的研究，旨在全球变化背景下，探讨全球变暖、UV-B 辐射增强和联合胁迫是否对西南地区大面积人工亚高山针叶林更新的种子萌发和幼苗定居阶段产生影响。 本文以青藏高原东缘亚高山针叶林主要树种云杉为研究对象，研究云杉种子萌发及幼苗的生长和生理对UV-B辐射增强与气候变暖的响应。采用UV-B荧光灯（UV-lamp）来模拟增强的UV-B 辐射，此外，采用开顶式有机玻璃罩（OTCs）来模拟气候变暖。本试验包括四个处理：（1）大气UV-B 辐射+大气温度（C）；（2）大气UV-B 辐射+模拟气候变暖（W）；（3）增强的UV-B辐射+大气温度（U）；（4）增强的UV-B辐射+模拟气候变暖（U+W）。 根据本试验结果，UV-B辐射增强对云杉种子萌发没有显著影响，它对萌发云杉幼苗的影响主要体现在幼叶展开以后。根据两年的试验结果，增强的UV-B辐射降低了云杉幼苗抗氧化酶活性，降低了抗氧化物质的含量，此外，造成了膜质的过氧化，表现为MDA在针叶中的积累。增强的UV-B照射处理萌发云杉幼苗两年后，幼苗的生长受到显著抑制。我们的结果显示，OTCs分别提高了空气（10 cm）和土壤（5 cm）温度1.74℃和0.94 ℃。增温显著地促进了云杉种子提前萌发，提高了萌发速率和萌发比率，而且，明显地促进了幼苗的生长，表现为株高和生物量累积的显著增长。此外增温还有利于云杉幼苗根的伸长生长以及生物量的累积，这可以使云杉幼苗更好地利用土壤中的水分和营养元素。 根据本试验结果，温度升高显著地促进了增强UV-B辐射下云杉萌发幼苗的生长，这说明，温度升高缓解了UV-B辐射增强对云杉萌发幼苗的负面影响。这种缓解作用可能是温度升高对UV-B辐射增强处理下幼苗的抗氧化系统活性改善的结果。温度升高还缓解了高UV-B辐射对云杉幼苗根生长的抑制作用，这也可能是增温缓解伤害的原因之一。此外，根据我们的试验结果，增温与UV-B辐射增强联合作用（U+W）下云杉萌发幼苗的生长状况好于大气温度与大气UV-B辐射联合（C）处理，表现为株高、地径、根长和生物量积累均高于C处理，因此可以推断，UV-B辐射增强与气候变暖同时存在对萌发幼苗在两年之内的生长没有产生抑制作用，也就是说，气候变暖的缓解作用完全弥补了UV-B辐射增强的有害作用。 同样，增强的UV-B辐射显著影响了云杉幼苗的光合作用，表现为净光合速率（Pn）和表观量子效率（Φ）的提高，此外，根据我们的试验结果，它还造成了PSII的光抑制。增强的UV-B辐射显著抑制了云杉幼苗对营养元素的吸收，表现为大量营养元素、碳、钙、镁和锌含量的降低，但是，它却显著促进了铁在植株体内的积累。增温显著地提高了净光合速率，但是，它对光系统II（PSII）的光化学效率影响不大。温度升高缓解了UV-B增强对云杉幼苗光合作用的伤害，表现为净光合速率、表观量子效率以及PSII光化学效率的提高。此外，温度升高还缓解了UV-B辐射增强对离子吸收的抑制作用。 Enhanced UV-B radiation due to the reduction of O3 layer and global warming induced by increased greenhouse gases in the air have become the two pressing aspects of global climate changes. Moreover, enhanced UV-B radiation and warming have profound and long-term impacts on terrestrial plants and ecosystems, and the studies focusing on the two factors have attracted many attentions. Qinghai-Tibetan Plateau is the third in elevation in the world, and enhanced UV-B radiation and climate warming are especially prominent in this region. Our research located in the main forest belt in the eastern Qinghai-Tibetan Plateau where large areas of subalpine coniferous forests distributed. Based on that, we carried out a research to study the effects of enhanced UV-B radiation and climate warming on seed germination and seedlings growth of seedlings which are the important basic stage in forest regeneration. This research was arranged by a complete factorial design and included two factors (UV-B radiation and temperature) with two levels. The UV-lamps were used to manipulate the supplemental UV-B radiation and open-top chambers (OTCs) were adopted to increase temperature. The four treatments were: (1) C, ambient UV-B without warming; (2) U, enhanced UV-B without warming; (3) W, ambient UV-B with OTCs warming; (4) U+W, enhanced UV-B with OTCs warming. The main results were exhibited as follows: 1. Based on our results in this research, OTCs increased temperature on average 1.74℃ in air (10 cm above ground) and 0.92 ℃ in soil (5 cm beneath ground). Furthermore, OTCs also slightly reduced soil moisture and relative air humidity, however, the differences was not statistically significant. 2. Our results showed that enhanced UV-B had no significant effects on the seeds germination of P. asperata. Enhanced UV-B affected sprouts of P. asperata until the needles unfolded. During two years, enhanced UV-B inhibited the efficiency of the antioxidant defense systems, and as a result, it induced oxidant stress and the accumulation of MDA in needles. After two years of exposure to enhanced UV-B, the growth of P. asperata sprouts was markedly restrained compared with those under ambient UV-B radiation and temperature (C). Warming significantly stimulated the germination speed and increased the germination rate of P. asperata seeds. In the next place, it prominently facilitated the growth of P. asperata sprouts, represented as improvements in stem elongation and biomass accumulation. Furthermore, warming also increased root growth of P. asperata sprouts, which could made sprouts more efficient to use water and nutrient elements in soil. In this research, warming alleviated the deleterious effects of enhanced UV-B on P. asperata sprouts. It markedly stimulated the growth of P. asperata sprouts exposed to enhanced UV-B. The ease effects of warming on the abilities of the antioxidant defense systems might account for its amending effects on growth. After two years of exposure to enhanced UV-B radiation and warming, the growth of P. asperata sprouts was better than those under ambient UV-B radiation without warming (C), which could be seen from the higher plant height, basal diameter, root length and total biomass accumulation compared with C. 3. Enhanced UV-B radiation significantly influenced the photosynthesis processes of two-year old P. asperata seedlings. Our results showed that enhanced UV-B reduced the net photosynthetic rate (Pn) and the apparent quantum efficiency (Φ), and induced photoinhibition of photosynthetic system II (PSII). Enhanced UV-B significantly decreased the concentration of nitrogen (N), phosphorous (P), potassium (K), calcium (Ca), magnesium (Mg) and zinc (Zn), however, it increased the accumulation of iron (Fe) in the whole plant of P. asperata seedlings. Warming significantly stimulated Pn of P. asperata seedlings but it had no prominent impacts on the photochemical efficiency of PSII. In our research, warming also alleviated the harmful effects of enhanced UV-B on photosynthesis and absorption of ions of P. asperata seedlings. It increased Pn, Φ and the photochemical efficiency of PSII in seedlings exposed to enhanced UV-B. Moreover, warming also increased the absorption of ions of the seedlings exposed to enhanced UV-B radiation.

Conformal irradiation to moving targets in heavy ion radiotherapy with raster-scanning beam delivery system: (II) feasibility experiments

Within the framework of the pilot heavy-ion therapy facility at GSI equipped with an active beam delivery system of advanced raster scanning technique, a feasibility study on actively conformal heavy-ion irradiation to moving tumors has been experimentally conducted. Laterally, real-time corrections to the beam scanning parameters by the raster scanner, leading to an active beam tracing, compensate for the lateral motion of a target volume. Longitudinally, a mechanically driven wedge energy degrader (called depth scanner) is applied to adjust the beam energy so as to locate the high-dose Bragg peak of heavy ion beam to the slice under treatment for the moving target volume. It has been experimentally shown that compensations for lateral target motion by the raster scanner and longitudinal target shift by the depth scanner are feasible.

Response of cyanobacterial carbon concentrating system to light intensity: a simulated analysis

Cyanobacteria possess a delicate system known as the carbon concentrating mechanism (CCM), which can efficiently elevate the intracellular inorganic carbon (Ci) concentration via active transportation. The system requires energy supplied by photosystems; therefore, the activity of the Ci transporter is closely related to light intensity. However, the relationship between CCM and light intensity has rarely been evaluated. Here, we present an improved quantitative model of CCM in which light is incorporated, and developed a CCM model that modified after Fridlyand et al. in 1996. Some equations used in this model were inducted to describe the relationship between transport capacity and light intensity, by which the response of the CCM to light change is simulated. Our results indicate that the efficiency of the carbon concentrating system is sensitive to light intensity. When the external Ci concentration was low, CO2 uptake dominated the total Ci uptake with increasing light intensity, while under high external Ci concentrations HCO3- uptake primarily contributed to the total Ci uptake. Variations in the ratio of energy allocated between the transport systems could markedly affect the operation of CCM. Indeed, our simulations suggest that various combinations of Ci fluxes can provide a possible approach to detect the way by which the cell distributes energy produced by the photosystems to the two active Ci transport processes. The proportion of the energy consumed on CCM to the total energy expenditure for the fixation of one CO2 molecule was determined at 18%-40%.

移动机器人运动目标跟踪系统设计

利用SONYEV-D31摄像机和自主研发的摄像机控制模块,构建了一套主动视觉子系统,并将该子系统应用于RIRA-II型移动机器人上,实现了移动机器人运动目标自动跟踪功能。RIRA-II移动机器人采用了由一组分布式行为模块和集中命令仲裁器组成的基于行为的分布式控制体系结构。各行为模块基于领域知识通过反应方式产生投票,由仲裁器产生动作指令,机器人完成相应的动作。在设置了障碍、窄通道以及模拟墙体的复杂环境下进行运动目标跟踪实验,实验表明运动目标跟踪系统运行可靠,具有较高的鲁棒性。

Autothermal reforming of n-octane on Ru-based catalysts

In an attempt to effectively integrate catalytic partial oxidation (CPO) and steam reforming (SR) reactions on the same catalyst, autothermal reforming (ATR) of n-octane was addressed based on thermodynamic analysis and carried out on a non-pyrophoric catalyst 0.3 wt.% Ru/K2O-CeO2/gamma-Al2O3. The ATR of n-octane was more efficient at the molar ratio Of O-2/C 0.35-0.45 and H2O/C 1.6-2.2 (independent parameters), respectively, and reforming temperature of 750-800 degrees C (dependent parameter). Among the sophisticated reaction network, the main reaction thread was deducted as: long-chain hydrocarbon -> CH4, short-chain hydrocarbon -> CO2, CO and H-2 formation by steam reforming, although the parallel CPO, decomposition and reverse water gas shift reaction took place on the same catalyst. Low temperature and high steam partial pressure had more positive effect on CH4 SR to produce CO2 other than CO. This was verified by the tendency of the outlet reformate to the equilibrium at different operation conditions. Furthermore, the loss of active components and the formation of stable but less active components in the catalyst in the harsh ATR atmosphere firstly make the CO inhibition capability suffer, then eventually aggravated the ATR performance, which was verified by the characterizations of X-ray fluorescence, BET specific surface areas and temperature programmed reduction. (c) 2005 Elsevier B.V. All rights reserved.

90°全息记录衍射效率分析与提高

对光折变全息记录特别是双中心全息记录中90°记录结构下较低的衍射效率进行了研究, 采用局域衍射理论对90°记录结构的衍射进行了分析,表明在同样的折射率变化和2 mm的光束宽度的情况下, 只有当折射率光栅振幅大于10-4时, 90°记录结构衍射效率才能够与小角度透射记录结构的衍射效率大致相当。针对环境干扰导致的干涉条纹振动影响光栅记录, 提出了有效调制度概念, 根据分析90°记录结构的干涉条纹间距很小, 容易受外界环境干扰而导致低的折射率变化率, 因此应采用主动条纹锁定系统。此外在双中心全息记录中, 微观光

An anionic antimicrobial peptide from toad Bombina maxima

Amphibian skin is a rich resource of antimicrobial peptides like maximins and maximins H from toad Bombina maxima. A novel cDNA clone encoding a precursor protein that comprises maximin 3 and a novel peptide. named maximin H5. was isolated from a skin cDNA library of B. maxima. The predicted primary structure of maximin H5 is ILGPVLGLVSDTLDDVLGIL-NH2,. Containing three aspartate residues and no basic amino acid residues. maximin H5 is characterized by an anionic property. Different from cationic maximin H peptides. only Gram-positive strain Staphylococcus aureus was sensitive to maximin H5. while the other bacteria] and fungal strains tested ere resistant to it. The presence of metal ions. like Zn2+ and Mg2+, did not increase its antimicrobial potency. Maximin H5 represents the first example of potential anionic antimicrobial peptides from amphibians, The results provide the first evidence that. together kith cationic antimicrobial peptides. anionic antimicrobial peptides may also exist naturally as part of the innate defense system. (C), 2002 Elsevier Science (USA). All rights reserved.

Maximins S, a novel group of antimicrobial peptides from toad Bombina maxima

Amphibian skin secretions are rich in antimicrobial peptides acting as important components of innate defense system against invading microorganisms. A novel type of peptide, designated as maximin S, was deduced by random sequencing of 793 clones from a constructed Bombina maxima skin cDNA library. The putative primary structures of maximin S peptides can be grouped into five species, in which maximin S I has 14 amino acid residues and the rest of maximin S peptides (S2-S5) all have 18 amino acid residues. Unlike most of the amphibian antimicrobial peptides so far identified, the newly characterized four maximin S precursors are composed of maximin S I and different combinations of tandem repeated maximin S2-S5 linked by internal peptides. Except maximin S I, the predicted secondary structures of maximin S2-S5 show a similar amphipathic alpha-helical structure. MALDI-TOF mass spectrometry analysis of partially isolated skin secretions of the toad indicates that most of the deduced maximin S peptides are expressed. Two deduced maximin S peptides (S1, S4) were synthesized and their antimicrobial activities were tested. Maximin S4 only had an antibiotic activity against mycoplasma and had no antibacterial or antifungal activity toward tested strains. Maximin S1 had no activity under the same conditions. (C) 2004 Elsevier Inc. All rights reserved.

基于消息中间件的分布式查询系统

在三层结构中,中间层的实现是整个系统的核心.提出了一个基于消息中间件实现中间层的结构框架,能够以较少的花费实现一个分布式查询系统.中间层各个业务组件利用消息中间件通信,屏蔽了网络复杂性,实现异构平台的互操作,利用持久队列可以确保通信的可靠性,减轻了系统的开发工作和复杂度.

一种分布式转发基站测控系统的研究与实现

布式监测系统(DCS)在许多领域具有重要的应用价值.针对目前分布式监测系统造价高、运行不稳定等问题,该文提出了一种解决方案--基于多种通讯链路的分布式转发基站监测系统.该文详细介绍了阐述了该监测控制系统的工作原理,并对监测控制系统的结构(包括软件的结构和硬件系统的结构)进行了具体地说明,然后详细描述了监控系统软件、硬件以及通讯协议的设计与实现;文章最后,对基于该系统的一个成功应用--无线寻呼基站无人测控系统的实现作了介绍.无线寻呼基站运行实践中所表现出的低成本、高性能的特点进一步验证了该方案的可实施性.

干旱胁迫下蚕豆叶片抗氧化酶活性的变化

抗氧化防御系统在植物抗旱中发挥着极大的作用。本试验采用PEG胁迫和叶片35℃烘干处理的方法,研究了模拟干旱胁迫条件下蚕豆叶片SOD、POD、CAT活性变化。结果表明,三种抗氧化酶随胁迫时间的延长活性升高;随胁迫程度增加SOD活性活性降低,POD和CAT活性变化规律性不明显。总体而言,SOD活性对胁迫的耐受性更强。

一种新的分布式控制系统容错调度算法

目前多数容错调度算法在调度非周期任务时采用预留时间的方法,非周期任务无法得到充分响应.针对该问题,提出一种新的分布式控制系统容错调度算法,采用任务集划分的方法在不同处理机上运行不同的周期任务子集,使每个处理机具有不同的非周期任务预留时间,当非周期任务发生时,即可得到有效响应.结果表明,该方法能提高容错调度的效率.

基于分布式内存数据库的HIRFL-CSR真空监控系统

This paper introduced a real-time vacuum monitor system based on multilayer Web architecture for HIRFL-CSR(Heavy Ion Research Facility of Lanzhou & Cooler Storage Ring) project in Lanzhou.It combined with COM/DCOM to develop the application layer,and developed the web layer with ActiveX and Ajax technology.It provided a facility and efficiency method for real-time control.The application shows that this system runs stably and accurately.中文文摘：简要介绍了国家"九五"重大科学工程——兰州重离子加速器冷却储存环(HIRFL-CSR)真空监控系统的总体结构,分析了在Web构架下,基于分布式内存数据库的多层真空监控系统的实现方法。采用分布式内存数据库,解决了基于Web构架的分布式实时应用环境下对系统和网络资源的消耗问题。在软件控制方面采用了统一调度,既简化了软件实现过程,又提高了系统的安全性、高效性和易维护性。该系统已成功运行。