Study of n=2, Delta n=0 transition of Be-, B-, C-, N- and O-like sequence in the beam-foil spectrum of titanium

The foil-excited the spectrum of highly stripped titanium ions between 12-40 nm has been studied. Titanium ions of 80 and 120 MeV were provided by the HI-13 tandem accelerator at the China Institute of Atomic Energy. GIM-957 XUV-VUV monochromator was refocused to get highly-resolved spectra. Our experimental results and the published spectral data of laser-produced plasma show agreement in nearly all cases within +/- 0.03 nm. The spectra contained some weak or strong lines previously unclassified. These spectral lines mainly belong to 2s2p(2) for TiXVIII, 2p(3) for TiXVIII, 2s2p(3) for TiXVII, 2p(6)4p for Ti XII and 2p(6)3d for Ti XII transitions.

增强UV-B辐射对暖温带落叶阔叶林下土庄绣线菊水分生理和氮素利用及形态特性的影响

在中国北方大部分地区，水分始终是影响植物生长和分布的最主要限制性因子之一，植物在其生长期经常遭受水分胁迫。不仅如此，随着大气同温层中臭氧浓度的减少，过量的有害紫外辐射（主要是UV-B，280nm-320nm）将穿透大气层达到地球表面。随着全球变化的加剧，这些地区的植物将不可避免地受UV-B和水分胁迫的共同作用。 本实验是在北京东灵山暖温带森林生态系统中，选择常见灌丛土庄绣线菊(Spiraea pubescens)，建立UV-B控制实验。连续三个生长季每天增补9.4kJ•m-2的辐射剂量，模拟臭氧衰减17%时近地表面UV-B辐射的增强。本实验的目的是观测在野外环境下，长时间人工增强UV-B辐射对土庄绣线菊水分生理、氮素利用以及形态特征的影响。具体对以下指标进行测定：叶片的气孔导度、碳同位素比率（δ13 C）、叶含水量、叶面积、水分利用效率（WUE）、叶全氮含量、叶氮素再吸收率。 实验结果表明，增强UV-B辐射显著减少了土庄绣线菊的叶面积（50.1%），提高了叶片全氮含量(102%)，处理植株的氮素再吸收率比对照植株高出50.9%。同时，UV-B辐射还在一定程度上（尽管统计显示不显著）降低了气孔导度(16.1%)、胞间CO2浓度与大气CO2浓度之比(Ci/Ca) (4.0%)、提高了碳同位素比率（δ13 C）(20.5‰)、叶含水量(3.1%)及比叶重（SLW）(5.2%)，从而导致水分利用效率（WUE）的增加(4.1%)，植物的抗旱能力增强。值得注意的是，深层土壤（30-40cm）含水量变化会影响气孔导度、δ13 C、WUE对紫外辐射的响应程度：在土壤干旱的季节（6月和9月），气孔导度、δ13 C、WUE这些指标处理和对照的差异很小，但是当土壤水分充足时（7月和8月），处理和对照的差异就较为显著。另外，随着实验处理时间的延长UV-B的效应变得不显著。相关分析表明，UV-B辐射降低了土壤含水量（30-40cm）与土庄绣线菊叶含水量、δ13 C、Ci/Ca���气孔导度的相关系数，增强了WUE与土壤含水量的相关性，这也许是由于UV-B辐射增强了WUE对土壤水分变化的敏感性。本研究的结果表明UV-B辐射对土庄绣线菊的形态和生长有显著的影响，但对主要水分生理指标影响不显著。

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.

稻属的系统发育基因组学研究

稻属（OrvzaL．）是禾本科(Poaceae)中的重要植物类群，包含20多个野生种和两个栽培种，共有十个基因组类型，即A，B，C，E，F，G，BC，CD，HJ和HK，蕴藏了极为丰富的遗传资源，是水稻遗传改良的重要基因库。考虑到该属现存物种中的多倍体都是由二倍体杂交起源的，因此，弄清二倍体基因组之间的进化关系对于正确理解整个稻属的进化历史至关重要，同时也为稻属及其近缘类群的进化生物学、比较基因组学和功能基因学研究等提供了一个重要的工作基础。迄今，对稻属各基因组之间的系统发育关系还没有一致的结论，特别是对A、B和C基因组三者之间的关系，以及稻属基部类群的归属问题还存在争议。本研究选取来自不同二倍体基因组的6个稻属物种为研究对象，以近缘属Leersia中的L，tisserantti作外类群，通过对基因组水平的多基因序列数据的详尽分析，探讨了稻属二倍体基因组之间的亲缘关系问题，基因树与基因树之间冲突的机理，以及利用基因组水平的多基因序列做系统发育分析的方法，主要研究结果如下。 利用已完成的水稻两亚种（O．sativaL．ssp. indica���O．sativaL．ssp.japonica���的全基因组序列，筛选并扩增出遍布核基因组12条染色体的142个单拷贝核基因片段。通过对全部基因位点的合并分析，我们得到了一棵有完全分辨并得到显著统计支持的系统树。分别提取各基因的外显子区、内含子区和第三密码子进行合并建树时发现，除了合并外显子区的MP分析以外，所得系统树的树形均不变，说明这棵树基本上不会因为选取基因组不同区域或碱基位点而改变，尽管不同区域或碱基位点受到不同的选择约束力。以基因为单位进行放回式抽样也强烈支持合并建树的分析结果，表明多基因合并序列的系统发育估计并没有受到少数特殊基因的支配。为了考察基因组内物种取样对建树的影响，我们增加了2个A基因组物种以及C基因组的另外两个物种，随机选取其中的62个基因位点进行扩增和测序（增加的O．sativa的序列来自BGI-RIS数据库）。将全部II个物种62个基因位点的序列合并建树分析，得到基因组之间的进化关系均未改变。我们进一步评估了合并数据的系统误差，结果发现，合并数据的系统发育重建也未受到系统误差的影响。综上所述，本研究通过系统发育基因组学方法所得到的系统树反映了类群真实的进化关系。 为了深入探讨以往研究中出现相互矛盾的系统发育关系的原因，我们对142个基因位点分别做了单独的建树分析，并用系统发育网络方法分析了数据中基因之间系统发育信息矛盾的集中位置及其矛盾程度。基于单基因的建树分析及系统误差分析，我们排除了随机误差和系统误差直接造成基因之间信息冲突的可能性。基于溯祖理论( Coalescence theory)的进一步分析表明，稻属进化过程中发生了两次世代间隔较短的连续分化事件，由于祖先居群较大引起基因的谱系分选，进而使得在利用现有物种基因序列来重建这些分化事件时基因树不能正确反映物种树，且呈现出基因组水平的基因树冲突现象。这两次间隔较短的连续分化事件分别对应了稻属中两次物种快速分化过程，整个稻属基因组的多样性几乎都是在这两次物种快速分化过程中形成的。随机抽样分析表明，需要大量的分子序列数据才能正确分辨稻属二倍体基因组的系统发育关系（若取95%的概率，则至少需要120个基因或50kb的随机碱基位点）。本研究用基因组水平的多基因合并数据克服了谱系分选对构建系统树所带来的“噪音”，在存在广泛单基因系统发育信息矛盾的前提下获得了对物种树的正确估计，这充分证明系统发育基因组学方法在解决快速分化类群的进化关系问题中有着巨大潜力和广阔的应用前景。 基于本文所采用的142个核基因，我们初步探讨了利用多基因序列数据构建系统树时如何进行模型选择和插入缺失编码等问题，并评估了数据缺失对基因组水平系统发育重建的影响。结果表明，对合并数据而言，混合模型比单一模型能更好的拟合数据的进化模式;找到合并数据中异质性的根源并做出适当的数据分割是成功运用混合模型的关键;某些模型成分在提高模型对数据的适合度上发挥着重要作用，尤其要考虑位点之间以及谱系之间的突变速率异质性。我们认为，在设置模型时，最复杂的不一定是最好的，把握数据中最重要的进化特征远比简单的增加模型的复杂度重要。插入缺失的编码分析表明，编码后显著增加了对A基因组和B基因组聚为一枝的支持，但对稻属基部类群的分辨状况改善不明显。另外，我们通过去除数据缺失比例较大的类群来降低数据缺 失对系统发育推断的影响，结果所得的系统发育关系不变，支持率也仅有极微小的变化，说明基因组水平的多基因数据由于具有丰富的系统发育信息，因而对数据缺失具有很好的缓冲能力。

杜泊羊冷冻胚胎移植的影响因素

下载PDF阅读器为进一步提高杜泊羊的冻胚移植成功率,于春秋两季同期处理湖羊和小尾寒羊受体共997只(次),同期发情782只(次),发情率达78.4%,其中湖羊春秋两季平均发情率为84.6%,显著高于小尾寒羊(73.9%)(P＜0.01),秋季两品种平均发情率83.3%,显著高于春季75.8%(P＜0.01);对431只发情受体羊进行移植,总妊娠率为58.5%(252/431),产羔率为58.0%(250/431).其中湖羊为受体的春秋两季平均妊娠率62.5%,高于小尾寒羊(54.7%);秋季两品种的平均妊娠率为64.8%,显著高于春季(52.5%).囊胚移植后的平均妊娠率为61.5%,显著高于桑椹胚(41.5%),其中A级囊胚为67.4%,显著高于B级囊胚(P＜0.05)和所有桑椹胚(P＜0.01);B级囊胚显著高于B级桑椹胚(P＜0.05),B级囊胚与A级桑椹胚间及A、B级桑椹胚间均无显著差异;C级囊胚和桑椹胚均未见妊娠.此外,受体羊卵巢黄体发育状况及移植技术熟练程度对妊娠率也有显著影响.

云南高黎贡山白颌大角蟾的核型、C-带及Ag-NORs的研究

比较了云南高黎贡山地区的贡山独龙江和腾冲大蒿坪白颌大角蟾（Megophryslateralis）两个地理种群的核型、C-带和Ag-NORs结果表明，两个地理种群在核型和带型上都有差异两个地理种群的核型均为2n＝26，NF＝52染色体形态差异不明显，而次缢痕的位置完全不同，贡山独龙江标本的次缢痕位于No．2的长臂上近着丝点处，腾冲标本的次缢痕位于No．5的短臂上近着丝点的部位在腾冲标本中发现一雄性个体中有一条额外的染色体，可能是B染色体两地标本的C-带差异不太显著，贡山独龙江标本的C-带相对较为显著．贡山独龙江标本的Ag-NORs位于No．2长臂近着丝点处，与次缢痕的部位对应，两条同源染色体上大小有显著差异．腾冲标本的Ag-NORs位于No．5短臂上近着丝点处，与次缢痕的部位对应依据核型和带型的比较，对白颌大角蟾的分类和进化问题进行了讨论。

银额果蝇的B染色体研究 1: 昆明群体的Bs数目和频率

银额果蝇昆明群体有丝分裂中期核型中存在B染色体, 出现频率为69.1%在已 研究过的来自各个地区的银额果蝇中, 昆明群体的B染色体频率最高。B染色体 数目为1—6条。该群体内单雌系间的B染色体数目不同, 个体间和细胞间的B染色 体数目也不同。在核型中, B染色体最小, 形态稳定, 点状, C-带和G-带呈阳性 。 图版1图2表1参12

基于细胞色素b基因序列的鲤科鱼类系统发育研究(鱼纲:鲤形目)

鲤科是鱼类最大的科,在中国淡水鱼类组成中鲤科鱼类的成分占一半以上.鲤科鱼类的演化过程代表了东亚淡水鱼类的整体演化过程.为探讨东亚鲤科鱼类系统发育关系,共分析了包括18种新测序列在内的54种鲤科鱼类细胞色素b基因的全序列.分析的物种涵盖了鲤科鱼类的12个亚科并对问题较多的(鱼丹)亚科(Danioninae)和雅罗鱼亚科(Leuciscinae)进行了广泛的采样.系统发育树的建立使用了多种方法,包括邻接法、最大简约法和最大似然法.亚口鱼科(Catostomidae)的胭脂鱼(Myxocyprinus asia

稀土过渡金属复合氧化物的制备结构，电学性质及气敏性研究

本文首次合成了Lar_xSr_xFe_yCor_yO_3(x、y:0.1、0.3、0.5、0.7、0.9)系列化合物和Lar_xBa_xFe_yCor_yO_3(x、y:0.1、0.3、0.5、0.7、0.9)系列化合物，并对其结构，电性及气敏性质进行了研究。关于ABO_3型稀土过渡金属复合氧化物的结构研究，文献上报道比较混乱，不同的人在进行结构研究中采用不同的结构基元得到了不同的晶型和相应的晶胞参数。本文根据上述化合物的X射线谱图，对其进行指标化，得到了上述两系列化合物为主方晶系结构，晶胞参数计算结果表明：在Y = 0.7时，化合物Lar_xSr_xFe_(0.7)Co_(0.3)O_3的晶胞参数随X值的增大而减小。化合物Lar_xBa_xFe_(0.7)Co_(0.3)O_3的晶胞参数随X值的增大而增大。在X = 0.3时，上述两条系列化合物的晶胞参数均随Y值的增大而增大。对以上两系列化合物所表现出的结构变化规律，我们用起决定作用的离子半径大小进行了解释。针对上述两系列化合物，我们研究了它们的电学性质，研究结果表明，上述两系列化合物，在Y = 0.7时，其室温电阻率均随X在 0 < x < 0.5内增大而减小。在0.5 < x < 1内随X值增大而增大。在X = 0.5时的两个化合物具有最小的室温电阻率。在此方面，其电阻率变化规律与LarxMxBO_3(M:Ca��� Sr、 Ba、 B:Fe Co)化合物的变化规律相似。在X = 0.3时，上述两系列化合物的室温电阻率均随Y值的增大而增大，上述两系列化合物所表现出的室温电阻率变化规律可以运用C. Zener的双交换模型加以解释，同时，低温电阻率测定表明：上述两系列化合物在温度100-263K内，表现半导体性质。液氮温度下它们不具有超导性。除以上研究之外，我们针对Lar_xSr_xFe_yCor_yO_3 (X = 0.3、 Y:0.1、0.5、 0.9, Y = 0.7, X:0.1、 0.9）系列化合物初步地进行了气敏性研究。结果为：化合物La_(0.7)Sr_(0.3)Fe_yCor_yO_3 (Y:0.1、 0.5、 0.9)都不同程度地对乙醇、石油醚、 乙炔、烟具有气敏性，它们对乙醇的气敏响应时间约为1分钟，而对石油醚、乙炔和烟的气敏响应时间要用5分钟左右，在上述化合物中，La_(0.7)Sr_(0.3)Fe_(0.5)Co_(0.5)O_3化合物表现出最强的对乙醇、石油醚、乙炔的气敏性。对化合物La_(0.7)Sr_(0.3)Fe_(0.5)Co_(0.5)O_3的进一步研究表明，在乙醇气氛下，化合物La_(0.7)Sr_(0.3)Fe_(0.5)Co_(0.5)O_3在工作电流I_(Dn) = 0.20A时具有最佳的气敏数应。工作电流高于或低于此值都将导致其气敏效应的大小顺序为La_(0.7)Sr_(0.3)Fe_(0.5)Co_(0.5)O_3 > La_(0.7)Sr_(0.3)Fe_(0.9)Co_(0.1)O_3 > La_(0.7)Sr_(0.3)Fe_(0.1)Co_(0.9)O_3对化合物Lar_xSr_xFe_(0.7)Co_(0.3)O_3 (X:0.1、 0.9)的气敏性研究表明：它们只对乙醇和烟具有气敏性。对上述两种气氛的气敏响应时间为5分钟。上述两种化合物中，La_(0.1)Sr_(0.9)Fe_(0.7)Co_(0.3)O_3气敏效应最强。

吲哚生物碱Desbromoarborescidine A 的全合成及烯胺C-亚磺酰化反应研究

从新几内亚核桃木的树皮中分离得到的吲哚类喹诺里西定生物碱10-Desbromoarborescidine A，因发现其具有阻滞钙离子通道的活性而倍受关注。10-Desbromoarborescidine A由A、B、C、D四个环组成，只有一个手性中心，是吲哚生物碱中结构较简单的一种，常作为此类生物碱全合成方法的模型化合物。但迄今为止，能高效而简便的实现手性10-Desbromoarborescidine A不对称全合成方法线路不多，大多数以不对称诱导的方式建立其手性中心，手性催化的方式仅有一例金属催化。从逆合成分析可知，Desbromoarborescidine A的全合成可以通过亚胺不对称催化还原进行关键的手性中心构建，而本课题组在之前的研究中通过手性有机小分子催化剂的发展，已将三氯硅烷氢转移还原亚胺发展成了一类简便实用、高效、高对映选择性并具有优良底物适应范围的不对称催化反应，我们希望以这一反应作为关键手段，发展一条Desbromoarborescidine A及其类似物不对称合成新路线。 根据我们设计的新路线，首先成功合成了其关键中间体，然后我们进行了关键的不对称催化尝试。用本实验室已有的高性能有机小分子催化剂虽得到了较好的对应选择性，但是产率很低。同时，为了验证整条线路的可行性，我们也用消旋的中间体进行拉通线路的尝试。但不幸的是，在脱除保护基时遇到了很大困难。尝试换不同的保护基，或改变脱保护基的顺序，都未能成功合成目标产物。究其原因可能是由于吲哚的特殊性造成的，吲哚类亚胺与常规的芳香亚胺有较大的差异，其NH基团无论保护还是不保护，对与其2位相联接的C=N双键均有很大的影响，导致其不对称催化还原难以进行。另外，由于所设计的还原产物含有处在吲哚苄位的胺基，稳定性较差，造成保护基脱除困难。 烯胺C-亚磺酰化反应是本课题组最近发现的一个新反应，之前未见文献报道。本研究对该反应进行了反应条件优化和底物扩展，发现带Cbz，Ac，COt-Bu，CO2Et，Bz等保护基的一系列环状和非环状烯胺在亚磺酸钠、DMAc和MeSiCl3的共同作用下能高效高产率生成β-胺基烯基亚砜类新化合物，为合成多官能团化的烯基亚砜新化合物提供了一条简便实用的途径。 The main constituent of Dracontomelum mangiferum B1, indoloquinolizidine alkaloid 10-Desbromoarborescidine A, has drawn great attention due to its calcium channel blocking activity. Its molecular structure is relatively simple compared with the other alkaloids of the same type, which has only one chiral center, albeit with four cycles A, B, C, and D. This compound is often used as a model target for exploring different strategies for the total synthesis of indole alkaloids. Nevertheless, so far there still lack practical and highly efficient methods for the asymmetric total synthesis of 10-Desbromoarborescidine A. Most of the current available methods rely on stoichiometric asymmetric synthesis for the construction of the chiral center. There is only one example reporting utilization of asymmetric catalysis, but with transition metal complex as the catalyst. Our retrosynthetic analysis shows that catalytic asymmetric reduction of imine could be used as the key step for the construction of the chiral center of Desbromoarborescidine A. Since in the previous studies our group has developed the asymmetric reduction of imines by trichlorosilane into a practical and highly efficient and enantioselective method using newly designed chiral organocatalysts, we hope to apply this method to develop a novel synthetic route for the total synthesis of Desbromoarborescidine A and its analogues in this study. According to the newly designed synthetic route, we first accomplished the synthesis of the key intermediates which was then examined for the critical asymmetric catalysis. The asymmetric reduction using the highly efficient organocatalysts, developed in our lab afforded high ee but poor yield. We tried different reaction conditions to improve the yield, but failed to get any good results. Simultaneously, to vertify the feasibility of the synthetic route we designed, we also tired to go through the route toward the racemic synthesis of Desbromoarborescidine A. But unfortunately, protection and deprotection proved to be big hurdles. All the different protection groups and different sequences of protection and deprotection we tried failed to get us through the designed synthetic sequence and furnish the final product. Most likely, the indole part is the culprit behind the failures.The NH group of the indole, no matter protected or not, may impact the catalytic asymmetric reduction of C-N double bond connected with 2-C. Additionally, the reduction product we designed contains an amino group in the β-position of the indole, which may cause problems due to its instability. C-sulfenylation of enamines is a novel reaction discovered recently by our group, which has not been seen before in the literature. In this study, optimization of the reaction conditions and exploration of the substrate scope were further undertaken for this reaction, which reveal that a series of enamines with N-Cbz, Ac, COt-Bu, CO2Et protection groups could all undergo smooth C-sulfinylations with the comined use of sodium benzene sulphinate, DAMc and MeSiCl3, efficiently furnishing the β-amino vinylsulfoxide products in high yield, affording a practical and highly efficient methods for synthesis of functional vinylsulfoxides.

青藏高原东缘几种树苗对增强紫外线-B和氮供应的响应

大气臭氧的损耗导致了地球表面具有生物学效应的紫外线-B(UV-B)辐射增强。同时，大气成分变化中除了UV-B辐射增强外，氮沉降是一个新近出现而又令人担忧的环境问题，其来源和分布正在迅速扩展到全球范围，并不断向陆地和水生生态系统沉降。本试验在四川省境内的中国科学院茂县生态站内进行，以云山、冷杉、色木槭和红椋子幼苗为模式植物，从生长形态、光合作用、抗氧化能力和矿质营养等方面研究了青藏高原东缘4种树苗对全球变化－增强UV-B辐射和氮供应(氮沉降)的响应。该试验为室外盆栽试验，包括四个处理：(1)大气UV-B辐射+无额外的氮供应(C)；(2)大气UV-B辐射+额外的氮供应(N)；(3)增强UV-B辐射+无额外的氮供应(UV-B)；(4)增强UV-B辐射+额外的氮供应(UV-B+N)。其目的：一方面有助于丰富我国对全球变化及区域响应研究的全面认识，进一步完善在全球气候变化条件下臭氧层削减和氮沉降对陆地生态系统影响的内容；另一方面，在一定程度上有助于我们更好的理解在全球变化下森林更新的早期过程。具体结果如下： 增强的UV-B辐射在生长形态、光合、抗氧化能力、活性氧和矿质营养方面对4种幼苗都有显著的影响。UV-B辐射增强对幼苗的影响不仅与物种有关，而且，还与氮营养水平相关。总体表现为，高的UV-B辐射导致了色木槭和红椋子幼苗叶片的皱缩和卷曲，并降低了色木槭幼苗的叶片数和叶重，在额外的氮供应下，云杉、冷杉和红椋子的叶重也显著地降低了；色木槭和红椋子幼苗叶片的解剖结构受到了增强的UV-B辐射的影响，增强的UV-B辐射显著地降低了色木槭叶片的栅栏组织厚度，提高了红椋子叶片的厚度；增强的UV-B辐射显著地降低了4种幼苗的单株总生物量、植物地下部分的生长、总叶绿素含量 [Chl (a + b)]、净光合速率和最大量子产量(Fv/Fm)，提高了4种幼苗叶片的膜脂过氧化(MDA含量)，改变了植物体不同器官中的矿质元素含量；增强的UV-B辐射提高了冷杉、色木槭和红椋子叶片中的过氧化氢含量(H2O2)、超氧负离子(O2-)生成速率，在额外的氮供应下，云杉叶片中的活性氧含量也显著地提高了；在无额外的氮供应条件下，增强的UV-B辐射显著地提高了4种幼苗叶片中的UV-B吸收物质、脯氨酸含量和抗氧化酶的活性(SOD、POD、CAT、GR和APX)。在额外的氮供应条件下，UV-B辐射的增强却显著地降低了冷杉叶片中脯氨酸含量和红椋子叶片中UV-B吸收物质含量，但是，在4种幼苗叶片中，5种抗氧化酶的活性对UV-B辐射的增强没有明显的规律性，增强的UV-B辐射显著地提高了云杉叶片中的POD、SOD和GR的活性，提高了冷杉叶片中的POD和GR活性，提高了色木槭叶片中的POD、SOD和CAT活性和红椋子幼苗叶片中的POD和SOD活性。从这些结果可知，植物在遭受高的UV-B辐射导致的过氧化胁迫时，植物体内形成了一定的保护机制，但是，这种保护不能抵抗高的UV-B辐射对植物的伤害。 额外的氮供应在生长形态、光合、抗氧化能力、活性氧和矿质营养方面对4种幼苗都有一定的影响，不同幼苗对额外的氮供应响应不同，并且受到UV-B辐射水平的影响。在当地现有的UV-B辐射水平下，额外的氮供应显著地提高了幼苗的单株总生物量、植物地下部分的生长、Chl (a + b)、净光合速率(红椋子除外)、UV-B吸收物质(冷杉除外)、脯氨酸含量(红椋子除外)和部分抗氧化酶的活性，降低了H2O2的含量、O2-的生成速率和MDA含量(红椋子除外)，改变了植物体内部分矿质元素含量，显著地提高了云杉和冷杉叶片中的Fv/Fm。这些指标总体表明，在当地现有大气UV-B辐射水平下，额外的氮供应对植物的生长和发育是有利的。在增强的UV-B辐射水平下，4种幼苗的生长形态和光合大部分指标都没有受到额外氮供应的影响，额外的氮供应提高了红椋子幼苗的单株总生物量和Chl (a + b)含量，提高了冷杉和色木槭叶片中的活性氧含量和MDA含量，却降低了红椋子叶片中的活性氧含量；额外的氮供应也提高了云杉、色木槭和红椋子叶片中UV-B吸收物质和脯氨酸含量，降低了冷杉叶片中UV-B吸收物质和脯氨酸含量；在抗氧化酶活性方面，额外的氮供应降低了云杉、冷杉叶片中5种抗氧化酶的活性和红椋子叶片中POD和GR的活性，提高了色木槭叶片中的POD和SOD的活性；4种幼苗植物体内的矿质元素含量对额外的氮供应没有显著的规律性。从这些结果可知，在高的UV-B辐射下，额外的氮供应提高了云杉、冷杉和色木槭幼苗对高的UV-B辐射的敏感性，然而，额外的氮供应却促进了红椋子幼苗的生长，原因可能是，在高的UV-B辐射下，额外的氮供应增加了红椋子叶片的厚度、叶重和叶片数，降低了叶片中活性氧含量的结果。表明在高的UV-B辐射水平下，额外的氮供应降低了红椋子幼苗对高的UV-B辐射的敏感性。 在全球变化的趋势下，UV-B辐射增强和氮沉降可能同时存在，我们的研究表明，与大气UV-B辐射+无额外的氮供应处理相比，增强UV-B辐射+额外的氮供应处理显著地降低了幼苗的单株总生物量(红椋子除外)、Chl (a + b)、净光合速率、Fv/Fm(冷杉除外)和MDA含量(红椋子除外)，提高了活性氧含量 (云杉除外)、UV-B紫外吸收物质含量(冷杉除外)、脯氨酸含量和部分抗氧化酶的活性，改变了植物体不同器官中的矿质元素含量。结果表明，在当地现有条件下，全球变化(UV-B辐射增强和氮沉降)对云杉、冷杉和色木槭幼苗的生长是不利，尽管植物体内一些抗氧化性指标提高了，然而，却对红椋子幼苗的单株总生物量的累积没有显著的影响。 The depletion of the ozone led to the increase of ultraviolet-B (UV-B) with biological effects in the earth’s surface. At the same time, except for enhanced UV-B radiation, nitrogen deposition was an anxious environmental problem at present, rapidly expanding to the global scope and continuously depositing to land and aquatic ecosystem. The experiment was conducted in Maoxian Ecological Station of Chinese Academy of Sciences, Sichuan province, China. Picea asperata, Abies faxoniana, Acer mono Maxim and Swida hemsleyi (Schneid. et Wanger.) Sojak seedlings were selected as model plants to assess the effects of enhanced UV-B radiation and supplemental nitrogen supply on growth, morphological, photosynthesis, antioxidant and mineral nutrient traits of 4 species seedlings in east Qinghai-Tibetan Plateau. The experiment was potted outdoor, including 4 treatments: (1) ambient UV-B without supplemental nitrogen (control, C); (2) ambient UV-B with supplemental nitrogen (N); (3) enhanced UV-B without supplemental nitrogen (UV-B); (4) enhanced UV-B with supplemental nitrogen (UV-B+N). One hand, it was helpful for enriching our country to comprehensive understanding of the researches in the global change and the region response, further perfecting the effects of the depleted ozone layer and nitrogen deposition on land ecosystem under the global change; the other hand, it was favorable for us to better understanding of the early process of forest renews under the global change. The results were as follows: Enhanced UV-B radiation had significant effects on 4 species seedlings in growth, morphological, photosynthesis, antioxidant and mineral nutrient traits of 4 species seedlings. The effects of enhanced UV-B on plants were not only related with species, but also related with nitrogen nutrient level. Generally, the increase of UV-B radiation led to the shrinkage and curl of leaves in Acer mono Maxim and Swida hemsleyi (Schneid. et Wanger.) Sojak seedlings, and reduced the number of leaf and leaf weight of Acer mono Maxim seedlings, under supplemental nitrogen supply, leaf weight of Picea asperata, Abies faxoniana and Swida hemsleyi (Schneid. et Wanger.) Sojak seedlings significantly also reduced; the anatomical features of leaf in Acer mono Maxim and Swida hemsleyi (Schneid. et Wanger.) Sojak seedlings affected by enhanced UV-B radiation, the increase of UV-B radiation markedly reduced the palisade tissue thickness of Acer mono Maxim leaf and enhanced the leaf thickness of Swida hemsleyi (Schneid. et Wanger.) Sojak seedlings; the enhanced UV-B radiation significantly reduced total biomass per plant of 4 species seedlings, the growth of the underground parts, Chl (a + b), net photosynthetic rate and maximum potential quantum yield of photosynthesis (Fv/Fm), and increased the degree of lipid peroxidation (MDA content) and changed the content of mineral elements in different parts of plants; the enhanced UV-B radiation also increased the rate of superoxide radical (O2-) production and hydrogen peroxide (H2O2) content in leaves of Abies faxoniana, Acer mono Maxim, Swida hemsleyi (Schneid. et Wanger.) Sojak seedlings, under supplemental nitrogen supply, the reactive oxygen species in leaves of Picea asperata seedlings also significantly increased by enhanced UV-B radiation; under without supplemental nitrogen supply, enhanced UV-B radiation evidently induced an increase in UV-B absorbing compounds, proline content and the activities of antioxidant enzymes (SOD, POD, CAT, GR and APX) of leaves in 4 species seedlings. Under supplemental nitrogen supply, enhanced UV-B radiation induced a decrease in proline content of leaves in Abies faxoniana seedlings and UV-B absorbing compounds of leaves in Swida hemsleyi (Schneid. et Wanger.) Sojak seedlings, but, there were no obvious rules in the activities of five antioxidant enzymes of 4 species seedling leaves to enhanced UV-B radiation, enhanced UV-B radiation significantly increased the activities of POD, SOD and GR in Picea asperata leaves, the activities of POD and GR in Abies faxoniana leaves and the activities of POD, SOD and CAT in Acer mono Maxim leaves. The results indicated that some protective mechanism was formed when plants were exposed to enhanced UV-B radiation, but the protection could not counteract the harm of high UV-B radiation on plants. Supplemental nitrogen supply had some effects on 4 species seedlings in growth, morphological, photosynthesis, antioxidant and mineral nutrient traits. The response of 4 species seedlings was different to supplemental nitrogen supply, and was affected by UV-B levels. Under local ambient UV-B radiation, supplemental nitrogen supply significantly increased the total biomass per plant, the growth of underground parts, Chl (a + b), net photosynthetic rate (except for Acer mono Maxim seedlings), UV-B absorbing compounds (except for Abies faxoniana seedlings), proline content (except for Swida hemsleyi (Schneid. et Wanger.) Sojak seedlings) and the activities of some antioxidant enzymes, and reduced H2O2 content, the rate of O2- production and MDA content (except for Swida hemsleyi (Schneid. et Wanger.) Sojak seedlings) and changed the content of mineral elemental in different parts; supplemental nitrogen supply also evidently increased Fv/Fm in Picea asperata and Abies faxoniana seedlings. These results indicated that supplemental nitrogen supply was favorable for the growth of plants under local ambient UV-B radiation. Under enhanced UV-B radiation, mostly parameters in growth and morphology of 4 species seedlings were not affected by supplemental nitrogen supply. Supplemental nitrogen supply increased the total biomass per plant and Chl (a + b) of Swida hemsleyi (Schneid. et Wanger.) Sojak seedling, increased the reactive oxygen species and MDA content in Abies faxoniana and Acer mono Maxim leaves, and reduced the reactive oxygen species in Swida hemsleyi (Schneid. et Wanger.) Sojak leaves; supplemental nitrogen supply also increased UV-B absorbing compounds and proline content in Picea asperata, Acer mono Maxim and Swida hemsleyi (Schneid. et Wanger.) Sojak leaves, decreased UV-B absorbing compounds and proline content in Abies faxoniana leaves; in the activities of antioxidant enzymes, supplemental nitrogen supply significantly reduced the activities of antioxidant enzymes in Picea asperata and Abies faxoniana leaves and the activities of POD and GR in Swida hemsleyi (Schneid. et Wanger.) Sojak leaves, and increased the activities of POD and SOD in Acer mono Maxim leaves; the content of mineral elements in 4 species seedlings was no significantly rule to supplemental nitrogen supply. We knew from the results, under enhanced UV-B radiation, supplemental nitrogen supply made Picea asperata, Acer faxoniana and Acer mono Maxim seedlings more sensitivity to enhanced UV-B radiation, however, accelerated the growth of Swida hemsleyi (Schneid. et Wanger.) Sojak seedlings. The reason was probably that supplemental nitrogen supply increased the leaf thickness, leaf weight and leaf number, reduced the reactive oxygen content of leaf in Swida hemsleyi (Schneid. et Wanger.) Sojak seedlings grown under high UV-B radiation. This showed that supplemental nitrogen supply reduced the sensitivity of Swida hemsleyi (Schneid. et Wanger.) Sojak seedlings to high UV-B radiation. Under the tendency of the global change, enhanced UV-B radiation and nitrogen deposition may probably coexist. The results showed, compared with the treatment of ambient UV-B radiation without supplemental nitrogen supply, the treatment of enhanced UV-B radiation with supplemental nitrogen supply significantly reduced the total biomass per plants (except for Swida hemsleyi (Schneid. et Wanger.) Sojak seedlings), Chl (a + b), net photosynthetic rate, Fv/Fm and MDA content (except for Swida hemsleyi (Schneid. et Wanger.) Sojak seedlings), and increased reactive oxygen content (except for Picea asperata seedlings), UV-B absorbing compounds (except for Abies faxoniana seedlings), proline content and part antioxidant enzymes, and changed the content of mineral elements of different parts. The results indicated that the global change (enhanced UV-B and nitrogen deposition) were not favorable for the growth of plants under local ambient UV-B radiation and nitrogen nutrient level,, though increased some antioxidant indexes, however, the treatment of enhanced UV-B with supplement nitrogen supply did not significantly affect on the biomass accumulation of Swida hemsleyi (Schneid. et Wanger.) Sojak seedlings.

贡嘎山麦吊杉(Plcea brachytyly)群落的结构研究

群落结构的确定是群落研究的基础。本文立足于个体、种群、群落三级水平，从空间和时间两种概念出发，对贡嘎山麦吊杉(Picea brachytyla)群落的结构进行了研究。经初步统计，在麦吊杉林分布的主要地段共有维管束植物93科、263属、约560种，其中种子植物71科、220属、479种。通过种子植物区系地理成份的分析表明，麦吊杉群落的区系组成具有区系成分复杂、特有现象明显和成分古老的特点。在生活型组成上，麦吊杉群落的高位芽植物所占比例最大，其中小高位芽植物最多，而在叶级谱中小叶类型占有较明显的优势。通过种—面积曲线和重要值—面积曲线两种方法求得的麦吊杉群落的最小面积在800-900平方米之间，实际应用时可选用1000平方米的保守面积。在物种的综合特征分析中，群落表现出优势种明显的特征，而存在度II占有最大的比例。物种多样性的研究表明，贡嘎山麦吊杉群落的Shannon-Wiener指数在2.33-3.26之间，Simpson指数在0.43-0.70之间，种间相遇(PIE)在0.42-0.79之间，而以Shannon-Wiener指数为基础的均匀度在34.45%-62.90%之间。麦吊杉群落的垂直结构较为复杂，分层明显。一般可划分出乔木层、灌木层、草本层和活地被层四个基本层次，乔木层通常还可划分为2-3个亚层，由高海拔至低海拔成层现象有逐渐复杂的趋势。构成麦吊杉群落的层片类型较多，其中以常绿针叶大高位芽植物为其建群层片。麦吊杉林中的层外植物较丰富，种子植物、蕨类植物、以及苔藓植物和地衣植物皆可构成其空中层片，其中苔藓植物生长繁茂，反映出群落结构的完整性。麦吊杉群落结构的水平分化较明显，经研究，其密度值在0.32-0.41之间，平均距离在1.56-1.41之间。应用Raunkiaer的频度指数方法对整个麦吊杉群落的种群频度进行调查后表明，其频度分布情况与Raunkiaer的频度定律基本上是符合的，即A>B> C