LBO晶体上1064nm，532nm二倍频增透膜的设计及误差分析

采用矢量合成法设计了LiB3O5（LBO）晶体上1064nm，532nm二倍频增透膜，在1064nm处的反射率为0．0014％，532nm处的反射率为0．0004％。根据误差分析，薄膜制备时沉积速率精度控制在＋6．5％时，1064nm处的反射率增加至0．22％，532nm处增加至0．87％。材料折射率的变化控制在＋3％时，1064nm处的反射率达0．24％，532nm处达0．22％。沉积速率和折射率控制的负变化不增大特定波长处的剩余反射率。与膜层折射率相比，薄膜物理厚度对剩余反射率的影响小。低折射率膜层的

LBO晶体上1064，532nm倍频增透膜的镀制及性能分析

用电子束蒸发沉积方法在X切LBO（X-LBO）晶体上镀制了两种不同膜系结构的1064和532nm倍频增透膜，其中一种膜系结构为基底／ZrO2／Y2O3／A12O3／SiO2／空气，另一种为基底／0．5Al2O3／ZrO2／Y2O3／A12O3／SiO2／空气，两种膜系结构的主要差别在于有无氧化铝过渡层。测量了薄膜的反射率光谱曲线，发现两种增透膜在1064和532nm处的反射率均小于0．5％，实际镀制结果与理论设计曲线的差异主要是由材料折射率的变化引起的。且对样品在空气环境中进行了温度为473K的退火处理，

Estimating the encounter rate of Atlantic capelin (Mallotus villosus) with fish eggs, based on stomach content analysis

The number of pelagic fish eggs (cod and cunner) found in stomachs of capelin (Mallotus villosus) sampled in coastal Newfoundland was used to estimate the encounter rates between capelin and prey, and thus the effective volume swept by capelin. Fish eggs were found in 4−8% of capelin stomachs, represented an average of 1% of prey by numbers, and their abundance increased as relative stomach fullness decreased. The average number of eggs per stomach doubled for each 5-cm increase in length of capelin. The effective volume swept for eggs by capelin ranged from 0.04 to 0.84 m3/h—a rate that implies either very slow capelin swimming speeds (<1 cm/s) or that fish eggs are not strongly selected as prey. The predation rate estimated from stomach contents was higher than that predicted from laboratory studies of feeding pelagic fish and lower than that predicted by a simple foraging model. It remains uncertain whether capelin play an important regulatory role in the dynamics of early life stages of other fish.

Ecology and growth of juvenile California spiny lobster, Panulirus interruptus (Randall)

ABSTRACT TRANSCRIBED FROM ENGLE'S PH.D. ORAL DEFENSE PAMPHLET: The natural history of juvenile California spiny lobster, Panulirus interruptus (Randall), was investigated, with primary emphasis placed on ascertaining juvenile habitats, determining juvenile growth rates and component growth processes, and evaluating ecological and behavioral phenomena associated with juvenile survival and growth. Habitat surveys of island and mainland localities throughout southern and lower California revealed that small, greenish juveniles typically inhabit crevices or temporary burrows in 0-4m deep, wave-swept rocky habitats covered by dense beds of surf grass, Phyllospadix torreyi S. Watson. Phyllospadix beds were more abundant on gradually sloping rocky mainland beaches than on steeply sloping island shores. Phyllospadix abundance was positively correlated with P. interruptus abundance; however, at Santa Catalina Island, the Phyllospadix habitat was not extensive enough to be the sole lobster nursery. In laboratory tests, puerulus larvae and early juveniles chose Phyllospadix over rubble rocks or broad-bladed kelp, but did not consistently prefer Phyllospadix over reticulate algae. Ecology, growth, and behavior of juvenile P. interruptus inhabiting a discrete Phyllospadix habitat at Bird Rock, Santa Catalina Island, were investigated from October 1974 through December 1976 by means of frequent scuba surveys. Pueruli settled from June to November. Peak recruitment occurred from July to September, when seasonal temperatures were maximal. Settled larvae were approximately one year old. Juvenile growth was determined by size-frequency, single molt increment, mark-recapture, and laboratory culture studies. Carapace length vs. wet weight relationships fit standard power curve equations. Bird Rock juveniles grew from 7 to 32mm CL in 10-11 molts and from 32 to 56mm CL in 5-6 molts during their first and second benthic years, respectively. Growth rates were similar for males and females. Juveniles regenerating more than two limbs grew less per molt than intact lobsters. Long-term growth of laboratory-reared juveniles was 20% less than that of field lobsters. Growth component multiple regression analyses demonstrated that molt increment was directly proportional to premolt size and temperature for age 1+ lobsters. Molt frequency was inversely proportional to size and directly proportional to temperature. Temperature affected age 2+ lobsters similarly, but molt increment was independent of size, and molt frequency declined at a different rate. Juvenile growth rates more than doubled during warm water months compared to cold water months, primarily because of increased molt frequency. Based on results from this study and from previous investigations, it is estimated that P. interruptus males and females become sexually mature by ages 4 and 5 years, respectively, and that legai size is reached by 7 or 8 years of age. Juvenile P. interruptus activity patterns and foraging behavior were similar to those of adults, except that juvenile home ranges were proportionally smaller, and small juveniles were apparently not attracted to distant food. Small mollusks, abundant in Phyllospadix habitats, were the major food items. Size-dependent predation by fish and octopus apparently caused the considerable juvenile mortality observed at Bird Rock. Juveniles approaching 2 years of age gathered in mixed size-class aggregations by day and foraged beyond the grass beds at night. In autumn, these juveniles migrated to deeper habitats, coincident with new puerulus settlement in the Phyllospadix beds. Based on strong inferences from the results, it is proposed that size-dependent predation is the most important factor determining the !ife history strategy of juvenile P. interruptus. Life history tactics promoting rapid growth apparently function dually in reducing the period of high vulnerability to predation and decreasing the time required to reach sexual maturity. The Phyllospadix habitat is an excellent lobster nursery because it provides shelter from predators and possesses abundant food resources for sustaining optimum juvenile growth rates in shallow, warm water.

硬粒小麦（Triticum durum Desf.）单倍体诱导新技术单倍体原生质体植株的再生

硬粒小麦DR147授以超甜玉米(ss7700)的花粉后，83.4%的小麦柱头上的玉米花粉萌发，花粉管经由花柱抵达胚囊，受精率和成胚率分别为44.4%和42.6%。杂种合子核型高度不稳定，在细胞分裂过程中来自父本玉米的染色体逐渐被排除，最后形成硬粒小麦单倍体胚。尽管硬粒小麦×玉米存在较高频率的双受精(32.7%)，同时形成胚和胚乳，但由于胚乳发育异常及败育，最后难以获得有生活力的种子。 硬粒小麦授以玉米的花粉后用100ppm 2，4-D进行处理（浸蘸穗子或向穗茎节间注射），可以延长杂种胚在植株上的存活时间。授粉9-13天后将颖果表面灭菌后在实体显微镜下剥取不同发育时期的幼胚，分别接种于含或不含2.0mg／l2，4-D，3%蔗糖，200mg／l水解酪蛋白，146mgl谷氨酰氨，300mg／l天冬氨酸的MS固体培养基上进行胚拯救或诱导愈伤组织。结果表明，发育程度较高的胚（具盾片的胚，长度大于0.5mm）容易通过胚拯救获得单倍体植株或诱导出愈伤组织，而发育程序较低的胚（琏形胚，梨形胚，鱼雷形胚，长度小于0.3mm）不易获得单倍体植株或诱导愈伤组织而常常变褐，最后死亡。如果将这些胚预先接种子含0.1mg／l BAP，3%蔗糖，200mg/l水解酪蛋白，146mg/l谷氨酰胺，300mg/l天冬氮酸的MS固体培养基上预培养20天，再转移至愈伤组织诱导培养基上则易于产生愈伤组织，通过选择和继代培养可以获得淡黄色，结构致密的胚性愈伤组织。将这种愈伤组织转移至含1.Omg/l BAP和0.1mg/l NAA的MS固体分化培养基上培养20天后即可分化出小植株和绿色芽点，将这些小植株和绿色芽点再在分化培养基上继代培养20天，形成大量根系发达的健壮植株及次生小植株。其中一个胚性愈伤组织系的分化频率高达70. 6%。从获得的100余棵植株中随机取6棵再生植株进行根尖细胞染色体计数发现它们均为单倍体。具发达根系的健壮植株移入实验田后成活率可达80％以上，并生长至成熟。 利用硬粒小麦×玉米建立的单倍性胚性愈伤组织系进行了原生质体培养的研究。胚性愈伤组织经液体悬浮培养4个月后形成了生长迅速的由大小不同(0.5mm至5mm)的愈伤组织块组成的混合悬浮愈伤组织系，酶解试验表明2.0%纤维素酶RS和0.5%离析酶Y-23组合效果最好，而液体悬浮培养物和固体培养的愈伤组织（在酶解时用锋利的解剖刀片切成1mm左右的块）都能释放出大量原生质体，但悬浮培养物释放出的原生质体状态较好，胞质更浓厚，用KM8p培养基以琼脂糖包埋培养方式培养时得到了较高的（5%左右）分裂频率。 原生质体再生的小愈伤组织经增殖、筛选后可获得胚性愈性组织，将其转移至分化培养基Ⅰ（0.2mg/l 2，4-D，1.0mg/l BAP，0.1mg/l NAA，3%蔗糖，200mg/l水解酩蛋白，146mg／l谷氨酸胺，300m8/l天冬氨酸的MS固体培养基）和Ⅱ（不含2，4-D，其它成份同I）上进行分步分化培养可再生出完整植株，分化频率约为20%。从获得的22棵原生质体再生植株中，随机取4株进行根尖细胞染色体计数表明，它们均为单倍体。

玉米的单倍体育种及基因转化的研究

玉米的单倍体育种，是利用花药培养或孤雌生殖产生单倍体后，进行人工或自然加倍，迅速获得稳定的新品种的育种方法。单倍体育种可以缩短育种时间，单倍体培养体系如果作为转基因的受体，可保证外源基因在后代中稳定遗传，而不发生分离。因此，玉米单倍体育种无论在实践中还是在理论研究方面都具有重大的意义。 本文针对玉米花药培养中长期以来未能解决的诱导频率低、基因型之间差异大、小苗移栽不容易成活等问题，重点探讨了各种因素对玉米花药培养的影响。结果表明：不同基因型之间的诱导频率差异明显，杂交种的诱导频率比纯系高，并选择出诱导频率高达20%的材料“中0198”;接种时花药中的花粉处于单核中期时，其诱导频率最高;采用液体培养基比采用固体培养基诱导频率提高一倍;培养基中加入0.5%的活性炭，可使诱导频率由5.25%提高到9.35%;15%的蔗糖浓度对玉米的花药培养是最适宜的，培养2周后，将培养基的蔗糖浓度从15%调整为10%，将明显提高诱导频率;培养基中高浓度的KT和低浓度的BA有利于诱导体细胞胚的发生，而低浓度的KT和高浓度的BA有利于诱导芽的发生;接种前将花药在4℃条件下进行低温预处理，可将诱导频率从3.13%提高到11.71%;培养基中添加2 mg/l的多效唑，可有效地促进小苗的生根;再生植株于冬季拿到海南种植，可明显提高移栽的成活率。 在玉米孤雌生殖的实验中，将未受粉的玉米雌穗接种在成份为N6 + 2,4-D 1mg/L + NAA 1mg/L + BA 1mg/L + CH 200mg/L + colchicine 2 mg/L + sucrose 5% + agar 0.7% 的培养基上。第一轮实验共接种了三个材料的26个雌穗（约3900个未受精的子房）。每种材料均有单性结实，诱导频率由高到低分别3.06%，2.29%，1.90%。直接获得了5株再生植株，通过染色体检查，发现其中3株为单倍体（n=10），另外2株为二倍体。移栽到土壤中后，有4株成活，其中一株二倍体植株能够正常开花、结实。得到的种子播种于实验田中，表现整齐一致，有纯系的特征，而且出现了2株白化苗。通过石蜡切片初步观察了孤雌生殖的胚胎发生过程，发现胚胎发生是从胚囊里的单倍体细胞起源的。第二、三轮实验又接种了10个基因型的玉米材料，证实了上述结果。 外源基因转导是利用生物技术进行玉米育种的一个有效途径。本文首次尝试了用离体子房注射法对玉米进行基因转化。首先构建了含有开花促进因子基因FPF1及植物选择标记抗除草剂基因pat的植物表达载体pFBR，采用离体注射培养法，取授粉24小时后的玉米雌穗，剥去苞叶，在超净工作台进行微量注射，然后切成小块接种在培养基上，在光照培养箱内培养，3-4周可直接获得种子或小植株。种子萌发后进行植株抗性筛选和分子检测，共注射了3个品种的47个雌穗（约16450个子房）得到再生植株109株，其中经PPT筛选有抗性的植株为23株，占再生植株的21.1%。经PCR检测，13株植株有阳性反应。但Southern杂交检测有杂带出现。出现杂带的原因、RNA水平的分子检测、转基因后代T1代的分子检测和早开花农艺性状的观察，由于时间关系没有完成，还需要进一步的实验。实验初步证明了离体子房注射法对玉米进行基因转化的可行性，而且与田间注射法相比，此方法具有省力省时，容易控制污染，转化效率提高的优点, 克服了玉米培养再生植株受基因型限制的困境, 将为玉米分子育种的基因工程提供更易行的手段。 同时，也为子房较大的其它植物的基因转化提供了方法。

Atmospheric carbon dioxide and the climatic record

This paper is an attempt to provide a summary review of conclusions from previous studies on this subject. They have been organized under the following subject headings: Conceptualization of the greenhouse effect; The climatic effect of doubled carbon dioxide; Interpretation of the climatic record; Diagnosis of apparent and possible model deficiencies; The paleoclimatic record.

CO2倍增对紫花苜蓿的生态生理作用及模型

本论文是国家自然科学基金重大项目“中国陆地生态系统对全球变化的反应模式研究”下子项目“对全球变化反应植物生态生理学的基础模型研究”中的重要部分。 本文研究了紫花苜蓿(Medicago Sativa L．)在C02倍增下光合作用、蒸腾作用、气孔导度、叶面积、物候进程、高度、以及生物量的生态生理变化，并在此基础上对苜蓿进行了生态生理模型化的研究。 在倍增(694ppm)和对照(375ppm) C02浓度下，对紫花苜蓿的生态生理学的研究表明，以整个生育期计，倍增组的表观光合作用比对照组可提高18.7%：气孔导度略有下降(2%);蒸腾作用减少了2.7%;水分利用效率提高了30.1%;叶面积增加了48.9%;每株植物白天的净光合总量可提高76.7%，另外，植株高度和整株生物量的测定也显示了C02增加对苜蓿的正效应。 本文还对生理指标的实测数据进行了模型化的研究。对光合作用模型和气孔导度模型中参数的拟合结果表明，C02倍增下，苜蓿的光能转化效率(α)，电子传递速率(Jmax)比对照组都有明显的提高，最大气孔开度(Gsmax)略有下降．

植物个体的生理生态动力学模型

GCTE（全球变化和陆地生态系统），作为IGBP的核心计划之一，其目的是研究陆地生态系统与全球气候变化及人类社会经济和土地利用改变之间相互作用的耦合机理关系，预测生态系统结构、功能的未来变化。其中，植物个体水平的生理生态学模型研究是GCTE中必不可少的重要环节，它不仅可以揭示植物在个体水平上对全球变化的动态响应机制，而且可通过揭示大尺度响应所隐含的微观生物学机理，为大尺度研究提供重要的生理学参数和规律，在全球变化各尺度研究中发挥着不可替代的作用。本文主要围绕植物个体的生理生态学模型开展了如下研究：在开顶式气室CO2倍增大豆生长实验基础上，建立描述植物主要生理过程的生理生态模型，分析植物个体的光合作用、气孔传导度、蒸腾作用以及水分利用效率在全球场变化下的动态响应机制;在此基础上，建立起以统计性天气模型驱动的植物个体生长发育系统动力学模型，通过敏感度分析探讨植物个体的生理生态特性，如光合、呼吸、绿色及非绿色生物量等，对全球变化，特别是对CO2增加，气温升高及降水改变共同作用的响应机制;针对固氮植物的特点，将前一模型发展成为基于共生固氮和同化过程相互作用机制的植物个体生理生态系统动力学模型，模拟不同CO2浓度、气候变化以及固氮与不固氮条件下植物个体生物量的动态响应，并分析CO2浓度、气候条件和是否具固氮能力在对植物生长发育影响方面的相互作用;以中间锦鸡儿为研究材料进行水分控制实验，观测水分对植物同化物分配等过程的影响;将水分利用效率模型应用到NECT样带的主要植物种，得出各植物种的描述其水分利用效率特性的参数，结合样带上各植被类型的结构特征，得到沿样带各植被类型在植物种类组成方面的水分利用效率参数;应用系统聚类分析、因子分析等多元统计方法对样带上锡林河流域122种植物的化学成分与植物类群和所处生境的关系进行了定量分析。结果表明： 1）CO2倍增情况下，净光合速率提高45%，其中光量子效率显著增加，而CO2传导系数略有下降;气孔传导度、蒸腾速率下降约30%;水分利用效率随CO2浓度增加几乎呈线性增长，倍增后提高近一倍。（当气温，水分适宜，光合有效辐射为1000μmol photons m-2 s-1); 2）在北京地区仅CO2倍增而气候条件维持现状的情况下可导致大豆总生物量峰值提高70%，绿色部分提高56%，其中，全生育期内总净光合量增加，而单位干重的暗呼吸速率下降;由于受同化物分配中物候因素的影响，绿色生物量比总生物量提前10日左右到达其峰值。 3）CO2浓度增加和具固氮能力在模拟范围内对植物生长均产生正效应;而在水分为植物生长限制因子的干旱半干旱地区，降水增加对植物生长产生正效应，气温升高则具负效应; 4）随着C供给条件的好转，具固氮能力对植物生长的影响增强;反之随植物吸收N能力的提高，C供给对植物生长的作用加剧。 5）气温、降水在对植物生长发育影响方面，随着一方条件的好转，另一方对植物生长产生的效应增强; 6）具固氮能力对植物生长的正效应随气候条件的好转而增强，气候变化对植物生长的影响随植物具备了固氮能力而加剧; 7）气候条件越恶劣，如在此半干旱区变得更为干旱，CO2浓度增加对植物生长的正效应越加显著;且随CO2浓度的增加，气候因子的效应逐渐减弱。这主要是因CO2增加提高了植物个体的水分利用效率，从而使得CO2的正效应在水分胁迫下更为明显;同时由于水分利用效率的提高，使得植物个体抵御和适应外界环境变化，特别是由气温、降水改变导致的水分条件变化，的能力得到增强。 8）锦鸡儿水分生理生态实验的初步结果表明，土壤水分状况影响着植物的同化物分配，随着水分胁迫的加剧，同化物分配向根部集中，植物的根冠比增加。 9）沿样带水分递减梯度，植被类型在植物种类组成方面的反映水分利用效率特性的参数kv逐渐增加，从而显示出随着水分条件的不足，植被类型中耐旱品种，尤其是C4种增加;人为活动干扰，主要是对草场等的过度利用而导致的盐渍化、沙化，使得退化了的植被类型中k_v值显著提高，表明原有的植物种逐渐被耐旱、耐盐碱的品种，特别是C4植物所代替;在样带动上，这种由于人为活动干扰所引起的植被类型在植物种类组成方面反映水分利用效率特性的参数kv的变化明显大于因样带水分梯度改变而带来的变化。 10）锡林河流域草原植物化学成分一方面与植物类群有关，受自身历史演化的决定，另一方面更受到所处生境条件的极度大影响和制约。其中，禾本科、豆科植物分别具有明显的化学成分特征;撂荒地群落与自然群落中植物、沙质与非沙质生境中植物化学成分差异较显著;因子分析中认为存在大量元素与微量元素两个公共因子，豆科与禾本科相比，豆科植物因其固氮能力，所含大量元素水平较高，而禾本科植物因细胞壁硅质化，含微量元素稍高;沙质生境因其养分贫瘠，植物的大量与微量元素均较非沙质生境中的低;特别是本区地带性土壤-栗钙土与特异性生境沙带中的疏林沙土相比，疏林沙土上植物大量与微量元素含量较栗钙土区植物明显偏低。

植物根系、根区微生物对大气CO2浓度倍增的反应及其生态学意

预测下世纪中叶，大气CO_2浓度将高到目前的两倍（即达到700μ1•1~(-1)）。CO_2倍增对植物地上部的影响已经有了较多的研究，胆是由于方法学上的困难，至今关于倍增CO_2对植物根及根区微生物的研究仍是非常匮乏。本文应用国际上最新的根研究方法，以根系为中心，研究开顶式CO_2C熏蒸培养室中，CO_2倍增条件下根系与地上部，根系与根区微生物[共生的泡囊－丛枝菌根（VAM）真菌，非共生的土壤微生物]的关系。 1. CO_2倍增对根系的影响目前CO_2倍增对根系影响的研究多集中在根生物量的测定，或根／冠比值的测定，而善于其它参数如根长度则很少涉及，而根表面的反应目前还未见文献报道。本实验以幼苗期小麦“青323”（Triticum aestivum）、水稻“中作 29”(Oryza sativa)、大豆“科农4号”（Glycine max）、玉米“农大3138”（Zea mays）、甜高粱“M－81E”（Sorghum saccharatum）为材料，研究CO_2倍增对植物生物量的影响，发现CO_2倍增使C_3植物水稻、大豆的地上部、根系干重均显著增加，使小麦的根系干重显著增加，地上部无显著差异;C_4植物玉米和甜高粱的地上部和根系均没有显著反应。植物干重反应资料表明在光合产物的分配方面，C_3和C_4植物之间存在巨大的差异。 为了解根系获取土壤资源的能力的变化，我们对根系总长度和总表面积进行了分析。用样格交叉法研究根系长度的变化，结果显示，幼苗期的小麦、大豆的根系长度均被显著促进，尤其值得注意的是，尽管玉米根系干重没有显著改变，但是根长度已发生显著变化。同时应用研究根系表面积的最新方法－Na NO_2吸附法，研究发现幼苗期小麦、水稻和大豆的根系表面积在CO_2倍增条件下均显著增加，C_4植物玉米的根表面积亦有显著增加，但甜高粱的根表面积却没有显著反应，这说明即使在C_4植物类型中，根系表面积的反应在不同物种间仍存在很大差异。由于根长度和根表面积增幅大于根干重的增幅，所以推断在CO_2倍增条件下，植物根系细根比例增加，这有利于植物获取更多的养分。由于不同植物之间根系的反应不同，这将改变群落中原有的根系竞争关系，从而影响群落中物种的组成。 2. CO_2倍增对VAM真菌侵染强度和活力的影响本文应用NBT染色法，并结合浸染强度等级和活力等级标准，首次对CO_2倍增条件下，植物VAM真菌的侵染强度和活力的变化进行了检测。对比常规的酸性品红乳酸甘油法和NBT法，发现两者在显示侵染强度时元显著差异，但后者能同时用于侵染活力等级的研究。对幼苗期大豆以及不同生长期的小麦和玉米根系VAM真菌的侵染强度和活力进行观测，结果显示，倍增CO_2对大豆的侵染强度和活力均没有显著效应;使幼苗期玉米的侵染强度显著增加，但侵染活力无显著差异，但随生长期的推移，侵染强度所受的CO_2倍增效应逐渐减小，与14天苗龄（DAP）和35DAP相比，侵染活力在22DAP时所受效应最大;使10DAP小麦的VAM侵染强度和活力均显著增加，而且这种效应在30DAP小麦中的表现与10DAP小麦的相同。说明C_3、C_4植物中，菌根真菌对CO_2倍增反应不同，这也许是C_3、C_4植物对CO_2倍增反应不同的原因之一。倍增CO_2改善了VAM真菌的发育，所以较之于非菌根侵染植物，菌根侵染植物将因为CO_2倍增而获益更多，另一方面不同种植物中，VAM真菌的发育反应不同，这将使植物群落中，根系获取无机营养的竞争能力发生变化，最终影响植物群落的物种丰度和生物多样性以及群落的演替。 3. CO_2倍增对非共生土壤微生物的影响CO_2倍增使生长70天的小麦、垂柳（Salix babylonica）、藜(Chenopodium album)、繁穗苋（Amaranthus cruentus）品种“红苋K112”的地上部和根系的生物量增加。以这些植物所在土壤为材料，用氯仿熏蒸直接提取法研究土壤微生物生物量C（C_(mic)）和生物量N（N_(mic)）的变化，发现CO_2倍增尽管使各类型植物的C_4植物）土壤中C_(mic)的变化趋势不完全相同（小麦和藜所在土壤的C_(mic)下降，垂柳中C_(mic)升高，而在繁穗苋中无显著差异），但N_(mic)在各物种所在土壤中均有不同程度的上升，在繁穗苋中增幅最大。C_(mic):N_(mic)比值在4个物种所在土壤中均明显下降，这意味着CO_2倍增后在植物生长后期，土壤微生物活性提高，分解植物凋落物和土壤中其它有机质的能力加强，从而改善贫瘠土壤中有机质质量。 4.CO_2倍增对植物呼吸和光合作用及C素积累的影响 1）CO_2倍增对植物暗呼吸的影响：以杜仲（Eucommia ulmoides）、紫花苜蓿(Medicago sativa)和玉米等10种植物的离体成熟叶片或整株为材料，研究不同测定温度（15～35 ℃）下，CO_2倍增对植物暗呼吸的影响。结果表明：在较低温度（15 ℃、20 ℃）下，CO_2倍增对植物暗呼吸没有显著效应;在较高温度（30 ℃、35 ℃）时，多数被测植物的暗呼吸显著增强。由于植物在不同温度时它们的暗咱吸受CO_2倍增的促进幅度不同，这将导致不同地区（环境温度不同）的植物暗呼吸反应有差异，而且由于不同物种的暗呼吸增幅不同，综合光合效应，它们的生物量的反应也会不同。 2）CO_2倍增对整株植物的CO_2气体交换及植物C素积累的影响：利用自行设计的一套CO_2气体测定装置，首次尝试同步测定CO_2倍增条件下幼苗期小麦地下部和地上部的气体交换在昼夜24小时内的变化及C素的积累。发现CO_2倍增不仅使小麦地上部C素的积累增加，也使地下部释放的C素增加，但整株植物的C素收入仍高于对照两倍多，这从植物与环境的CO_2气体交换角度为CO_2倍增促进植物生物量的增加提供了依据。并首次提出：植物的整体性及植物所在的环境条件（主要是温度和光照强度）决定着植物暗呼吸对CO_2倍增的响应方式：被抑制或无效应。

Tapered bow-tie lasers for high energy Q-switched pulse generation

A new kind of Q switched laser, the bow tie laser is introduced. This type of laser permits large area facets at both ends so that generation of high optical powers involve low optical intensities to prevent optical damage. The incorporation of doubled tapered waveguide structure to the Q switched multicontact laser has increased the optical pulse energies and peak powers of the laser.

Mapping chromosomal homologies between humans and two langurs (Semnopithecus francoisi and S-Phayrei) by chromosome painting

Chromosomal homologies were established between human and two Chinese langurs (Semnopithecus francoisi, 2n=44, and S. phayrei, 2n=44) by chromosome painting with chromosome-specific DNA probes of all human chromosomes except the Y. Both langur species showed identical hybridization patterns in addition to similar G-banding patterns. In total, 23 human chromosome-specific probes detected 30 homologous chromosome segments in a haploid langur genome. Except for human chromosomes 1, 2, 6, 16 and 19 probes, which each gave signals on two non-homologous langur chromosomes respectively, all other probes each hybridized to a single chromosome. The results indicate a high degree of conservation of chromosomal synteny between human and these two Chinese langurs. The human chromosome 2 probe painted the entire euchromatic regions of langur chromosomes 14 and 19. Human chromosome 1 probe hybridized to three regions on langur autosomes, one region on langur chromosome 4 and two regions on langur chromosome 5. Human 19 probe hybridized on the same pattern to one region on chromosome 4 and to two regions on langur chromosome 5, where it alternated with the human chromosome 1 probe. Human 6 and 16 probes both hybridized to one region on each of the two langur autosomes 15 and 18. Only two langur chromosomes (12 and 21) were each labelled by probes specific for two whole human chromosomes (14 and 15 and 21 and 22 respectively). Comparison of the hybridization patterns of human painting probes on these two langurs with the data on other Old World primates suggests that reciprocal and Robertsonian translocations as will as inversions could have occurred since the divergance of human and the langurs from a common ancestor. This comparison also indicates that Asian colobines are karyotypically more closely related to each other that to African colobines.

Proteomic Analysis of Proteins Involved in Spermiogenesis in Mouse

Spermiogenesis is a unique process in mammals during which haploid round spermatids mature into spermatozoa in the testis. Its successful completion is necessary for fertilization and its malfunction is an important cause of male infertility. Here, we report the high-confidence identification of 2116 proteins in mouse haploid germ cells undergoing spermiogenesis: 299 of these were testis-specific and 155 were novel. Analysis of these proteins showed many proteins possibly functioning in unique processes of spermiogenesis. Of the 84 proteins annotated to be involved in vesicle-related events, VAMP4 was shown to be important for acrosome biogenesis by in vivo knockdown experiments. Knockdown of VAMP4 caused defects of acrosomal vesicle fusion and significantly increased head abnormalities in spermatids from testis and sperm from the cauda epididymis. Analysis of chromosomal distribution of the haploid genes showed underrepresentation on the X chromosome and overrepresentation on chromosome 11, which were due to meiotic sex chromosome inactivation and expansion of testis-expressed gene families, respectively. Comparison with transcriptional data showed translational regulation during spermiogenesis. This characterization of proteins involved in spermiogenesis provides an inventory of proteins useful for understanding the mechanisms of male infertility and may provide candidates for drug targets for male contraception and male infertility.

A study on the effect of Zataria multiflora Bioss essential oil and Nisin on the growth of Lactococcus garvieae in the rainbow trout fillet (Oncorhynchus mykiss)

The ever-increasing population of the world and the growing need for animal protein has doubled the modern man’s demand for food. Additionally, the improvement in the general public health, and the worsening of environmental/ecological pollution have prompted today’s world to look for ways to procure healthy food. And one such attempt is the use of natural preservatives to decrease the bacterial load in foodstuffs, in other words, to increase their durability. This study evaluates the effects of different concentrations of Zataria multiflora Bioss (EO 0, 0.005, 0.015, 0.045, 0.135, 0.405%) and Nisin (0, 0.25, 0.5, 0.75 μg/ml) and storage time (9 days) on the growth of Lactococcus garvieae Ir-170A(856bp) alone, and their combination in a food model system (fillets of the rainbow trout (Oncorhynchus mykiss). Additionally, the growth of a sample of this bacteria in laboratory conditions was studied. The results of this study showed that different concentrations of Nisin had a significant impact (p<0.05) on Lactococcus garvieae. With the value of t in 0.75 μg/ml, the effectiveness rose to 65.77%; the biggest effect on Lactococcus garvieae. And the effect at 4 0C exceeded 80C. The study has also demonstrated that all concentrations of Zataria multiflora Bioss were effective against Lactococcus garvieae. However, with the value of t at 0.405%, the effectiveness was 71.91%. This value had the biggest effect on Lactococcus garvieae. At 4 0C, the effect surpassed the one at 80C. The synergistic effects of the EO and Nisin showed that with the value of t at 0.405% EO and 0.75 μg/ml Nisin was 14.62% had the greatest effect on Lactococcus garvieae. In this study, multi-factorial effects for different concentrations of Zataria multiflora Bioss (EO 0, 0.005, 0.015, 0.0025%), three different concentrations of 122 Nisin (0, 0.25,0.75 μg/ml) and two different levels of PH (5.5 , 7) at two incubation temperatures (15,37) on logp% of Lactococcus garvieae during 43 days in BHI broth were evaluated. Most of the effects on Lactococcus garvieae occurred in PH 5.5 and at a temperature of 150C.

Epigenetic remodeling of meiotic crossover frequency in Arabidopsis thaliana DNA methyltransferase mutants.

Meiosis is a specialized eukaryotic cell division that generates haploid gametes required for sexual reproduction. During meiosis, homologous chromosomes pair and undergo reciprocal genetic exchange, termed crossover (CO). Meiotic CO frequency varies along the physical length of chromosomes and is determined by hierarchical mechanisms, including epigenetic organization, for example methylation of the DNA and histones. Here we investigate the role of DNA methylation in determining patterns of CO frequency along Arabidopsis thaliana chromosomes. In A. thaliana the pericentromeric regions are repetitive, densely DNA methylated, and suppressed for both RNA polymerase-II transcription and CO frequency. DNA hypomethylated methyltransferase1 (met1) mutants show transcriptional reactivation of repetitive sequences in the pericentromeres, which we demonstrate is coupled to extensive remodeling of CO frequency. We observe elevated centromere-proximal COs in met1, coincident with pericentromeric decreases and distal increases. Importantly, total numbers of CO events are similar between wild type and met1, suggesting a role for interference and homeostasis in CO remodeling. To understand recombination distributions at a finer scale we generated CO frequency maps close to the telomere of chromosome 3 in wild type and demonstrate an elevated recombination topology in met1. Using a pollen-typing strategy we have identified an intergenic nucleosome-free CO hotspot 3a, and we demonstrate that it undergoes increased recombination activity in met1. We hypothesize that modulation of 3a activity is caused by CO remodeling driven by elevated centromeric COs. These data demonstrate how regional epigenetic organization can pattern recombination frequency along eukaryotic chromosomes.