哥斯达黎加农产品对外贸易问题研究

农业是哥斯达黎加三大支柱产业之一.哥斯达黎加农业以生产热带作物为主,主要产品有热带水果、咖啡、蔗糖、乳产品等.哥斯达黎加是农产品净出口国,农产品出口额占总出口额的比例较大.哥斯达黎加在自由贸易区农业谈判中注重维护农业利益.中国在与哥斯达黎加自由贸易区农业谈判中应争取温带水果等优势农产品出口利益.     

哥斯达黎加海域茎柔鱼角质颚稳定同位素研究

头足类的角质颚具有结构单一和不易腐蚀的特性,其稳定同位素分析已成为头足类生态学研究的主要方法之一。根据2009年7-8月我国鱿钓船在哥斯达黎加外海捕捞的茎柔鱼样本,对其角质颚进行稳定同位素分析,探讨其与胴长、日龄、性腺成熟度等之间的关系。结果表明,茎柔鱼样本的胴长范围在25.6～35.8 cm之间,体重范围在447.6～1 122.3 g之间,为小型群体;上、下角质颚的δ13C和δ15 N有所差别,但无显著性差异（P〉0.05）;δ13C和δ15N值随着胴长和日龄的增大而增大,两者均符合线性关系;不同性成熟度的个体也有着不同的δ13C和δ15 N值,其中性成熟度为Ⅲ期个体的值最大。δ13C和δ15N值反应出茎柔鱼在生长过程中,其栖息环境从大陆架向大洋转变,活动范围也向着生产力更高的海域聚集,同时与性成熟和个体生长过程密切相关。建议今后应结合研究海域的浮游生物,对角质颚等不同硬组织及其不同部位稳定同位素进行深入分析,以便为了解和掌握茎柔鱼的生态学提供理论参考。     

哥斯达黎加畜牧业发展现状及趋势

哥斯达黎加是中美洲经济发展水平较高的国家,其畜牧业是农业的主要产业之一,文章就哥斯达黎加畜牧业发展的历史及其现状、优势和存在问题进行了研究,同时对哥斯达黎加畜产品外贸出口的规模和结构进行了分析．为中国与哥斯达黎加畜牧业进行合作提供借鉴。     

Assessment of Non-chemical Alternatives for Controlling the Burrowing Nematode on Banana in Costa Rica

The objective of this study was to technically and economically assess the effect of biopesticides on the serious plant parasitic nematode Radopholus similis on banana in Costa Rica. The following treatments were evaluated： a mixture of nematode trapping fungi-Arthrobotrys oligospora, A. botryospora, Dactylella brochophaga and Drechmeria coniospora; DiTera DF which consist of a ＂dead＂ fungus Myrothecium spp. and its fermentation substrate; Savitan produced from desert plant extracts; QL Agri which contain Quillaja saponaria extracts; Japanese-style compost called Bokashi; two application of a chemical nematicide; and an absolute control. Results of root sampling on a six month basis showed that the biopesticides had lower nematode population densities than the control with the nematode trapping-fungi having statistically significant differences over the other treatments. Chemical control was highly effective and produced the lowest nematode density. However, there were no significant differences between the chemical treatment and the trapping-fungi treatment. The functional root weight and bunch weight showed no significant differences between treatments. Conversely, economic analyses indicated that using nematode trapping-fungi, chemical nematieide, or the QL Agri treatments gave a detectable profit. The land expectation value （LEV） of the banana plantation was higher than the price of banana land which indicated that under normal conditions in the banana sector, production is economically sustainable / profitable. Other results confirm that profit in banana production is affected by the price of a banana box, production and discount rate. The optimal production cycle was obtained in year ten after farm establishment, which refers to the year with the highest profit following plantation renewal. Finally, economical results highlighted the importance of nematodes control, since profitability indexes were sensitive to the efficiency and cost of nematode management technology adopted by the banana company.     

Use of Trichoderma spp. on soil microbiology improvement for organic agriculture in Costa Rica

The soil is a complex system where processes have direct influence on crop nutrition and plant health. Unfortunately, most of the agricultural soil management practices, compact them producing poor oxygenation, low benefic microorganism populations and metabolic disorders in plants. Those factors induce abnormal plant development and predisposition to the attack of soil borne plant pathogens as: Sclerotium cepivorum, Sclerotium rolfsi, Sclerotinia sclerotiorum, Rhizoctonia solani, Rosellin…     

Influence of Siphonophore Behavior upon Their Natural Diets: Evidence for Aggressive Mimicry

Collection by divers permitted determination of the natural diets of siphonophore species within II genera. Siphonophores that swim rapidly to spread their tentacles capture small prey, whereas those that swim very weakly capture much larger prey. Nematocyst batteries of two species of weak swimmers closely resemble copepods and fish larvae. Morphology, behavior, and diet suggest that these two species attract large prey by mimicking other zooplankton.     

哥斯达黎加外海茎柔鱼生物学特性初步研究

根据2009年7-8月在哥斯达黎加外海探捕期间采集的281尾茎柔鱼样本,对其生物学特性进行初步分析。结果表明：茎柔鱼样本胴长范围为205~429 mm,优势胴长为260~360 mm,占81.14%;体重范围为0.17~1.69 kg,优势体重为0.2~1.0 kg,占88.26%;雌雄性比约为3.76∶1,性腺成熟度以Ⅲ和Ⅳ期为主,雄性、雌性性成熟的比例分别为94.92%和66.67%;摄食等级以0~1级为主,占89.32%。体重与胴长关系W=2.35×10^-7L_M^2.5944。相对于加利福尼亚湾、秘鲁和智利外海的茎柔鱼,哥斯达黎加外海茎柔鱼个体较小且体型偏瘦,属于小型或中型群体。     

Preferential Mating versus Mimicry: Disruptive Selection and Sex-limited Dimorphism in Papilio glaucus

Spermatophore counts in wild females of Papilio glaucus show that the monomorphic nonmimetic male mates less frequently with the mimetic female morph than with the nonmimetic female morph. Female dimorphism in this species cannot be maintained by heterozygous advantage. Mating preference for the nonmimetic female may sufficiently counteract avian predation pressure favoring the mimetic female to account for the maintenance of the nonmimetic morph in the population in those areas in which the model is abundant and to account for the reduction in frequency or elimination of the mimetic morph in those areas in which the model is less numerous or absent.     

哥斯达黎加外海茎柔鱼个体与耳石间生长关系研究

根据2009年7-8月哥斯达黎加外海采集的茎柔鱼样本,利用多种统计方法分析了茎柔鱼耳石与个体生长之间的关系。研究认为,耳石各形态参数与胴长(ML)关系显著(P<0.01),其中背侧区间长(DDL)、耳石总长(TSL)与其相关性最大。耳石生长存在两个阶段,当ML小于26～30 cm时,其耳石生长迅速,之后耳石生长减慢。在生长过程中,耳石背区长(DL)、吻区内长(RIL)、DDL生长快于TSL,背侧区夹角(DDA)、吻侧区夹角(RDA)、吻区夹角(RA)则随着ML的增大出现减小趋势,侧区、吻区形态变化显著(P<0.05)。耳石形态先于生长速度发生显著性变化,同时各形态参量发生显著性变化时间不同,但形态特征变化主要发生在ML为23～29 cm个体中,之后趋于稳定。耳石生长及形态显著性变化与茎柔鱼栖息水层改变相关,茎柔鱼与中上层头足类耳石特征相符。     

秸秆自然降解过程中优势菌群的筛选

[目的]筛选降解秸秆的优势菌。[方法]通过室内试验模拟秸秆在土壤中的状态,观测不同时期秸秆上微生物的变化及不同土层中碱解氮和总糖含量的变化。[结果]秸秆降解40d时,优势菌中真菌所占比例较大,降解60d时,细菌优势菌所占比例较大,其中菌株j-15、14和木霉12的数量占优势;第2层土壤中细菌数量最多,其次为第3和第6层,表层和底层土壤中细菌数量最少;表层土壤中真菌种类较多,第2和第3层土壤中木霉占绝对优势,其他菌层以毛霉为主。[结论]第3层土壤中优势菌较多,碱解氮和总糖含量最高;分离出的细菌以球菌为主,真菌以木霉为主。     

左家自然保护区立体干燥花素材筛选

本试验采用自然干燥、保色干燥和漂白染色干燥的方法,对左家自然保护区56种植物进行立体干燥花素材筛选,结果筛选出38种自然干燥花素材、9种保色干燥花素材和9种漂白染色干燥花素材。利用这些特色优良的素材,通过艺术构思,可以制作出具有较高欣赏价值的干燥花产品。     

含二氧化碳天然气集输管道管材的优选

分析了二氧化碳腐蚀对地面集输管道造成的严重危害,结果表明,分压、温度、流速等是影响二氧化碳腐蚀的重要因素.通过设计研究和现场应用实践,初步获得了二氧化碳酸性天然气田集输管材的优选方法.     

鄂西北红椿天然林优树选择研究

为建立湖北红椿优良种质资源圃,在鄂西北地区红椿种质资源调查的基础上,确定3个环境条件接近的优良天然林分进行优树选择。按3 a和4 a为龄级间隔分组,并对所选候选优树材积进行校正,首选出47株优良候选优树。对生长指标实测计算,设立红椿不同龄级(16~18 a、19~21 a、22~25 a)生长量年平均值和选优基准线。各生长量指标高于年生长量平均值的红椿有19株,高于基准线的单株有15株。对干形、枝下高、冠幅、冠高树高比、分枝角、枝粗细等6个无量纲形质指标进行主成分分析,确立冠幅、干形和分枝角等3个形质评分因子。通过权重计算确立各形质评分值,复选红椿优树10株,入选率为52.63%。基准线法和形质评分结合选优,既确保了红椿生长指标具有较高的平均增益,又有效避免了因过度评分造成优良遗传性状的丢失。     

Natural Variation of Pto and Fen Genes and Marker-Assisted Selection for Resistance to Bacterial Speck in Tomato

The resistance in tomato plants to bacterial speck caused by Pseudomonas syringae pv. tomato is triggered by the interactions between the plant resistance protein Pto and the pathogen avirulence proteins AvrPto or AvrPtoB. Fen is a gene encoding closely related functional protein kinases as the Pto gene. To investigate the status of resistance to the pathogen and natural variation of Pto and Fen genes in tomato, 67 lines including 29 growing in China were subject to disease resistance evaluation and fenthion-sensitivity test. Alleles of Pto and Fen were amplified from genomic DNA of 25 tomato lines using polymerase chain reaction (PCR) and sequences were determined by sequencing the PCR products. The results indicated that none of the 29 cultivars/hybrids growing in China were resistant to bacterial speck race 0 strain DC3000. Seven of eight tomato lines resistant to DC3000 were also fenthion-sensitive. Analysis of deduced amino acid sequences identified three novel residue substitutions between Pto and pto, and one new substitution identified between Fen and fen. A PCR-based marker was developed and successfully used to select plants with resistance to DC3000.     

黄淮海区玉米青枯病的田间自然筛选及接种鉴定

[目的]研究黄淮海区玉米青枯病的田间自然筛选及接种鉴定。[方法]采用试验室接种鉴定及大田自然鉴定的方法,研究25份玉米自交系和61份群体材料对玉米青枯病的抗病表现。[结果]筛选出9份自交系及26份群体材料的抗病等级都在R(抗病)以上。多数种质资源的抗病性集中在3级和5级,为R(抗病)和MR(中抗)材料;未发现有9级(高感)材料。[结论]该研究为玉米青枯病在黄淮海区的防治提供技术参考。     

基于自然选择理论的动物利他行为研究

介绍了学术界关于动物利他行为的一些理论,包括群体选择理论、基因选择理论、亲缘选择理论、互惠利他理论、纯粹利他行为、操纵假说、相互依赖假说以及＂自私的基因＂理论。研究表明,自然选择学说能够很好地解释动物的利他行为,除此之外的其他学说只能用于利他行为的分类,而不能用来解释动物的利他行为。     

Intense Natural Selection in a Population of Darwin's Finches (Geospizinae) in the Galapagos

Survival of Darwin's finches through a drought on Daphne Major Island was nonrandom. Large birds, especially males with large beaks, survived best because they were able to crack the large and hard seeds that predominated in the drought. Selection intensities, calculated by O'Donald's method, are the highest yet recorded for a vertebrate population.