世界湿地松引种经营之现状——兼谈我国的对策

本文综述了世界各国引种湿地松及其人工林经营的概况,总结了近十多年来人工林发展缓慢的原因,探讨分析了我国已出现或将面临的一些问题,并提出相应的对策。     

关于我国林业科研体系的探讨

我国林业科研管理宏观失控是造成研究方向任务不明、课题重复、力量分散的主要原因。文章借鉴国外经验,结合国情,提出了以间接调控为主的观点。即通过规划、课题、情报信息实行间接调控;强调区域性研究,将中国划分为东北地区、南方山地丘陵区、西南高山区、华北中原农用林区和西北干旱半干旱区等5个大区。对西北区提出建立以甘肃为研究中心的构想。此外,本文还提出了各级林业研究单位的方向和任务。特别提及中国林科院应在学科、机构、信息网络和宏观决策等方面加强建设。     

建设木材培育基地是扭转我国森林资源危机的关键措施——兼议三亿美元

作者通过剖析国外解决用材资源短缺经验,总结我国林业发展的教训,提出为尽快扭转我国森林资源危机,必须走建设"木材培育基地"的道路。对建设速生丰产林的3亿美元世行贷款,主张各省要相对集中地使用这笔资金,尽速建成一批优质高产的用材林。     

南亚东南亚地区的自然保护

1962-1983年间,该地区自然保护区从96个增加到292个。印度1984年国家公园和野生动物保护区数量达275个,面积1000万公顷,占国土面积3%;泰国国家公园和野生动物保护区面积518万公顷,占国土面积10%。孟加拉国、尼泊尔不丹、巴基斯坦、越南的自然保护工作面临很大困难。介绍了南亚和东南亚地区自然保护的目标措施和存在的问题。     

新西兰人工林的发展

新西兰造林事业始于1898年,历史上曾出现两次造林高潮。新西兰现有人工林总面积为1 133 022公顷,其中90%为辐射松。新西兰人工林的主要特点是:(1)几乎全部由外来树种组成;(2)人工林的生产周期较长,25-35年,经营强度高;(3)政府大量投资营建人工林;(4)政府采取各种方针和政策刺激和鼓励私营公司和个体农场主营建人工林;(5)人工林已经发展成为独立的产业,与其它产业部门一样,具有商业性的竞争能力。     

全球气候变暖与热带林业的对策

本文介绍了全球热带林消失率、温室气体的释放量及它在整个环境污染中所占比例。作者在国际研讨会上提出,最合理的解决方案是控制人口、发展经济、合理而有效地利用森林资源。     

Assignment of new loci to river buffalo chromosomes confirms the nature of chromosomes 4 and 5

Introduction Rapid development of the river buffalo physical map can be achieved by coupling its development to that of the cattle gene map. Syntenic conservation between cattle and buffalo has been demonstrated, mainly using somatic cell hybrids (de Hondt et al. 1991; El Nahas et al. 1993, 1996, 1998; de Hondt et al. 1997; El Nahta 1996; Oraby et al. 1977), and by using in situ hybridization as reviewed by Iannuzzi (1997). G- and R-banding comparisons between cattle (2n = 60) and river buffalo (2n = 50) chromosomes have revealed a large number of banding homologies between the two species, both at early-metaphase (Gupta and Ray -Chaudhury 1978; Di Berardino et al. 1981) and prometaphase stages (Iannuzzi et al. 1990). Banding homology indicates that the five river buffalo biarmed pairs originate from centric fusion translocation between two of ten homologous cattle autosomes, which is very supportive of the hypothesis that both species have a common ancestor (Wurster and Benirschke 1968). Based on cytological analysis and banding homology between cattle and buffalo chromosomes, the five biarmed chromosomes of the river buffalo BBU1, BBU2, BBU3, BBU4, BBU5 were thought to originate from fusion of cattle chromosome (BTA) 1/25; 2/23; 8/19; 5/28; and 16/29 respectively (Iannuzzi et al. 1990; Report of the Committee for the Standardization of Banded Karyotopes of the River Buffalo 1994). However, the analysis of synteny between molecular markers assigned to different cattle syntenic groups demonstrated that BBU1 results from fusion of BTA 1 and 27 rather than 1 and 25 (El Nahas et al. 1977). This called for expanding the analysis of syntenic relationships between marker loci to confirm the nature of the other biarmed buffalo chromosomes. The purpose of this study is to test synteny between markers in buffalo and to confirm the nature of the biarmed buffalo chromosomes 4 and 5, using marker loci and somatic cell hybrids.     

Synaptonemal complex investigations on lamas (Lama glama) with differing fertility recordings

The present study involved three male lamas ( Lama glama ). Mitotic preparations from fibroblast culture and an electron microscopic observation on the synaptonemal complexes (Scs) were reported. Special attention was given to the morphology and behaviour of the chromosomes at the zygotene and pachytene substages of prophase I in primary spermatocytes from lamas. Analysis of mitotic preparations show diploid and triploid cells, with a relatively high frequency of polyploidy. Analyses of synaptonemal complexes in primary spermatocytes were carried out on 89 cells. Pairing abnormalities were only recorded in an average of 63% of the cells of the animal Tabasco. The other two animals were normal. The photographed cells give an upper limit estimate of the existing abnormalities, as there was a deliberate tendency towards selecting abnormal cells for photography. The presence of degenerating primary spermatocytes in SC preparations as well as in testicular sections, and the absence of spermatozoa in ejaculates confirm the chromosomally derived male sterility of one animal.     

Homology of DNA sequences encompassing malignant hyperthermia mutation site in the ovine (Ovis aries) and porcine (Sus scrofa) ryr1 gene

The PCR products of ryr1 gene amplified from genomic DNA of Sus scrofa and synthetic prolific lines of Ovis aries were analysed. The polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP), and sequencing analysis for research on ovine, ryanodine receptor ( ryr1 ) gene. The ovine fragment of ryr1 gene did not differ from exon 17 of the porcine ryr1 gene.     

Assortative mating and other observations based upon the relationship between true and apparent breeding values in the Australian thoroughbred

Studies of heritability in thoroughbred populations are confounded somewhat by the presence of assortative mating. Although assortative mating itself will not make great changes to the magnitude of the assessment of heritability, it can exert a significant impact upon the accuracy of any conclusions made from the study. In order to remove the effects of assortative mating from the data available, use was made of the best linear unbiased predictor (BLUP) method. This procedure was followed using two combinations: sire and dam, and sire and damsire. Due to the size of the datasets it was not possible to directly solve the matrices produced; instead they were solved by approximation over fifty iterations.