汾河太原段河漫滩草地土壤种子库研究

研究了汾河太原段河漫滩草地土壤种子库的基本特征。结果表明：汾河太原段河漫滩草地土壤种子库有草本植物17种，灌木2种。其中一年生植物15种，占总种数的78．9％，典型的湿地植物14种，占总种数的73．7％，是河漫滩草地土壤种子库的优势成分。平均密度为33033粒／m^2，种平均密度最大为21464粒／m^2，最小为400粒／m^2。种平均密度决定于种的生态特性或结实特性；河漫滩草地土壤种子库的特性受河水动态、土壤水分和质地、人为扰动等因素的影响，在横向上表现为距河流越远种子库密度越大。     

重庆上市公司互保圈现象的会计思考

在市场经济环境下，贷款担保作为上市公司融通资金的一种方式，是企业的一种正常的经营行为。它可以减少交易风险、促进资本市场发展。然而，目前由于种种原因，上市公司互保不仅没有起到化解市场风险的作用，反而加大了证券市场和金融市场的风险，严重扰乱了资本市场的正常运行。因此，本文拟通过思考重庆“互保圈”现象，分析“互保圈”形成的原因及危害，并由此提出相应的对策与建议。     

浅析饲用甜菜的发展前景

从畜牧业的发展作为农民增收和经济发展的重要途径入手，阐述了饲料行业的重要性，论述了饲用甜菜在饲料行业的优势，说明了饲用甜菜在我国畜牧业中的关键性和发展前景．     

基于ERDAS的森林资源遥感信息初步研究

以图像处理系统ＥＲＤＡＳ为基础，以ＴＭ卫星遥感图像和地面森林资源调查数据为材料，讨论了ＥＲ－ＤＡＳ计算机图像处理的有关过程，研究了如何把遥感图像和森林资源调查数据相结合并从中提取相关信息的方法，建立了遥感图像与ＧＩＳ资源数据库之间的对应关系。结果表明，该研究方法正确可行，输出图像精度高，可为森林资源管理工作提供重要的遥感基础信息。     

Evaluation of regeneration potential of Pinus koraiensis in mixed pine-hardwood forests in the Xiao Xing’an Mountains, China

Large scale harvest of Korean pine(Pinus koraiensis) seeds as a food product in the mixed Korean pine-hardwood forest of northeastern China poses a serious threat to the sustainability and restoration of this endangered regional ecosystem.Seed collection over past decades greatly reduced the seed bank and subsequent seedling and sapling recruitment,and impacting a wide array of granivorous animals that rely on the pine seeds.We surveyed Korean pine seeds,including solid seeds(SS),insect consumed seeds(ICS) and other(animal) consumed(OCS) kernels,of the seed bank(forest floor and the top 10 cm of mineral soil),the seedlings and saplings from 1 m 2 sample plots in five forest types in Liangshui Nature Reserve(LNR) of the southern Xiao Xing’an Mountains in northeastern China to provide accurate information for assessing the Korean pine regeneration potential.The average number of pine seeds in the seed bank were 11.2 seeds/m 2,9.1 seeds/m 2,4.6 seeds/m 2,1.1 seeds/m 2,and 0.2 seeds/m 2 in Korean pine-basswood forest,mixed Korean pine-hardwood forest,mixed conifer-hardwood forest,white birch forests,and oak forests,respectively.In the first three forest types,percentages of SS(potentially viable seeds) were 11.2%,3.5% and 27.8%,respectively.The percentages of ICS(not viable seeds) were consistent at around 35%.The higher but variable percentages of OCS(not viable seeds) indicated high seed predation in these forests.Compared with other studies,we recorded higher percentages of seed damage,probably due to our survey approach and the increased depth of seed bank sampled in our study.Depletion of pine seeds in the seed bank greatly reduced seedling and sapling recruitment.Densities of pine seedlings varied from about 180 trees/ha in the mixed Korean pine-hardwood forest to about 5,400 trees/ha in the mixed conifer-hardwood forests and showed a high degree of spatial variation.Saplings were rare in the mixed Korean pine-hardwood forest,but ranged in the thousands in other forests.Large scale pine seed harvest has seriously threatened the sustainability of the mixed Korean pine-hardwood forest ecosystem.Scaling down the seed harvest or supplemental planting of pine saplings are urgently needed to maintain the health of the existing Korean pine forests and to restore this endangered ecosystem.     

红掌种质资源数据库的建立

2003年1月开始陆续从国内外收集112份花烛属种质资源,其中红掌品种104个、火鹤花品种6个、观叶花烛品种2个。2004年3月将其种植于环控温室内资源保存苗床上,建成了国内首个红掌种质资源库。通过栽培观察和性状调查,获得112份花烛属种质资源的定量性状数据43000多个、定性性状数据2000多个,经过整理后利用广东生物种质资源数据管理与分析系统,将112份种质资源的各类信息发布上网,至2004年5月初步建成了国内首个红掌种质资源数据库。     

Analyses on Stability of Saturated-Unsaturated Bank Slope with Revetment During Rise and Fall of River Level

The bank slope failure is closely related to the rise and fall of river level generally. In order to analysis the influence of the rise and fall of river level on Jin’an River bank slope stability in Fuzhou, the saturated-unsaturated seepage of bank slope with revetment was modelled based on the engineering geological condition of some bank of Jin’an River, and the effect of rise and fall of river induced by the DRWWOS(Drawing River Water to Wash Out Sewage) project on bank slope stability was studied. The results show the silt lying on the slope toe impedes pore water change, manifesting as in its sphere of influence river water is hard to flow into the bank when river rises, and the pore water pressure can not dissipate in time when drawdown. The faster the river rises, the more stable the bank slope becomes. On the contrary, the larger river level falling rate is more likely to leads to bank slope failure. Due to the poor bank drainage performance, the frequent rise and fall of river level results in pore water pressure increasing further, then impairing the bank slope stability. During DRWWOS project, the river level falling rate control and pore water pressure dissipation must be paid enough attention to. Also, replacing silt lying on the slope toe by good permeable material is a good choice to reinforce the bank slope.     

Belangrike ongewingsfaktore wat die natuurlike verspreiding van schmidtia kalahariensis stent en enneapogon cenchroides (licht) c. e. hubbard (e. mollis lehm) in Suidwes‐Afrika beïnvloed 1

Die resultate van ‘n studie van die reaksie van twee belangrike eenjarige weidingsgrasse van Suidwes‐Afrika, Schmidtia kalahariensis en Enneapogon cenchroides, teenoor verskillende omgewingsfaktore word gerapporteer. Verskille tussen die twee spesies ten opsigte van ligenergievereistes, lengte van die lewensiklus, voedingsbehoeftes, smaaklikheid (veroorsaak deur suurafskeidmg) en ontkiemingseienskappe is uitgewys. Dit is moontlik om hierdie verskille in verband te bring met die natuurlike verspreiding van die twee spesies.     

The histology of dermal glands of mating Breviceps with comments on their possible functional value in microhylids (Amphibia: Anura)

During mating male and female Breviceps become ‘glued’ together. The distribution of multicellular dermal glands varies between the sexes. The mate has a large number of holocrine glands on the ventrum, while the female has similar glands on the dorsum of the back. II thus appears that both sexes contribute to the ‘glueing’ mechanism. New hypotheses to explain the adhesion between the sexes are proposed, viz., that the shift to terrestrial habils and subterranean laying in Breviceps have secondarily resulted in male si2e diminution. In other microhylids which adhere during aquatic oviposition, yet demonstrate a terrestrial morphology and habits, bouyancy is suggested to be of primary functional value.     

西藏林芝高山松土壤种子库空间分布特征研究

通过研究西藏林芝高山松土壤种子库的空间分布特征,可以深入了解当地高山松林地土壤中种子数量的分布情况,以及高山松种子的质量状况,有助于高山松林的可持续发展。选取林芝附近有大面积高山松林分布的东久乡东久桥样地、林芝镇林芝桥样地以及八一镇比日神山样地为研究对象,采用野外采样、室内试验和数据分析相结合的方法,探讨高山松土壤种子库的空间分布格局。结果表明,高山松土壤种子库中的种子数量在水平方向上的差异不显著,种子数量随着与母树距离的增加而逐渐减少,表现出近母树分布的趋向。在不同土层深度中,高山松土壤种子库中的种子数量差异显著(P=0.01),随土层深度的增加而逐渐减少,并且单因素分析发现海拔对高山松土壤种子库中种子数量的变化影响不大。土壤种子库中有活力种子仅占种子总量的1.05%,其中72.44%的有活力种子集中在枯落物层;虫蛀种子所占比例最高,占总量的47.41%,败育种子占种子总量的12.32%,腐败种子所占比例最小,为3.02%,可见种子丧失活力的首要原因是被啮齿类动物或鸟类的取食。地表枯落物层是种子进入土壤的一大阻碍,及时扰动地表枯落物有助于高山松种子进入土壤和萌发。