三叶青的研究进展

三叶青是我国特有的珍稀药用植物,自发现具有抗肿瘤作用以来,价格不断攀升,对三叶青的研究逐渐增多.本文就三叶青在开发利用价值、种质资源、种苗繁育、栽培技术等方面进行综述,并探讨了今后的研究方向,为三叶青的开发利用提供参考.     

黑老虎的研究进展

黑老虎是一种历史悠久的民间用药,也是近年来发展林下经济的一种药食两用水果,具有极大的开发利用价值.现就近30年来黑老虎在生物学特性、资源现状、开发利用价值及栽培繁育等方面进行综述,并对其发展趋势进行了分析,为黑老虎的研究、开发与利用、为林下经济的发展提供依据.     

青风藤药用成分、药理作用及栽培繁育研究进展

青风藤是一种具有较高临床药用价值的传统中药,随着风湿和类风湿病发病率不断上升,近年来,越来越多的国内外学者开始对该植物进行关注.青风藤药理活性成分明确,分析方法成熟,人们开始更多的关注其药理作用、临床应用等.该文概述了近年来国内外对青风藤药理成分、药理作用、栽培繁育等方面的研究进展,为该植物进一步的研究与开发提供依据.     

环青海湖地区草地蝗虫发生的生态环境条件分析

为了有效地进行草地蝗虫的防治,必须摸清其生长和繁殖与生态环境条件的关系。研究表明,在环青海湖地区气温对草地蝗虫影响较为明显是在蝗卵越冬期和孵化期。降水量太多不利于草地蝗虫的发育,但降水适量因有利于蝗蝻出土可能会增加蝗虫基数。青海湖级湖成阶地和构造台地有利于蝗虫的繁育。土壤的温度、质地及水分和盐分含量对草地蝗虫的发生和繁育也有一定影响。     

麻疯树种质资源遗传多样性的ISSR分析

采用ISSR分子标记技术对大戟科属麻疯树9个自然居群的遗传多样性水平和遗传结构进行了研究.用10个引物对9个居群共135个样品进行了扩增,共获得169条清晰的扩增位点,其中多态性位点164个.POPGENE分析结果表明,麻疯树居群具有丰富的遗传多样水平(多态百分率PPB=97.04%,Neis遗传多样性H=0.2357,Shannon信息指数I=0.3760).AMOVA分析表明,9个自然居群间遗传多样性出现了较大的遗传分化(Gst=0.5398)可能与其有限的基因流(Nm=0.4667)和遗传漂变有关;而居群内有限的遗传分化可能是由于麻疯树自交、近交占主导方式的繁育方式有关.并进行了麻疯树居群的聚类分析.图3表4参19     

三倍体毛白杨引种育苗试验研究

采用2000年引进的三倍数体毛白杨73、80、96、330、331及本地繁育的303、304、305等品种在不同土壤上进行育苗、造林试验.育苗试验表明:土壤质地及肥力对育苗成活率无明显影响,成活率引最高69.4%,苗木高、径生长8月达到高峰,最高达0.93 m (331号)和0.51 cm (96号);造林试验表明:造林成活率与土壤湿度、地下水位密切相关,生长量与品种及土质密切相关,造林密度为89-110株/667㎡,截干高度1.8-2.3 m为宜,综合表现以96号最佳.     

湖南濒危中药材黑老虎野生资源调查

为调查湖南省黑老虎野生资源分布、种群、群落特征及其中药材储量,对湖南21个县市的黑老虎资源状况进行了实地考察.调查结果表明:黑老虎主要分布于湖南的怀化、湘西、张家界、郴州、永州、邵阳等地,生长在海拔300 m～1 500 m的山地疏林中;种群密度较小,仅为1株/m2,平均株高约8.91 m,平均基径约1.25 cm;其群落结构由乔木、灌木、草本组成,且乔木层的物种多样性大于灌木层和草本层,伴生植物种类丰富,包括22个科41个属共50种植物;湖南黑老虎中药材总蕴藏量较少,约为12 288 kg.因此,建议应重视和加强黑老虎野生资源保护,进行人工繁育和栽培,保证黑老虎资源的可持续利用.     

葫芦科化学分类学

葫芦科为全世界约有110～122个属,775～960种的大科,我国有38属,约150种.该科植物中许多种类作为栽培植物,用作观赏、果蔬或药用,其化学成分十分复杂,大多数属中具有葫芦素类化合物.由于长期的栽培和人为繁育,化学成分的组成变得更加复杂,而化学成分的研究也不是十分全面,难以找到规律性.本文在葫芦科化学成分研究的基础上,探讨了其化学成分与各个属植物之间的相互联系.本文的讨论对整个葫芦科的化学分类学特征的化合物很难确定,但从化学系统学的角度,以葫芦科各个属的化学成分研究结果为基础,结合分类学的分属依据,讨论了葫芦科近缘属间关系,化学成分的结构类型基本上支持Takhtajan的葫芦科分类系统.表1参49     

濒危红树植物红榄李开花生物学特征及繁育系统

为了解红树植物红榄李[Lumnitzera littorea(Jack.)Voigt]濒危的生殖生物学原因,结合野外观测,综合运用杂交指数、花粉-胚珠比、花粉活力和柱头可授性观测、人工授粉以及套袋实验等方法,对红榄李的开花生物学和繁育系统进行研究.结果表明:红榄李群体花期从1月底到8月底.单花开放过程可分为萌动、初展、盛开、凋落4个阶段.单花花期约为(12.60±0.80)d,单花序花期约持续(29.70±1.00)d,单株花期约为(115.20±6.00)d.单株平均开花数量为(9.60±0.03)万朵,单株平均开花振幅为(83.47±1.50)朵/d);红榄李的杂交指数为4,花粉胚珠比为21 649.08.实验发现红榄李繁育系统为兼性异交,传粉过程需要传粉者;红榄李的花粉生活力低于10%,花粉活力可维持至散粉后的第4天.但散粉2 d后,柱头可授性显著下降,花粉的高活力期与柱头可授期有1-2 d的重叠;在自然状况下,红榄李结果率较高但同时空胚率也高.人工辅助异株异花授粉对提高结果率和降低空胚率有明显作用.综上,红榄李"花期分散"的开花模式,花粉生活力低,自然状态下传粉效率低、胚败育严重和花果期虫害严重是导致其濒危的主要原因.     

环青海湖地区草地蝗虫发生的生态环境条件分析

为了有效地进行草地蝗虫的防治，必须摸清其生长和繁殖与生态环境条件的关系，研究表明，在环青海湖地工温对草地蝗虫影响较为明显是在蝗卵越冬期和卵化期。土壤的温度、质地及水分和盐分含量对草地蝗虫的发生和繁育也有一定的影响。     

辽西褐土施肥及养分循环再利用中长期试验Ⅰ. 作物产量

在辽宁西部褐土上历时10 a的田间试验结果表明：氮肥对提高作物产量效果最好，平均增产率50%，平均每千克 N增产粮食21 kg。供试褐土富磷，试验前3 a施磷肥不显增产作用，之后增产明显，10 a平均增产率10.9%，平均每千克 P增产粮食47 kg。供试褐土富钾，连续10 a施钾肥不显增产作用。 在施用化肥基础上每年以60%收获产品直接堆腐回田，可比对应的化肥处理分别增产（10 a平均）40.6%（无肥对照）、19.5%（N肥基础）、12.1%（NP肥）和8.1%（NPK肥），平均年增产粮食（混合、烘干）分别为1.54、1.08、0.79、0.52 t/hm2。养分循环再利用的作物增产效益在试验的10 a中有着逐年增长的趋势，表明以堆肥形式循环回田养分的作物增产作用有着明显的残效叠加效应。     

Circadian rhythm of swimming activity in juvenile pink salmon (Oncorhynchus gorbuscha)

The circadian rhythm of swimming activity and the role of the daily illumination cycle in the synchronization of this rhythm were studied in individual juvenile pink salmon. Sixty eight percent of all fish examined (n=38) were day-active when exposed to a 12 h L:12 h D cycle; the remaining fish were nocturnally active. One half of the fish tested under laboratory conditions of continuous, constant light intensity (LL) and constant temperature showed unambiguously endogenous activity rhythms with circadian periods for up to 10 d. The remaining fish were arrhythmic. Mean period length of the free-running activity rhythms for diurnal fish in LL shortened with constant light intensity increasing from 6 to 600 lx, as predicted by the circadian rule. In contrast, mean free-running period for nocturnal fish did not vary significantly with similarly increasing constant light intensity. Mean swimming speed (activity level) of both diurnal and nocturnal fish increased significantly with increasing light intensity. This is suggestive of a positive photokinetic response. When subjected to a phase-delayed LD cycle, the fish resynchronized their daily rhythms of activity with this new LD cycle after only one transient cycle in most instances. Hence, the timing of the daily activity rhythms appeared to occur through the direct masking action of the illumination cycle on activity, rather than through entrainment of an endogenous circadian system.     

Minimax regret discounting

The paper considers an environmental policy decision in which the appropriate approach for discounting future costs and benefits is unknown. Uncertainty about the discount rate is formulated as a decision under Knightian uncertainty. To solve this, we employ minimax regret, a decision criterion that is much less conservative then the related criterion maximin—in particular, it can be shown to implement a “proportional response” in that it equally balances concern about the mistake of doing too little with that of doing too much. Despite the criterion's balanced nature, the minimax regret solution mimics a policy that maximizes the present discounted value of future net benefits with an effective (certainty-equivalent) discount rate that declines over time to the lowest possible rate. In addition to reinforcing Weitzman's (1998) original limiting result, the approach generates concrete policy advice when decision makers are unable to specify a prior over possible discount rates. We apply it to the Stern–Nordhaus discounting debate and find that the effective discount rate converges to the Stern rate in just under 200 years.     

Minimax regret discounting

The paper considers an environmental policy decision in which the appropriate approach for discounting future costs and benefits is unknown. Uncertainty about the discount rate is formulated as a decision under Knightian uncertainty. To solve this, we employ minimax regret, a decision criterion that is much less conservative then the related criterion maximin—in particular, it can be shown to implement a “proportional response” in that it equally balances concern about the mistake of doing too little with that of doing too much. Despite the criterion's balanced nature, the minimax regret solution mimics a policy that maximizes the present discounted value of future net benefits with an effective (certainty-equivalent) discount rate that declines over time to the lowest possible rate. In addition to reinforcing Weitzman's (1998) original limiting result, the approach generates concrete policy advice when decision makers are unable to specify a prior over possible discount rates. We apply it to the Stern–Nordhaus discounting debate and find that the effective discount rate converges to the Stern rate in just under 200 years.     

轻质陶粒滤料生态滤床的挂膜与启动研究

以自行设计的反应器作为生态滤床的基础,采用活性污泥作为接种污泥,采用轻质陶粒作为生态滤床的滤料,对其进行挂膜.在整个挂膜过程中,温度控制在中温条件下,进水pH值控制在7左右,水力停留时间为24 h,进水方式为连续进水,并根据需要对曝气量进行调节.在挂膜过程中对进、出水的COD、NH_3-N、TP、Cl~-和pH进行检测,并刮取少量轻质陶粒上的生物膜制成镜检切片后用多媒体显微镜对生物膜的形态进行观察.研究结果表明,在中温条件下采用活性污泥作为接种污泥,以轻质陶粒为滤料的生态滤床在15 d内挂膜成功;且随着进水污染负荷的提高,其去除率也逐渐提高,其中COD的去除率最后稳定在95%左右,NH3-N的去除率稳定在85%左右,TP的去除率在挂膜后期达到了80%以上;Cl~-作为微生物所需的微量元素在微生物生长高峰期为50%,稳定期保持在20%左右;进水pH保持在7左右,出水pH略高于进水,在8左右;从第13 d和第15 d的切片可观察到轮虫这种象征生物膜成熟的微生物的出现,此外还有大量的丝状菌和菌胶团.     

Shoreline morphological changes and the human factor. Case study of Accra Ghana

The interface between the sea and land is a very dynamic system that is always migrating landward or seaward. The landward migration results in the shoreline threatening coastal infrastructure and destroying the coastal environment. Coastal erosion has resulted in both social and economic problems. Coastal cities have also experienced increasing infrastructure development and population growth. This has resulted in a land “squeeze situation” in which both the shoreline and the “humanline” are competing for space along the coast. This struggle for space could result in serious environmental disaster as a result of the dynamics of the oceanic system, which could impact the immediate environs severely. The aim of this study was to determine if the rate of human encroachment of coastal lands for development exceed the rate at which the shoreline is moving inland as part of its natural cyclic behaviour. This study used 1985 aerial photographs and 2005 orthophoto map of the Accra western coast. Major land cover was identified, classified and overlayed in GIS environment. This enabled changes to be estimated. The shorelines were also digitised and the rate of change computed using the DSAS software. The results indicate that the estimated total area of land lost by human encroachment on the coastal land within the period under study is about 242,139.7 m2. However, the rate of land lost to human development is about 8,349.64 m2/year, which is relatively high. The historic rate of erosion computed for the period under study is about 1.92 m/year. Comparing the two rates indicates that human activities are moving closer to the shoreline as compared to the rate at which the shoreline is moving inland. This study recommends that setback lines should be put in place to protect lands for the shoreline’s cyclic activities.     

不同光照度下南方鲇稚鱼的摄食强度及摄食动力学

在10^3-10^-1lx光照度范围内，南方鲇稚鱼对团鲂鱼苗的摄食强度随光照度减弱而增强，在10^9lx时达最大值，随后下降，摄食率在开始摄食后10min，光照强度为10^0lx时最同，并随摄食时间延长而下降。     

Quantification of singlet oxygen and hydroxyl radicals upon UV irradiation of surface water

We measured the formation rate and the steady-state concentration of hydroxyl radicals and of singlet oxygen upon irradiation of lake water. There is controversy about the importance of singlet oxygen in the environmental photochemistry, but here we show that the steady-state concentration of ¹O₂ under irradiation can be higher by about two orders of magnitude compared to the hydroxyl radical. The higher occurrence of singlet oxygen in surface waters is mainly due to a higher rate of formation, because the transformation rate constants of ¹O₂ (collision with the solvent) and of ^·OH (reaction with dissolved compounds) are comparable.     

Anthropogenic nitrogen sources and exports in a village-scale catchment in Southeast China

An experimental village-scale catchment was selected for investigation of nitrogen (N) sources and exports. The mean N application rate over the catchment was 350.2 kg N ha⁻¹, but this rate varied spatially and temporally. The N leaching loss rate varied from 8.1 to 52.7 kg N ha⁻¹ under different land use regimes. The average N leaching loss rate was 13.4 kg N ha⁻¹ over the whole catchment, representing about 3.8% of the total N inputs. The N export rate through stormflows was 28.8 kg N ha⁻¹, about 8.2% of the total N inputs. Seasonal patterns showed that 95% of N exports through stormflows occurred during July to September in 2002. Overall, the maximum riverine N exports were 12.1% of total N inputs and 15.5% of the inorganic fertilizer N applied. Understanding N sources and exports in a village-scale catchment can provide a knowledge base for amelioration of diffuse agricultural pollution.     

不同基质体系中白腐菌对喹啉和吲哚的降解

采用单基质及混合基质体系,探讨了白腐菌Pleurotus ostreatusBP对氮杂环化合物的降解规律．结果表明,在弱酸性环境下,白腐菌能有效降解喹啉和吲哚．单基质体系中,喹啉的降解率15d内能达到89．48％,98．17％的吲哚6d内被降解;混合基质体系中,基质（喹啉、吡啶、苯酚及氨氮）的加入能促进白腐菌对吲哚的降解,但（吲哚、吡啶、苯酚及氨氮）却抑制了白腐菌对喹啉的降解．不同基质体系中,白腐菌对喹啉和吲哚的降解分别遵循零级和一级反应动力学．相对单基质而言,混合基质的存在对白腐菌生物学特性产生明显影响,可缩短生长周期,提高生长速率和漆酶活性．漆酶存吲哚的降解中起着重要的作用,但不能完全决定喹啉的降解．图5表2参14