樊净山自然保护区黔金丝猴生境选择的研究

适宜的生境是珍稀濒危生物生存的决定性条件,对珍稀濒危生物生境的系统研究是生物多样性保护的前提。金丝猴是中国特有并且珍稀的濒危物种,黔金丝猴又是三种金丝猴中分布最为狭窄、对生境要求最为苛刻的一种。本文从黔金丝猴的最佳适宜生境、适宜生境和较适宜生境三个生境选择方面对生境内植物群落特征、环境因子、极端环境因子等进行了系统分析,对黔金丝猴的季节活动规律、活动区域和食物特点进行了系统的研究。结果表明常绿针阔混交林是黔金丝猴的最佳生存的植被群落,其最适宜的年均温度为8～15C,极端最低温度为-2.5C,极端最高温度为25C,最适宜生存的海拔高度为1500～1700m。在同一区域,植物多样性越多,越适宜黔金丝猴的生存。温度和食物是决定黔金丝猴种群活动范围大小的主要生境因子,海拔高度、植被群落特征、温度是黔金丝猴对生境选择的主要限制因子。图3表3参16。     

Spatial heterogeneity of soil water content in the reversion process of desertification in arid areas

Sandy soils in arid,rain-fed environments have low and limited water content,which is a principal factor limiting vegetation development,and a key constraint controlling the structure and functions of the ecological systems in arid areas.The spatial heterogeneity of soil water content is a major soil property,and a focus of soil science and hydrology.On the southern edge of the Tengger Desert,sample plots were selected from mobile sand dunes in desertified lands that had been enclosed for 5,15 and 25 years,respectively.This study explored the dynamic and spatial heterogeneity of soil water content in these different layers of soil that were also in the reversion process of desertification.The results showed that the soil water content of the mobile sand dunes was highest when in the initial stages of the reversion process of desertification,while the soil water content in the 0-20 cm,20-40 cm and 40-60 cm layers of soil was 1.769%,3.011%,and 2.967% respectively,presenting a restoring tendency after 25 years of enclosure.There were significant differences,as a whole,in the soil water content among different restoration stages and different soil layers,respectively.Changes in soil water content,in different soil layers,at different restoration stages,exhibited exponential or spherical patterns.The spatial distribution of soil water content exhibited a mosaic patch pattern with obvious spatial heterogeneity.The ratio of the heterogeneity of spatial autocorrelation to gross spatial heterogeneity was greater than 50%.The gross spatial heterogeneity of the 0-20 cm layer of soil improved gradually,while those of the 20-40 cm and 40-60 cm layers improved initially,then weakened in the reversion process of desertification.This study revealed that restoration with sand-binding vegetation reduced soil water content,and increased its spatial heterogeneity in arid areas.However,after 25 years of vegetation-soil system restoration,the soil water content started to increase and its spatial heterogeneity started to weaken.These results will further benefit the understanding of the ecological mechanism between soil water and sand-binding vegetation.     

我国耕地数量变化与保护政策关系的实证分析

以耕地数量的统计数据耕地、保护政策的颁布和实施为基础,借助经济计量学理论以及Eviewes5.1软件,运用协整分析、Granger因果关系检验和脉冲响应等分析方法,分析了改革开放以来我国耕地数量变化与耕地保护政策之间的互动关系。结果显示:耕地数量变化与耕地保护政策之间存在一种长期均衡关系,说明二者之间存在着某种机制在制约着变量的运动,使二者之间短期内的偏离不会太远,长期则会走向均衡;耕地数量变化与耕地保护政策之间存在单向的因果关系,即耕地数量变化与是耕地保护政策的Granger原因,而耕地保护政策不是耕地数量变化的Granger原因;脉冲响应以及方差分解表明,耕地数量变化对耕地保护政策具有较为持续的促进作用,且作用程度随着滞后期的加大而加强;耕地保护政策具有较强的惯性,主要受其自身以前水平的影响,因此耕地保护政策对耕地保护政策的促进作用不太显著。这也从一个侧面佐证了Granger因果检验的结果。因此,应制定长期而非短期的策略,强化耕地保护政策理论研究,加大耕地保护政策的制定、执行和监督力度,这是解决耕地过快减少问题的重要途径。     

马鞍山市向山垃圾填埋场抽气实验研究

本文根据马鞍山市向山垃圾填埋场的现场抽气实验，分析了影响垃圾填埋气体产生的各因素的变化规律，确定了抽气压力、气体流量和甲烷含量的关系及其影响因素，并以此为基础对填埋气体收集利用工程中填埋场的选择和系统的设计提出了建议。     

石家庄污灌区污水灌溉技术的研究

分析了国内外污水灌溉的研究和发展,以石家庄市污灌区为研究对象,在分析预测未来30年污水水质水量特点的基础上,采用不同的灌水技术,利用环境容量法,分析预测了在不同务件下土壤和作物中重金属和石油类浓度的发展以及相应的污清水的灌溉需水量。针对该灌区土壤现状和污水水质特点,提出了建议的合理污水灌溉技术,以保证以土壤为中心的生态系统的可持续发展。     

The importance of an indigenous tree to southern African communities with specific relevance to its domestication and commercialization:a case of the marula tree

Local communities in southern Africa derive many benefits from marula [Sclerocarya birrea(A.Rich.) Hochst.subsp.caffra(Sond.) Kokwaro].These include the contribution of this species towards health,nutrition,food security and conservation by sharing local skills and knowledge related to it.Marula fruits can be eaten fresh,squeezed to make juice,brewed in traditional beer or used to make jam and jelly.The kernels are also edible and can be pressed to extract oil for cooking and cosmetics,i.e.,for skin and hai...     

草莓生物技术育种研究进展

应用生物技术是草莓品种改良和种质创新的重要手段。本文综述了近几十年来国内外生物技术在草莓育种研究中的应用主要进展,内容包括草莓的遗传转化、草莓的细胞悬浮培养、草莓的原生质体培养、草莓的花药培养、草莓的离体胚培养、草莓突变体的筛选等方面的研究。最后根据草莓生物技术育种存在的问题探讨了今后草莓育种工作的发展方向。     

美洲黑杨杂种优良无性系转抗虫基因(Bt和CpTⅠ)的研究

以美洲黑杨杂种优良无性系南林895杨(Populus×euramericanac‘v.Nanlin895’)为转基因受体材料,以嫩芽或腋芽为外植体材料组织培养再生植株,利用农杆菌介导法转化Bt基因和CpTI基因。结果显示较合适的组培再生与遗传转化系统为:叶分化培养基为MS+6-BA0.5mg/L+TDZ0.002mg/L,芽伸长培养基为MS+6-BA0.2mg/L+TDZ0.001mg/L+Km10mg/L+Carb500mg/L,生根培养基为1/2MS;预培养3d,菌液浓度OD6001.0～1.3左右,侵染时间20min,共培养4d,叶盘转化频率可达28.7%。对Kmr植株经PCR分析,筛选获得了18株整合有Bt基因和1株整合有CpTI基因的转基因植株。部分转基因植株的初步饲虫实验表明,饲喂转基因杨树叶片可明显抑制杨小舟蛾的生长发育。     

龙牙百合的植株再生与遗传转化

以龙牙百合鳞片叶切块为外植体，通过多种培养基的比较试验，得出MS 2，4-D 2mg／L 6-BA 0．2mg／L是诱导愈伤的最佳培养基，MS 6-BA 1mg／L NAA 0．05mg／L是不定芽诱导及伸长的适宜培养基。MS N_AA2mg／L是生根的最佳培养基。本试验已建立了适用于龙牙百合遗传转化的快速高频再生系统。用携带有几丁质酶基因和β—1、3葡聚糖酶基因的工程菌，通过农杆菌介导法和基因枪转化法转化龙牙百合，经PCR和点杂交检测证明外源基因已经整合到植物染色体中。同时对农杆菌介导法和基因枪法进行比较，发现农杆菌介导法的转化率为16．7％，基因枪法的转化率为50％，因此可能基因枪转化法更适于龙牙百合的遗传转化。