华北土石山区不同林分结构与功能的研究

在调查北京八达岭林区刺槐(Robinia pseudoacacia)、侧柏(Platycladus orientalis)及其混交林生长量、土壤理化性质、水源涵养能力、病虫害的基础上,研究其结构与功能关系.结果表明,混交林比纯林具有更好的生长量,土壤理化性质得到进一步改善,从而提高水源涵养能力.另外,混交林还能够提高林分抵抗病虫害的能力.采用混交的方式为:1行刺槐3行侧柏循环混交,刺槐株数不超过1/4.本项研究以期对北京市森林健康经营具有一定的指导意义.     

降低471QE发动机排气温度的试验研究

分析了造成471QE发动机排气温度高的原因,提出对471QE发动机气缸盖改进设计的技术措施,并进行有针对性的试验研究。通过试验分析得出了燃烧室容积、点火提前角、燃烧室结构和气缸盖冷却水道内表面粗糙度对发动机排气温度的影响程度。     

二维伊辛模型自旋状态图样的蒙特卡罗模拟

以Ｍｅｔｒｏｐｏｌｉｓ蒙特卡罗模拟方法考察了在２０×２０正方格子上的二维伊辛自旋模型，得到了该模型不同温度下自旋状态的图样，符合统计力学分析。     

Growth attributes of potato and their inter-relationship with yield

Summary In the mild and short winter of the Ganges plains, the yield contributing characters such as number of shoots/plant, plant height, leaflet size, tuber yield/plant and tuber number/plant were studied for fifty varieties of potato. From the simple, partial and genotypic and phenotypic correlation studies it was observed that leaflet size, number of tubers/plant and plant height were closely connected with the yield of potato tubers. A multiple regression equation was also prepared and it was found that the leaflet size had the maximum influence on yield followed by number of tubers/plant and plant height.     

陇南山区农林复合模式划分与种植结构研究

甘肃省陇南坡耕地占总耕地面积的80.15%。坡耕地及不合理的耕作方式是造成水土流失的主要原因之一,在山坡地及梯田中进行农林复合栽培,可提高土地产出率,有效防治水土流失。根据生产方式和栽培结构将陇南山区农林复合栽培的模式种类划分为林药复合、林粮间作、田间地埂利用、果菜种植、特种林粮复合、庭院经营、小流域综合治理、林草复合等8种农林复合栽培模式,以便在坡改梯、退耕还林等生态工程中较好地应用复合农林业技术。     

Beware of changes: Conservation of Indo‐Pacific humpback dolphins in disturbed habitats

1. Protecting critical habitats of the Indo‐Pacific humpback dolphin, Sousa chinensis, is a hot topic of discussion for marine biodiversity conservation in China and many Southeast Asian countries. In practice, sound habitat protection action (HPA) planning often suffers from information gaps in macroscopic habitat configurations and changes in the habitat conditions of humpback dolphins.
2. Recent publications in the journal Aquatic Conservation: Marine and Freshwater Ecosystems (AQC) have served to advance humpback dolphin conservation in Chinese waters by resolving such habitat configurations and indicating significant changes in distribution patterns and habitat characteristics under intense coastal anthropogenic activity.
3. We highlight an integrative research framework to investigate habitat configuration and long‐term habitat changes when planning a holistic HPA programme for humpback dolphins. When constructing habitat configuration baselines, field surveys should be designed and conducted in a systematic manner to ensure survey efforts cover diverse environments equally, in either a spatially stratified or gridded pattern, to minimize potential spatial sampling biases. Long‐term habitat changes can be revealed by comparing satellite images from different decades. Changes in habitat preferences and habitat characteristics can be explored through questionnaire surveys on local ecological knowledge, associating historical occurrences with coastline features and projecting historical habitat configuration by species distribution modelling exercises.
4. A lack of good communication and sharing of information between research and management sectors can still be an obstacle to the implementation of sound conservation practices, however, even though there is robust scientific evidence to fill knowledge gaps in distribution and habitat baselines. We have addressed the need to establish a mechanism to improve and streamline information sharing between research teams, management sectors, and stakeholder groups.

     

Influences of human activity and climate on the stock-recruitment dynamics of whitefish, Coregonus lavaretus, in Lake Geneva

Abstract  Analysis of long-term catches from the deep peri-alpine Lake Geneva, showed a shift in the stock-recruitment relationship of Coregonus lavaretus (L.), a target species of commercial fishing. This change was mainly related to large-scale meteorological factors. Higher spring water temperatures may have improved larval survival and hence recruitment of whitefish via: (1) a better match between the hatching date of whitefish larvae and development of their zooplankton prey; and (2) the positive temperature effect on larval growth. In Lake Geneva, changes in regulatory mechanisms coupled with stocking and improved water-quality have led to an explosion in the C. lavaretus population in recent years. These results highlight the relevance of long-term changes in the stock-recruitment relationship for management of aquatic ecosystems that are sensitive to climate forcing.     

我国高校校园植物景观研究——以江苏省徐州市高校为例

介绍了我国高校校园植物景观的发展历程,以徐州高校为例,运用植物造景的配置原则、方法等理论,分析和评价了徐州高校校园典型区域的植物景观,总结了徐州市高校校园植物景观的特点,并对徐州高校校园植物景观存在的问题进行了探讨。     

Intraspecific Relationship of Plasmopara halstedii Isolates Differing in Pathogenicity and Geographic Origin Based on ITS Sequence Data

Sequence parts of the internal transcribed spacer (ITS) region of nuclear ribosomal DNA were analysed to screen for the intraspecific variability of a non-coding genomic region in 15 Plasmopara halstedii populations of different pathotype and geographic origin. Samples revealed uniformity in a ca. 790 Bp fragment comprising of the ITS-1, 5.8S and front parts of the ITS-2. In contrast, clear differences were found in a ca. 810 Bp fragment of the ITS-2 thus allowing differentiation between populations of pathotype 100, 310 and 330 and a group of populations representing pathotypes 700, 701, 703, 710 and 730. Samples of pathotypes 700 to730 originated from Slovakia, France, and Germany, but were uniform in both ITS sequence parts, thus indicating very recent origin of these highly aggressive physiological races. The potential use of ITS sequences for pathotype differentiation and phylogenetic studies in P. halstedii is discussed.     

Role of Aeciospores in Outbreaks of Pea (Pisum sativum) Rust (Uromyces fabae)

Aeciospores in Uromyces fabae were found to be repeating spores and play an important role in pea rust outbreaks in the North Eastern Plain Zone (NEPZ) of India. Experiments conducted on pea rust from 2001 to 2004 revealed the dominance of aeciospores at all growth stages of pea in this region. Urediospore production was erratic and was only observed in a few samples of stems and tendrils (5–10%). Inoculation of pea plants either by aeciospores or urediospores resulted in the production of aeciospores. Production of aeciospores was observed at a temperature range of 10–25 °C, with a maximum at 25 ± 2 °C. Among the different growth stages of pea, the pod formation stage was highly susceptible and produced the maximum number (744) of aecidia/leaf at 20–25 °C. Significant effects of growth stages and temperature were also noticed for pustule number. Urediospore production mainly coincided with the senescence of the pea plants. Maximum germination (2%) of aeciospores was observed at 25 °C, whereas maximum urediospore germination (3.5%) was at 15 °C. Temperatures > 15 °C decreased urediospore germination. A relative humidity (RH) of 100% was favourable for aeciospore germination while 98% RH favoured urediospore germination. Typical histo-pathological behaviour of the aeciospores was observed.