Just small potatoes (and ulluco)? The use of seed-size variation in “native commercialized” agriculture and agrobiodiversity conservation among Peruvian farmers

Farmers of the Peruvian Andesmake use of seed-size variation as a source offlexibility in the production of ``nativecommercial' farmer varieties of Andeanpotatoes and ulluco. In a case study of easternCuzco, the use of varied sizes of seed tubers isfound to underpin versatile farm strategiessuited to partial commercialization (combinedwith on-farm consumption and the next season'sseed). Use of seed-size variation also providesadaptation to diverse soil-moistureenvironments. The importance and widespread useof seed-size variation among farmers isdemonstrated in the emphasis and consistency oflinguistic expressions about this trait. Smalland small-medium seed is typically sown in thecommunity's ``Hill' unit of sub-humid,upper-elevation agriculture. Seed tubers ofmedium-size and larger are needed fordrought-stressed locales in lower-elevationlandscape units. Farm-level preferences for theseed-size of tubers also suggest potentialrelations to resource endowments of farmhouseholds and gender-related management,although these tendencies were notstatistically significant in the study. Anintra-varietal, landscape-environmentalperspective on seed-size management, whichincludes an emphasis on within-fieldversatility, helps to strengthen the researchsupport of local seed production in policiesand programs aiming for in situagrobiodiversity conservation, marketingcapacity, and food security.     

Quantifying the expression of potato genetic diversity in the high Andes through growth analysis and modeling

Crop growth analysis and modeling based on a slightly modified version of the LINTUL model was used for the assessment of the effect of genetic diversity, as expressed by differences in characteristics such as ploidy, parentage and other specific traits, on the growth and yield responses of Andean potatoes to agroecological conditions in Bolivia. The aim of the present study was to conduct a comparative growth analysis of nine genotypes to describe their performance under the prevalent conditions in the high Andes. We also simulated the performance of nine genotypes from the species Solanum tuberosum subspecies andigenum and tuberosum, Solanumajanhuiri, and their hybrids as affected by frost. The simulations were run using a user-friendly simulation model based on the LINTUL framework.     

Mobility of the forearm skeleton in the Asiatic black (Ursus thibetanus), brown (U. arctos) and polar (U. maritimus) bears

In several primates and carnivores, pronation/supination angles of the forearm skeleton were examined, and it is thought that a larger angle is useful to acquire dexterous behaviors in feeding and/or life style, including climbing. In this study, the pronation/supination angles in Asiatic black, brown and polar bears were nondestructively examined. These specimens were classified as adult or non-adult. Three or four carcasses of each group of Asiatic black and brown bears were used for CT analysis, whereas only one adult polar bear was used. The forearms were positioned within the gantry of a CT scanner in both maximally supinated and pronated states. Extracted cross-sectional CT images of two positions were superimposed by overlapping the outlines of each ulna. The centroids of the radii were detected, and then the centroid of each radius and the midpoint of a line which connects between both ends of the surface of each radius facing the ulna, were connected by lines to measure the angle of rotation as an index of pronation/supination. In adult brown and polar bears, the angles were smaller as compared with the other groups (Asiatic black and non-adult brown bears). Asiatic black and non-adult brown bears can climb trees, whereas adult brown bears and polar bears cannot. This suggests that the pronation/supination angle is related to arboreal activity in Ursidae.     

Wound healing during hibernation by black bears (Ursus americanus) in the wild: elicitation of reduced scar formation

Even mildly hypothermic body or limb temperatures can retard healing processes in mammals. Despite this, we observed that hibernating American black bears (Ursus americanus Pallas, 1780) elicit profound abilities in mounting inflammatory responses to infection and/or foreign bodies. In addition, they resolve injuries during hibernation while maintaining mildly hypothermic states (30-35 °C) and without eating, drinking, urinating or defecating. We describe experimental studies on free-ranging bears that document their abilities to completely resolve cutaneous cuts and punctures incurred during or prior to hibernation. We induced small, full-thickness cutaneous wounds (biopsies or incisions) during early denning, and re-biopsied sites 2-3 months later (near the end of denning). Routine histological methods were used to characterize these skin samples. All biopsied sites with respect to secondary intention (open circular biopsies) and primary intention (sutured sites) healed, with evidence of initial eschar (scab) formation, completeness of healed epidermis and dermal layers, dyskeratosis (inclusion cysts), and abilities to produce hair follicles. These healing abilities of hibernating black bears are a clear survival advantage to animals injured before or during denning. Bears are known to have elevated levels of hibernation induction trigger (delta-opioid receptor agonist) and ursodeoxycholic acid (major bile acid within plasma, mostly conjugated with taurine) during hibernation, which may relate to these wound-healing abilities. Further research as to the underlying mechanisms of wound healing during hibernation could have applications in human medicine. Unique approaches may be found to improve healing for malnourished, hypothermic, diabetic and elderly patients or to reduce scarring associated with burns and traumatic injuries.     

种间杂交培育的5个核桃早实新品系

通过在国内外首次选用我国南方著名的晚实良种“漾鼻泡核桃”“三台核桃”（Juglans sigillata L.)与新疆早实核桃优株“云林A7号”（Juglans regia Dode)进行种间杂交，培育出我国南方核桃产区首批5个早实杂交核桃新品系，即云新7914，云新7926，云新8034，云新8064，云新85227。5个新品系综合了双亲优势性状，具有早实，早熟，丰产，优质，树体矮化，适应性广等优良性状，增产潜力巨大，推广前景广阔。     

Predation relationships between introduced salmonids and the native fish fauna in lakes and reservoirs in northern Patagonia

Abstract– A few native and exotic fish species are caught frequently in Andean lakes and reservoirs of northwestern Patagonia. Puyen ( Galaxias maculatus ) prey on zooplankton and benthos. Percichthys trucha has a wide range of prey, mainly benthos, while P. colhuapiensis become piscivorous when grown. Pejerrey ( Odonthestes hatcheri ) is omnivorous and large size individuals can be piscivorous. A siluroid, Diplomystes viedmensis , preys on benthos, insects, and fishes. Introduced salmonids are potential piscivorous. The puyen is the major prey category among fishes. Salmonids and perchichtids seem to partially overlap their diets but predation on Diplomystes appears to be restricted to salmonids. Present abundance of puyen, pejerrey and Percichthys spp. does not indicate a strong salmonid effect. However, the low abundance of D. viedmensis does. We studied present predation relationships among native and introduced fishes and postulated possible effects upon native fish fauna.     

Threatened aquatic Andean frogs and mining activity in the Lithium Triangle of South America: Can both coexist?

相似文献   

论名茶承载的社会功能

名茶作为茶中珍品,不仅能带给人们良好的经济效益,而且在人类社会发展的各个阶段,它始终承载着重要的社会功能。名茶承载的社会功能,主要是交流功能、记忆功能、教育功能和审美功能。     

Agrophysiological characterisation and parametrisation of Andean tubers: Potato (Solanum sp.), oca (Oxalis tuberosa), isaño (Tropaeolum tuberosum) and papalisa (Ullucus tuberosus)

Bolivia is part of the eight most important centres of biodiversity and domestication of plants in the world, including a broad diversity of Andean grains, roots and tubers. A study was implemented to obtain the quantitative information to develop and validate, a simple growth potential model of Andean tubers in production areas located above 3000 m altitude, and to analyze the difference between species in growth attributes and the resulting tuber production. Three potato species and sub-species (Solanum tuberosum ssp. andigenum and ssp. tuberosum, and Solanum juzepczukii) as well as Oca (Oxalis tuberosa), Isaño (Tropaeolum tuberosum) and Papalisa (Ullucus tuberosus) were studied. Trials were conducted under normal field conditions prevailing in Bolivia but with the best cropping techniques available locally to obtain optimal growing conditions. Data on dry weight (of leaves, stems, tubers and roots) and leaf area were taken at several dates in five trials conducted between 1993 and 2003. The percentage of ground cover was also measured. Beta functions were fitted to data of dry weight and leaf area to establish growth curves. The potato groups have a smaller cycle duration than other Andean tubers. The Crop Growth Analysis indicated three important characteristics differentiating Andean tubers: the S. juzepczukii potato has a high Relative Growth Rate (RGR) and a higher leaf mass ratio but a smaller tuber yield, due to a smaller harvest index (HI) and a very low Net Assimilation Rate (NAR). S. tuberosum ssp. tuberosum potatoes have smaller Leaf Area Index (LAI), and RGR than juzepczukii, but their NAR and HI are higher. S. tuberosum potatoes are quite productive for the size of their LAI. The Tropaeolum tuberosum or Isaño has a great capacity of Ground Cover (GC) or a great LAI that is not translated into a greater tubers yield. It has low RGR, NAR and HI compared to all the other species studied. The crop growth was interpreted in Light Use Efficiency (LUE) and evolution of light interception through a linear model. The LUE of potato group is more elevated than the LUE of the other Andean tubers. Within each group there is no statistical difference for the LUE value. The relationship of LAI with GC or fraction of light interception was determined with both linear and exponential relations. The low slope value for the relationship between LAI and GC characterises all Andean tubers studied compared to results reported for potato under other latitudes.     

熊胆滴眼液对兔角膜烧伤和角膜翳的治疗实验研究

为研究熊胆滴眼液对角膜烧伤和角膜翳的治疗效果 ,采用“电热角膜瘢痕复制器”制作家兔角膜烧伤与斑模型 ,以生理盐水、去熊胆滴眼液、氯霉素眼药水和狄奥宁眼药水作对照 ,用熊胆滴眼液进行治疗实验。实验结果表明 :熊胆滴眼液对家兔角膜烧伤及并发结膜炎的治疗效果显著 ,优于去熊胆滴眼液和氯霉素眼药水 (P<0 .0 5 ) ;对角膜翳的治疗效果非常显著 ,优于去熊胆滴眼液和狄奥宁眼药水 (P<0 .0 1)。扫描电镜观察了熊胆滴眼液对角膜翳的治疗作用 ,结果显示 :治疗 2月后 ,角膜上皮细胞呈现更新速率较快的结构像 ,治疗 5月后 ,上皮细胞表面的微皱襞及微绒毛排列规则、细密 ,与正常角膜上皮细胞的超微结构相一致。表明复方熊胆滴眼液具有使角膜翳处的角膜上皮恢复正常的作用。