利用MODIS数据估测毛竹林总初级生产力

通过集成中分辨率成像光谱仪(MODIS)卫星影像数据与地面通量台站的观测数据,基于遥感的植被光合模型(VPM),估测了浙江省安吉县山川乡2011年的毛竹Phyllostachys edulis林总初级生产力(PGP)。研究表明:VPM模型估测的PGP(PGPVPM)在季节变化趋势上和通量站点数据获得的PGP(PGPobs)保持一致,VPM模型估算的2011年毛竹林总初级生产力为1 848.54 g·m-2,通量塔数据获得的2011年毛竹林总初级生产力为1 899.69 g·m-2,相对误差为2.69%。在全年累积总量上接近,但是估测值和观测值之间仍然存在一定的差异,尤其是在生长季节,PGPVPM的值要高于PGPobs;VPM模型估测的PGP和通量塔数据获取的PGP之间的决定系数为0.747,相关系数为0.864;且时间序列的增强植被指数(IEV)比PGP的相关关系强于归一化植被指数(INDV)与PGP的关系。研究表明:VPM对于站点和区域尺度的毛竹林生态系统PGP的模拟具有很大的潜力。     

The role of exotic tree species in Nordic forestry

The selection of suitable tree species is a prerequisite for successful forestry, and the use of exotic species as an alternative to native species is often a relevant option. In this paper, we discuss this option in relation to the present and future wood production in Nordic forestry. We revisit the vegetation and forest history and its implications for the interest in using exotic species. We review to what extent exotic species can contribute to increased economic returns from forest plantings and the potential negative ecological effects associated with introduction of new species. Considering the expected climate changes, we discuss whether and how the increased use of exotic species can contribute to sustained and increased health and productivity of Nordic forests without jeopardising ecological and social values.     

果园化栽培模式杜仲雄花、果实和叶片产量的调查分析

正杜仲(Eucommia ulmoides Oliv)属杜仲科(Eucommiaceae),本科仅1属1种,是仅存于我国的第三纪孑遗植物,名贵经济树种,国家二级保护树种[1,-2]。杜仲叶、雄花、果皮和杜仲皮都含有多种具有独特的医疗保健功能的活性物质[2-3]。例如     

3种落叶松苗期光能利用效率的比较

正林木90%以上的干物质来自光合作用,单位时间内光能利用效率(包括光能截获能力和光能转化效率)是衡量林木生长潜力的重要指标。光能截获能力主要与叶面积大小及其发展有关,光能转化效率主要与单叶光合速率有关。自发现光合速率在不同个体间存在明显差异后,以提高光能利用效率为目标的"高光效育种"受到育种学家的重视[1-3],而通过选配高光效种质进行有目的杂交已成为高光效育种的重要手段[4]。落叶松(Larix spp.)种间杂交     

农户流域补偿浅析——一个从刘易斯拐点进行思考的角度

随着可持续发展理念的深入与推广,开展对流域生态服务提供区的生态补偿成为必然,其中不乏对补偿重点的探讨。本文以刘易斯拐点作为出发点,对农户流域补偿的侧重进行浅析,并寻求实现生态服务持续提供的良性机制。     

基于广义 Malmquist 指数的江西早籼稻生产率分析

为了解江西省早籼稻生产率状况,提高农户早籼稻生产率,利用2009－2013年江西省早籼稻生产成本收益追踪调查数据,采用产出定位的随机前沿方法,使用广义 Malmquist 指数分析江西省早籼稻的全要素生产率。结果表明。1）江西省早籼稻生产率提升主要得益于技术进步,技术效率和规模效率对早籼稻生产率贡献较小。2）江西省早籼稻生产率北部地区高于南部地区,其中,奉新县和南昌县最高,会昌县和遂川县最低。     

森林生产力区划和量化分级方法研究——以辽宁省为例

采用宏观区划和微观量化分级相结合的方法,利用气候、植被和立地区划数据,首次在全国大区域尺度上实现森林生产力三级区划,同时,结合多期森林资源清查地面样地数据实现森林生产力量化分级。以辽宁森林生产力区划和量化分级成果为案例,详细介绍本研究的技术路线和方法。该研究可为林业区划、森林生态系统功能评价等研究和实践提供理论和方法依据。     

MAGNETIC RESONANCE IMAGING OF PRIMARY AND CONCOMITANT FLEXOR ENTHESOPATHY IN THE CANINE ELBOW

Flexor enthesopathy is a recently recognized elbow disorder in dogs and considered to be an important differential diagnosis for elbow lameness. Primary and concomitant forms of the disease have been previously described and treatments differ for the two forms. The goal of this prospective study was to compare magnetic resonance imaging (MRI) findings for dogs with primary flexor enthesopathy (n = 17), concomitant flexor enthesopathy (n = 23), elbow dysplasia alone (n = 13), and normal elbows (n = 7). Each elbow joint underwent MRI using the same low‐field scanner. Sequences included transverse and sagittal T1‐weighted (before and after IV contrast), transverse and sagittal T2‐weighted, and dorsal STIR. For each elbow, MRI lesions were recorded based on a consensus of two observers unaware of group status. Magnetic resonance imaging lesions involving flexor tendons were found in 100% of clinically affected joints with primary flexor enthesopathy and 96% of clinically affected joints with concomitant flexor enthesopathy. Thickened flexor muscles were the most common lesions, followed by hyperintense tendon signal and contrast enhancement. Irregular, thickened medial humeral epicondyle, edema, and calcified body lesions were less frequently observed. Magnetic resonance imaging characteristics of flexor enthesopathy were not found in normal joints or those affected by elbow dysplasia alone. No significant differences in frequencies and details of individual MRI characteristics were found between primary and concomitant flexor enthesopathy groups. Findings indicated that MRI is a sensitive technique for detection of flexor enthesopathy lesions in dogs, however, MRI characteristics do not allow differentiation of primary versus concomitant forms of the disease.     

中国蜡梅种质资源核心种质的初步构建

该文对中国蜡梅野生资源和品种资源分别构建了核心种质。并按居群进行分组,共分为2大组13个小组。各组内在9个表型性状聚类的基础上,按平方根法取样,并依遗传多样性指数和遗传丰富度进行调整,构建了中国蜡梅种质资源的163份初选核心种质,其中野生初选核心种质77份,占总数的26·9%,几乎覆盖了蜡梅的全部分布区,品种初选核心种质86份,占总数的50·6%。根据对9个性状遗传多样性指数的t检验和观赏性状特征值检验,结果表明,初选种质较好地代表了全部供试种质的遗传变异幅度。     

碧流河水库渔业基础调查和渔业利用的研究

１９８８￣１９９１年对碧流河水库的理化特性，饵料生物，初级生产力，鱼类区系及渔业资源利用情况作了全面的调查研究。提出该水库属中营养型，产鱼潜力为２５０ｋｇ／ｈｍ＾２，并对凶猛鱼类的利用和控制，鱼类的合理放养与捕捞进行了探讨。