20 years later: Does reduced soil area change overall tree growth?

Urban conditions have been thought to affect tree growth, but there is little conclusive evidence as to the severity of those influences or how various species respond differentially to urban stress. Reduced growth expectations are important to understand, because they affect design choices for the urban tree canopy, particularly as required by legislative mandate. Five tree species (Acer rubrum, Prunus serrulata, Pyrus calleryana, Quercus pallustris and Zelkova serrata) grown in parking lots ranging from 18 to 23 years old in central and northern New Jersey, USA were studied. Tree height, diameter at breast height (DBH), and canopy radius were measured, as was apparent plant available soil (nonpaved planting zone area). Tree DBH, commonly recorded for many municipal inventories, was found to be a useful predictor of canopy area. Data were normalized within site, to facilitate multiple site analysis. Across different parking lots, reductions in tree size were consistently associated with reduced apparent soil access. A previous study from Florida, USA was used for comparison of regional data, permitting conclusions on canopy reductions, relative to specification of design space for tree establishment.     

论中国农业信息化体系的建立与完善

论证了我国实施农业信息化的必要性,分析了目前农业信息化存在的问题,并从6个方面提出了建立农业信息化体系的对策。     

Reduced tree health and seedling production in fragmented Fagus sylvatica forest patches in the Montseny Mountains (NE Spain)

Habitat fragmentation results in smaller and more isolated populations that may be at higher risk of extirpation or further decline in comparison with their more continuously distributed progenitors. Risks to fragmented populations have frequently been considered from the perspective of population genetics, however, disruption of normal plant demography may be an equal or greater threat to population persistence. We compared demographic performance and tree health in continuous and fragmented forest plots with similar tree size structure and local climatic and physiographic conditions in order to determine if fragments are characterized by poor health and reproduction. We found that beech forest fragments showed lower seedling density, more tree crown damage and also higher percentage of dead trees. However, mortality of juveniles in the youngest age class was substantially lower in fragments such that long-term population structure remained similar between the two forest types. If reduced mortality compensates for reduced seedling establishment, as our data suggest, then fragmented populations should show greater long-term persistence than would be predicted based on comparison of young age cohorts alone. However, despite such demographic compensation, the decreased health of adult trees may pose an increasing future threat to the fragmented populations. Our results demonstrate the importance of integrating demographic patterns over long time periods and not relying on single year or cohort comparisons and may partly explain population genetic differences previously reported for the same populations.     

河北省滨海平原区设施类型及灌水技术发展分析

为解决河北省蔬菜设施存在的诸如设施老化,结构不合理,参数不合理,灌水技术落后等问题,本研究对河北省滨海平原区的秦皇岛、山海关、昌黎至滦河口片的设施类型及灌水方式进行调研,了解了该分区设施类型及灌水方式的发展演变过程,并且提出适合该分区发展的理想设施类型为第四类日光温室,合理的前屋面采光角应该为33°5′￣33°18′;后屋面角应为34°￣35°。这一结果为研究区以后发展新日光温室及旧温室改造工作提供参数参考依据。     

用胶原酶消化法培养德保矮马耳缘组织成纤维细胞初探

 将德保矮马耳缘组织经胶原酶消化法培养成原代细胞，并成功建立起该组织成纤维细胞系。这种细胞贴壁生长，具有密度接触性抑制性质；该方法获得的原代细胞经传代后接种，细胞群体倍增时间（PDT）为35.9 h；细胞染色体众数2n = 64的细胞数占91.3%～92.8%；乳酸脱氢酶（LDH）、苹果酸脱氢酶（MDH）同工酶分析，没有其它细胞系污染；细菌、真菌、病毒、支原体检测阴性。该系符合ATCC要求的细胞系鉴定项目，成为保护矮马这一国家重要畜禽品种的宝贵遗传资源，并为相关遗传学研究提供了有效的试验材料。同时得出胶原酶消化培养法比组织块培养法在获得原代细胞速度快；组织块培养法的细胞群体倍增时间（PDT）为48 h。     

石阡县马尾松种子园的营建

摘要：从优树选择、园址选择、嫁接技术等方面介绍了马尾松种子园的建立和经营管理技术,种子园的营建加速了石阡县马尾松良种化进程,获得不断提高的良种提供理论依据和科学保障,可以为马尾松良种选育与良种生产奠定坚实的物质基础。     

耕地资源管理信息系统下节水灌溉模型建立的初步构想

通过对区域节水规划、水文地质、水利工程、气候、土壤、作物、区域生态、经济及社会发展状况的研究,在耕地资源管理信息系统下建立相对独立完整又密切相关的符合区域水分管理和农业生产实际的节水灌溉专家咨询决策系统和模型,并结合及时必要的数据更新与扩充,从而实现区域农业灌溉的宏观调控、最佳灌溉的预测预报、实现节水知识的技术咨询、耕地资源水肥气热计算机管理、节水灌溉与作物布局、结构调整、现代化管理的同步发展。     

芝麻资源核心收集品的建立

通过对预选出的８８４ 份芝麻资源核心收集品农艺性状的进一步鉴定核查和修正之后,采用离差平方和法分组进行系统聚类分析,依据决选核心收集品数量为预选核心品的５０％ 的原则、并考虑组间遗传多样性差异,随机挑选出４５３ 份核心资源,建立了中国芝麻资源核心收集品。对４５３ 份核心收集品代表性分析结果表明：核心资源的株型、花色等１０ 个非数值型性状共３５ 种表现型各占比例与预选核心品基本一致,含油量、千粒重等４ 个数量性状的均值,标准差等６ 个特征值与预选品相近     

羊踯躅离体叶片再生体系的建立

为了建立羊踯躅规模化无性繁殖和高效遗传转化体系,以羊踯躅试管苗叶片为外植体,探讨了基本培养基类型、叶片切割方式、叶位、暗培养时间及不同激素组合等因素对叶片再生不定芽的影响。结果表明：WPM培养基为最适基本培养基。垂直于主脉切割一刀并去除叶柄和叶稍的叶片再生不定芽的频率最高。羊踯躅试管苗中、上部叶片的再生能力较强,其中第5和第6位叶的不定芽诱导效果最佳。初始暗培养有利于叶片再生,暗培养10~15天的效果最佳。诱导羊踯躅试管苗叶片再生不定芽的适宜培养基为WPM+TDZ 1.0 mg/L+IAA 1.0 mg/L,其不定芽分化率和平均分化芽数分别达到82.3%和7.2个。     

高丝胶蛋白含量家蚕品种资源库的构建及应用

利用杂交育种、丝胶蛋白含量跟踪检测等方法,构建了能分泌白色、绿色、黄色、橘红色丝胶蛋白的18个品种组成的资源库,其丝胶蛋白含量位于93.92～100%,为制备纯天然、不变性的高品质丝胶蛋白及其在化妆品、医药、食品和纤维改性材料等领域的利用提供高品质原料。