日本落叶松体细胞胚胎发生的研究

[目的]对日本落叶松体细胞胚胎发生进行系统研究。[方法]以日本落叶松5个品种的未成熟合子胚为外植体,研究基本培养基、品种基因型、杂交系和纯系品种对日本落叶松愈伤组织诱导的影响,以及ABA对体细胞胚成熟及植株再生的影响。[结果]通过对日本落叶松胚性愈伤组织的诱导和体细胞胚的成熟培养获得再生植株。2种基本培养基中,DCR对胚性愈伤组织的诱导频率最高,达54.0%;落叶松品种之间的愈伤组织诱导率有差异,以杂交品种愈伤组织的诱导率最高,达71.4%,优于纯系的落叶松品种（27.3%～50.0%）;在体细胞胚的成熟培养过程中,ABA可严重影响体细胞胚的发育,并影响到其以后的萌发能力和植株再生。[结论]杂交品系更有利于胚性愈伤组织诱导,ABA对日本落叶松体细胞胚胎发育起重要作用。     

A quasi-experimental analysis on the causal effects of COVID-19 on urban park visits: The role of park features and the surrounding built environment

Although many studies have explored the correlations between mobility intervention policies and park use during COVID-19, only a few have used causal inference approaches to assessing the policy’s treatment effects and how such effects vary across park features and surrounding built environments. In this study, we develop an interrupted time-series quasi-experimental design based on three-month mobile phone big data to infer the causal effects of mobility intervention policies on park visits in Shenzhen, including the first-level response (FLR) and return-to-work (RTW) order. The results show that the FLR caused an abrupt decline of 2.21 daily visits per park, with a gradual reduction rate of 0.54 per day, whereas the RTW order helped recover park visits with an immediate increase of 2.20 daily visits and a gradual growth rate of 0.94 visits per day. The results also show that the impact of COVID-19 on park visits exhibited social and spatial heterogeneities: the mobility-reduction effect was smaller in low-level parks (e.g., community-level parks) with small sizes but without sports facilities and water scenes, whereas parks surrounded by compact neighborhoods and land use were more impacted by the pandemic. These findings provide planners with important insights into resilient green space and sustainable neighborhood planning for the post-COVID era.     

醉蝶花栽培技术

介绍珠三角地区高温季节醉蝶花播种繁殖技术。在高温季节播种前,种子经过2~4℃低温和遮光催芽处理4~5 d可提高发芽率至95%以上;生长过程中用600~700 mg/kg多效唑处理能有效控制植株高度;病虫害发生期应用科学有效地防治方法,能大大提高产品观赏性。     

PDA森林资源数据智能采集和质检控制技术

结合福建省掌上森林资源调查系统的项目开发实践探讨PDA森林资源信息智能采集和质检控制技术.在充分考虑PDA硬件资源条件的基础上,分析森林资源数据特征,提取、归类数据间复杂的逻辑关系;通过构建"数据字典"进行封装,编写通用程序进行解析,实现了森林资源野外采集的智能化与质检控制的自动化.     

A New Biomass Control Method Using Ozone in Biofilters Treating Gaseous VOCs

Excessive biomass accumulation is one main problem which will deteriorate the performance stability of biofilters during long-term operation. In order to systematically explore the feasibility of using ozone to control biomass accumulation within biofilters, the influence of ozone on toluene removal performance, pressure drop through filter bed and porosity, biomass growth and carbon balance of biofilters was examined. The results showed adding ozone of concentration no more than 220 mg/m3 wouldn’t adversely affect toluene removal capacity of biofilters. When the inlet ozone concentration achieved 180~220 mg/m3, ozone could significantly control excessive biomass accumulation, improve the filter bed structure and stabilize the pressure drop through filter bed. Furthermore, accelerating the mineralization rate of toluene was the dominant way of biomass accumulation control by ozone.     

国内外主题公园发展研究动态

通过查阅国内外大量文献资料,对国内外有代表性的主题公园相关文献进行了系统分析。结果表明,欧美等国的主题公园研究主要集中于主题公园与区域旅游经济发展关系、主题公园与消费者行为和主题公园发展的影响因素与主题创新等领域,且偏重微观研究。国内主题公园研究主要侧重于主题公园的规划建设、发展趋势和主题公园对旅游业发展及城市建设的影响等宏观领域研究。在此基础上,对国内主题公园研究进行展望,提出今后的研究中应注意主题文化的明晰,软硬件同时研究;宏观与微观研究的协调发展,对主题公园的进一步研究具有指导意义。     

基于RS和GIS的毛乌素沙地生物量估测

 选取毛乌素沙地东北部的伊金霍洛旗为研究区域,以少量野外定位调查数据与其对应的遥感信息和GIS信息为基础,利用岭估计分析方法,对影响生物量估测的遥感因子和GIS因子进行了筛选优化。找出了影响生物量估测的主要因子,建立了以像元为单位的生物量估测模型,实现了区域性生物量定量估测与自动制图。     

基于GIS的黄土高原水土流失监测站点布设方法研究

在GIS空间分析的基础上,借助领域专家知识归一化各侵蚀因子,对归一化的各侵蚀因子团进行叠加再分类和定量分析计算,为黄土高原地区水土流失监测网络布设的复杂空间决策过程提供辅助决策信息。在充分考虑黄土高原地区已有水土流失监测站、点的基础上,遵循国家有关水土流失监测站、点布设的相关规程规则,采用一级控制性监测点与二级局部监测点相结合的办法共布设监测站点138个。     

MSP430单片机中SCAN IF模块在流量检测中的应用

介绍了利用LC传感器实现旋转运动测量的原理,阐述了用MSP430单片机中的SCAN IF模块实现流量检测的设计.     

旅游活动对植被的影响研究综述

综述了20世纪70年代以来有关旅游活动对植被影响的研究文献,指出旅游活动对植被的影响主要包括:影响种子发芽及苗木的成活,影响植物的生理及形态,降低植物高度及阻碍成长,影响植物的健康与活力,影响开花及结实,影响植物的更新和侵移,影响植物种类的多样性和植物群落的结构。分析了旅游活动对植物影响效应的因子,主要有:植物的生活型、生境条件、演替阶段及适应性,以及游客数量和游憩使用方式等。参76