Distribution of phosphatase activity and various bacterial phyla in the rhizosphere of Hordeum vulgare L. depending on P availability

Despite the importance of the rhizosphere for nutrient turnover, little is known about the spatial patterns of organic phosphorus mineralization by plants and by microorganisms in the rhizosphere. Therefore, the distribution of acid and alkaline phosphatase activity and the abundance of bacteria belonging to various bacterial phyla were investigated in the rhizosphere of barley (Hordeum vulgare L.) as dependent on the availability of inorganic P. For this purpose, we conducted a greenhouse experiment with barley growing in inclined boxes that can be opened to the bottom side (rhizoboxes), and applied soil zymography and fluorescence-in situ-hybridization (FISH). Acid phosphatase activity was strongly associated with the root and was highest at the root tips. Due to P fertilization, acid phosphatase activity decreased in the bulk soil, and less strongly in the rhizosphere. Alkaline phosphatase activity, i.e., microbial phosphatase activity was high throughout the soil in the control treatment and was reduced due to inorganic P fertilization especially in the rhizosphere and less strongly in the bulk soil. P-fertilization slightly increased the total number of bacteria in the rhizosphere. Moreover, P-fertilization decreased the abundance of Firmicutes and increased the abundances of Beta- and Gamma-Proteobacteria. The total number of bacterial cells was significantly higher at the root surface than at the root tip and at a distance of 30 μm from the root surface. Our results show that alkaline phosphatase activity decreased more strongly in the rhizosphere than in the bulk soil due to P fertilization, which might be because of greater C deficiency in the bulk soil compared to the rhizosphere. Furthermore, the results indicate a spatial separation between hotspots of acid phosphatase activity and hotspots of bacteria in the rhizosphere of H. vulgare. Taken together, our study shows that bacteria and phosphatase activity were very heterogeneously distributed in soil, and that the effects of P fertilization on phosphatase activity differed strongly between bulk soil and rhizosphere as well as between various zones of the rhizosphere.     

小安溪小流域治理突出生物过滤带建设效果好

在小安溪小流域综合治理中,合川市树立生态优先、科学防治的理念,将水土流失治理与生物过滤带建设以及溪河水质保护、生态观光旅游有机地结合起来,取得了较好的效果。     

海洋文化要素在滨海旅游中的作用——以舟山群岛为例构建文化承载力模型实证分析

在推进海洋文化建设的背景下对文化要素在滨海旅游中的作用进行量化,基于对滨海旅游文化承载力的分析,以舟山地区为例测量出该地区对文化感知度或是接受容纳程度的数值,结果表明:文化因素在滨海旅游中具有重要作用,并提出了加大滨海旅游中文化建设的建议。     

滨海盐土暗管排水降渍脱盐效果研究

在江苏省滨海盐土按不同埋深和间距埋设地下暗管,其降渍、脱盐作用主要表现在丰水期(7～9月)内,在试验范围内,10 m间距暗管的降渍效果最显著,但与15 m间距暗管的脱盐效果相差不明显;在较小间距(10 m)时,1.4 m埋深暗管的降渍效果优于1.2 m埋深,埋设间距≥15 m后,埋深对暗管降渍效果无明显影响,而在所有埋设间距处理中,1.4 m埋深暗管的脱盐效果均优于1.2 m埋深。综合比较分析各相关试验结果,并考虑暗管埋设的初期投资和后期维护成本,推荐间距15 m、埋深1.4 m为江苏滨海盐土降渍脱盐的地下暗管工程最佳布设参数。     

华北滨海地区土地整治中的管道输水灌溉工程研究

河北省沧州市滨海地区耕地整治潜力大,水资源严重不足,节水灌溉措施成为区域土地整治持续的重要基础。该文以沧州市南大港孔庄子南土地整治项目为例,在种植业资源环境分析的基础上,针对滨海地区土地整治项目中管道输水工程的设计,从灌溉水源情况、取水工程布置、田间管道输水灌溉工程中管道布置及保护装置的设置等方面进行了分析和探讨,认为发展管道输水灌溉工程应是滨海地区扩大土地整治规模的重要措施。     

基于3S技术的广西海岸带管理信息系统设计与研究

分析广西海岸带管理信息系统的功能模块组成、广西海岸带管理信息数据库结构和系统构建技术流程,建立广西海岸带管理信息系统,实现海岸带资源信息共享,为广西海岸带的开发利用提供技术支持。     

苏北滨海盐土区稻田轮作的改良效应

分别以耕种两年的稻-菜和稻-麦轮作地为研究对象,并以邻近未轮作的滨海盐土为对照,通过田间试验,研究稻田轮作对土壤理化及生物学性质的影响。结果表明:各稻田轮作对土壤均有程度不等的改良作用,尤以稻-菜轮作改良效果较佳,且上层土壤改良优于下层。与对照相比,稻-菜轮作0～20 cm土层的土壤密度、pH值和全盐量分别减小了13.42%、0.94和71.48%,有机质、蛋白酶、脲酶、蔗糖酶、过氧化氢酶和磷酸酶活性分别增加了0.48、0.61、3.50、0.17、8.11、4.50倍,细菌、真菌、放线菌和微生物总数增加了128.14、13.83、1.54、24.66倍。因此,稻-菜轮作可以降低盐分,改善土壤结构,增加有机质,提高土壤生物活性,是改良滨海盐土的有效措施。     

外来树种在天津滨海地区的引进及在园林中的应用

综述了天津滨海地区引进外来树种的背景及背景和可行性,总结了外来树种在园林中的应用情况。指出外来树种丰富了该地区物种,增加了景观色彩,提高了生态安全。讨论了滨海地区近期外来树种的引进、应用等问题。     

建设冀中南经济区生物产业新增长极战略研究

在简述冀中南生物产业发展现状及问题的基础上,提出冀中南经济区生物产业发展重点,即不断提升冀中南生物产业发展战略地位,高度重视以石家庄为核心的冀中南地区在河北省生物产业发展中的战略地位,全面加强以石家庄为核心的冀中南地区生物产业新增长极建设。     

辽宁省海岸带木本植物属的分布区类型与地理成分分析

通过对辽宁省海岸带1 km内木本植物进行的统计,确定该区域共有木本植物40科75属127种,隶属于中国种子植物在世界上属的15个大分布区类型中的13个分布类型,占86.7%,说明辽宁省海岸带木本植物属的分布十分丰富,其中温带分布类型在辽宁省海岸带中占绝对优势,达65%以上;而热带分布仅占一定的比例,为20.0%。分析表明辽宁省海岸带温带性质占主导成分,同时具有明显的热带性质,起源古老。