陆地生态系统中人为因素对DOM影响研究进展

尽管DOM和WEOM只占土壤有机质的一小部分,却是土壤溶液的重要组成部分,参与众多土壤过程。本文着重介绍DOM和WEOM的定义、研究方法及森林和农田两种不同生态系统中DOM和WEOM的研究现状及耕作、施肥等农业措施对DOM和WEOM的影响。已有研究主要集中于DOC,而缺乏对DON、DOP的研究,且研究方法间差异较大。森林生态系统DOM／WEOM含量要高于草地和耕地。土地利用方式变化对DOM的影响主要取决于改变后的土地利用方式。管理措施对DOM／WEOM通常只有短暂的影响．且不同因素作用结果不一。     

Major limitations to achieving “4 per 1000” increases in soil organic carbon stock in temperate regions: Evidence from long‐term experiments at Rothamsted Research,United Kingdom

We evaluated the “4 per 1000” initiative for increasing soil organic carbon (SOC) by analysing rates of SOC increase in treatments in 16 long‐term experiments in southeast United Kingdom. The initiative sets a goal for SOC stock to increase by 4‰ per year in the 0–40 cm soil depth, continued over 20 years. Our experiments, on three soil types, provided 114 treatment comparisons over 7–157 years. Treatments included organic additions (incorporated by inversion ploughing), N fertilizers, introducing pasture leys into continuous arable systems, and converting arable land to woodland. In 65% of cases, SOC increases occurred at >7‰ per year in the 0–23 cm depth, approximately equivalent to 4‰ per year in the 0–40 cm depth. In the two longest running experiments (>150 years), annual farmyard manure (FYM) applications at 35 t fresh material per hectare (equivalent to approx. 3.2 t organic C/ha/year) gave SOC increases of 18‰ and 43‰ per year in the 23 cm depth during the first 20 years. Increases exceeding 7‰ per year continued for 40–60 years. In other experiments, with FYM applied at lower rates or not every year, there were increases of 3‰–8‰ per year over several decades. Other treatments gave increases between zero and 19‰ per year over various periods. We conclude that there are severe limitations to achieving the “4 per 1000” goal in practical agriculture over large areas. The reasons include (1) farmers not having the necessary resources (e.g. insufficient manure); (2) some, though not all, practices favouring SOC already widely adopted; (3) practices uneconomic for farmers—potentially overcome by changes in regulations or subsidies; (4) practices undesirable for global food security. We suggest it is more realistic to promote practices for increasing SOC based on improving soil quality and functioning as small increases can have disproportionately large beneficial impacts, though not necessarily translating into increased crop yield.     

Proton NMR quantitative profiling for quality assessment of greenhouse-grown tomato fruit

Tomato is an essential crop in terms of economic importance and nutritional quality. In France, the third most important region for tomato (Solanum lycopersicum L.) production is Aquitaine where the major part of production is now grown soilless under greenhouse conditions with harvest from March to November. Tomato fruit quality at harvest is a direct function of its metabolite content at that time. The aim of this work was to use a global approach to characterize changes in the fruit organoleptic quality at harvest under commercial culture conditions during an entire season for two varieties and two different fertilization practices (with or without recycling of the nutrient solution) for one variety. Absolute quantification data of 32 major compounds in fruit without seeds were obtained through untargeted (proton nuclear magnetic resonance, ¹H-NMR) quantitative profiling. These data were complemented by colorimetric analysis of ascorbate and total phenolics. They were analyzed with chemometric approaches. Principal component analysis (PCA) or partial least square analyses (PLS) revealed more discriminant metabolites for season than for variety and showed that nutrient solution recycling had very little effect on fruit composition. These tendencies were confirmed with univariate analyses. ¹H-NMR profiling complemented with colorimetric analyses therefore provided a diagnostic tool to follow the changes in organoleptic and nutritional quality of tomato. In addition the quantitative information generated will help to increase our knowledge on the mechanisms of plant response to environmental modifications. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

黄土高原环境异质性与植被的恢复与重建

黄土高原是一个独特的地理区域,由于对其原生植被的不同认识,自然区划历来富有争议.为因地制宜地进行植被建设,在辨析植被属性有关论点(黄土无林、草原次生等)的基础上,主要由现代植被证据进一步讨论黄土高原的自然地带.分析了生物气候条件在不同地域之间的分异性,阐述了植被地带特征.为充分说明植被地带性,还从历史的角度探讨了植被建设的效果.表明黄土高原环境的非均质性可表征为森林、草原等地带,不能认为黄土高原不具有森林发育的地带性环境.相对于森林地带北界森林线,森林草原地带北界应为树木线.植被建设不应局限于一种土地利用模式,不能无视疏林及稀疏灌丛在森林草原地带的客观存在.     

以能力培养为导向的基于工厂化生产实践指导的“发酵工程”教学研究与应用

"发酵工程"是生物技术和生物工程等专业的核心基础课程,应用性非常强,其工艺流程包括上游的菌种和培养基,中游发酵动力学和过程控制,以及下游的发酵产物分离制备与精制等。在实际生产过程中,工艺流程的每个阶段都是理论知识在生产实践中的具体应用。授课过程中,如果教师只介绍教材的基础理论知识,而不结合具体生产实践,学生不仅难以掌握知识点,而且对利用发酵工程生产产品的工艺流程没有深刻的认识,更不知道如何去应用理论知识指导实际生产。由于发酵工程应用的重要性,发酵工程教学质量的好坏直接影响学生的专业素质与就业情况。因此,本课程组开展了基于生产实践指导的发酵工程教学方法的研究与应用,在发酵工程课程教学中,结合生产实践中的科研经验,总结教材的理论知识与生产实践的结合点,使教材中较为抽象、复杂的理论知识具体化。这样不仅激发了学生的学习兴趣,加强了学生对理论知识的理解,更为重要的是,结合实际科研、生产过程中曾面临的问题,引导学生如何利用基础理论知识去解决这些问题,这种授人以渔的方法对于指导学生的科研和毕业后的生产实践具有重要的应用价值。     

Both landscape and local factors influence plant and hexapod communities of industrial water‐abstraction sites

1. At the landscape level, intensification of agriculture, fragmentation, and destruction of natural habitats are major causes of biodiversity loss that can be mitigated at small spatial scales. However, the complex relationships between human activities, landscapes, and biodiversity are poorly known. Yet, this knowledge could help private stakeholders managing seminatural areas to play a positive role in biodiversity conservation.
2. We investigated how water‐abstraction sites could sustain species diversity in vascular‐plant communities and two taxonomic groups of insect communities in a fragmented agricultural landscape.
3. Landscape‐scale variables (connectivity indices and surrounding levels of herbicide use), as well as site‐specific variables (soil type for vascular plants, floral availability for Rhopalocera, and low herbaceous cover for Orthoptera), were correlated to structural and functional metrics of species community diversity for these taxonomic groups, measured on 35 industrial sites in the Ile‐de‐France region in 2018–2019.
4. Rhopalocera and Orthoptera consisted essentially of species with a high degree of dispersal and low specialization, able to reach the habitat patches of the fragmented landscape of the study area. Sandy soil harbored more diverse vascular‐plant communities. Plant diversity was correlated to a greater abundance of Rhopalocera and a lower richness of Orthoptera.
5. Increasing landscape connectivity was related to higher abundance of plants and Rhopalocera, and a higher evenness index for Orthoptera communities. Higher levels of herbicide use were related to a decrease in the biodiversity of plants and Rhopalocera abundance. High levels of herbicide favored high‐dispersal generalist plants, while high levels of connectivity favored low‐dispersal plants. Specialist Orthoptera species were associated with low herbaceous cover and connectivity.
6. Water‐abstraction sites are valuable seminatural habitats for biodiversity. Changing intensive agricultural practices in surrounding areas would better contribute to conserving and restoring biodiversity on these sites.

     

大保高速公路老营段路域植被生态恢复

路域植被生态系统的恢复与重建不仅是道路生态学的重要研究内容,而且也是恢复生态学的重要研究领域.以大保高速公路老营段路域植被生态系统为对象,对比分析了8种植被恢复模式的作用效果与作用机理.研究结果表明,在相同的恢复时间内,自然恢复的植物群落中本土植物的比例相对较高,自然恢复是该区路域植被恢复的理想模式之一.随着恢复演替时间的推移,所有群落中木本植物的比例不断增加,草本植物的比例不断下降,植物群落分层现象明显,植物群落向原生植被发生进展或偏途演替.补播本土植物是促进植被恢复演替进程的主要途径之一,不仅可以增加乡土物种的比例、增加植物群落的多样性和均匀度,而且随着恢复时间的推移,可以形成层次明显、功能群组合合理的植物群落.人工蓝桉经济林不仅降低了植物群落及各功能群的多样性、丰富度和均匀度,而且在一定程度上增加了潜在生态风险.研究结果还表明,植物群落中当地物种的比例、植物群落的物种多样性和植物群落的盖度可以作为植被恢复成功与否的重要判定指标.     

"Taming tradition": medicalized female genital practices in western Kenya

This article considers the question of female genital practices at the hands of health workers in western Kenya. Recent articles in Medical Anthropology Quarterly have critically engaged with the biomedical arguments condemning such practices. This article studies the case of medicalized circumcision in which biomedical concerns over health risks have become incorporated in their vernacular practice. Although some suggest that medicalization may provide a harm-reduction strategy to the abandonment of the practice, research in one region challenges this suggestion. It argues that changing and conflicting ideologies of gender and sexuality have led young women to seek their own meaning through medicalized practice. Moreover, attributing this practice to financial motivations of health workers overlooks the way in which these "moral agents" must be situated within their social and cultural universe. Together, these insights challenge the view that medicine can remain neutral in the mediation of tradition.     

Tissue banking in South Africa: a 19-year history

The establishment of a Tissue Bank and the science of Tissue Banking in South Africa started in the 1960s and is still developing. This article describes the development and growth of Tissue Banking in South Africa. The current emphasis is to supply viable bone products that have been produced under the best possible quality controlled circumstances; with the collaboration between different Organ Donation Organisations. Through collaboration, a dramatic increase in the number of donors was noted over the years. Concurrently, there was a dramatic increase in the usage of different allograft products and now necessitates the development of new graft materials for expanding patient options. As an ongoing concern, the Tissue Bank in South Africa experienced an ever increase in costs to enhance quality/safety controls: increase in historical patient information, documentation and serological testing in a population struggling to control HIV. To date, the South African Tissue Bank has not experienced any untoward patient incidence since the 1960s and currently is getting over 500 donors per year.     

Tillage and herbicide reduction mitigate the gap between conventional and organic farming effects on foraging activity of insectivorous bats

The increased use of pesticides and tillage intensification is known to negatively affect biodiversity. Changes in these agricultural practices such as herbicide and tillage reduction have variable effects among taxa, especially at the top of the trophic network including insectivorous bats. Very few studies compared the effects of agricultural practices on such taxa, and overall, only as a comparison of conventional versus organic farming without accurately accounting for underlying practices, especially in conventional where many alternatives exist. Divergent results founded in these previous studies could be driven by this lack of clarification about some unconsidered practices inside both conventional and organic systems. We simultaneously compared, over whole nights, bat activity on contiguous wheat fields of one organic and three conventional farming systems located in an intensive agricultural landscape. The studied organic fields (OT) used tillage (i.e., inversion of soil) without chemical inputs. In studied conventional fields, differences consisted of the following: tillage using few herbicides (T), conservation tillage (i.e., no inversion of soil) using few herbicides (CT), and conservation tillage using more herbicide (CTH), to control weeds. Using 64 recording sites (OT = 12; T = 21; CT = 13; CTH = 18), we sampled several sites per system placed inside the fields each night. We showed that bat activity was always higher in OT than in T systems for two (Pipistrellus kuhlii and Pipistrellus pipistrellus) of three species and for one (Pipistrellus spp.) of two genera, as well as greater species richness. The same results were found for the CT versus T system comparison. CTH system showed higher activity than T for only one genus (Pipistrellus spp.). We did not detect any differences between OT and CT systems, and CT showed higher activity than CTH system for only one species (Pipistrellus kuhlii). Activity in OT of Pipistrellus spp. was overall 3.6 and 9.3 times higher than CTH and T systems, respectively, and 6.9 times higher in CT than T systems. Our results highlight an important benefit of organic farming and contrasted effects in conventional farming. That there were no differences detected between the organic and one conventional system is a major result. This demonstrates that even if organic farming is presently difficult to implement and requires a change of economic context for farmers, considerable and easy improvements in conventional farming are attainable, while maintaining yields and approaching the ecological benefits of organic methods.