植物蔗糖转运基因家族功能分化的生物信息学分析

［目的］用生物信息学方法分析植物蔗糖转运基因家族的功能分化,并明确具有正选择作用的点突变在植物蔗糖转运基因进化过程中的作用。［方法］在基因组水平上对植物的蔗糖转运基因进行鉴别和分类,并利用DIVERGE和PAML软件分别进行功能分化和正选择替代分析。［结果］经基因组检测,发现蔗糖转运基因家族除在单细胞藻类植物中不存在外,在其他植物中均普遍存在;系统发育分析将植物中蔗糖转运基因分成了5个亚群,并发现亚群间存在Ⅰ型功能分化现象;此外,在3个亚群内检测出了显著的正选择效应。［结论］植物蔗糖转运基因家族在长期进化过程中形成了亚群间的功能分化,同时,具有正选择作用的点突变在该基因家族进化过程中起到重要作用。     

木兰门作物RubisCO大亚基的分子适应性进化研究

[目的]研究玉米、水稻等木兰门作物RubisCO大亚基的分子适应性进化。[方法]以玉米、水稻等木兰门作物为研究对象,利用利用密码子替换模型和位点间取不同∞值的最大似然法模型对叶绿体rbcL基因进行分子适应性进化分析。[结果]RubisCO受到正选择作用,并鉴定出了6个正选择位点。[结论]该研究鉴定的6个正选择位点对于研究RubisCO大亚基催化活性和作物改良具有重要的指导意义。     

The multi-functionality of paddy farming in Korea

The multi-functionality of paddy field and irrigation water has become a hot issue recently in Asian monsoon regions. Asian people know why they have to conserve the paddy farm where the sustainable functions have been historically inherited and maintain the rural community where the unique cultures have been traditionally created. But, the real value of multi-functionality has not been clearly highlighted as much worthy as it has. We should evaluate the characteristics of multi-functionality of paddy farming correctly and transmit them to the people of Western countries under quite different conditions of upland fields. In Korea, several studies on the multi-functionality of paddy farming have been performed with positive and negative viewpoints. This paper shows the results and the discussion of the researches to get global recognition on the multi-functionality of paddy farming.

依赖于参数的泛函微分方程正周期解的存在性

考虑依赖于参数的泛函微分方程x′(t)=-a(t)g(x(t))x(t)+λb(t)f(t,x(t-τ_1(t)),x(t-τ_2(t)),…,x(t-τ_n(t))).利用不动点定理,得到了上述方程正周期解存在的充分条件。     

中国冰川的规模及其评价方法探讨

本文采用以“冰川覆盖率”为首要指标的多指标综合分析,讨论了中国冰川的规模及分布。作为分析方法,又提出“有效冰川作用正差”概念,并对其特征及应用进行了尝试性探讨。上述研究表明,“有效冰川作用正差”与“冰川覆盖率”呈良好的指数相关,反应了冰川发育规模及分布的自然规律。     

日本“肯定列表制”对中国莲藕出口的影响

笔者通过分析比较了日本“肯定列表制”和中国无公害蔬菜规定的农业化学品的残留限量标准。得出:“肯定列表制”对莲藕等蔬菜的农业化学品的残留限量标准种类多,要求严格,对中国莲藕等蔬菜产品的对日出口增加了难度。“肯定列表制”实施3个多月来,中国的莲藕的出口量和创汇额与2005年“肯定列表制”实施前同期相比分别下降了约7.7%和6.6%。对照“肯定列表制”,中国的无公害标准简单,欠具体,农民和莲藕加工出口企业在生产和加工中对“肯定列表制”的认识和重视不够,原料基地建设不能满足加工出口的需要等是中国莲藕生产和加工中存在的主要问题。按“肯定列表制”的要求完善中国的莲藕标准化生产体系,引导农民按标准组织生产,帮助企业建立生产基地,提高莲藕产品的深加工程度,拓展日本以外的出口市场等,是促进中国莲藕出口的有效途径。     

山药栽培数学模型及优化农艺的研究

对山药综合栽培措施进行了二次旋转回归正交试验,建立了优化产量模型,根据数学中函数极大值的概念和农业经济学边际效应理论,分析了5个试验因素的关系,筛选了优化产量数学模型的山药农艺措施,并分别求出五因素中4个因素处于平均水平时,山药获取最高产量和最大经济效益(优质产品最高)的山药种块重量、种植密度和氮、磷、钾施用量。为总结山药高产、优质配套栽培、优化农艺措施提供了可靠的科学依据。     

具功能性反应和干扰的三种群食饵-捕食者扩散系统的周期解

利用重合度理论中的延拓定理,讨论了具有功能性反应和干扰的食饵-捕食者扩散系统的全局正周期解的存在性,得到了保证周期解存在的充分条件．     

Origin of positive δC of emitted CO2 from soils after application of biogas residues

Bioenergy production from renewable organic material is known to be a clean energy source and therefore its use is currently much promoted in many countries. Biogas by-products also called biogas residues (BGR) are rich in partially stable organic carbon and can be used as an organic fertilizer for crop production. However so far, many environmental issues relevant when BGR are applied to agricultural land (soil C sequestration, increased denitrification and nutrient leaching) still have to be studied. Therefore a field experiment was set up to investigate the degradation of BGR and its impact on the decomposition of native soil organic matter based on a natural abundance stable isotope approach. Maize, a C₄ plant has been used as bioenergy crop, therefore the δ¹³C of total C in BGR was −16.0‰_PDB and soil organic matter was mostly derived from C₃ plant based detritus, SOM thus showed a δ¹³C of −28.4‰_PDB. Immediately after BGR application, soil-emitted CO₂ showed unexpectedly high δ¹³C of up to +23.6‰_PDB, which has never been reported earlier. A subsequent laboratory scale experiment confirmed the positive δ¹³C of soil-emitted CO₂ after BGR addition and showed that obviously, the added BGR led to a consumption of dissolved inorganic C in soils. Additionally, it was observed that the δ¹³C of CO₂ driven from inorganic C of BGR (BGR-IC) by acid treatment was +35.6‰_PDB. Therefore, we suggest that also under field conditions the transformation of BGR-IC into CO₂ contributed largely to CO₂ emissions in addition to the decomposition of organic matter, which affected both the amount and the carbon isotope signature of emitted CO₂ in the initial period after BGR application. Positive δ¹³C of inorganic C contained in BGR was attributed to processes with strong fractionation of C isotopes during anaerobic fermentation in the biogas formation process.     

Effects of ecological compensation meadows on arthropod diversity in adjacent intensively managed grassland

An important goal of ecological compensation areas (ECAs) is to increase biodiversity in adjacent intensively managed farmland and the agricultural landscape at large. We tested whether this goal can be achieved in the case of the agri-environmental restoration scheme implemented for Swiss grassland using five large arthropod taxa (bees, true bugs, orthopterans, ground beetles and spiders) representing different ecological and functional groups. The species richness and abundance of all groups and species, respectively, was measured along 100 m transects from ECA-meadows into the adjacent intensively managed grassland at 24 sites. Species richness of all arthropod taxa except ground beetles, and the abundance of 63% of the 234 arthropod species sampled with at least five individuals were higher in ECA-meadows than in their surroundings, while the total abundance of spiders and ground beetles was higher in intensively managed meadows. The abundance of 8% of these species were only increased in the ECA-meadows themselves (“stenotopic” species) but 40% had increased abundance both in the ECA-meadows and the adjacent grassland, declining exponentially with increasing distance from ECA-meadows (“edge species”). The 90%-decay distances for these edge species differed among taxonomic groups (117 ± 18 m for true bugs, 137 ± 24 m for spiders, 152 ± 34 m for bees, 167 ± 5.7 m for orthopterans, 185 ± 34 m for ground beetles; mean ±1 standard error) and independent of taxonomic group were larger for large-sized or predacious species than for small-sized or phytophagous species. Because the average distance between neighbouring ECA-meadows in Swiss grassland is only 73 ± 4 m, the current agri-environment scheme very likely enhances arthropod diversity and possibly associated ecosystem services in the Swiss agricultural landscape at large.