城市化对区域生态足迹供需的影响

基于1994-2003年吉林省生态足迹时间序列,建立了城市化水平与生态足迹、生态盈亏、生态足迹强度的关系模型.结果表明:吉林省生态足迹、生态盈亏、生态足迹强度与城市化率呈显著相关;生态足迹随城市化的发展由1994年的每人1.59 hm2增至2003年的每人2.23 hm2,主要受城市化率和第三产业比例的影响;建筑用地、草地和化石燃料用地生态足迹的变化较显著,建筑用地生态足迹变化的驱动因素以人均GDP和第三产业比例为主,草地和化石燃料用地生态足迹主要受居民消费水平的影响;源于居民消费水平的驱动作用,吉林省生态赤字渐趋恶化,从1994年的每人0.319 hm2增至2003年的每人0.923 hm2;草地和化石燃料用地生态盈亏的变化最显著;在经济结构和消费结构优化的驱动下,研究期间生态足迹强度从每万元4.14 hm2降至2.35 hm2,而且仍具有较大的降低空间.通过调整经济结构和消费结构,吉林省可以消除生态赤字、实现自然资源的供需平衡.     

武夷山森林土壤生化特性的初步研究

研究了武夷山自然保护区森林土壤生化特性．结果表明,不同生境土壤呼吸作用、纤维分解作用和硝化作用等３项生化强度有明显差异,先峰岭（常绿阔叶林）＞大竹岚（毛竹林）．同一生境中的不同小生境３项生化强度的差异也很显著,尤其是呼吸作用强度,落叶层＞腐殖层＞土壤层;纤维分解作用强度,腐殖层＞落叶层＞土壤层;硝化作用强度,土壤层＞落叶层＞腐殖层．无论那一种生境３项生化强度之间,呼吸作用强度与纤维分解作用强度有一定相关性,而硝化作用强度与前两项未显示相关．不同生境土壤蔗糖酶、纤维素酶和蛋白酶等活性显著不同,大竹岚＞先峰岭．同一生境中的不同小生境３种酶活性随土壤剖面深度而降低;蔗糖酶是各生境中活性最大酶类,变化较剧;纤维素酶和蛋白酶则活性较小,变化较缓和．     

苹果斑点落叶病致病菌的鉴定及生物学特性研究

目的:明确l株分离于感病苹果株系群体的供试菌株AML0801的种类,探讨其生物学特性,为苹果抗病分子育种研究奠定基础.方法:通过形态特征描述,显微形态、超微结构观察等方法,从形态学上明确AML0801的分类.室内模拟侵染试验,了解AML0801致病性.ITS序列测定分析辅助验证供试菌株AML0801.结果:菌株AML0801的分生孢子、产孢表型等形态特征,符合苹果链格孢(Alternaria mali Roberts,A.mali)种的描述,ITS序列分析表明,AML0801与A.mali标准菌株同源性达99％.通过比较病原菌侵染试验证实AML0801具备一定的致病性.结论:结合供试菌株AML0801形态特征、ITS序列分析结果,以及室内模拟的致病性研究,可将供试菌株AML0801鉴定为苹果链格孢(A.mali).     

光合细菌H3菌株的分离及其生物学特性研究

H3菌株系由盐田微生物垫中分离获得的光合细菌株。革兰氏阴性杆菌,0.5-0.7×15-2.5μm,在培养条件改变时呈多形态,其膨大细胞可达4.0-7.0μm.单根极生鞭毛,二均分裂。菌落及液体培养物呈深紫红色。菌体蛋白质含量约50%,各种必需氨基酸齐全,并含有丰富的细菌叶绿素a和类胡萝卜素。H3菌株在光照和黑暗条件下均可生长,能利用多种有机和无机碳、氮源,并能固N2.在含0.5-7.0%NaCI培养基中均可生长。但光照、盐浓度、温度、pH和通气等条件对其生长量有明显的影响。作者对其分类地位和应用潜力作了讨论。     

湖南中部山区虫草类型及其虫草菌的生物学特性

据资料统计,虫草属Cordyceps现知的有300余种,我国约有50多个种,多分布于长江以南的亚热带和热带地区.作者曾多次去湖南,安徽虫草产地调查,在湖南中部山地发现除巳报道的亚香棒虫草之外的另一种类型的虫草,与亚香棒虫草形态有明显区别.由于该种类子座头部极少有膨大,未见产生子囊孢子,难以鉴定出种名,现将两种虫草生物学特性作出比较,供鉴别时参考.     

商陆生物学特性的初步研究

本文介绍了商陆(Phytolacca americana L.)芽萌发、叶展开、枝梢及叶生长、开花及幼果生长与果实成熟等定期观测结果,探索了其规律及相互关系.     

生姜生物学特性的研究

目的：观察生姜的生长特性与光照、土壤、水分、肥料等的关系。方法：试验观察采用随机抽样与盆栽实验相结合的方法。结果掌握了生姜的生物学特性和生长规律。结论：生姜在半遮荫的砂质土壤中生长较好,适宜的氮磷钾用量及比例,能提高生姜的产量和质量。     

球形红杆菌L2的生物学特性及其应用

从淀粉废水中分离获得一株光合细菌,经形态特征,培养特征,生理生化特征及Ｇ＋Ｃｍｏｌ％含量等生物学特性分析,确定为球形红杆菌（Ｒｈｏｄｏｂａｃｔｅｒｓｐｈａｅｒｏｉｄｅｓ）Ｌ２。该菌应用于淀粉废水处理,ＣＯＤ去除率达９５．７％发酵产类胡萝卜素,产量达２９５ｍｇ／Ｌ;作为饲料添加剂进行肉鸡饲喂,增重１６．４０％。     

烟草甲的生物学特性研究

烟草甲在安徽每年发生2～3代,以3龄以上幼虫越冬,幼虫期5～6龄,极少4或7龄。贮存期2年左右的烟叶受其为害最重（虫口密度最大）。米象金小蜂为其天敌优势种。     

沟眶象的生物学特性及行为观察

沟眶象Eucryptorrhynchus chinensis(Olivier)是臭椿林木的主要害虫之一。在宁夏银川地区该虫1年发生1代,世代不整齐,以成、幼虫越冬。卵期7~10d,幼虫共有6龄,化蛹时间为4月下旬至5月和7月下旬至8月上旬,蛹经过10~14d羽化为成虫。成虫主要啃食椿树枝条幼芽和韧皮部,幼虫危害衰弱木,有时危害生长健旺的幼树韧皮部或木质部。成虫具有假死性,喜光,活动高峰在11~17时。雌、雄虫间的单次交配时间可持续10~20min;有重复交配现象,交配的时间间隔大约是20~40min;交配结束后,雄虫仍伏于雌虫背上达20~30min。雌虫蛀孔产卵,每产1粒卵约需15min左右,每雌平均产卵40粒左右。     

乐陵金丝小枣区不同土体构型土壤的主要表征

研究表明,乐陵金丝小枣区３ 种土体构型的优劣依粘质物土体构型＞ 泥壤质土体构型＞ 砂壤质土体构型排序,此序列恰与土壤营养素含量的多寡呈正相关,与该土体构型区枣果品质优中劣相对应．     

不同土壤类型和肥力玉米地土壤养分根际效应研究

采集吉林省玉米植株及土壤样品,研究不同土壤类型和肥力,玉米不同品种和生育时期土壤－植物系统根际养分动态变化及植物吸收的相互关系,结果表明,玉米地土壤ＮＨ＾＋４－Ｎ、ＮＯ＾－３－Ｎ在根际富集,其变化主要与化肥供应有关,高肥力土壤根际有效磷亏缺,种植密度越大,根际亏缺率超大;低肥力土壤则有效磷在根际略高。高肥力土壤有效钾较高,根际有效钾富集也更明显,茎叶、根对养分的吸收量顺序为：Ｎ     

The influence of omnivorous elaterid larvae on the microbial carbon cycle in different forest soils

Summary Data are presented on the influence of Athous subfuscus larvae (Coleoptera, Elateridae) on the microbial carbon cycle in the biotically most active horizons of three contrasting beech forest soils: the A_h horizon of a mull soil on limestone (Göttinger Wald, FRG), the F/H horizon of a moder soil on new red sandstone (Solling area, FRG) and in the F/H horizon of a lime ameliorated area close to the second site. Gut content analyses demonstrated that the larvae of A. subfuscus are humiphagous and that this unspecific feeding behaviour is widely independent of soil conditions. Differences in ¹⁴C incorporation demonstrated that only the larvae in the F/H horizon of the limed moder soil directly affected primary decomposer organisms. However, the burrowing activity of the larvae in the topsoil indirectly modified the time course of beech leaf-litter decomposition in the litter layer of all three soils. The microflora of the mull soil contained 2.6%, that of the moder soil 0.7% and that of the limed moder soil 2.2% of total C. The metabolic quotient (qCO₂, 10°C) of the soil microflora was 0.0010 (mgCO₂-C·mg^-1 biomass-C·h^-1) in the mull soil, 0.0034 in the moder soil and 0.0012 in the limed moder soil. The A. subfuscus larvae generally reduced the size of the microbial C pool (<-30%) and increased the metabolic quotient of the microflora (>+50%). Considering these soil-independent effects of A. subfuscus on the C turnover of the soil microflora, the burrowing activity of humiphagous soil arthropods may generally increase nutrient availability to primary producers. The results of this study reveal that some of the micro- and mesoscale effects of humiphagous arthropods on the microbial carbon turnover in beech forest soils are surprisingly similar, even under very different soil conditions. The long-term modification of the time course of leaf litter decomposition, in contrast, indicates that the influence of humiphagous arthropods on the formation of the humus layer is soil-specific. There are profound differences in the role of humiphagous arthropods in limed moder soils and in naturally base-rich soils. It is concluded that liming increases competition within the microfloral population due to accelerated humification. The negative effect of A. subfuscus on ¹⁴C mineralization in the limed substrate could thus be explained by its effects on a microflora that was strongly limited by the availability of carbon.     

Silicate weathering in temperate forest soils: insights from a field experiment

Few studies of silicate mineral weathering have been conducted in carbonate-bearing temperate forest soils. With climate and vegetation held constant, we compared soil mineralogy and major element chemistry of soil waters from a carbonate-free temperate aspen forest site in the Cheboygan watershed, northern Michigan, with that from carbonate-containing soils from experimental tree-growth chambers (low- vs. high- fertility). All soils were well-drained sands (quartz, Na-rich plagioclase, and K-feldspar) with minor amounts of carbonate present only in the experimentally manipulated soils. The Na⁺ concentrations in soil waters corrected for atmospheric deposition (Na*) were used to compare relative rates of plagioclase feldspar weathering across sites. In natural soil water profiles, maximum concentrations of Na*, Si, and dissolved organic carbon (DOC) were observed by a depth of 15 cm, a soil zone free of carbonate minerals. Mean Na* and DOC concentrations were different in the three soils, and increased in the order natural soil < low-fertility chambers < high-fertility chambers. While low pH environments are generally viewed as enhancing weathering rates, here higher Na* appears to be related to high DOC, which is consistent with observed increases in active organic functional groups as pH increases. Our results suggest that under a specific vegetative cover, the soil carbon environment affects the weathering flux observed. Our study also suggests that disturbed soils provide an enhanced physical and chemical environment for weathering. Generalized silicate weathering models may benefit from including the enhancing effects of organic anions at moderate pH in addition to precipitation and temperature.     

Assays of invertase activity in acidic soils: Influence of buffers

Summary The influence of buffered and unbuffered systems for assays of invertase activity in a range of acidic soils (pH4.9–6.8), and a neutral soil (pH 7.1), from under pasture was determined. The buffers were those recently recommended in other studies,viz. a modified universal buffer (MUB) and a potassium phosphate buffer. The optimum pH for the invertase activity of a moderately acid soil (pH 5.5) wasc 4.0 and for the neutral soil was 5.0 With the acidic soils, invertase activity was lower in the assay system with MUB (initial pH 5.0) than in the unbuffered system, and decreased with increasing MUB molarity. The phosphate buffer was more satisfactory, even though the pH (5.0) was below its most effective range. Generally, either phosphate buffer or unbuffered systems appear suitable for measuring invertase activity in these acidic soils.     

Receptiveness of forest soils to ectomycorrhizal association:

 Soil receptiveness to a mycorrhizal association can be estimated by standard bioassay from a dose-response relationship. The method was developed using the association Pinus pinaster or Pseudotsuga menziesii with Laccaria bicolor as a model and was successfully used to characterize the receptiveness of two forest soils. From a physical and chemical point of view, both soils were receptive to the Laccaria bicolor association. Our results show that microbial factors are very important in the receptiveness of soil to ectomycorrhizal association. Ectomycorrhizal development on seedlings at outplanting sites is discussed in relation to soil receptiveness and the ecological competence of selected strains. Accepted: 11 October 1996