Conservation status of the world's hagfish species and the loss of phylogenetic diversity and ecosystem function

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灌溉模式对红壤稻田土壤环境及水稻产量的影响

为优化红壤丘陵区水稻生产的水分管理模式,以中国科学院桃源农业生态试验站长期田间定位试验为研究对象,模拟分析了江南红壤丘陵区4种不同灌溉模式对稻田的土壤环境及系统生产力的影响。结果表明,土壤环境方面,雨养稻田与模拟节水灌溉相比,水稻生育期白天平均土壤温度高0.3～0.5℃;长期淹灌红壤稻田土壤体积质量相对较低,土壤蓄水能力较强,有利于土壤有机质的累积和氮素质量分数的提高,淹灌表层（0～20 cm）土壤全氮质量分数较雨养和湿灌分别高10.8%和8.8%,土壤有机质质量分数分别高7.0%和6.1%。由于江南丘陵区降雨资源丰富,早稻期间雨量充沛,处理间早稻产量差异主要来自不同灌溉模式下土壤环境尤其是土壤养分条件的改变;晚稻期间,水分则成为水稻产量提高的限制因子,雨养区晚稻产量显著低于其他灌溉处理。相对于其他水分管理模式,红壤双季稻田淹水灌溉模式能够获得更高的水稻产量。     

Resource patch array use by two squirrel species in an agricultural landscape

Eastern grey squirrels (Sciurus carolinensis) and North American red squirrels (Tamiasciurus hudsonicus) were studied among wooded patches within an agricultural mosaic. Fifteen sites south of Ottawa, Canada, with differing landscape and local features were censused using tracking boards placed in a woods or wooded fencerow. Regression analyses of landscape compositional and physiognomic variables within a 1-km radius isolated the best predictors of grey and red squirrel abundance and activity. Grey squirrels were found in both small woods and fencerows in farm landscapes but were not found in large woods. A polynomial regression of wooded patch size explained 79% of the variance in grey squirrel abundance. Grey squirrel activity was correlated with the percent cover of soybeans in the landscape. Red squirrels were found in fencerows, small and large woods; activity was correlated with the percent cover of both woods and corn crop in the surrounding landscape. These results indicate that distributions of both species are influenced by multiple landscape elements, but that grey squirrels may rely on fragmented agricultural landscapes whereas red squirrels make more use of both native woodland and altered landscapes.     

赤泥基质改良及种植植物的筛选研究

采用四因素三水平正交改良方案对盐分含量较高的赤泥基质进行了改良研究和植物种植试验。结果表明:4种改良剂均能降低土壤的pH值,其中磷石膏对赤泥基质的pH影响最大;赤泥基质的持水率则主要受膨润土的影响,膨润土对赤泥基质的盐分具有一定的吸附或交换作用,添加量为20%时,赤泥可溶性盐含量降低了50%;3种供试植物中黑麦草最适宜改良后的赤泥基质种植。     

缅甸魔芋(Amorphophallus Muelleri)资源分布及产业基本概况

在缅甸13个含葡甘聚糖的野生魔芋种中，黄魔芋、白魔芋和红魔芋是当地民众习惯上按色泽进行区分的3类魔芋，每类又各包含几个种。其中, 上缅甸以红魔芋和缅甸白魔芋居多，下缅甸则以黄魔芋和耐热型白魔芋(A. variabilis)为多。缅甸魔芋现仍以野生资源为主，加工品以干片为多，大宗产品出口中国，部分销往日本。因比较优势明显，日本已开始与缅方合作在缅规模化种植弥勒魔芋。     

Genotypic Differences in Root Hair Deformation and Subsequent Nodulation for Red Clover under Different Additions of Starter N Fertilization

Red clover cultivars, including diploid and tetraploid, are commonly used in legume‐based pasture mixtures. However, information on nodulation under different starter N regimens is limited. We hypothesized that there is genetic variability among different red clover cultivars for nodulation. A root hair deformation assay was conducted using three diploid (AC Christie, Tapani and CRS15) and three tetraploid (Tempus, CRS18 and CRS39) red clover cultivars by inoculating them with Rhizobium leguminosarum biovar trifolii. Nodulation and morphological characteristics of two selected red clover cultivars, AC Christie and Tempus, were determined under five starter N concentrations (0, 0.2, 0.4, 0.8 and 1.6 mg per plant). Inoculation with rhizobia increased root hair deformation with significant interaction across cultivars. Nodulation was delayed under high starter N concentrations, and genotypic differences were evident for days‐to‐nodule initiation. There was a positive quadratic response to starter N for AC Christie and a negative quadratic response for Tempus for nodulation. Tempus had more active nodules (92 %) than AC Christie (73 %). The genetic variability of red clover cultivars should be considered in N fixation studies and their response to availability of initial N.     

Antigen-nonspecific macrophage factors modulating the antibody response in vitro

Antibody response to an antigen involves the co-operation between three types of cells: macrophages, T cells and B cells. The cognate interactions between these cells play a fundamental role in the expression of a specific antibody response, but the last is modulated by antigen-nonspecific soluble factors produced either by macrophages or by T cells. Macrophages elaborate a spectrum of molecules modulating the function of lymphoid cells; among them are IL1 and prostaglandins of the E series, which are respectively enhancer and inhibitor of the antibody response in vitro. These molecules alter T cell and B cell activities through different mechanisms involving activation or inhibition of IL2 production, or alteration of cells surface antigens. However, the cellular events following the fixation of soluble factor on its receptors are not known.     

The effects of physostigmine on the electroretinogram in the beagle dog

The purpose of the study was to correlate electroretinogram (ERG) parameters with increasing levels of plasma, erythrocyte and ocular tissue cholinesterase inhibition using the beagle dog as a model for human neurovisual toxicity. The anticholinesterase compound physostigmine was administered at various steady-state intravenous infusion rates based on pharmacokinetic estimates of plasma and red blood cell cholinesterase inhibition. The most sensitive parameter was the b-wave amplitude of the rod response, which was significantly depressed compared to pretreatment at all levels of acute cholinesterase depression. The overall maximal ERG response demonstrated a trend of declining a-and b-wave amplitudes, which corresponded with the increased levels of cholinesterase depression, but these differences were not significant. The depression of the electroretinogram rod and cone amplitudes appeared to parallel plasma cholinesterase inhibition more closely than erythrocyte cholinesterase activity. Ocular tissue cholinesterase activity was significantly depressed in the retina (70%), cornea (60%) and dorsal rectus extraocular muscle (46%). Electroretinography may be a useful physiological tool for evaluating the ocular toxicity of certain chemicals or pharmaceuticals associated with cholinesterase biomarker activity.Abbreviations AChE acetylcholinesterase - Amp amplitude - BuChE butyrylcholinesterase - C _p plasma level - C _ss steady-state plasma concentration - D _L loading dose - e ^–kt the rate of elimination over time (t) - ERG electroretinogram - k elimination rate constant - Lat latency - MBW metabolic body weight - O₁–O₅ consecutive oscillatory potential wavelets - PreTx pretreatment - R rate of infusion - R _Inf rate of infusion - V _d volume of distribution     

7种药剂对苹果红蜘蛛的防治作用研究

通过试验,明确了7种药剂对苹果红蜘蛛的防治作用,为安全、合理使用和大面积推广提供一定理论依据。     

多效唑对高羊茅叶片糖酶活性的影响

高羊茅草坪草施用多效唑后，叶片的垂直生长受抑，叶片光合同化物向根系运输增强，叶片和根系中淀粉及可溶性糖含量升高。数据表明：叶片中淀粉含量与淀粉酶活性呈正相关（r=0.88)。，另外，叶片中酸性转化酶活性增加，但中性转化酶活性降低，且叶片中可溶性碳水化合物含量一直维持在较高水平，说明酸性转化酶在多效唑对草坪草叶片垂直生长的调节中起重要作用。草坪草生长动态的变化与多效唑改变碳水化合物代谢酶活性有关。可溶性糖的积累有利于增强草坪草抗逆性，促进新器官的发生。