林板纸一体化的动力、模式与障碍

在对福建省林纸林板企业办原料林基地调查的基础上,运用资产专用性理论及契约理论.从微观行为层次揭示了福建集体林区林纸林板企业40多年来林板纸一体化的动力、模式与障碍等行为机理;得出林纸林板企业林板纸一体化动力的收益最大化机制,分析了企业林板纸一体化历年来主要实施的6种模式的机理及特点,指出阻碍企业实施林板纸一体化的3个深层次原因.     

施肥模式对茶叶品质、产量构成及土壤肥力的影响

采用田间试验,比较分析了撒施、沟施和沟施覆膜3种施肥模式及沟施覆膜下氮肥施用量对茶叶品质成分、产量构成因子和茶园土壤肥力状况的影响。结果表明:沟施覆膜在一定程度上增加了茶叶产量并改善了品质,提高了茶园土壤的基本肥力状况,沟施次之,撒施效果最差。与沟施相比,沟施覆膜下茶叶的水浸出物、咖啡碱、游离氨基酸含量分别提升2.24%、7.26%、14.68%,茶多酚下降1.88%,芽叶密度、芽叶长度分别提升8.50%、8.15%;土壤表层和深层pH分别下降8.16%和5.30%,表层有机质、全氮、速效氮、速效磷、速效钾分别提升10.87%、26.74%、17.95%、34.69%、25.42%,深层有机质、全氮、速效氮、速效磷、速效钾分别提升10.38%、28.22%、25.64%、15.34%、17.97%。比较沟施覆膜下45 kg·hm-2、60 kg·hm-2、75 kg·hm-2、90 kg·hm-2 4种施氮量对茶叶品质、产量构成以及土壤肥力提高的效果,结果表明随着施氮量的增加,茶叶品质及产量构成和茶园土壤肥力增加,但施氮75 kg·hm-2与90 kg·hm-2处理的茶叶品质及产量构成因子间差异不显著,说明沟施覆膜条件下施氮肥75 kg·hm-2即可满足茶园生产需求。     

Prevalence of stocked whitefish in River Kemijoki,Finland, inferred by micro X‐ray fluorescence analysis of otoliths

Micro X‐ray fluorescence (µ‐XRF) analysis of otoliths was evaluated as a method to estimate the proportion of stocked one‐summer‐old whitefish Coregonus lavaretus L. in catches of adult fish (n = 20) ascending the River Kemijoki to spawn. Laser ablation inductively coupled plasma mass spectrometry (LA‐ICP‐MS) analysis was applied as control. Polished otoliths were scanned with µ‐XRF to obtain strontium maps that were used to infer visually the provenance of the whitefish. Thirteen of the fish showed signs of being stocked as one‐summer‐old fingerlings. LA‐ICP‐MS was applied to determine the elemental composition in a spot outside the core of the otolith. The results were largely consistent with the visual inspection of the µ‐XRF mapped otoliths. In conclusion, µ‐XRF mapping successfully identified whitefish stocked as one‐summer‐old fingerlings. The vast majority of whitefish returning to the River Kemijoki to spawn were stocked fish.     

汉中市农村生活源水污染物排放系数调查及核算

为研究汉中市农村居民生活水污染物在全国范围内的赋存特征及其对环境的污染负荷,测算农村居民生活污水的排放系数,通过实地采样与问卷调查的方式收集数据并采用排污系数法核算了汉中市地区居民污染物排放量。结果表明,受地理地貌、人均日用水量、经济状况、年龄组成和日用餐次数等因素的影响,汉中市不同区域居民的生活水污染物的排放系数有所不同;村处理设施对化学需氧量、五日生化需氧量、氨氮、总氮和总磷的去除率效果显著,但对动植物油的去除效率不明显。调研可为陕西省首次进行的农村生活源水污染物排放量的核算提供数据支撑,进一步健全我国生活污染源信息数据库。     

黑水虻油替代豆油对草鱼生长性能、抗氧化能力和肠道菌群的影响

为研究黑水虻油替代豆油在草鱼生产实践中的效果,本实验以黑水虻油替代草鱼基础饲料中0（SO）、25%（BSO25）、50%（BSO50）、75%（BSO75）和100%（BSO100）的豆油并配制成5种等氮等脂的饲料,饲喂草鱼[初始体质量（13.37±1.07 g）]56 d后检测生长性能、体成分、血清生化指标、抗氧化能力、肠道和肝脏组织结构及肠道菌群组成等变化。结果显示,各组之间草鱼增重率（WGR）、特定生长率（SGR）、饲料系数（FCR）、肥满度（CF）、脏体比（VSI）和肝体比（HSI）变化均不显著。与SO组相比,BSO25和BSO50组血清超氧化物歧化酶（SOD）活性显著增加,SM75和SM100组的丙二醛（MDA）含量均显著降低,BSO50、BSO75和BSO100组的过氧化氢酶（CAT）活性均显著上升。BSO100组肝细胞呈现为不规则形状,血清中谷草转氨酶（AST）、谷丙转氨酶（ALT）及低密度脂蛋白（LDL-C）的水平均显著高于SO组。BSO100组群落多样性指数Sobs、Shannon和丰富度指数Chao、Ace均显著高于SO组。研究表明,在本实验条件下,黑水虻油替代饲料中100%的豆油虽然不会影响草鱼的生长,能提高草鱼抗氧化能力及肠道菌群的丰度和多样性,但在BSO100组中,草鱼肝脏受损,长期饲喂会对机体产生不利影响,因此在草鱼饲料中黑水虻油不应全部替代豆油,建议替代比例不超过75%。     

Do changes in carbon allocation account for the growth response to potassium and sodium applications in tropical Eucalyptus plantations?

Understanding the underlying mechanisms that account for the impact of potassium (K) fertilization and its replacement by sodium (Na) on tree growth is key to improving the management of forest plantations that are expanding over weathered tropical soils with low amounts of exchangeable bases. A complete randomized block design was planted with Eucalyptus grandis (W. Hill ex Maiden) to quantify growth, carbon uptake and carbon partitioning using a carbon budget approach. A combination of approaches including the establishment of allometric relationships over the whole rotation and measurements of soil CO(2) efflux and aboveground litterfall at the end of the rotation were used to estimate aboveground net production (ANPP), total belowground carbon flux and gross primary production (GPP). The stable carbon isotope (δ(13)C) of stem wood α-cellulose produced every year was used as a proxy for stomatal limitation of photosynthesis. Potassium fertilization increased GPP and decreased the fraction of carbon allocated belowground. Aboveground net production was strongly enhanced, and because leaf lifespan increased, leaf biomass was enhanced without any change in leaf production, and wood production (P(W)) was dramatically increased. Sodium application decreased the fraction of carbon allocated belowground in a similar way, and enhanced GPP, ANPP and P(W), but to a lesser extent compared with K fertilization. Neither K nor Na affected δ(13)C of stem wood α-cellulose, suggesting that water-use efficiency was the same among the treatments and that the inferred increase in leaf photosynthesis was not only related to a higher stomatal conductance. We concluded that the response to K fertilization and Na addition on P(W) resulted from drastic changes in carbon allocation.     

A synthetic lectin analog for biomimetic disaccharide recognition

Carbohydrate recognition is biologically important but intrinsically challenging, for both nature and host-guest chemists. Saccharides are complex, subtly variable, and camouflaged by hydroxyl groups that hinder discrimination between substrate and water. We have developed a rational strategy for the biomimetic recognition of carbohydrates with all-equatorial stereochemistry (beta-glucose, analogs, and homologs) and have now applied it to disaccharides such as cellobiose. Our synthetic receptor showed good affinities, not unlike those of some lectins (carbohydrate-binding proteins). Binding was demonstrated by nuclear magnetic resonance, induced circular dichroism, fluorescence spectroscopy, and calorimetry, all methods giving self-consistent results. Selectivity for the target substrates was exceptional; minor changes to disaccharide structure (for instance, cellobiose to lactose) caused almost complete suppression of complex formation.     

Weathering of sulphide minerals and trace element speciation in tailings of various ages in the Guanajuato mining district, Mexico

We studied the behavior of the trace elements (TE) As, Cu, Pb and Zn associated with sulphide minerals in tailings of different age at the Guanajuato mining district, Mexico. The objective was to determine the dominant fractions into which the TE move as tailings age and to identify how much time is needed until the dominant metal fractions approach equilibrium. We collected 21 samples from the surface of mine waste deposits of different ages (0, 2 , 4, 16, 70, 75, and 100 years), and measured their aqua regia extractable contents of As, Cu, Pb and Zn. We also applied a sequential extraction procedure to quantify water soluble TE as well as TE associated with carbonates, iron oxides, sulphides and the residual fraction. The mineralogy was analysed by X-ray diffraction, and selected samples were studied on polished specimens through a stereoscopic microscope. The TE in samples extracted with aqua regia ranged between 10 and 168 mg kg^− 1 for As, 12 to 194 mg kg^− 1 for Cu, 31 to 308 mg kg^− 1 for Pb, and 122 to 1129 mg kg^− 1 for Zn, and varied in a wide range within each age group of tailings. Water soluble Cu, Pb and Zn contents were below detection limits in almost all samples, which was attributed to the alkaline pH (7.17 to 8.61) in the tailings. Water extractable As was detected only in tailings older than 16 years, and concentrations ranged between 0.06 and 7.58 mg kg^− 1. The proportion of TE associated with sulphides decreased in the tailings as they age, while the proportion of TE associated with iron oxides increased with time of exposure to the atmosphere, approximating equilibrium after 60 years for As, Cu and Zn, and after 40 years for Pb. Observations of polished specimens suggests that oxidation proceeds until coatings of secondary minerals cover and protect sulphide mineral grains from further weathering. First order rate equations were adjusted to the proportions of TE associated with either sulphides or iron oxides. Assuming that the TE in sulphide fractions correspond to arsenopyrite (FeAsS), chalcopyrite (CuFeS₂), galena (PbS) and sphalerite (ZnS), the relative oxidation rate of sulphides followed the order: PbS > ZnS > FeAsS ≈ CuFeS₂, while the relative affinity of the elements with iron oxides followed the sequence Cu ≈ Zn > As > Pb.     

Effects of nucleo-cytoplasmic interactions on leaf volatile compounds from citrus somatic diploid hybrids

Three diploid citrus somatic hybrids (cybrids) were produced by fusions combining nucellar callus-derived protoplasts of Willow Leaf mandarin (Citrus deliciosa Ten.) and Commune clementine (Citrus clementina Hort. ex Tan.) with, respectively, leaf protoplasts of Eureka lemon [Citrus limon (L.) Burm.] and Marumi kumquat [Fortunella japonica (Thunb.) Swing.] and leaf protoplasts of Marumi kumquat. Ploidy and origins of the nuclear, chloroplastic, and mitochondrial genomes were investigated by flow cytometry and nuclear and cytoplasmic simple sequence repeat analyses. Volatile compounds were extracted from the leaves of the three cybrids by a pentane/ether (1:1) mixture, analyzed by GC-MS, and compared to those of their parents. The cybrids were found to be very close to their nucleus-giving parent, suggesting that the main information for volatile compounds biosynthesis is contained in the nucleus. However, nucleo-cytoplasmic interactions occurred: the (mandarin + lemon) cybrid, possessing nucleus and chloroplasts of lemon and mitochondria from mandarin, synthesizes more monoterpene alcohols and esters than its nucleus-giving parent; the (clementine + kumquat) cybrid, possessing nucleus from kumquat and organelles from mandarin, synthesizes more monoterpene and sesquiterpene hydrocarbons and sesquiterpene alcohols than its nucleus-giving parent.