出土梓木形态结构及物理力学性质研究

为了解木质文物的腐蚀状况,并为保护技术的研究提供科学依据,该文以长台关出土的棺木为研究对象,对出土梓木的绝对含水率、基本密度、顺纹压缩强度、木材中纤维素的结晶度等物理力学性质进行了测试,对出土梓木的干湿形态结构、结晶形态进行了显微观察,并与梓木新材做了比较。出土梓木最大含水率是饱水梓木新材的4.25倍,基本密度仅为梓木新材的1/3,顺纹压缩强度0.04 MPa;湿态下,出土梓木的细胞壁严重空化、松动;超临界脱水干燥后的出土梓木胞间层保存完好,次生壁变薄,多数已塌陷,并与胞间层脱离;出土梓木中不仅非结晶区纤维素降解,而且近一半的结晶纤维素遭受降解而流失。研究表明,长台关出土梓木已遭受严重降解,高度腐朽。      

不同棚龄大棚土壤微形态特征研究

 从微观角度研究分析不同棚龄的蔬菜大棚土壤的微形态特征,结果表明大棚土壤微形态结构随种植时间、耕作管理措施而产生较大变化。为大棚蔬菜生长发育创造良好环境条件提供了相关的理论依据。     

The optimum dietary isoleucine requirement of juvenile hybrid grouper (Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂)

A six‐week growth trial was conducted to evaluate the optimum dietary isoleucine requirement of juvenile hybrid grouper (Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂). Seven isoenergetic (3,400 kcal/kg of dry matter), isoproteic (496 g/kg of dry matter) and isolipidic (70 g/kg of dry matter) diets were formulated to contain graded Ile levels (7.3, 11.3, 15.7, 19.6, 23.5, 26.8 and 30.8 g/kg, dry‐matter basis). Each experimental diet was fed to triplicate groups of 12 hybrid grouper juveniles (average initial body weight: 6.00 ± 0.01 g/fish). Experimental fish were randomly distributed into 21 glass tanks (L 60 × W 45 × H 50 cm) connected to mechanical and biological water filters as a recycling system. Fish were fed twice daily (08:00 and 16:00) to apparent satiation. After the sampling of the growth trial, the remaining fish in each group were fed their corresponding diets for 2 d and then exposed to 4 mg Cu²⁺ · L^?1 water for 24 hr. Results showed that growth performance and feed utilization were significantly affected by different dietary Ile levels (p < .05). Weight gain percentage (WG%), protein productive value (PPV), protein efficiency ratio (PER) and feed efficiency (FE) were increased as dietary Ile level increased, reaching a peak value at 19.6 g/kg dietary Ile, and thereafter, these four parameters declined as dietary Ile level continued to increase. Daily feed intake (DFI) showed an opposite tendency of variations as FE. The quadratic regression analysis of WG%, PPV, PER and FE against dietary Ile levels indicated that the optimum dietary Ile requirement for hybrid grouper was estimated to be 19.8, 20.8, 19.4 and 19.1 g/kg dry matter, respectively. Among all experimental treatments, fish fed 19.6 g/kg dietary Ile had the highest expression of growth and protein synthesis‐related genes, including growth hormone (GH) in pituitary, insulin‐like growth factor 1 (IGF‐1), growth hormone receptor 1 (GHR1), target of rapamycin (TOR) and S6‐kinase 1 (S6K1) in liver. Gut micromorphology was significantly influenced by dietary Ile levels. After the exposure to 4 mg Cu²⁺ · L^?1 water for 24 hr, fish fed 19.6 g/kg dietary Ile had the highest survival and the best immunologic manifestation among all experimental treatments. Generally, the optimum dietary Ile requirement for maximum growth of hybrid grouper was estimated to be 19.8 g/kg dry matter, corresponding to 39.9 g/kg dietary protein.     

The impact of rainfall in remobilising particulate matter accumulated on leaves of four evergreen species grown on a green screen and a living wall

Green walls have recently been identified as a green infrastructure (GI) solution to the problem of particulate matter (PM) air pollution. Green wall systems mostly use evergreen plants as the leaves are retained throughout the year; however, researchers have argued that evergreen foliage becomes saturated with PM and fails to capture more due to a long retention time on the leaves. This study evaluated the potential of (simulated) rainfall to remobilise these captured PM and renew the capture ability of the leaf surfaces of four evergreen species (Heuchera villosa Michx, Helleborus × sternii Turrill, Bergenia cordifolia (Haw.) Sternb., Hedera helix L.) used in a living wall and a green screen located along a busy road in Stoke-on-Trent, UK. The approach used compared PM densities on pre- and post-rain exposed leaf surfaces (using leaf halves of the same leaf) and using a paired t-test to identify any significant reduction in PM due to the rainfall. An Environmental Scanning Electron Microscope (ESEM) and ImageJ image analysis software were employed to quantify the PM densities on leaves. The reduction of PM on leaves, following exposure to 16 mm hr⁻¹ simulated rain in six different rainfall durations was estimated in all four species in order to evaluate any variable impact of rainfall on different species of plants. PM wash-off levels on leaves of H. helix by 41 mm hr⁻¹ rain was also evaluated, using the same rainfall durations, to assess any differential impact of rainfall intensity on PM wash-off. This study revealed a significant impact of rainfall in washing the particles off the leaves in all rainfall durations used. A one-way Anova in a Generalised Linear Model showed a differential impact of rainfall in remobilising PM on different species of plants. The rainfall with higher intensity (41 mm hr⁻¹) showed a significantly higher impact on PM wash-off compared to 16 mm hr⁻¹ rain. The results of this study demonstrated the potential of green walls to act as good PM traps throughout the year by recycling their capture surfaces.     

Radiocarbon and optically stimulated luminescence dating based chronology of a polycyclic driftsand sequence at Weerterbergen (SE Netherlands)

The chronology of polycyclic driftsand sequences in cultural landscapes has mainly been based on the combination of radiocarbon (¹⁴C) dating of intercalated organic horizons and pollen analysis. This approach, however, yields indirect age information for the sediment units. Also, as soils are dynamic systems, the pedogenetical interpretation of the ¹⁴C ages is often quite difficult.     

加积型红土剖面成壤特征及网纹化成因的土壤微形态证据

亚热带加积型红土很好地记录了中国南方第四纪以来风化特征及其变化趋势,但相应风化强度下古土壤成壤细节仍尚待进一步揭示。本文以庐山东麓海会剖面（L-HH）为研究对象,借助土壤微形态研究方法分析不同风化强度下古土壤成壤特征,并结合粒度、色度、磁化率、地球化学等指标,进一步探讨加积型红土成土环境及网纹机制。结果表明：（1）加积型红土土壤基质以黏土、胶体为主,并具有一定铁质侵染。沿剖面自下而上,胶体含量由70%减少至50%,黏土胶体与碎屑配比由8:2逐渐变化为6.5:3.5,成壤强度呈减弱趋势。（2）土壤孔隙和形成物类型沿剖面的变化差异较好地记录了土壤水分及其干湿变化。网纹红土层以线状大孔道为主,连通性好,铁质迁移活跃,铁锰质胶膜沿孔道分布且多层叠置,部分铁质胶膜有脱色现象,指示水分充足,干湿变化频繁。网纹黄棕色土层大孔道减少,孔洞、囊状孔隙增加,有一定连结性,铁锰胶膜多沿孔隙壁淀积,铁锰质结核也尤为丰富,指示水分减少,干湿变化仍然频繁。黄棕色土层,孔道极少,以面状裂隙、囊状及不规则状孔隙、孔洞为主,连结性差,淀积胶膜多为扩散-团聚型,水分少,铁游离程度降低。（3）土壤孔隙及其发育程度与网纹化程度有较好的对应关系,裂隙产生、加宽、连通是网纹化的物理学基础。（4）剖面土壤微形态特征与粒度、色度、磁化率等环境指标间有良好对应关系,是解读红土形成环境、季风演化和网纹化机制的重要土壤学指标。     

河北小五台山18种蒿属植物果皮微形态学研究

光镜和扫描电镜观察了小五台山18种1变种蒿属(Artemisia L.)植物的果皮纹饰特征。结果表明:光镜下果皮纹饰在属内具有极大的相似性,表现为纵条纹状;扫描电镜下果皮纹饰差异明显,依其特征可分为光滑波纹状、光滑搓板样梯形、宽粗糙搓板样梯形和窄粗糙搓板样梯形等4种类型。不同海拔高度,同种植物果皮纹饰稳定,近缘种的纹饰相似。在研究的5个组中,组内纹饰相似性大,组间某些种有交叉现象。说明蒿属植物果皮微形态特征在该属分类与系统进化研究中有一定意义,可以作为分类的辅助依据。     

Distribution and genesis of Fahlerden (Albeluvisols) in Germany

Fahlerden dominate large areas of the young and old moraine landscapes of N and E Germany. Fahlerden (part of Fahlerden corresponds to Albeluvisols) and their transitional subtypes are supposed to have a higher intensity of clay illuviation than Parabraunerden (Luvisols). Besides this macroscopic feature reflecting periglacial influence, micromorphological features such as lenticular platy microstructure, vesicles, and fragments of clay coatings in Bt streaks document the initiation of Fahlerde genesis, which began in the Late Glacial. A model of Fahlerde genesis chronologically connects sedimentological and periglacial processes, vegetation development, and soil‐forming processes like decalcification, clay illuviation, and humification. The classification criterion of larger differences in clay contents between E and Bt horizons to distinguish Fahlerden from Parabraunerden needs to be reconsidered, because most Fahlerden have developed in stratified parent material in periglacially influenced landscapes. The interpretation of a soil data base listing data of both soil types distributed in Brandenburg demonstrates that the difference in clay contents between E and Bt horizons may even be smaller in Fahlerden than in Parabraunerden.     

十字花科十九种种皮微形态学研究

对十字花科19种植物种皮微形态学研究的结果表明,与花粉形态相比,种皮表面的纹饰具有丰富的多样性,系非保守性状;在科以下类群的分类学研究中有较高的价值。这些种的种皮纹饰可分成4种类型,即双层网纹型(diploreticulum),乳突网网纹型(papilla-reticulum),网纹型(reticulum)和荠菜型(shepherdspure);其中前3种类型又可分为多个亚型。种皮纹饰类型与种皮化学组分之间也有一定联系。     

合欢种子硬实与萌发特性及种皮微形态与结构特征的研究

光暗交替(8h/16h)、全光照、全黑暗及70,85,100℃热水浸种处理合欢硬实种子,结合扫描电镜观察和石蜡切片技术,探讨合欢硬实种子萌发特性与种皮微形态及结构特征的关系,为合欢种苗的规模生产提供理论依据。结果表明,合欢种皮对种子的吸胀作用具有明显的机械障碍作用;交替光照和70℃热水浸泡处理效果最好,发芽率达48.9%;引起合欢种皮不透性的部位可能与种皮表层、栅栏层、骨状石细胞层均有关系,合欢种子硬实现象可能与种皮无深度裂隙有关;合欢种皮侧缘厚壁(薄壁)细胞层中有维管束,它为种皮的发育提供水分与营养。