Residual ridge atrophy in complete denture wearers and relationship with densitometric values of a cervical spine: a hierarchical regression analysis

doi: 10.1111/j.1741‐2358.2011.00589.x Residual ridge atrophy in complete denture wearers and relationship with densitometric values of a cervical spine: a hierarchical regression analysis Background: The rate of residual ridge atrophy (RRR) and its association with mineral density of other bones have not yet been fully explained. Objective: To measure RRR over a 5‐year period in complete denture wearers and relate it to the density of a cervical spine (CSBD). Materials and methods: Sixty‐two patients (different gender, age, body mass index, duration of edentulousness (DE) and different denture‐wearing habits) participated. A copper stepwedge was attached to the cassette, and 50 lateral radiograms met the criteria to be included. Results: A significant decrease in vertical height was observed in all measured sites. The amount of RRR was highest in frontal areas of both jaws and decreased gradually towards lateral regions. Hierarchical regression analysis revealed that the amount of RRR in the maxillary frontal area could be explained up to 48.4% by the variable DE and only up to 6.1% by the CSBD, while gender had almost no influence (1%). Similar results were obtained for the lateral maxillary RRR (33.9%; 7%; 2%), frontal mandibular RRR (40; 8.4; 0.4%) and lateral mandibular RRR (31.5%; 3.4%; 7.7%). Conclusion: Skeletal bone density, reflecting systemic and hereditary factors, is weakly related to RRR (3.4–8.4%).     

Tackling the taxonomic impediment: a global assessment for ant‐nest beetle diversity (Coleoptera: Carabidae: Paussini)

We evaluated the completeness and historical trends of the taxonomic knowledge of the myrmecophilous ground beetle tribe Paussini (Coleoptera, Carabidae, Paussinae). Species accumulation curves were modelled using a logistic function. Similar analyses were conducted for genera and subgenera. Although not all biogeographical regions have been equally explored, accumulation curves reached a plateau in all cases. Our models predict that about 96% of the world fauna has been already described. However, the asymptotes calculated for the Australian and Oriental species should be interpreted as false plateaus because of the lack of recent research. Similarly, patterns of genera accumulation indicate that a plateau has been reached. As a result of continued debate on the use and validity of Paussini subgenera, the accumulation curves of subgenera showed stepped patterns, with no evidence of plateaus. Thus, although relatively few species are expected to be described in the future, the species accumulation curves indicate that the taxonomic inventory is not yet complete. Differences in accumulation patterns among biogeographical regions can be used to highlight the areas where more species are expected, and hence where taxonomical efforts should be concentrated. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 105 , 330–339.     

黑龙江省市县林区落叶松人工林碳储量成熟的研究

基于42株碳密度测定样木和黑龙江省各市县落叶松人工林固定样地（2006~2007年）生物量及含碳量调查数据,构建落叶松人工林单木碳储量相容性模型及林分碳储量预估模型,探讨落叶松人工林在不同立地下碳储量变化规律,确定碳储量成熟龄。结果表明：以碳储量直接作为因变量建立的单木碳储量相容性模型,拟合效果较好。在Ⅰ、Ⅱ、Ⅲ级立地条件下落叶松人工林碳储量成熟龄分别为37.8、39.2、42.5 a。研究认为,相同年龄落叶松人工林林分的碳储量随立地条件质量的提高而增加。相同立地条件下落叶松人工林林分的碳储量随年龄的增大而增加,林分平均碳积累量与连年碳积累量呈现先增大后减小的趋势,这表明林分的碳储量增长过程并不是一成不变的,其达到一定年龄后增长的幅度随年龄的增加而逐渐减少。     

煤矸石山上不同种植年限和生长期香根草各部位全氮含量及其分配比例的比较

为了探明香根草〔Vetiveria zizanioides(Linn.)Nash〕在尾矿生态系统恢复中的作用机制,以贵州省六盘水市大河煤矿煤矸石山种植3、6、8和13 a的香根草为研究对象,分别在返青期、快速生长期、成熟期和枯黄期对香根草根、茎、叶和全株的全氮含量及其分配比例进行了比较.结果表明:在种植3、6、8和13 a,香根草根、茎、叶和全株的全氮含量均在快速生长期最高,并显著高于其余生长期.随种植年限增加,返青期、成熟期和枯黄期根的全氮含量,枯黄期茎的全氮含量以及返青期全株的全氮含量均逐渐升高;返青期茎和叶的全氮含量逐渐降低;快速生长期根的全氮含量,快速生长期和成熟期茎的全氮含量以及快速生长期、成熟期和枯黄期叶和全株的全氮含量先升高后降低,并在种植8 a最高.在种植6、8和13 a,快速生长期根的全氮含量分配比例最低,而快速生长期叶的全氮含量分配比例却最高.随种植年限增加,返青期根的全氮含量分配比例逐渐升高,而返青期茎和叶的全氮含量分配比例却逐渐降低;在种植8 a,快速生长期、成熟期和枯黄期根的全氮含量分配比例以及枯黄期茎的全氮含量分配比例最低或较低,而快速生长期和成熟期茎的全氮含量分配比例以及快速生长期、成熟期和枯黄期叶的全氮含量分配比例最高.在相同种植年限和生长期,香根草茎的全氮含量及其分配比例明显低于根和叶;总体来看,返青期、成熟期和枯黄期根的全氮含量及其分配比例高于叶,而快速生长期根的全氮含量及其分配比例却低于叶.研究结果显示:随着种植年限增加和生长期推移,香根草能够合理分配氮素资源,使其在煤矸石山立足,据此认为,香根草可用于煤矸石山的生态恢复和植被重建,但种植年限不宜超过8a.     

Genotypic differences in leaf biochemical, physiological and growth responses to ozone in 20 winter wheat cultivars released over the past 60 years

Ozone (O₃) concentrations in periurban areas in East Asia are sufficiently high to decrease crop yield. However, little is known about the genotypic differences in O₃ sensitivity in winter wheat in relation to year of cultivar release. This paper reports genotypic variations in O₃ sensitivity in 20 winter wheat cultivars released over the past 60 years in China highlighting O₃‐induced mechanisms. Wheat plants were exposed to elevated O₃ (82 ppb O₃, 7 h day^?1) or charcoal‐filtered air (<5 ppb O₃) for 21 days in open top chambers. Responses to O₃ were assessed by the levels of antioxidative activities, protein alteration, membrane lipid peroxidation, gas exchange, leaf chlorophyll, dark respiration and growth. We found that O₃ significantly reduced foliar ascorbate (?14%) and soluble protein (?22%), but increased peroxidase activity (+46%) and malondialdehyde (+38%). Elevated O₃ depressed light saturated net photosynthetic rate (?24%), stomatal conductance (?8%) and total chlorophyll (?11%), while stimulated dark respiration (+28%) and intercellular CO₂ concentration (+39%). O₃ also reduced overall plant growth, but to a greater extent in root (?32%) than in shoot (?17%) biomass. There was significant genotypic variation in potential sensitivity to O₃ that did not correlate to observed O₃ tolerance. Sensitivity to O₃ in cultivars of winter wheat progressed with year of release and correlated with stomatal conductance and dark respiration in O₃‐exposed plants. O₃‐induced loss in photosynthetic rate was attributed primarily to impaired activity of mesophyll cells and loss of integrity of cellular membrane as evidenced by increased intercellular CO₂ concentration and lipid peroxidation. Our findings demonstrated that higher sensitivity to O₃ in the more recently released cultivars was induced by higher stomatal conductance, larger reduction in antioxidative capacity and lower levels of dark respiration leading to higher oxidative damage to proteins and integrity of cellular membranes.     

基于人林共生时间的森林文化价值评估

森林的文化价值是森林价值的重要组成部分,探索森林文化价值量化评估方法具有重要意义。通过文献成果集成、理论分析、案例验证相结合的方法,研究了公园尺度和区域尺度森林文化价值的量化评估方法;运用评估方法评估全国和各省森林的文化价值。森林的文化价值是森林对人类的身体健康、生活质量和精神发展所产生的积极影响。评估森林文化价值的高低,可采用以"人林共生时间"为核心的评估方法,以"文年"作为计量单位,简称"文年评估法"。森林公园的文化价值用游人在森林公园中逗留的时间来反映。区域森林的文化价值由居住人口与森林共生的基本生活时间和森林文化活动时间的两者之和共同反映。评估结果表明,中国森林公园的文化价值总体上具有很大提升空间;全国不同省份的森林文化价值总量、地均、人均、林均状况都存在很大差异;四川、广东、云南、福建、黑龙江是森林文化价值大省;上海、福建、浙江、广东、北京对单位土地森林文化价值开发充分;福建、吉林、云南、黑龙江、四川人均森林文化福利优厚;上海、天津、江苏、北京、河南对森林文化价值的需求旺盛。     

Differences in parasitic ability of Beauveria bassiana (Moniliales: Moniliaceae) in relation to Pantana phyllostachysae (Lepidoptera: Lymantridae) when feeding on different Phyllostachys pubescens (Poales: Poaceae) leaves

Differences in composition of on‐year, off‐year and new leaves in Phyllostachys pubescens (moso bamboo) forests will affect the resistance of Pantana phyllostachysae larvae and the parasitic ability of Beauveria bassiana. Pantana phyllostachysae fed on mixed leaves of on‐year, off‐year and new bamboo leaves. The activities of acetylcholine esterase (AChE) and glutathione S‐transferase (GSTs) in P. phyllostachysae larvae fed on mixed leaves were significantly higher, greatly reducing the pathogenicity of B. bassiana to P. phyllostachysae larvae compared with the treatments of off‐year and new bamboo leaves. The phenoloxidase (PO) activity in P. phyllostachysae larvae feeding on mixed leaves varied within three days after parasitization by B. bassiana, which indicated higher and less changeable PO activity compared with treatments of off‐year and new bamboo leaves. Inclusion of new leaves differed greatly due to its growth, in which, both AChE and GSTs activities were higher than the off‐year leaf treatment, leading to a lower pathogenicity of B. bassiana to P. phyllostachysae larvae feeding on new leaves compared with off‐year leaves. On the contrary, the pathogenicity of B. bassiana to P. phyllostachysae larvae feeding on on‐year leaves was lower than other treatments. AChE and GSTs activities in P. phyllostachysae larvae were lower and PO activity was less changeable, which might be related to the disadvantage of the larval surface structure to B. bassiana infection in the on‐year leaf treatment.     

银杏大小年结果植株叶片的营养元素比较研究

对银杏大、小年结果植株的不同部位的水分及N、P、K等矿质营养元素含量的月变化进行监测,并比较其差异。结果表明,在银杏的年生长周期内,大年结果植株体内比小年结果植株体内含有较足够的水分及N、P、K等矿质营养元素,能稳而均匀地供应植株各器官的生长发育;大年结果植株果叶的N、P营养元素的年平均含量高于一年生和二年生营养叶,而小年结果植株的果叶的N、P营养元素的年平均含量高于一年生营养叶,低于二年生营养叶;大、小年的一年生营养叶的N,二年生营养叶的水分和果叶的P及种子硬核期前后果叶的K含量及P/N,K/N比差异显著。因此,可采取科学的水肥管理方法,在大年过后,落叶以前,及时补充种子所消耗和带走的营养物质,维持植株体内的养分平衡,恢复树势,克服大小年结果现象。