山西桑干河流域湿地植被优势种群种间关系研究

采用χ2检验、Pearson积矩相关系数和Spearman秩相关系数检验研究了山西桑干河流域湿地植物群落的种间关系,分别测定了36种植物,共630个种对的种间关联(或相关)。结果表明,1)χ2检验共有79个种对为正关联,16个种对为负关联(P<0.05或P<0.01,下同);Pearson相关系数有51个种对为正相关,34个种对为负相关;Spearman秩相关系数有61个种对呈正相关,14个种对呈负相关。2)χ2检验不能反映两个种对间的数量变化关系,应用Pearson积矩相关系数和Spearman秩相关系数来刻划种对间的数量变化关系;与Pearson积矩相关系数检验相比,Spearman秩相关系数检验具有较高的灵敏度。3)物种之间正相关或正关联,主要是由于它们具有相近的生物学特性,对生境具有相似的生态适应性和相互分离的生态位所致;而物种之间负相关或负关联,则主要是由于它们具有不同的生物学特性,对生境具有不同的生态适应性和相互重叠的生态位所致。     

喀斯特山地青冈栎群落优势种的种间关系分析

采用2×2列联表的χ2检验和Spearman秩相关系数分析了喀斯特山地青冈栎（Cyclobalanopsis glauca）群落22个优势种的种间联结性和相关性。结果表明,在所组成的231个种对中,χ2检验中有100个种对为正联结,110个种对为负联结;Spearman秩相关系数检验有114个种对为正相关,117个种对为负相关,正、负联结或相关的种对数相近。正联结或正相关的种对主要体现了种间对生境具有相似的生态适应性和生物学特性,而负联结或负相关关系则主要由于对生境的不同偏好或相异的生物学特性所致。喀斯特山地高度的生境异质性促使优势种间的生态位相互分化,对生境的偏好趋异,负联结或负相关的种对趋于增加,因而喀斯特山地高度的生境异质性对植物种间关系的形成具有重要的影响。研究结果对于指导喀斯特地区进行人工植被恢复和重建具有一定的实践指导意义。     

喀斯特山地青冈栎群落优势种的种间关系分析

采用2×2列联表的χ2检验和Spearman秩相关系数分析了喀斯特山地青冈栎(Cyclobalanopsis glauca)群落22个优势种的种间联结性和相关性。结果表明,在所组成的231个种对中,χ2检验中有100个种对为正联结,110个种对为负联结;Spearman秩相关系数检验有114个种对为正相关,117个种对为负相关,正、负联结或相关的种对数相近。正联结或正相关的种对主要体现了种间对生境具有相似的生态适应性和生物学特性,而负联结或负相关关系则主要由于对生境的不同偏好或相异的生物学特性所致。喀斯特山地高度的生境异质性促使优势种间的生态位相互分化,对生境的偏好趋异,负联结或负相关的种对趋于增加,因而喀斯特山地高度的生境异质性对植物种间关系的形成具有重要的影响。研究结果对于指导喀斯特地区进行人工植被恢复和重建具有一定的实践指导意义。     

青藏高原东北边缘桦木林木本植物种间联结

青藏高原东北边缘地区位于我国东部季风区、西北干旱区与青藏高原高寒区的交汇地带,该区既兼具3大自然区的特点,又具有边缘地带气候波动不稳定性和自然生态环境的脆弱性,是全球变化重点监测的地区之一。研究青藏高原东北边缘亚高山桦木林的种间联结,不仅有助于更深刻地认识该地区桦木群落的结构、功能和演替,对于维持该地区群落稳定性以及生态恢复具有重要意义。本文选取青藏高原东北边缘桦木林中20个优势种,采用方差比率法(VR)检验多物种间的联结性,2×2列联表分析共同出现百分率(JI)、点相关系数(Ф)、Dice指数(DI)来表示种间联结程度,用重要值的Pearson相关和Spearman秩相关来检验相伴出现的机率等方法分析其种间关联性。结果表明:群落总体联结VR值为1.094,说明20个种群间表现出净正关联,其统计量W值为10.94说明20个种群之间在总体上的正关联不显著;大多数种对的JI值、DI值在0.4以下,说明种对之间联结程度不显著,Φ值大部分处于[-0.2, 0.2]值域内,说明种对之间的正或负的联结性较弱;而Spearman秩相关所测得的正负关联比要大于Pearson相关所测得的,且Spearman秩相关要优于Pearson相关。从以上结果可以看出,青藏高原东北边缘三种桦树天然次生林处于不稳定的状态,即演替的中期阶段,其逐渐会被地带性植被所取代。     

路域和保护区油松林种间关联比较研究

根据大量野外调查和室内测算,运用多物种方差比率(VR)、χ~2检验、Pearson相关系数和Spearman秩相关系数以及关联测度(OI指数、AC值和点相关系数)等7个指标,对宝天高速公路路域以及与该路段毗邻的小陇山国家级自然保护区油松(Pinus tabulaeformis)群落进行种间关联的对比研究,为确定群落动态发展提供理论依据.结果表明:(1)路域生态带油松群落的总体关联性表现为显著负相关,保护区油松群落的总体关联性表现为显著正相关,保护区油松群落较路域生态带油松群落稳定;(2)χ~2检验、Pearson相关系数和Spearman秩相关系数表明路域生态带与保护区油松群落主要物种与伴生物种多以负相关为主,说明不同生境主要种群对群落内环境的要求不同;(3)关联测度值表明路域生态带油松群落中正关联程度低于保护区,负关联程度高于保护区,且多种群表现为独立分布;(4)依据路域油松林和保护区油松林种间关联度性质的不同,将路域生态带和保护区组成群落的主要物种分别划分为3个生态组:正关联生态组、负关联生态组和独立生态组,与保护区相比,路域生态带独立生态种组物种较多,显示了群落成员之间的生态协调性不同.综上表明路域生态带油松群落种间关系不密切,独立种对较多;群落内环境不够协调,种间搭配关系还不够稳定.     

泥石流频发流域失稳性坡面主要植物种间关联性

为揭示生态环境脆弱的泥石流频发流域植被群落结构特征及物种种间关系,在样方调查的基础上,基于2×2联列表,使用方差分析、χ~2检验、Jaccard指数、Pearson相关系数和Spearman秩相关系数检验,研究失稳性坡面稳定区、失稳区、堆积区的主要植物种间关联性.方差分析检验显示:稳定区与堆积区各45个种对整体上均表现显著负关联,失稳区45个种对整体表现为不显著负关联,趋于独立分布.不同检验结果显示:χ~2检验的稳定区、失稳区、堆积区种对种间显著联结的分别有1对、4对、4对,种间正、负关联的种对数量比例分别为0.55、0.67、0.67.Pearson相关分析检验的稳定区、失稳区、堆积区种对种间显著联结的分别有8对、5对、5对,种间正、负关联的种对数量比例分别为0.36、0.45、0.45.Spearman秩相关分析检验的稳定区、失稳区、堆积区种对种间显著联结的分别有10对、6对、9对,种间正、负关联的种对数量比例分别为0.5、0.55、0.6.各检验结果总体上具有相似性,但相互之间也有差异,在3个分区的各45个种对中,都是负关联种对数大于正关联种对数,大多数物种呈独立性分布且种间关系不显著.上述研究表明失稳性坡面整体上植物群落还不稳定,泥石流频发流域生态脆弱区的物种种间关系易受环境的干扰;因此在植被恢复过程中应根据种间联结关系,合理选择配置物种,以促进群落结构发展与生态环境改善.     

巨枝人工林灌木层优势种的种间联结性分析

种间联结的研究对于人工林群落的生物多样性保育和可持续经营与管理具有重要的意义,目前对巨桉人工林灌木层物种之间的作用关系知之甚少。根据野外60个样方的调查数据,运用x^2检验、Jaccard指数和Spearman秩相关系数研究了巨桉（Eucalyptusgrandis）人工林灌木层18个优势种的种间关联和相关关系。结果表明,灌木层优势种具有总体上的正联结性,但在153个种对中,具有显著正联结性的种对数约占总种对数的10％,绝大数种对表现为弱联结性或无联结性,种间关系较为松散,表明巨桉林下灌木种群具有相对独立分布的特性。研究种间关系时,种间关联结合种间相关得出的结果较好。根据分析结果将18个优势种划分为4个生态种组,生态种组内的种其资源利用方式和生态要求相似,而组间表现出明显的差异。生态种组的划分能为巨桉人工林林下灌木层的管理提供理论依据。     

桂花次生林群落主要树种种间关联及其对混交度的响应

根据2×2联列表,运用方差分析、χ2统计量度量、Ochiai指数系列技术,测定福建省长汀县桂花次生林群落14个主要树种间的总体联结关系、种对间联结显著性和关联系数,并首次引入混交度,阐述种间关联性与种间空间隔离程度之间的关系.结果表明,桂花次生林群落14个主要树种的总体种间关联性呈无关联,反映该群落处于演替的初期阶段;14个主要树种的种间联结关系中,7对具显著正关联性,2对具极显著正关联性,4对具显著负关联性,2对具极显著负关联性.91个种对中,有76个种对未达到显著水平,种对间的相互独立性较强.根据群落特征,以混交度贡献率为辅助指标,探讨呈显著关系的种对与混交度贡献率的关系,得出具生态位重迭性且呈显著正关联的种对表现出高混交度贡献率,具生态相似性且呈显著正关联的种对为避免竞争表现出较低混交度贡献率,呈显著负关联的种对表现出低混交度贡献率,混交度贡献率可为判别种间关联性提供一定的参考作用.表2参17     

塔里木荒漠绿洲过渡带植物种间关联性分析

采用2×2联列表,应用方差比率(VR)、χ2检验、种间关联指标和Pearson相关系数、Spearman秩相关系数检验等方法研究了塔里木荒漠绿洲过渡带植物群落种间关系,测定了8个主要种群种间关联性。结果表明:胡杨、柽柳和甘草、骆驼刺重要值较大(49.78%、31.21%、11.99%、11.86%),它们是构成乔木层、灌木层及草本层的优势种。植物群落大多数种对(78.57%)呈中性关联,负关联的种对数(6)多于正关联(0),种间联结松散,物种趋向于独立分布。植物群落总体关联性为显著负关联(0.568 8),不同检验方法对种对间的检验结果均为正负关联比1,反映出塔里木荒漠绿洲过渡带正处于不稳定的演替前期阶段,易受外界因素干扰而演替。乔灌木层为不显著的正关联,而乔灌木-草本层和草本-草本主要物种间呈显著负关联。因此,塔里木荒漠绿洲过渡带植被恢复应选择乔灌木作为恢复目标。     

安太堡露天煤矿复垦地不同植被类型下草本植物群落优势种种间关联

为探明煤矿复垦地不同植被类型下草本植物群落优势种种间关系和生态位特征,采用χ2检验、Pearson相关系数、Spearman秩相关系数、生态位宽度与重叠指数,研究安太堡露天煤矿复垦地不同植被类型下草本植物群落13个优势种的种间关系和生态位.结果显示,13个优势种的78个种对中,3种检验方法的正负关联比分别为37.2%、28.2%和32.1%;优势种冰草/披碱草/紫花苜蓿与西北针茅、披碱草与白榆幼苗/紫花苜蓿呈正相关;13个优势种划分为3个生态种组,导致其生态种组分化的主导因子是土壤水分;13个优势种的生态位宽度与重要值呈显著正相关,而其生态位宽度与重叠之间不存在直接的线性关系.综上表明,安太堡露天煤矿复垦地不同植被类型下草本植物群落种间联结较为松散,优势种冰草/披碱草/紫花苜蓿与西北针茅、披碱草与白榆幼苗/紫花苜蓿可用于该矿区植被恢复的优选先锋草本植物种进行混合种植.     

Applications of chitosan in food,pharmaceuticals, medicine,cosmetics, agriculture,textiles, pulp and paper,biotechnology, and environmental chemistry

Environmental Chemistry Letters - Chitosan is a biopolymer obtained from chitin, one of the most abundant and renewable materials on Earth. Chitin is a primary component of cell walls in fungi, the...     

Seaweed for climate mitigation,wastewater treatment,bioenergy, bioplastic,biochar, food,pharmaceuticals, and cosmetics: a review

The development and recycling of biomass production can partly solve issues of energy, climate change, population growth, food and feed shortages, and environmental pollution. For instance, the use of seaweeds as feedstocks can reduce our reliance on fossil fuel resources, ensure the synthesis of cost-effective and eco-friendly products and biofuels, and develop sustainable biorefinery processes. Nonetheless, seaweeds use in several biorefineries is still in the infancy stage compared to terrestrial plants-based lignocellulosic biomass. Therefore, here we review seaweed biorefineries with focus on seaweed production, economical benefits, and seaweed use as feedstock for anaerobic digestion, biochar, bioplastics, crop health, food, livestock feed, pharmaceuticals and cosmetics. Globally, seaweeds could sequester between 61 and 268 megatonnes of carbon per year, with an average of 173 megatonnes. Nearly 90% of carbon is sequestered by exporting biomass to deep water, while the remaining 10% is buried in coastal sediments. 500 gigatonnes of seaweeds could replace nearly 40% of the current soy protein production. Seaweeds contain valuable bioactive molecules that could be applied as antimicrobial, antioxidant, antiviral, antifungal, anticancer, contraceptive, anti-inflammatory, anti-coagulants, and in other cosmetics and skincare products.

     

Lead,cadmium, copper,zinc, iron,and calcium in human hair as a function of gender,age, smoking,and hair dyeing

Hair samples were collected randomly from 110 subjects (55 male and 55 female) ranging in age from (<15–60) years. Each subject was asked to complete a personal questionnaire describing his/her sex, age, general health, smoking, use of hair dyes, occupational area, and living habits. Concentrations of Pb, Cd, Cu, Zn, Fe, and Ca in human hair samples were evaluated using atomic absorption spectrometry. Results indicated that concentrations of Pb, Cd, Cu, and Zn in the hair of smokers were higher than those in the hair of non-smokers, whereas, Fe and Ca concentrations in hair of smokers were lower than those in hair of non-smokers. Moreover, the concentrations of these elements are higher in dyed hair compared with undyed hair.     

Metal passivity as mechanism of metal carcinogenesis: Chromium,nickel, iron,copper, cobalt,platinum, molybdenum

For the transition metals chromium, nickel, iron, copper, cobalt, platinum, and molybdenum, mechanisms of stable bonding in biochemistry (emphasis on carcinogenic mechanisms), chemistry, industrial chemistry, as well as epidemiological, occupational, orthopedic (implant devices) effects related to carcinogenesis, were reviewed. Hypothetically, the propensity to stable bonding (inertness), which ensures the metals’ performance capacity for consumers and industrial application, relates to their carcinogenicity. For chromium, a relationship between industrial/chemical and biological reactivity was noted for the tendency of Cr(III) ions to cause hydrolysis previous to stable bonding, as occurs during anodic passivation, leather tanning, and as indicated in biochemical studies pertaining to a mechanism of DNA condensation, which was suggested as a carcinogenic mechanism. The involvement of metal hydrolysis in both anodic passivation and biochemistry was noted also for nickel, iron, and platinum; the DNA interaction of platinum (cis-platin) is known to depend on hydrolysis. For nickel, issues of potential (V) were found important in both passivation and carcinogenicity. Comparably, the passivity behavior of cobalt and copper was found atypical, and their carcinogenicity yet unclear. Molybdenum, contained in passivated metallic implants, may relate to implant-associated carcinogenesis. Occupational carcinogenic effects were indicated for chromium, nickel, iron, and cobalt as caused by both reactive and passivated metal species. Exposure to acids and chronic respiratory irritation/infection/inflammation in workers were important cofactors in metal carcinogenesis. For wood and leather workers exposed to dust, the assumed presence in dust of metal particles abraded from alloys (sawing or cutting blades) may be a carcinogenic exposure hazard.     

Concentrations of V,Cr, Mn,Fe, Ni,Co, Cu,Zn, As and Cd in mesopelagic crustaceans from the North East Atlantic Ocean

Specimens of oceanic decapods, mysids and euphausiids, collected from the North East Atlantic Ocean during July 1985, were analysed for V, Cr, Mn, Fe, Ni, Co, Cu, Zn, As and Cd. Measurement of the metals was carried out using two techniques: inductively-coupled plasma-source mass spectrometry (ICP-MS) and atomic absorption (AAS). With the exception of the iron data, good agreement was observed between the data from the two techniques. Baseline-metal data are presented for the species measured, along with any effects of animal size on metal concentration. The data presented for oceanic animals from different trophic levels are important in studies of metal fluxes and for the assessment of markers within the food web in the oceans.