Germination of seeds of annual and biennial celery (Apium graveolens)

Seeds of 4 annual cultivars of celery ( Apium graveolens L. No. 15, 16, 17 and 143) were able to germinate in the dark, under high temperature, in relatively high concentrations of NaCl solutions and in the presence of relatively high concentrations of the inhibitors of the biosynthesis of gibberellin, paclobutrazol and ancymidol. Seeds of two biennial cultivars [Florida and Earlibell (EB)] showed very low germinability, or failed to germinate under the same conditions. These results are discussed in terms of endogenous gibberellin levels, which may be higher in the seeds of annual cultivars as compared to biennial ones.     

Germination of annual celery (Apium graveolens) seeds: Inhibition by paclobutrazol and its reversal by gibberellins and benzyladenine

Plants of annual celery ( Apium graveolens L.) were treated with paclobutrazol during anthesis. Seeds collected from the treated plants showed a marked reduction in germination in light and failed to germinate in the dark. Application of GA_4/7 to the imbibition solution reversed the inhibitory effect of paclobutrazol while gibberellic acid (GA₃) was ineffective. Benzyladenine (BA) interaction with GA_4/7 was light and concentration-dependent. At relatively low concentrations in the dark there was a synergistic effect, but at higher concentrations, especially in the light, BA, antagonized the GA_4/7 effect. Seedlings emerging from the seeds from paclobutrazol-treated plants were only slightly shortened. It is suggested that paclobutrazol applied to the mother plants inhibited the biosynthesis of endogenous GAs, which normally enable the germination of annual seeds under unfavorable conditions. Exogenously applied GA_4/7 fulfills the function of the absent endogenous GAs.     

A study by cryo-scanning electron microscopy of the initiation and early development of an inflorescence in glasshouse celery (Apium graveolens L. var. dulce (Miller) Pers.) grown under inductive conditions

The morphology of flower initiation and early development in glasshouse celery (Apium graveolens L. var. dulce (Miller) Pers.) cv. Celebrity was studied by means of apical dissections and cryo-scanning electron microscopy. Easily recognisable morphological features were used to define seven stages in the early development of the inflorescence. A highly significant linear regression was established between the logarithm of the apical diameter (measured diametrically across the apical dome between the two most recently initiated leaf or inflorescence primordia) and these discrete floral stages. There was no strong evidence that either the origin or the slope of the regression varied with different combinations of temperature (viz. 10°C or 14°C) and daylength (viz. natural, short or long) which were conducive for the initiation and development of an inflorescence. It is suggested that both apical diameter and floral stage may be used as parameters for assessing the influence of environmental factors such as temperature and daylength on the floral development of glasshouse celery.     

Evaluating evolutionary pressures and phylogenetic signal in earthworms: a case study – the number of typhlosole lamellae in Hormogastridae (Annelida,Oligochaeta)

Rarely have phylogenetic comparative methods been used to study the correlation between phenotypic traits and environmental variables in invertebrates. With the widespread convergence and conservativeness of the morphological characters used in earthworms, these comparative methods could be useful to improve our understanding of their evolution and systematics. One of the most prominent morphological characters in the family Hormogastridae, endemic to Mediterranean areas, is their multilamellar typhlosole, traditionally thought to be an adaptation to soils poor in nutrients. We tested the correlation of body size and soil characteristics with the number of typhlosole lamellae through a phylogenetic generalized least squares (PGLS) analysis. An ultrametric phylogenetic hypothesis was built with a 2580‐bp DNA sequence from 90 populations, used in combination with three morphological and 11 soil variables. The best‐supported model, based on the Akaike information criterion, was obtained by optimizing the parameters lambda (λ), kappa (κ), and delta (δ). The phylogenetic signal was strong for the number of typhlosole lamellae and average body weight, and was lower for soil variables. Increasing body weight appeared to be the main evolutionary pressure behind the increase in the number of typhlosole lamellae, with soil texture and soil richness having a weaker but significant effect. Information on the evolutionary rate of the number of typhlosole lamellae suggested that the early evolution of this character could have strongly shaped its variability, as is found in an adaptive radiation. This work highlights the importance of implementing the phylogenetic comparative method to test evolutionary hypotheses in invertebrate taxa.     

The logic of protein post-translational modifications (PTMs): Chemistry,mechanisms and evolution of protein regulation through covalent attachments

Protein post-translational modifications (PTMs) play a crucial role in all cellular functions by regulating protein activity, interactions and half-life. Despite the enormous diversity of modifications, various PTM systems show parallels in their chemical and catalytic underpinnings. Here, focussing on modifications that involve the addition of new elements to amino-acid sidechains, I describe historical milestones and fundamental concepts that support the current understanding of PTMs. The historical survey covers selected key research programmes, including the study of protein phosphorylation as a regulatory switch, protein ubiquitylation as a degradation signal and histone modifications as a functional code. The contribution of crucial techniques for studying PTMs is also discussed. The central part of the essay explores shared chemical principles and catalytic strategies observed across diverse PTM systems, together with mechanisms of substrate selection, the reversibility of PTMs by erasers and the recognition of PTMs by reader domains. Similarities in the basic chemical mechanism are highlighted and their implications are discussed. The final part is dedicated to the evolutionary trajectories of PTM systems, beginning with their possible emergence in the context of rivalry in the prokaryotic world. Together, the essay provides a unified perspective on the diverse world of major protein modifications.     

区域生态合作机制下的可持续农户生计研究——以"稻改旱"项目为例

世界各国在协调生态保护和经济发展的过程中,常常面临着制度和管理问题,区域合作机制为解决这些难题提供了长效思路.京冀两地的“稻改旱”项目是区域合作机制下的一项有益尝试,农户生计的提升则是此项目成功的关键.基于可持续生计分析框架,对密云水库上游的农户生计进行了详细调查,对参加“稻改旱”项目的农户和未参加该项目的农户生计进行了比较分析.结果表明,“稻改旱”项目显著改变了当地农户的生计资本、生计行为和生计后果.参加“稻改旱”项目的农户拥有较多的生产性物质资本和社会资本,减少了种植业和养殖业种类,减少了碳酸氢铵使用量;增加了工资性劳动供给,“稻改旱”项目对农户的总体收入水平有着显著的正向作用.调查显示,农户普遍支持“稻改旱”项目和区域合作的长期继续进行.研究也为提升区域合作和构建可持续生计提出了建议.     

Vegetative multiplication and patch colonisation of Asarum europaeum subsp. europaeum L. (Aristolochiaceae) inferred by a combined morphological and molecular study

Asarum europaeum subsp. europaeum (Aristolochiaceae) is a rhizomatous herb forming distinct patches in calcareous broadleaved forests. Within natural stands, patches were mapped. In two regions, at least four patches were dug out, and connections between leaf modules through rhizomatous spacers were checked for signs of clonal reproduction (decay, breaking). Modules were sampled for amplified fragment length polymorphism (AFLP) fingerprinting to test whether they represent unique genets or are merigenets of a larger genet (split up by clonal reproduction), respectively.Morphologically, merigenet-relationships were only revealed in few cases with disrupted spacers between modules. With the obtained AFLP profiles for two primer combinations, the samples could be assigned to genets; clonal descendants of the same genet were readily identified. In one patch analysed in detail, 18 samples from 17 unconnected “plants” belonged to only two genets, which were morphologically divided into two and 15 merigenets, respectively. These two genets probably belonged to different maternal lineages and came into contact after lateral spread from the established clones. They showed divergent affinities to samples from adjacent patches (which all represented unique genets).The findings support the suitability of the combined morpho-ecological and molecular approach: compared to either method alone, it allows a more detailed analysis and interpretation of the fine-scale clonal structure, patch colonisation and especially of vegetative multiplication (with morpho-ecological studies to discern clonal growth and clonal reproduction and AFLP fingerprinting for genet and merigenet identification, respectively).     

Diet and dietary selectivity of Cane Toads (Rhinella marina) in restoration sites: a case study in Far North Queensland,Australia

Cane Toads (Rhinella marina, formerly Bufo marinus) in restoration sites on the Atherton Tableland in NE Australia consumed invertebrates belonging to 11 different taxa with ants being the most abundant prey item. Principal component analyses showed that the composition of invertebrates in Cane Toad diet is largely a reflection of invertebrates found in pitfall and leaf litter samples suggesting that the species is an indiscriminant feeder. However, pitfall samples contained more Collembola and Isopoda than were found in Cane Toad stomachs. The Cane Toad may benefit from restoration management practices by utilizing food resources enhanced by mulching and providing microhabitats (e.g. rock piles, logs) as shelter. While further studies would be needed to test this practitioners working in areas where the Cane Toad is problematic may consider trade‐offs between attracting invertebrates and Cane Toads by monitoring provided microhabitat features.     

山水林田湖草健康发展时空异质性及其驱动力——以广西北部湾经济区为例

深入评估典型资源要素生态健康的时空异质性及其社会经济自然驱动机理,对实现可持续发展目标具有重要意义。然而,探究区域山水林田湖草(海)健康发展时空异质性及其驱动力的研究案例较少。广西北部湾经济区覆盖内陆与沿海6市,定位为生态环境综合治理先行区。以此为研究区,运用正态云模型、Dagum基尼系数、主成分分析和时空地理加权回归等模型,在综合评价的基础上,分析其2005-2020年山水林田湖草(海)健康发展的时空异质性,并依据系统论深入解析驱动力。结果表明:(1)除北海市的山水林田湖草(海)为亚健康外,其他均为健康状态,经济区内陆3市健康指数的基尼系数(0.095)高于沿海3市(0.016),存在时空非均衡性,超变密度(46.71%)和市域间差异(44.93%)是主要原因;(2)影响健康发展的驱动因子主要为:城镇土地利用率(0.427)>城乡居民可支配收入(0.397)>年均降水量(0.377)>房地产开发投资规模(-0.333)>建成区绿化覆盖度(0.261);(3)影响健康发展的驱动要素表现为:土地投入程度(0.611)>土地利用程度(0.442)>经济城镇化(-0.393)>自然条件(0.23),各因素均存在时空非平稳性。研究表明土地集约利用、城镇化发展和自然环境条件是广西北部湾经济区山水林田湖草(海)健康发展的主要驱动力,表现为自然环境条件起基础保障、土地集约利用起正向促进、经济城镇化起负向抑制的作用机理,提高城镇土地利用率、提升城乡居民可支配收入、扩大建成区绿化覆盖度并控制房地产开发规模是促进健康发展的关键抓手。     

Mitochondrial DNA depletion and fatal infantile hepatic failure due to mutations in the mitochondrial polymerase γ (POLG) gene: a combined morphological/enzyme histochemical and immunocytochemical/biochemical and molecular genetic study

Combined morphological, immunocytochemical, biochemical and molecular genetic studies were performed on skeletal muscle, heart muscle and liver tissue of a 16‐months boy with fatal liver failure. The pathological characterization of the tissues revealed a severe depletion of mtDNA (mitochondrial DNA) that was most pronounced in liver, followed by a less severe, but still significant depletion in skeletal muscle and the heart. The primary cause of the disease was linked to compound heterozygous mutations in the polymerase γ (POLG) gene (DNA polymerase γ; A467T, K1191N). We present evidence, that compound heterozygous POLG mutations lead to tissue selective impairment of mtDNA replication and thus to a mosaic defect pattern even in the severely affected liver. A variable defect pattern was found in liver, muscle and heart tissue as revealed by biochemical, cytochemical, immunocytochemical and in situ hybridization analysis. Functionally, a severe deficiency of cytochrome‐c‐oxidase (cox) activity was seen in the liver. Although mtDNA depletion was detected in heart and skeletal muscle, there was no cox deficiency in these tissues. Depletion of mtDNA and microdissection of cox‐positive or negative areas correlated with the histological pattern in the liver. Interestingly, the mosaic pattern detected for cox‐activity and mtDNA copy number fully aligned with the immunohistologically revealed defect pattern using Pol γ, mtSSB‐ and mtTFA‐antibodies, thus substantiating the hypothesis that nuclear encoded proteins located within mitochondria become unstable and are degraded when they are not actively bound to mtDNA. Their disappearance could also aggravate the mtDNA depletion and contribute to the non‐homogenous defect pattern.     

基于山地-绿洲-荒漠系统的生态系统服务正负价值测算——以新疆玛纳斯河流域为例

基于不同生态单元分析生态系统服务正负价值有助于全面客观地了解生态系统服务的异质性。选择典型山地-绿洲-荒漠系统(Mountain-Oasis-Desert System,MODS)下的玛纳斯河流域作为研究区,以1990年、1995年、2000年、2005年、2010年及2015年Landsat系列遥感影像为数据源,采用修正后的生态系统服务价值系数对不同生态单元下的生态系统服务正负价值进行估算。结果表明:(1)1990—2015年玛纳斯河流域土地利用/覆被变化较为显著,耕地、水域及建设用地面积呈现增加趋势,林地、草地及未利用地面积呈减少趋势,其中耕地和未利用地面积变化最为剧烈,建设用地增幅最大,林地减幅最大。(2)研究时段内,研究区正向价值远高于负向价值,且净价值小幅度增加。正向价值在经历"增加-减少-减少-增加-增加"的变化过程后呈现增加趋势,并呈现山地区>绿洲区>荒漠区的特征;各负向价值均表现为不同程度的增大趋势,其中温室气体排放、化肥流失及水资源消耗是流域内最为突出的负向生态系统服务,三者价值之和占比在不同时间段上均达90%以上;净价值由研究初期的8947.89×10<...     

Characterisation and Normalisation Factors for Life Cycle Impact Assessment Mined Abiotic Resources Categories in South Africa: The manufacturing of catalytic converter exhaust systems as a case study (10 pp)

Goal and Background Current Life Cycle Impact Assessment (LCIA) procedures have demonstrated certain limitations in the South African manufacturing industry. The aim of this paper is to propose new characterisation and normalisation factors for classified mined abiotic resource depletion categories in the South African context. These factors should reflect the importance of mined resources as they relate to region-specific resource depletion. The method can also be applied to determine global factors. Methods The reserve base (as in 2001) of the most commonly produced minerals in South Africa is used as basis to determine characterisation factors for a non-renewable mineral resources category. The average production of these minerals from 1991 to 2000 is compared to economically Demonstrated and Demonstrated Marginal Reserves (and not ultimate reserves) to obtain the characterisation factors in equivalence units, with platinum as the reference mineral. Similarly, for a non-renewable energy resources category, coal is used in South Africa as equivalent unit as it is the most important fossil fuel for the country. Crude oil and natural gas resources are currently obtained from reserves elsewhere in the world and characterisation factors are therefore determined using global resources and production levels. The normalisation factors are based on the total economic reserves of key South African minerals and world non-renewable energy resources respectively. A case study of the manufacturing of an exhaust system for a standard sedan is used to compare LCIA results for mined abiotic resource categories that are based on current LCIA factors and the new South African factors. Results and Discussion The South African LCIA procedure differs from current methods in that it shows the importance of other mined resources, i.e. iron ore and crude oil, relative to PGMs and coal for the manufacturing life cycle of the exhaust system. With respect to PGMs, the current characterisation factors are based on the concentrations of the metals in the ores and the ultimate reserves, which are erroneous with respect to the actual availability of the mineral resources and the depletion burden placed on these minerals is consequently too high. Conclusions The South African LCIA procedure for mined abiotic resources depletion shows the significance of choosing a method, which is inline with the current situation in the mining industry and its limitations. Recommendations and Outlook It is proposed to similarly investigate the impacts of the use of other natural resource groups. Water, specifically, must receive attention in the characterisation phase of LCIAs in South African LCAs.