Age,sex and beauty: methodological dependence of age‐ and sex‐dichromatism in the great tit Parus major

Carotenoid‐based colour expression is frequently involved in sexual dichromatism, particularly in bird plumage, suggesting a role in sexual selection. Despite much work on expression of the carotenoid‐based ventral plumage coloration of the great tit (Parus major), which represents a popular model in evolution and ecology, a consensus on even the most basic demographic patterns of variation (e.g. age and sex differences) is lacking. This may reflect the use of variable methods for analysing colour variation, although what is not clear, either in this case or in general, is the extent to which these alternative methods are equally effective at describing age‐ and sex‐related dichromatism. Using data obtained over 4 years from a large sample of free‐ranging great tits, we examined how colour‐scoring methodology influences estimates of age‐ and sex‐related dichromatism. We compare: (1) principal components analysis‐derived scores; (2) tristimulus colour variables; (3) a visual model‐independent, carotenoid‐focussed colour score; and (4) two colour scoring methods based on avian visual models, examining how they assess colour variation with respect to age and sex to determine how methodology may influence results. We demonstrate clear age‐ and sex‐dependent expression of this colour trait, both in our own data and in meta‐analyses of results from great tit populations across Europe, and discuss the merits of the various colour scores, which yield very different estimates of the extent of age‐ and sex‐dependent dichromatism. We show variation is likely to be visible to conspecifics and propose a novel, visual model‐derived scoring system for describing variation in carotenoid‐based colour patches, where the perceived signal is divided into independent chromatic and achromatic components, in line with current understanding of visual perception. The present study highlights the impact of colour‐scoring methodology and shows that, as novel measures continue to be developed, researchers should consider carefully how they quantify colour expression. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 101 , 777–796.     

Use of terrestrial invertebrates for biodiversity monitoring in Australian rangelands,with particular reference to ants

Abstract Taken literally, the aim of biodiversity monitoring is to track changes in the biological integrity of ecosystems. Given the overwhelmingly dominant contribution of invertebrates to biodiversity, no biodiversity monitoring programme can be considered credible if invertebrates are not addressed effectively. Here we review the use of terrestrial invertebrates, with a particular focus on ants, as bioindicators in Australia in the context of monitoring biodiversity in Australia's rangelands. Ant monitoring systems in Australia were initially developed for assessing restoration success following mining, and have since been applied to a wide range of other land‐use situations, including grazing impacts in rangelands. The use of ants as bioindicators in Australia is supported by an extensive portfolio of studies of the responses of ant communities to disturbance, as well as by a global model of ant community dynamics based on functional groups in relation to environmental stress and disturbance. Available data from mining studies suggest that ants reflect changes in other invertebrate groups, but this remains largely undocumented in rangelands. The feasibility of using ants as indicators in land management remains a key issue, given the large numbers of taxonomically challenging specimens in samples, and a lack of invertebrate expertise within most land‐management agencies. However, recent work has shown that major efficiencies can be achieved by simplifying the ant sorting process, and such efficiencies can actually enhance rather than compromise indicator performance.     

南亚热带常绿阔叶林土壤微生物生物量碳氮年际动态特征及其影响因子

土壤微生物是土壤有机质和养分循环的主要驱动者,研究土壤微生物生物量碳氮变化、稳态特征及其对环境因子内在的长期响应机理具有重要意义。以南亚热带常绿阔叶林土壤为对象,对土壤微生物生物量碳和氮(MBC和MBN)、土壤有机碳(SOC)、总氮(TN)、总磷(TP)、可溶性碳(ROC)、速效氮(AN)、pH、土壤温度(ST)和土壤含水量(SWC)进行连续10年监测;应用方差分析、相关性和回归分析及稳态分析等探究MBC和MBN的年际变化和稳态特征及主要影响因素。研究结果表明:(1)旱季MBC和MBN含量分别在171.32-358.45和25.90-54.08 mg/kg区间波动,雨季分别在394.01-507.97和68.40-88.05 mg/kg区间波动;旱、雨季的MBC含量年际间变化显著(P < 0.05),但MBN含量仅在旱季变化显著(P < 0.05)。雨季MBC和MBN含量均显著高于旱季(P < 0.01),且雨季的MBC和MBN含量是旱季的2倍以上。(2)旱、雨季的MBC与MBN之间均呈显著正相关(P < 0.05)。在旱季,MBC和MBN均与ROC和AN含量显著正相关(P < 0.05),此外,MBN含量也与TP(P < 0.05)和SOC(P < 0.01)显著正相关。在雨季,仅SOC与MBN呈显著正相关(P < 0.05)。(3)在旱季,MBC含量变化主要受ROC(P < 0.05)和AN(P < 0.001)影响,MBN则受AN控制(P < 0.05)。在雨季,AN(P < 0.05)主导了MBC的变化,TP(P < 0.05)和SOC(P < 0.05)是MBN变异的主导因子。AN(P < 0.001)和SOC(P < 0.001)是旱、雨季土壤MBC和MBN变化的主导因子。(4)土壤MBC和MBC/MBN稳态指数在年际间均为绝对稳态型(P>0.05);雨季的MBN(P=0.685)为绝对稳态型,但旱季为非稳态(P < 0.01,H > 1)。雨季微生物熵显著高于旱季(P < 0.01),表明土壤有机质质量及养分利用效率更高。综上,MBC和MBN含量受季节更替显著影响,且主要受土壤SOC和AN的影响;受旱季水分限制,MBN的稳态更差。     

The importance of canopy complexity in shaping seasonal spider and beetle assemblages in saltmarsh habitats

1. Habitat structure, including vegetation structural complexity, largely determines invertebrate assemblages in semi‐natural grasslands. The importance of structural complexity to the saltmarsh invertebrate community, where the interplay between vegetation characteristics and tidal inundation is key, is less well known. 2. It was hypothesised that canopy complexity would be a more important predictor of spider and beetle assemblages than simple vegetation attributes (e.g. height, community type) and environmental variables (e.g. elevation) alone, measured in two saltmarsh regions, south‐east (Essex) and north‐west (Morecambe Bay) U.K. Canopy complexity (number of non‐vegetated ‘gaps’ in canopy ≥ 1 mm wide) was assessed using side‐on photography. Over 1500 spiders and beetles were sampled via suction sampling, winter and summer combined. 3. In summer, saltmarshes with abundant spider and beetle populations were characterised by high scores for canopy complexity often associated with tussocky grass or shrub cover. Simple vegetation attributes (plant cover, height) accounted for 26% of variation in spider abundance and 14% in spider diversity, rising to 46% and 41%, respectively, with the addition of canopy complexity score. Overwintering spider assemblages were associated with elevation and vegetation biomass. Summer beetle abundance, in particular the predatory and zoophagous group, and diversity were best explained by elevation and plant species richness. 4. Summer canopy complexity was identified as a positive habitat feature for saltmarsh spider communities (ground‐running hunters and sheet weavers) with significant ‘added value’ over more commonly measured attributes of vegetation structure.     

OsDMI3‐mediated activation of OsMPK1 regulates the activities of antioxidant enzymes in abscisic acid signalling in rice

In rice, the Ca²⁺/calmodulin (CaM)‐dependent protein kinase (CCaMK) OsDMI3 has been shown to be required for abscisic acid (ABA)‐induced antioxidant defence. However, it is not clear how OsDMI3 participates in this process in rice. In this study, the cross‐talk between OsDMI3 and the major ABA‐activated MAPK OsMPK1 in ABA‐induced antioxidant defence was investigated. ABA treatment induced the expression of OsDMI3 and OsMPK1 and the activities of OsDMI3 and OsMPK1 in rice leaves. In the mutant of OsDMI3, the ABA‐induced increases in the expression and the activity of OsMPK1 were substantially reduced. But in the mutant of OsMPK1, the ABA‐induced increases in the expression and the activity of OsDMI3 were not affected. Pretreatments with MAPKK inhibitors also did not affect the ABA‐induced activation of OsDMI3. Further, a transient expression analysis in combination with mutant analysis in rice protoplasts showed that OsMPK1 is required for OsDMI3‐induced increases in the activities of antioxidant enzymes and the production of H₂O₂. Our data indicate that there exists a cross‐talk between OsDMI3 and OsMPK1 in ABA signalling, in which OsDMI3 functions upstream of OsMPK1 to regulate the activities of antioxidant enzymes and the production of H₂O₂ in rice.     

Nitrate Uptake by Roots as Regulated by Nitrate Reduction Products of the Shoot

A mechanism is proposed by which secondary products of nitrate reduction in the shoot control the uptake of nitrate by the roots. KNO₃ enters the roots and is translocated to the shoot where nitrate is reduced and, at the same time, malate is produced. The reduction of nitrate is stoichiometric to the synthesis of malate (1). Part of the K-malate moves down to the root system in which malate is oxidized, yielding KHCO₃ which exchanges for KNO₃. Nitrate reduction in the shoot promotes the synthesis of malate which, after its translocation to the root, allows the preferential uptake of nitrate. Thus, plants reducing large amounts of nitrate may take up the anion without a superfluous accumulation of the cation. Furthermore, the utilization of nitrate by the shoot regulates its uptake by the root.     

检测HIV-1载量的荧光实时定量PCR技术的建立及其应用

准确测定HIV-1的前病毒载量和病毒载量的技术,在感染者预后和艾滋病患者药物治疗效果的评价以及艾滋病的其它研究方面,都具有十分重要的应用价值。以定量的HIV-1DNA和RNA为标准外参照,利用SYBRGreen荧光染料和GeneAmp5700 Sequence Detection System(5700系统),建立了测定HIV-1的前病毒载量和病毒载量的荧光实时定量PCR技术。以病毒感染细胞和培养上清为材料,测定了三种化合物(AZT,GL和WT)对细胞内的前病毒载量和培养上清中的病毒载量的抑制活性,并与合胞体形成抑制方法测定化合物抗病毒活性的结果进行了比较。根据病毒载量、前病毒载量和合胞体形成计算出的三种化合物的治疗指数均依次变小,提出以荧光实时定量PCR技术测定前病毒载量,会在评价药物在体内外根除或减少存在于CD4休止或记忆T淋巴细胞中的HIV-1前病毒方面有特别的价值。     

增强UV—B辐射对高山植物麻花艽净光合速率的影响

在高寒矮嵩草（Kobresia humilis)草甸地区以太阳短波辐射为背景,建立了人工增强UV－B辐射的实验装置,每天增补15．8kJ.m^-2的辐射剂量,模拟平流层臭氧破坏约5％时近地表面太阳UV－B辐射的增强。观测表明：UV－B辐射的增强对麻花艽（Gentiana stramianea)植物的光合作用无明显的抑制或伤害作用。相反,在早晨补充UV－B辐射的短时间内,叶片的Pn随Gs的增大而有所提高。随着UV－B辐射时间的延长,在11：30－12：30,Pn和Gs有所降低。UV－B辐射时间进一步延长后（约14：00以后）,处理和对照组叶片Pn和Gs的差异趋向不明显,增强太阳UV－B辐射后,麻花艽叶片的光合色素并无明显变化,UV－B吸收物质的含量无明显变化,麻花艽叶片厚度的直接测量表明,增强UV－B辐射能明显提高叶片的厚度。叶片厚度的增加可补偿增强UV－B辐射辐后引起的光合色素的光降解,改善单位叶面积为基础的光合速率,是高原植物对强UV－B辐射的一种适应方式。