Photochemical reflectance index as a mean of monitoring early water stress

Water stress in plants affects a number of physiological processes such as photosynthetic rate, stomatal conductance as well as the operating efficiency of photosystem II (PSII) and non-photochemical quenching (NPQ). Photochemical reflectance index (PRI) is reported to be sensitive to changes in xanthophyll cycle which occur during stress and could possibly be used to monitor changes in the parameters mentioned before. Therefore, the aim of this study was to evaluate the use of PRI as an early water stress indicator. Water stress treatment was imposed in a greenhouse tomato crop. CO₂ assimilation, stomatal conductance, light-adapted and dark-adapted fluorescence as well as PRI and relative water content (RWC_s%) of the rooting medium were repeatedly measured. The same measurements were also performed on well-irrigated plants that acted as a reference. The experiment was repeated in four consecutive weeks. Results showed a strong correlation between RWC_s% and photosynthetic rate, stomatal conductance, NPQ and operating efficiency of PSII but not with PRI when the whole dataset was considered. Nevertheless, more detailed analysis revealed that PRI gave a good correlation when light levels were above 700 µmol m⁻² s⁻¹. Therefore, the use of PRI as a water stress indicator cannot be independent of the ambient light conditions.     

Assessment of the C/N ratio as an indicator of the decomposability of organic matter in forest soils

The usefulness of the C/N ratio as an indicator of the decomposability of organic matter in forest soil was assessed. The assessment was based on the relationship between the C/N ratio and the contents of soil organic carbon (SOC), soil nitrogen (total N), dissolved total organic carbon (DTOC) and dissolved inorganic nitrogen (DIN). SOC, total N, DTOC and DIN were determined in soils sampled in coniferous and coniferous–deciduous forest sites from genetic horizons of 48 soil profiles. The variability of the above soil parameters was determined and the correlation between these parameters and the C/N values were calculated. It was found that the C/N ratio in soil was shaped by the difference in the mobility of both elements, whereas the decrease in the C content in subsequent horizons was mostly higher than the decrease in the N content, which means that the C/N value decreased with the depth of a soil profile. When the loss of SOC and total N contents occurs at a similar rate, the C/N ratio is maintained at a more or less stable level despite the advancing SOM mineralization. When the rate of the carbon release from SOM differs from that of nitrogen or when there is an N input from external sources, the C/N ratio does not adequately describe the process of SOM mineralization as well. The correlation coefficients between the C/N ratio and other parameters indicate that the relationships between them are not significant or that there is no correlation at all. It was found that the percentage of DTOC in SOC seemed to be a better indicator of SOM mineralization than the C/N ratio.     

Aggregating land use quantity and intensity to link water quality in upper catchment of Miyun Reservoir

Eutrophication resulting from nutrient enrichment decreases water quality and harms ecosystem structure and function, and its degree is significantly affected by land use in the catchment. Quantifying the relationship between eutrophication and land use can help effectively manage land use to improve water quality. Previous studies principally utilized land use quantity as an indicator to link water quality parameters, but these studies lacked insight into the impact of land use intensity. Taking the upper catchment of Miyun Reservoir as a case study, we developed a method of aggregating land use quantity and intensity to build a new land use indicator and tested its explanatory power on water quality. Six nutrient concentrations from 52 sub-watersheds covering the whole catchment were used to characterize the spatial distribution of eutrophication. Based on spatial techniques, empirical conversion coefficients, remote sensing data, and socio-economic statistical data, land use intensity was measured and mapped visually. The new land use indicator was calculated and linked to nutrient concentrations by Pearson correlation coefficients. Results demonstrated that our new indicator incorporating intensity information can quantify the different nutrient-exporting abilities of different land use areas. Compared to traditional indicators that only incorporate land use quantity, most Pearson correlation coefficients between the new indicator and water nutrient concentrations increased. This new information enhanced the explanatory power of land use on water nutrient concentrations, and so will be able to help us understand the impact of land use on water quality and guide decision making for better land use management.     

Cover‐weighted averaging of indicator values in vegetation analyses

Question: How should species cover be weighted when calculating average indicator values of vegetation relevés? Location: The Netherlands. Method: Various weighting methods were statistically investigated with 188 relevés from The Netherlands for which accurate groundwater levels were available. For each method the correlation between average Ellenberg indicator value for moisture and mean spring groundwater level was calculated. A permutation test on correlation coefficients revealed whether differences between methods were significant or not. Results: Optimization of a general weighting function did not produce a significantly higher correlation than disregarding cover and calculating the average as the arithmetical mean of indicator values. Giving a higher weight to species at both ends of the indicator scale and using indifferent species as indicators of mediocre conditions did improve the correlation significantly. Weighting species proportionate to their cover yielded a significantly lower correlation than the correlation obtained with the method that disregards cover. A significantly lower correlation was also established when taking into account the fact that cover is related to the growth strategy of species.     

Ethanol Production and Maximum Cell Growth Are Highly Correlated with Membrane Lipid Composition during Fermentation as Determined by Lipidomic Analysis of 22 Saccharomyces cerevisiae Strains

Optimizing ethanol yield during fermentation is important for efficient production of fuel alcohol, as well as wine and other alcoholic beverages. However, increasing ethanol concentrations during fermentation can create problems that result in arrested or sluggish sugar-to-ethanol conversion. The fundamental cellular basis for these problem fermentations, however, is not well understood. Small-scale fermentations were performed in a synthetic grape must using 22 industrial Saccharomyces cerevisiae strains (primarily wine strains) with various degrees of ethanol tolerance to assess the correlation between lipid composition and fermentation kinetic parameters. Lipids were extracted at several fermentation time points representing different growth phases of the yeast to quantitatively analyze phospholipids and ergosterol utilizing atmospheric pressure ionization-mass spectrometry methods. Lipid profiling of individual fermentations indicated that yeast lipid class profiles do not shift dramatically in composition over the course of fermentation. Multivariate statistical analysis of the data was performed using partial least-squares linear regression modeling to correlate lipid composition data with fermentation kinetic data. The results indicate a strong correlation (R² = 0.91) between the overall lipid composition and the final ethanol concentration (wt/wt), an indicator of strain ethanol tolerance. One potential component of ethanol tolerance, the maximum yeast cell concentration, was also found to be a strong function of lipid composition (R² = 0.97). Specifically, strains unable to complete fermentation were associated with high phosphatidylinositol levels early in fermentation. Yeast strains that achieved the highest cell densities and ethanol concentrations were positively correlated with phosphatidylcholine species similar to those known to decrease the perturbing effects of ethanol in model membrane systems.     

Proton transfer in the photoreceptors phytochrome and photoactive yellow protein.

Light-induced activation of the photoreceptors phytochrome and photoactive yellow protein (PYP) is accompanied by protonation changes of the respective chromophores and key residues in the protein moiety. For both systems, proton exchange with the external medium could be observed with pH electrode measurements and with UV-visible absorption spectroscopy using appropriate pH indicator dyes. From these signals, the stoichiometry of proton release and uptake, respectively, was determined by different calibration procedures which will be presented and discussed. Kinetic information on these processes is only available from time-resolved measurements with pH indicator dyes. Vibrational spectroscopy methods such as Fourier transform infrared spectroscopy and resonance Raman scattering provided information on the protonation state of individual functional groups suggesting that internal proton transfer processes are involved as well. Deuterium kinetic isotope effects that occurred in the Pr --> Pfr phototransformation of the bacteriophytochromes Cph1 and Agp1 were consistent with proton transfer reactions as rate-limiting steps. In contrast, the apparent rate constants in the photocycle of PYP exhibited only small kinetic isotope effects that could not be interpreted conclusively. Possible mechanisms of proton transfer in the activation of phytochrome and PYP will be discussed.     

Genotype by feeding system interaction in the genetic evaluation of Jersey cattle for milk yield

Results of studies in dairy cattle about the magnitude of the genotype-environment interaction (GEI) are variable, depending on the definitions of genotype and environment. Therefore, the objective of this study was to determine the magnitude of the interaction of genotype and feeding system (confinement and grazing) in the Mexican genetic evaluation of Jersey cattle for milk yield. The number of lactations and animals in the pedigree used were 5122 and 18 432. An animal model and the MTDFREML program were used to estimate genetic parameters and predict genetic values of the animals. Bivariate analysis was carried out considering the performance of confined and grazing cows as two different traits. Three indicator variables were used to assess GEI: (i) magnitude of the genetic correlation coefficients, (ii) correlation between predicted breeding values and (iii) frequency of coincidence in the ranking of top sires. The magnitude of GEI depended on the choice of the indicator variable. The estimate of genetic correlation coefficient less than unity (0.76; P < 0.05) suggested the presence of biologically important GEI. The differences in phenotypic averages and variances between confinement and grazing systems seem to be the main causes for the genotype by environment interaction detected. However, the correlation coefficient between breeding values from confined and grazing animals (0.96) and the frequency of coincidence between breeding values of common sires within the top 100 in confinement and grazing (0.86) indicated low-to-moderate re-ranking of animals or top sires. In addition, the high correlations between predicted breeding values of Mexican genetic evaluation and the two environments (0.99 and 0.93 for confinement and grazing) indicated that for the two feeding systems, breeding values from national analyses could be safely used.     

The occurrence of Candida Albicans in Lake Ontario bathing beaches.

There are inherent weaknesses associated with currently used bacterial fecal pollution indicator systems. Fecal pollution indicator data would be more meaningful if supplemented with information relating to the occurrence of pathogens in recreational water. Through surveys of four bathing beaches on Lake Ontario, it was established that the opportunistically pathogenic yeast Candida albicans occurs in near shore waters. The beaches surveyed could be differentiated on the basis of bacterial fecal pollution indicator levels and numbers of the pathogens C. albicans and Pseudomonas aeruginosa. The occurrence of C. albicans and P. aeruginosa appeared to be related to elevated fecal pollution indicator levels. Maximum numbers of all parameters were observed in July and August in association with peak bather loads at the beaches. In only one instance does the data suggest that a beach was subjected to human fecal contamination.     

Sister chromatid exchange (SCE) and structural chromosome aberration in mutagenicity testing

Summary Data from previous studies published on the induction by mutagens of sister chromatid exchanges (SCEs) and structural chromosome damage were compared qualitatively and quantitatively. Although a good correlation between the incidence of both cytogenetic phenomena has been pointed out in many previous publications, about 30% of the agents for which comparable data were available yielded non-corresponding qualitative results concerning both indicator effects. However, even in the group with good qualitative agreement distinct quantitative differences indicated different molecular mechanisms of the formation of SCEs and breaks. Additional information supporting the importance of these differences for the validity of both indicator systems has been derived from the results obtained using strong clastogens exhibiting a low or no SCE-inducing activity and vice versa, from special observations on chromosomal breakage syndromes, and from studies on the action of known co- and anti-clastogens on SCE-induction by chemical mutagens. As a result, it has been suggested that the SCE-technique should be considered as a valuable additional method for cytogenetic mutagenicity testing, which, however, is not adequate to replace the classical methods of analysis of structural chromosome damage.     

EEG parameters and their combination as indicators of depth of anaesthesia.

EEG parameters for assessment of depth of anaesthesia are typically based on different signal processing methods, such as spectral and complexity analysis. In the present study, the parameters investigated (WSMF, qWSMF, approximate entropy and Lempel-Ziv complexity) do not correlate monotonically to depth of anaesthesia. To obtain this correlation, parameters are combined based on fuzzy inference, whereby each parameter only operates in a specific range. Fuzzy inference seems to be a suitable approach, as the indicator designed separates wakefulness from unconsciousness as well as the best single parameter does and correlates to the depth of anaesthesia.     

Protein parameters of differential gene activation during development and tumorigenesis.

Various models of normal and abnormal developmental systems were addressed to get an insight into molecular parameters of cell differentiation at the level of protein gene products. Electrophoretic analysis of heterogeneous protein mixtures permitted qualitative analysis of developing systems, particularly during organogenesis in mammals, as well as of neoplastic growth in the animal and plant kingdoms. From our earlier findings indicating that the definite protein patterns characteristic of adult organs are acquired long after the adult morphological and histological characteristics of these tissues have developed, it has been repeatedly proven that quantitative changes in whole proteins is not a dependable indicator of cell differentiation.     

ORIGINAL ARTICLE: Can Ellenberg's indicator values for Mediterranean plants be used outside their region of definition?

Aim The aims of this study are: (1) to explore the relationships between the Ellenberg indicator values (light, temperature and moisture) recently developed for two Mediterranean regions (Italy and Greece); and (2) to evaluate the possibility of using these values in other Mediterranean areas. Location Southern Greece and the Mediterranean part of Italy. Methods A global matrix containing 966 items of information (161 species × 3 indicator variables × 2 values assigned in each study, one in Italy and one in Greece) was constructed. A test of the accuracy of the values in predicting actual environmental conditions was provided using a detrended correspondence analysis (DCA) on published vegetation relevés from the Mediterranean region. The gamma statistic was used to express relationships of ecological indicator values between the two regions, and pairs of indicator values calculated for each species were compared using Wilcoxon matched pairs tests. Results The results showed that indices developed for Greece and Italy were not similarly correlated to sample scores along DCA axis 1. Species’ indicator values for Italy and for Greece were highly significantly correlated for light and moisture and significantly correlated for temperature, but the correlations were weak (0.20 ≤ gamma ≤ 0.31). Pairwise testing gave significantly different indicator values for the two regions. Discrepancies below or equal to 2 units on 9‐point scales (12 points for moisture) were found for 88%, 70% and 54% of the species respectively for light, temperature and moisture indices. A substantial number of species showed higher discrepancies, from 3 up to 6 units. Main conclusions In the light of the present work, it seems clear that the indicator values developed for Italy and for Greece should not be used outside the region for which they were defined. This constitutes additional evidence that indicator values can be influenced by the identity of potential competitors. It also underlines the need to use standardized methods for calibrating indicator values against measured variables in such a way that indicator systems can serve as general reference systems.     

植物生活史型定量划分及其权重配置方法——以四棱豆生活史型划分为例

植物生活史型定量划分方法研究是植物生活史型研究的重要内容。现有的生活史型定量划分方法是基于主成分分析法(PCA)建立起来的,未考虑性状指标之间的相互影响,因此需要探索适用于"网状"结构指标体系的植物生活史型划分新方法。根据植物生活史型划分指标的层次性特点,以攀援型和矮生型四棱豆(Psophocarpus tetragonolobus)为例,分别采用主成分分析法(PCA)、层次分析法(AHP)和网络层次分析法(ANP)对性状指标进行权重配置,计算性状指标的综合得分和生活史型划分参数,结果如下:与ANP相比,PCA计算的V型(营养生长型)参数值偏低(x在0.39以下),S型(有性生殖型)参数值偏高(z在0.453以上);AHP计算的V型参数值偏高(x在0.614以上),S型参数值偏低(z在0.088以下);3种方法计算的生活史型划分参数差异明显。由于PCA、AHP均要求性状指标之间相互独立,不能排除性状指标之间的关联,因此基于PCA、AHP的四棱豆生活史型划分结果均出现了偏差,表明性状指标之间的相关性影响了生活史型划分结果。ANP的指标体系为"网状"结构,其控制层、网络层各个指标之间均存在关联。构建ANP的判断矩阵时提取了性状指标的相关矩阵信息,权重配置反映了性状指标之间的相关关系。基于ANP方法对攀援型和矮生型四棱豆生活史型的划分结果分别为V0.517C0.327S0.156和V0.416C0.43S0.154。当性状指标之间的相关不显著时,可采用PCA和AHP法分配权重;当性状指标之间存在显著相关时,采用ANP法进行权重配置更为恰当。综上所述,基于ANP的植物生活史型划分方法解决了性状指标之间相互影响问题,为植物生活史型定量研究提供了新的有效方法。     

Seasonal dynamics of sperm morphometric subpopulations and its association with sperm quality parameters in ram ejaculates

Sperm morphologic assessment is considered an irreplaceable part of standard laboratory routine analyses in the diagnosis of male fertility. Thus, in an attempt to quantify the effects of season on sperm morphology and its functional significance in relation to sperm quality parameters, sperm head morphometric traits were analyzed by using an objective computerized analysis combined with principal components analysis (PCA) cluster analysis to establish the relationship between the distribution of the subpopulations found and sperm quality in each season. There were slight variations on sperm motility and sperm membrane integrity indexes (P > 0.05). However, the mean values for sperm concentration substantially changed among seasons in all individuals studied (P < 0.01). There were significant differences in sperm morphometric parameters (P < 0.01) as well as in the distribution of morphometric subpopulations between seasons (P < 0.001). In conclusion, this study confirmed that there was an important seasonal effect on sperm morphometric traits. In addition, the distribution of these subpopulations seems to be related to the season studied and the ejaculate quality which would be a very important indicator of sperm function. The substantial information derived from these morphometric subpopulations has provided new knowledge which can be used in future studies using sperm morphometry as a seasonal indicator in ram ejaculates.     

Relationships among carcass weight, acid-base-balance of the blood, meat quality parameters and body composition of cultured rainbow trout (Oncorhynchus mykiss)

The relationshis among carcass weight, acid-base-balance of the blood as an indicator for metabolic load susceptibility, meat quality parameters, and body Composition were investigated in rainbow trout. Examinations were carried out in two replicates using a total of 300 trout from a Danish population. Within replicates, the trout were of aproximately the same age. In Replicate I trout, increasing carcass weight was accompanied by a more arkaline reaction of the blood. Carcass weight was significantly correlated with blood-pH and bicarbonate concentration (.19 and 26). Regression coefficients, however, confirmed only an increase of bicarbonate concentration with increasing carcass weight (b = .013 mmol/L per g, s_b= 0.005). In meat quality parameters, muscular pH₂₄ values decreased linearly in both replicates with increasing carcass weight, as shown by significant correlation estimates (-20 and -.27) and regression coefficients (b = -.0006, s_b=.0002, and b = -.001, s_b= .0003). Relationshis of other meat quality parameters to inmeasing carcass weight were evaluated differently by correlation and regression coefficients. No relationship was found between carcass weight and body composition. In general, correlation estimates describing interrelations between acid-base and meat quality parameters were on a very low level. Independent from carcass weight, there were clearly metabolically loaded and unloaded trout as well as trout with a mixed acid-base-status. Acid-base parameters were significantly correlated with each other. Generally, estimates for correlations between meat quality parameters were on a very low level. Body composition arameters, dry weight and crude fat content were highly significantly correlated (0.47) in Replicate II; in Replicate I there was no interrelation.     

Evaluating sustainable forest management

The concepts underlying the post-Brundtland drive towards sustainable forest management (SFM) have been relatively well defined since 1995. While substantial progress has been made in the science and policy fields related to SFM internationally, a number of significant challenges remain. Inter-jurisdictional examples include determining the appropriate sampling frequencies required to obtain meaningful trends or develop well-founded opinions, the correlation of indicators from different jurisdictions, and problems associated with extrapolation to varying scales of application. More specifically, issues related to monitoring and information reporting (including incentives, funding, the level of streamlined data and information systems, linkages between organizations, critical analyses designed to identify indicators, structured reports and the effectiveness of extension services), remain as challenges for policy makers and forest managers internationally. The papers included in this Special Issue of Ecological Indicators describe a range of innovative approaches to developing forest-related indicator frameworks at varying scales of management, and mark some significant developments in the science underlying indicator utility.     

Sustainability indicator systems within urban governance: Usability analysis of sustainability indicator systems as boundary objects

While sustainability indicator systems (SIs) have proven to be valuable rational tools for improving the availability of information related to the relationship of cities and communities to natural limits, the indicators movement has achieved limited instrumental uptake in policy. This paper begins from a recognition that instrumental use of sustainability indicator systems is rare. Greater potential impact exists for SIs designed to be much more attentive to their conceptual and political values within their particular social and political context. In other words, greater attention to what has been called the governance of indicator systems, or the ways in which SIs fit as policy tools within a multilevel and multiactor governance context, is key to increasing their utility. This is particularly true given the need for decisive policy change, or even the introduction of a new development path, which is asserted within the sustainability agenda.Understanding the real and potential utility of indicator systems within multiactor governance processes, in which their roles are primarily rhetorical, conceptual and political, is facilitated by thinking about indicator systems as boundary objects, tools which open up dialogue, information sharing, learning and consensus-building across different policy boundaries: between experts and nonexperts, formal government and different nongovernment actors, higher-order governments and lower-order governments. This paper offers a comparative analysis of three sustainability indicator systems in the North American context – Vancouver's Vital Signs (Vancouver Foundation), Seattle's Happiness Initiative, and LEED-ND (US Green Building Council) – all of which have shown some success in operationalizing a new policy boundary as a means of making conceptual and political contributions to governance practices. The specific boundaries operationalized, the different approach taken by each project, and the usability demonstrated by each project at that boundary in terms of salience, legitimacy and credibility, are assessed comparatively. In general, the trajectory in design and use of ecological and sustainability indicators demonstrates an increase in appetite, aptitude and numbers of channels for use in processes of governance; however, these factors vary with the local social–political opportunity structure. This analysis presents the advances made as well as the tradeoffs evident in these cases across the gamut of different forms of usability of nongovernmental indicator systems designed for use as boundary objects, and suggests a path forward for indicator work which aims to change policy, from a governance perspective.     

Ferns and Melastomataceae as indicators of vascular plant composition in rain forests of Colombian Amazonia

In a case-study from Colombian Amazonia, species information from ferns and Melastomataceae was used to explain the compositional patterns of other vascular plant species in 40 widely distributed 0.1-ha plots. Canonical correspondence analysis was applied to regress vascular plant species composition in the forests against information from these two indicator groups (summarized as axes of principal coordinate analyses), together with that from soils, landscape, and the spatial sampling design. In total, 53,941 individuals of 2480 vascular plant species were recorded. Of these, 17,473 individuals and 132 species were from ferns and Melastomataceae. In 19 well-drained upland (tierra firme) plots 19,622 vascular plant individuals and 1716 species were found, with 3793 plants and 91 species from ferns and Melastomataceae. In both the set of all landscapes and the subset of tierra firme forests the principal PCoA axes of the two indicator groups were highly related to the main patterns of forest species composition. In principle, therefore, ferns and Melastomataceae can be used to detect and forecast changes in the forest composition of the study area. However, evidence was not obtained that ferns and Melastomataceae show more potential to predict the main patterns in species composition of forests than soil, landscape, and spatial variables. The partioning of the total variation in forest composition showed that the correlation of ferns and Melastomataceae with other forest plants was quite independent from that of soil, landscape, and space. Direct effects of ferns and Melastomataceae on other plants might be obtained from experimental studies of between-plant interactions, concentrating on the seedling or juvenile stages of trees and lianas, both above-ground as well as in the rooting environment.     

Fluorescence correlation spectroscopy: past, present, future

In recent years fluorescence correlation spectroscopy (FCS) has become a routine method for determining diffusion coefficients, chemical rate constants, molecular concentrations, fluorescence brightness, triplet state lifetimes, and other molecular parameters. FCS measures the spatial and temporal correlation of individual molecules with themselves and so provides a bridge between classical ensemble and contemporary single-molecule measurements. It also provides information on concentration and molecular number fluctuations for nonlinear reaction systems that complement single-molecule measurements. Typically implemented on a fluorescence microscope, FCS samples femtoliter volumes and so is especially useful for characterizing small dynamic systems such as biological cells. In addition to its practical utility, however, FCS provides a window on mesoscopic systems in which fluctuations from steady states not only provide the basis for the measurement but also can have important consequences for the behavior and evolution of the system. For example, a new and potentially interesting field for FCS studies could be the study of nonequilibrium steady states, especially in living cells.     

Evaluation of chlorophyll fluorescence as a tool for salt stress detection in roses

The induction kinetic of the chlorophyll (Chl) fluorescence and the F_v/F_m ratio have been tested in order to find out the suitability of this technique to evaluate damage caused by salinity in plants of Rosa hybrida cv. Ilseta grafted on R. manetti growing in a greenhouse under non-saturating irradiance. Under these conditions salinity induced changes in plants morphology, nutrient and Chl contents and in the gas exchange parameters, but not in the F_v/F_m ratio. The Rfd index did not reveal more information. The F_v/F_m ratio as well as the fluorescence induction curves were more affected by salinity when an irradiation stress was added, therefore as an indicator of salt stress in roses, Chl fluorescence is of limited use when the plants are grown without additional stress. This revised version was published online in August 2006 with corrections to the Cover Date.