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As habitats change, species with higher intraspecific variation have more resources to adapt. Medicinal plants in the Himalayas are increasingly threatened by climate change and other anthropogenic influences. The intraspecific variation within and among 17 populations of the high-elevation herb Trillium govanianum Wall. ex D.Don was studied as an indicator of adaptability. The variation in 19 traits of population structure, morphology, and phytochemistry was assessed across habitats that varied in elevation (2452-3432 m a.s.1.), aspect, latitude (30.1-31.7[degrees]N), and arboreal community. The morphology and population structure were conserved among populations but varied among regions. The populations in the lower elevation mixed forests of Tirthan Valley produced smaller rhizomes but larger plant densities, such that plant biomass per square metre was conserved. The phytochemistry varied among regions and populations within regions, indicating significant variation among habitats. The aboveground morphology of the species masks considerable variations in belowground morphology and phytochemistry. The observed variations can help the species to adapt to the changing environmental conditions by provoking a functional response. Key words: adaptation, anthropogenic pressure, conservation, high-elevation medicinal plant, natural variations. Lorsque les habitats changent, les especes qui presentent une plus grande variation intraspecifique ont davantage de ressources pour s'adapter. Les plantes medicinales de l'Himalaya sont de plus en plus menacees par les changements climatiques et d'autres influences anthropiques. La variation intraspecifique au sein et entre 17 populations de Trillium govanianum Wall. ex D.Don, une herbe de haute altitude, a ete etudiee comme indicateur de l'adaptabilite. La variation de 19 traits de la structure de la population, de la morphologie et de la phytochimie a ete evaluee dans des habitats qui varient en matiere d'altitude (2452-3432 m a.s.1.), d'aspect, de latitude (30, 1 a 31, 7[degrees]N) et de peuplement frodicole. La morphologie et la structure de la population etaient conservees parmi les populations, mais elles variaient selon les regions. Les populations des forets mixtes de basse altitude de la vallee de Tirthan produisaient des rhizomes plus petits, mais des densites de plantes plus importantes, de sorte que la biomasse vegetale par [m.sup.2] etait conservee. La phytochimie variait entre les regions et les populations au sein des regions, indiquant une variation significative entre les habitats. La morphologie aerienne de l'espece masque des variations considerables dans la morphologie souterraine et la phytochimie. Les variations observees peuvent aider les especes a s'adapter aux conditions environnementales changeantes en provoquant une reponse fonctionnelle. [Traduit par la Redaction] Mots-cles : adaptation, pression anthropique, conservation, plante medicinale de haute altitude, variations naturelles., Introduction The rate at which species adapt to new or changing environments is dependent on their phenotypic plasticity and genetic variation (Fox et al. 2019). Species with a more flexible [...]

Introduction Soybean seeds provide major sources of oil and protein globally for human consumption and animal feed (Saha and Sultana 2008). Seed quality is determined by its composition of protein, [...], Pre-harvest soybean seeds in the field are susceptible to high temperature and humidity (HTH) stress, leading to pre-harvest seed deterioration, which will result in a reduction in grain quality, yield, and seed vigor. To understand the gene expression involved in seed deterioration response under HTH stress, in this study, we conducted an RNA-Seq analysis using two previously screened soybean cultivars with contrasting seed deterioration resistance. HTH stress induced 1081 and 357 differentially expressed genes (DEGs) in the sensitive cultivar Ningzhen No. 1 and resistant cultivar Xiangdou No. 3, respectively. The majority of DEGs in the resistant cultivar were up-regulated, while down-regulated DEGs were predominant in the sensitive cultivar. KEGG pathway analysis revealed that metabolic pathways, biosynthesis of secondary metabolites, and protein processing in endoplasmic reticulum were the predominant pathways in both cultivars during seed deterioration under HTH stress. The genes involved in photosynthesis, carbohydrate metabolism, lipid metabolism, and heat shock proteins pathways might contribute to the different response to seed deterioration under HTH treatment in the two soybean cultivars. Our study extends the knowledge of gene expression in soybean seed under HTH stress and further provides insight into the molecular mechanism of seed deterioration as well as new strategies for breeding soybean with improved seed deterioration resistance. Key words: soybean, high temperature and humidity, RNA-Seq, pre-harvest seed deterioration. Avant la recolte, les graines de soja au champ sont sensibles a un stress cause par une temperature et une humidite elevees (HTH), ce qui peut entrainer une deterioration des grains en pre-recolte, laquelle diminue la qualite des grains, le rendement et la vigueur des graines. Pour comprendre les profils d'expression genique associes a cette deterioration en reponse au stress HTH, les auteurs ont realise une etude RNA-Seq sur deux cultivars prealablement identifies comme presentant une resistance contrastee a cette deterioration. Le stress HTH a permis d'identifier, respectivement, 1081 et 357 genes a expression differentielle (DEG) chez le cultivar sensible Ningzhen No. 1 et le cultivar resistant Xiangdou No. 3. La majorite des DEG chez le cultivar resistant etaient exprimes a la hausse, tandis que les genes moins fortement exprimes etaient predominants chez le cultivar sensible. Une analyse des sentiers KEGG a revele que les 'sentiers metaboliques', la 'biosynthese des metabolites secondaires' et la 'maturation des proteines dans le reticulum endoplasmique' etaient les sentiers predominants touches lors de la deterioration des graines soumis a un stress HTH. Les genes impliques dans la photosynthese, le metabolisme des hydrates de carbone, le metabolisme des lipides et les proteines de choc thermique pourraient contribuer a la reponse differente observee entre les deux cultivars soumis a un traitement de stress HTH. Cette etude accroit les connaissances sur l'expression genique chez les graines de soja en reponse au stress HTH et fournit un eclairage sur le mecanisme moleculaire de la deterioration des graines ainsi que sur de nouvelles strategies pour selectionner des sojas dotes d'une meilleure resistance a la deterioration des graines. [Traduit par la Redaction] Mots-cles : soja, temperature et humidite elevees, RNA-Seq, deterioration des graines en pre-recolte.

Ecotypic differentiation reduces climatic niche breadth at the population level relative to a species' spatial distribution. For species that form climatic ecotypes, if future climate exceeds local population tolerance, climate change will precipitate the decline of extant populations range-wide. Here, we examine the variation in physiological and morphological traits of Eriophorum vaginatum L. collected from a 30-year-old reciprocal transplant experiment, in which six populations of E. vaginatum were transplanted along a latitudinal gradient from Eagle Creek to Prudhoe Bay, Alaska. We tested for ecotypic differentiation of photosynthesis, respiration, chlorophyll fluorescence, and biomass per tiller, which is a metric correlated with population growth in E. vaginatum. The light-saturated photosynthetic rate ([A.sub.max]) showed homesite advantage in that tussocks in their homesites had significantly higher values of [A.sub.max] relative to nonlocal populations. This pattern of homesite advantage was also observed for biomass per tiller, but not for fluorescence and respiration. Photosynthetic rate was positively correlated with biomass per tiller and survival, suggesting that adaptations related to photosynthesis may optimize performance of local populations to homesite conditions. Taken together, these findings indicate that a rapidly changing climate may elicit population decline of E. vaginatum, rendering this species at a competitive disadvantage to shrubs and boreal forest species, which are expanding northward as the climate changes. Transition from tussock-sedge tundra to boreal forest and shrubland alters features, such as albedo, soil temperature, and water-table depth, in ways that may accelerate climate change. Key words: climate change, fluorescence, local adaptation, photosynthesis, respiration, tussock tundra. La differenciation ecotypique reduit l'ampleur de la niche climatique au niveau populationnel relativement a la distribution spatiale d'une espece. En ce qui concerne les especes qui forment des ecotypes climatiques, si le climat futur excede la tolerance de la population locale, le changement climatique precipitera le declin des populations qui subsistent sur une large etendue. Les auteurs examinent ici la variation des traits physiologiques et morphologiques d'Eriophorum vaginatum L. recolte dans le cadre d'une experience de transplantation reciproque pendant 30 ans, dans laquelle six populations d'Eriphorum vaginatum ont ete transplantees en fonction d'un gradient latitudinal allant de Eagle Creek a Prudhoe Bay, en Alaska. Les auteurs ont teste la differenciation ecotypique de la photosynthese, de la respiration, la fluorescence de la chlorophylle et la biomasse par talle, une metrique qui est en correlation avec la croissance de la population chez E. vaginatum. Le taux de photosynthese en fonction de la densite du flux de lumiere ([A.sub.max]) revelait un avantage de l'habitat d'origine car les buttes gazonnees a leur lieu d'origine presentaient des valeurs d'[A.sub.max] superieures a celles des populations non locales. Ce patron d'avantage de l'habitat d'origine a aussi ete observe sur le plan de la biomasse par talle, mais non en ce qui concerne la fluorescence et la respiration. Le taux de photosynthese etait positivement correle avec la biomasse par talle et la survie, suggerant que les adaptations reliees a la photosynthese peuvent optimiser la performance des populations locales aux conditions de l'habitat d'origine. Dans leur ensemble, ces donnees indiquent qu'un changement climatique rapide peut induire un declin de la population de E. vaginatum, rendant cette espece competitivement desavantagee par rapport aux arbustes et aux especes forestieres boreales, qui s'etendent vers le nord au fur et a mesure des changements climatiques. La transition de la toundra a buttes de carex vers la foret boreale et les formations arbustives modifie des caracteristiques comme l'albedo, la temperature du sol et la profondeur de l'aquifere, de telle sorte que le changement climatique pourrait s'accelerer. [Traduit par la Redaction] Mots-cles : changements climatiques, fluorescence, adaptation locale, photosynthese, respiration, toundra parsemee de buttes de gazon., Introduction The formation of ecotypes--locally adapted, genetically distinct populations (Clausen et al. 1941, 1947; Kawecki and Ebert 2004; Turesson 1922)--is common across plant taxa (Linhart and Grant 1996; Savolainen et [...]

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.worlddev.2010.06.004 Byline: Mohamed A.M. Ahmed, Kamel Shideed, Ahmed Mazid Keywords: West Asia; Syria; policy-oriented research; policy influence; economic surplus; rate of return Abstract: In 1984, ICARDA and its Syrian partners initiated farming systems research that led to a change in national fertilizer allocation policy. Evidence is assessed on the policy influence of the fertilizer-response research and on the impact of switching to a more inclusive policy that relaxed the government's probation of fertilizer allocation to barley. Interviews with key informants make a persuasive case for attribution; estimates from economic surplus models are consistent with a high rate of return on investment in the policy-oriented research. This case study provides a contribution to the limited empirical literature on returns to research under policy distortions. Author Affiliation: International Center for Agricultural Research in Dry Areas, Aleppo, Syria Article History: Accepted 21 March 2010

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.worlddev.2010.06.005 Byline: Tom Walker Keywords: policy research; impact assessment; international agricultural research; influence; cost-benefit analysis Abstract: Assessing the impact of policy-oriented research is fraught with methodological difficulties ranging from attributing influence on policy change to constructing an appropriate counterfactual. The six case studies in this special section address these challenges in the context of international agricultural research. Methodological and analytical lessons are drawn about the uptake and influence of policy-oriented research on policy change and about the conduct of cost-benefit analysis for such research. The authors of the studies effectively used a key-informant approach to document uptake and influence for policy reforms that were believed to have incorporated well-defined outputs from policy research. Author Affiliation: Previously a Consultant to the former CGIAR Science Council, USA Article History: Accepted 21 March 2010

Byline: Claudio O. Stockle (1), Roger L. Nelson (1), Stewart Higgins (1), Jay Brunner (2), Gary Grove (3), Rick Boydston (4), Mathew Whiting (3), Chad Kruger (5) Abstract: An assessment of the potential impact of climate change and the concurrent increase of atmospheric CO.sub.2 concentration on eastern Washington State agriculture was conducted. Climate projections from four selected general circulation models (GCM) were chosen, and the assessment included the crops with larger economic value for the state (apples, potatoes, and wheat). To evaluate crop performance, a cropping system simulation model (CropSyst) was utilized using historical and future climate sequences. Crops were assumed to receive adequate water (irrigated crops), nutrients, and control of weeds, pests and diseases. Results project that the impact of climate change on eastern Washington agriculture will be generally mild in the short term (i.e., next two decades), but increasingly detrimental with time (potential yield losses reaching 25% for some crops by the end of the century). However, CO.sub.2 elevation is expected to provide significant mitigation, and in fact result in yield gains for some crops. The combination of increased CO.sub.2 and adaptive management may result in yield benefits for all crops. One limitation of the study is that water supply was assumed sufficient for irrigated crops, but other studies suggest that it may decrease in many locations due to climate change. Author Affiliation: (1) Department of Biological Systems Engineering, Washington State University, Pullman, WA, 99164-6120, USA (2) Tree Fruit Research and Extension Center, Washington State University, Wenatchee, WA, 98801, USA (3) Irrigated Agricultural Research and Extension Center, Washington State University, Prosser, WA, 99350-8694, USA (4) USDA-ARS at WSU IAREC, Prosser, WA, 99350-8694, USA (5) Center for Sustaining Ag & Nat Res, Washington State University, Wenatchee, WA, 98801, USA Article History: Registration Date: 24/03/2010 Received Date: 09/06/2009 Accepted Date: 23/03/2010 Online Date: 29/04/2010

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.earscirev.2010.02.004 Byline: Sonia I. Seneviratne, Thierry Corti, Edouard L. Davin, Martin Hirschi, Eric B. Jaeger, Irene Lehner, Boris Orlowsky, Adriaan J. Teuling Abstract: Soil moisture is a key variable of the climate system. It constrains plant transpiration and photosynthesis in several regions of the world, with consequent impacts on the water, energy and biogeochemical cycles. Moreover it is a storage component for precipitation and radiation anomalies, inducing persistence in the climate system. Finally, it is involved in a number of feedbacks at the local, regional and global scales, and plays a major role in climate-change projections. In this review, we provide a synthesis of past research on the role of soil moisture for the climate system, based both on modelling and observational studies. We focus on soil moisture-temperature and soil moisture-precipitation feedbacks, and their possible modifications with climate change. We also highlight further impacts of soil moisture on climate, and the state of research regarding the validation of the relevant processes. There are promises for major advances in this research field in coming years thanks to the development of new validation datasets and multi-model initiatives. However, the availability of ground observations continues to be critical in limiting progress and should therefore strongly be fostered at the international level. Exchanges across disciplines will also be essential for bridging current knowledge gaps in this field. This is of key importance given the manifold impacts of soil moisture on climate, and their relevance for climate-change projections. A better understanding and quantification of the relevant processes would significantly help to reduce uncertainties in future-climate scenarios, in particular with regard to changes in climate variability and extreme events, as well as ecosystem and agricultural impacts. Author Affiliation: Institute for Atmospheric and Climate Science, ETH Zurich, Switzerland Article History: Received 11 March 2009; Accepted 7 February 2010

To authenticate to the full-text of this article, please visit this link: http://dx.doi.org/10.1111/j.1365-2745.2009.01625.x Byline: Thomas J. Mozdzer (*[dagger]), Joseph C. Zieman Keywords: chlorophyll; conspecific; genotype; invasive; N; native; photosynthesis; Phragmites; physiology; SLA Abstract: Summary 1. Over the last century, native Phragmites australis lineages have been almost completely replaced along the North American Atlantic coast by an aggressive lineage originating from Eurasia. Understanding the mechanisms that facilitate biological invasions is critical to better understand what makes an invasive species successful. 2. Our objective was to determine what makes the introduced lineage so successful in the study area by specifically investigating if morphological and ecophysiological differences exist between native and introduced genetic lineages of P. australis. We hypothesized a priori that due to phenotypic differences and differences in plant nitrogen (N) content between lineages, the introduced lineage would have a greater photosynthetic potential. 3. In situ ecophysiological and morphological data were collected for 2 years in a mid-Atlantic tidal marsh and in a glasshouse experiment. We measured photosynthetic parameters (A.sub.max, water use efficiency, stomatal conductance) using infrared gas analysis, in conjunction with ecophysiological and morphological parameters [specific leaf area (SLA), leaf area, chlorophyll content, N content]. 4. Introduced P. australis maintained 51% greater rates of photosynthesis and up to 100% greater rates of stomatal conductance which are magnified by its 38-83% greater photosynthetic canopy compared to the native type. The introduced lineage also had a significantly greater SLA and N content. Glasshouse-grown plants and naturally occurring populations demonstrated similar trends in ecophysiological characteristics, verifying the heritability of these differences. These ecophysiological differences, when combined with an extended growing season, provide the mechanism to explain the success of introduced P. australis in North America. 5. Our findings suggest the native type is a low-nutrient specialist, with a more efficient photosynthetic mechanisms and lower N demand, whereas the introduced type requires nearly four times more N than the native type to be an effective competitor. 6. Synthesis. Our study is the first to combine field and laboratory data to explain a biological invasion attributed to ecophysiological differences between genetic lineages. Our data corroborates earlier work suggesting anthropogenic modification of wetland environments has provided the state change necessary for the success of introduced P. australis. Finally, our results suggest that genotypic differences within species merit further investigations, especially when related to biological invasions. Article History: Received 7 August 2009; accepted 2 December 2009 Handling Editor: Susan Schwinning Article note: (*) Correspondence author. E-mail: mozdzert@si.edu

To authenticate to the full-text of this article, please visit this link: http://dx.doi.org/10.1111/j.1477-8947.2009.01224.x Byline: Menale Kassie (1), Precious Zikhali (2), Kebede Manjur (3), Sue Edwards (4) Keywords: Sustainable agriculture; Technology adoption; Productivity; Trivariate probit; Stochastic dominance analysis; Ethiopia Abstract: Abstract In the wake of the resource constraints for external farm inputs faced by farmers in developing countries, sustainable agriculture practices that rely on renewable local or farm resources present desirable options for enhancing agriculture productivity. In this study, plot-level data from the semi-arid region of Ethiopia, Tigray are used to investigate the factors influencing farmers' decisions to adopt agriculture practices, with a particular focus on conservation tillage, compost and chemical fertilizer. A trivariate probit model is used to analyze the determinants of adoption of these practices. In addition, stochastic dominance analysis is used to compare the productivity impacts of compost with that of chemical fertilizer based on a six-year cross-sectional farm-level dataset. Our results indicate heterogeneity with regard to the factors that influence adoption decisions of the three practices and the importance of both plot and household characteristics on influencing adoption decisions. In particular, we found that household endowments and access to information, among other factors, impact the choice of sustainable farming practices significantly. Furthermore, the use of stochastic dominance analysis supported the contention that sustainable farming practices enhance productivity. They even proved to be superior to the use of chemical fertilizers - justifying the need to investigate factors that influence adoption of these practices and to use this knowledge to formulate policies that encourage adoption. Author Affiliation: (1)Department of Economics, University of Gothenburg, Sweden (2)Centre for World Food Studies, VU University Amsterdam, The Netherlands (3)Tigray Agricultural Research Institute, Alamata Agricultural Research Center, Ethiopia (4)Institute for Sustainable Development, Addis Ababa, Ethiopia Article note: Menale Kassie, Department of Economics, University of Gothenburg, Sweden. E-mail: menale.kassie@economics.gu.se

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.dsr.2009.03.001 Byline: Beatriz MouriA[+ or -]o-Carballido Keywords: (Sub)mesoscale; Photosynthesis; Respiration; Net community production; Sargasso Sea Abstract: An analysis of 9 years of data from the NW subtropical Atlantic reveals that variability in heterotrophic processes associated with (sub)mesoscale features has a major impact on the balance between photosynthesis and respiration. Higher indirect estimates of net community production (NCPe) are associated with the center of Mode Water Eddies (MWE) and frontal regions between cyclonic and anticyclonic eddies (CA). The increase in NCPe observed at the center of MWE is driven mainly by an increase in autotrophic production, whereas in CA enhanced NCPe rates are the result of an important reduction in bacterial respiration. Both features also exhibit a decrease in nitrate concentration, consistent with nutrient consumption, and relative increases in oxygen anomaly and particulate and dissolved organic carbon in the upper 200m. Plankton community composition in CA and MWE is characterized by the reduction in bacterial biomass, and the dominance of Prochlorococcus and Synechococcus in CA, and diatoms and dinoflagellates in MWE. Contrary to a common assumption, these results show for the first time that in ecosystems influenced by (sub)mesoscale dynamics, respiration can be as variable as photosynthesis. Author Affiliation: Applied Physics and Ocean Engineering Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543-1541, USA Article History: Received 31 July 2008; Revised 16 February 2009; Accepted 5 March 2009

To authenticate to the full-text of this article, please visit this link: http://dx.doi.org/10.1111/j.1600-0706.2009.17371.x Byline: Verena S. Brauer, Victor N. de Jonge, Anita G. J. Buma, Franz J. Weissing Abstract: The metabolic theory of ecology (MTE) is an intriguing but controversial theory that tries to explain ecological patterns at all scales on the basis of first principles. Temperature plays a pivotal role in this theory. According to MTE, the Arrhenius relationship that describes the effect of temperature on biochemical reactions extends to a 'universal temperature dependence' that encompasses all kinds of processes and scales up to the cellular, the organismal, and the community level. In this study we test the prediction that community growth rate is temperature dependent in an Arrhenius-like way. First, we performed a literature review of the scanty data on the temperature dependence of the rates of metabolism, photosynthesis and growth of communities. In contrast to the predictions of MTE, the community activation energies did not cluster around 0.32 eV, the activation energy of photosynthesis and primary production or around 0.65 eV, the activation energy of metabolism. However, in none of the published studies the conditions were sufficiently controlled to allow firm conclusions. We therefore also performed replicated and controlled experiments using natural assemblages of marine plankton. As predicted by MTE, the maximal growth rates of community biomass increased linearly in an Arrhenius plot, with a slope close to 0.32 eV. However, a diversity of other models for the temperature dependence of community growth rates fit our data equally well. Hence, our results are at best a weak confirmation of MTE. Article History: Manuscript Accepted 5 February 2009 Article note: V. S. Brauer (v.s.brauer@uva.nl), A. G. J. Buma and F. J. Weissing, Centre for Ecological and Evolutionary Studies, Univ. of Groningen, Kerklaan 30, NL-9751 NN Haren, the Netherlands. Present address for VSB: Aquatic Microbiology, Univ. of Amsterdam, Nieuwe Achtergracht 127, NL-1018 WS Amsterdam, the Netherlands. - V. N. de Jonge, Inst. of Estuarine and Coastal Studies, Univ. of Hull, Hull, HU6 7RX, UK.

To authenticate to the full-text of this article, please visit this link: http://dx.doi.org/10.1111/j.1365-2745.2009.01491.x Byline: Peter J. Vermeulen (1), Josef F. Stuefer (2), Niels P. R. Anten (1), Heinjo J. During (1) Keywords: canopy; coexistence; clonal; competition; exclusion; height; light; model; photosynthesis; resource acquisition Abstract: Summary Different views exist as to what traits will lead to dominance when plants compete for light. One view is that taller plants with better relative positions in the canopy will exclude shorter plants because they intercept almost all light and thus can achieve a higher carbon gain. Alternatively, resource competition models predict that plants that are capable of positive net photosynthesis at the lowest light level will win. In a 5-year-old dense competition experiment with 10 genotypes of the clonal plant Potentilla reptans, both these views were tested to see if either of them could explain the dominance of one of the genotypes, or the possible coexistence of several others. Using a combination of measured morphological and physiological traits, a canopy model was constructed to calculate whole-shoot daily photosynthetic rates of the genotypes in the different layers of the canopy in relation to the invested mass. Results show that the dominant genotype exhibited characteristics of relative shade tolerance: low rates of light-saturated photosynthesis and respiration. This resulted in a calculated daily carbon gain at the bottom of the canopy, where other genotypes could not achieve that. However, the dominant genotype did not have the highest photosynthetic rates throughout the whole canopy. Some genotypes that persisted in the stand in coexistence with the dominant one achieved greater daily carbon gain at the top of the canopy. Synthesis. The dominant genotype had characteristics similar to those predicted by resource competition models such as the ability to have positive growth at lower light levels. The persistence of several other genotypes, in contrast, may be explained by traits that allowed them to achieve higher carbon gains at the top of the canopy. This suggests that the light gradient formed by the plants themselves creates enough heterogeneity for strategies for dealing with different light requirements to coexist, even within a single species. Author Affiliation: (1)Department of Plant Ecology and Biodiversity, Institute of Environmental Biology, Utrecht University, PO Box 80084, 3508 TB Utrecht, The Netherlands (2)Experimental Plant Ecology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands Article History: Received 3 September 2008; accepted 11 February 2009Handling Editor: Stephen Bonser Article note: (*) Correspondence author. E-mail: peterjvermeulen@gmail.com

Describing, characterizing and interpreting the nearly infinite variety of carbonate rocks are conundrums--intricate and difficult problems having only conjectural answers--that have occupied geologists for more than two centuries. Depositional features including components, rock textures, lithofacies, platform types and architecture, all vary in space and time, as do the results of diagenetic processes on those primary features. Approaches to the study of carbonate rocks have become progressively more analytical. One focus has evolved from efforts to build reference models for specific Phanerozoic windows to scrutinize the effect of climate and long-term oscillations of the ocean-atmosphere system in influencing the mineralogy of carbonate components. This paper adds to the ongoing lively debates by attempting to understand changes in the predominant types of carbonate-producing organisms during the Mesozoic-Cenozoic, while striving to minimize the uniformitarian bias. Our approach integrates estimates of changes in [Ca.sup.2+] concentration in seawater and atmospheric C[O.sub.2], with biological evolution and ecological requirements of characteristic carbonate-producing marine communities. The underlying rationale for our approach is the fact that C[O.sub.2] is basic to both carbonates and organic matter, and that photosynthesis is a fundamental biological process responsible for both primary production of organic matter and providing chemical environments that promote calcification. Gross photosynthesis and hypercalcification are dependent largely upon sunlight, while net primary production and, e.g., subsequent burial of organic matter typically requires sources of new nutrients (N, P and trace elements). Our approach plausibly explains the changing character of carbonate production as an evolving response to changing environmental conditions driven by the geotectonic cycle, while identifying uncertainties that deserve further research. With metazoan consumer diversity reduced by the end-Permian extinctions, excess photosynthesis by phytoplankton and microbial assemblages in surface waters, induced by moderately high C[O.sub.2] and temperature during the Early Mesozoic, supported proliferation of nontissular metazoans (e.g., sponges) and heterotrophic bacteria at the sea floor. Metabolic activity by those microbes, especially sulfate reduction, resulted in abundant biologically-induced geochemical carbonate precipitation on and within the sea floor. For example, with the opening of Tethyan seaways during the Triassic, massive sponge/microbe boundstones (the benthic automicrite factory) formed steep, massive and thick progradational slopes and, locally, mud-mounds. As tectonic processes created shallow epicontinental seas, photosynthesis drove lime-mud precipitation in the illuminated zone of the water column. The resulting neritie lime-mud component of the shallow-water carbonate factory became predominant during the Jurassic, paralleling the increase in atmospheric pC[O.sub.2], while the decreasing importance of the benthic automicrite factory parallels the diversification of calcifying metazoans, phytoplankton and zooplankton. With atmospheric pC[O.sub.2] declining through the Cretaceous, the potential habitats for neritic lime-mud precipitation declined. At the same time, peak oceanic [Ca.sup.2+] concentrations promoted biotically-controlled calcification by the skeletal factory. With changes produced by extinctions and turnovers at the Cretaceous-Tertiary boundary, adaptations to decreasing [Ca.sup.2+] and pC[O.sub.2], coupled with increasing global temperature gradients (i.e., high-latitude and deep-water cooling), and strategies that efficiently linked photosynthesis and calcification, promoted successive changes of the dominant skeletal factory through the Cenozoic: larger benthic foraminifers (protist-protist symbiosis) during the Paleogene, red algae during the Miocene and modern coral reefs (metazoan-protist symbiosis) since Late Miocene. Keywords: carbonate factories; atmospheric C[O.sub.2]; dissolved Ca; photosynthesis

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2006.06.025 Byline: M.B. Galan (a), D. Peschard (a), H. Boizard (b) Keywords: Environmental indicator; Environmental impact; Farming practice; Environmental management system Abstract: Faced with society's increasing expectations, the Common Agricultural Policy (CAP) review considers environmental management to be an ever more critical criterion in the allocation of farm subsidies. With the goal of evaluating the environmental friendliness of farm practices, France's agricultural research and extension services have built a range of agricultural/environmental diagnostic tools over recent years. The objective of the present paper is to compare the five tools most frequently used in France: IDEA, DIAGE, DIALECTE, DIALOGUE and INDIGO. All the tools have the same purpose: evaluation of the impact of farm practices on the environment via indicators and monitoring of farm management practices. When tested on a sample of large-scale farms in Picardie, the five tools sometimes produced completely different results: for a given farm, the most supposedly significant environmental impacts depend on the tool used. These results lead to differing environmental management plans and raise the question of the methods' pertinence. An analysis grid of diagnostic tools aimed at specifying their field of validity, limits and relevance was drawn up. The resulting comparative analysis enables to define each tool's domain of validity and allows to suggest lines of thought for developing more relevant tools for (i) evaluating a farm's environmental performance and (ii) helping farmers to develop a plan for improving practices within the framework of an environmental management system. Author Affiliation: (a) AlternatecH section Agro-Transfert, F-80200 Estrees-Mons, France (b) INRA, Institut National de la Recherche Agronomique, Unite d'Agronomie de Laon-Reims-Mons, Estrees-Mons, BP 136, F-80203 Peronne cedex, France Article History: Received 30 October 2004; Revised 9 May 2005; Accepted 20 June 2006

Keywords: global change, net ecosystem production, photosynthesis, respiration, soil carbon pools, temperature sensitivity Abstract The coupled carbon-climate models reported in the literature all demonstrate a positive feedback between terrestrial carbon cycles and climate warming. A primary mechanism underlying the modeled positive feedback is the kinetic sensitivity of photosynthesis and respiration to temperature. Field experiments, however, suggest much richer mechanisms driving ecosystem responses to climate warming, including extended growing seasons, enhanced nutrient availability, shifted species composition, and altered ecosystem-water dynamics. The diverse mechanisms likely define more possibilities of carbon-climate feedbacks than projected by the kinetics-based models. Nonetheless, experimental results are so variable that we have not generated the necessary insights on ecosystem responses to effectively improve global models. To constrain model projections of carbon-climate feedbacks, we need more empirical data from whole-ecosystem warming experiments across a wide range of biomes, particularly in tropic regions, and closer interactions between models and experiments.

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.earscirev.2006.03.003 Byline: Michael M. Tice, Donald R. Lowe Keywords: carbonaceous matter; Archean; photosynthesis; microbial mat; chert Abstract: The geological record of carbonaceous matter from at least 3.5 Ga to the end of the Precambrian is fundamentally continuous in terms of carbonaceous matter structure, composition, environments of deposition/preservation, and abundance in host rocks. No abiotic processes are currently known to be capable of producing continuity in all four of these properties. Although this broad view of the geological record does not prove that life had arisen by 3.5 Ga, the end of the early Archean, it suggests a working hypothesis: most if not all carbonaceous matter present in rocks older than 3.0 Ga was produced by living organisms. This hypothesis must be tested by studies of specific early geological units designed to explore the form, distribution, and origin of enclosed carbonaceous matter. The carbonaceous, environmentally diverse 3416 Ma Buck Reef Chert (BRC) of the Barberton greenstone belt, South Africa, provides an opportunity for such a study. Upward facies progressions in the BRC reflect deposition in environments ranging from shallow marine evaporitic brine ponds to a storm- and wave-active shelf to a deep, low-energy basinal setting below storm wave base. Abundances and ratios of Al.sub.2O.sub.3, Zr, TiO.sub.2, and Cr track inputs of various types of volcaniclastic and terrigenous clastic materials. In particular, Zr/Al.sub.2O.sub.3 and Zr serve as proxies for concentration of windblown dust and, indirectly, as proxies for sedimentation rate. Cu, Zn, Ni, and FeO were concentrated in the most slowly deposited transitional and basinal sediments, inconsistent with a hydrothermal setting but consistent with a normal marine setting. The distribution of microfacies defined by associations and layering of clastic, ferruginous, and carbonaceous grains correlates with facies transitions. Fine carbonaceous laminations, which occur only in shallow platform settings, represent photosynthetic microbial mats. These were ripped up and the debris widely redistributed in shallow and deep water by waves and storms. The isotopic composition of carbonaceous matter ranges from -35a[degrees] to -30a[degrees] in shallow-water settings and to -20a[degrees] in deep-water units. The heavier [delta].sup.13C in deep-water carbonaceous matter is thought to reflect microbial processing, possibly by fermentation and methanogenesis, of organic matter originally produced in shallow water. Hydrothermal origins for BRC carbonaceous matter are clearly excluded by the inferred depositional setting of the rocks as a whole, an inference supported by field, petrographic, and geochemical analysis. We suggest that the biological model proposed here for BRC carbonaceous matter is the best currently available. The hypothesis that 'at least some carbonaceous matter present in rocks older than 3.0 Ga was produced by living organisms' should be regarded as likely until extraordinary contradictory evidence is presented. Author Affiliation: Department of Geological and Environmental Sciences, Stanford University, Stanford, California 94305, USA Article History: Received 4 October 2005; Accepted 17 March 2006

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.dsr.2004.12.008 Byline: E. Machu (a), A. Biastoch (b), A. Oschlies (b), M. Kawamiya (b), J.R.E. Lutjeharms (c), V. Garcon (a) Abstract: The greater Agulhas Current system has several components with high mesoscale turbulence. The phytoplankton distribution in the southwest Indian Ocean reflects this activity. We have used a regional eddy-permitting, coupled physical-biological model to study the physical-biological interactions and to address the main processes responsible for phytoplankton distribution in three different biogeochemical provinces: the southwest Subtropical Indian Gyre (SWSIG), the subtropical convergence zone (SCZ) and the subantarctic waters (SAW) south of South Africa. The biological model with four compartments (Nitrate-Phytoplankton-Zooplankton-Detritus) adequately reproduces the observed field of chlorophyll a. The phase of the strong modelled seasonality in the SWSIG is opposite to that of the SCZ that forms the southern boundary of the subtropical gyre. Phytoplankton concentrations are governed by the source-minus-sink terms, which are one order of magnitude greater than the dynamical diffusion and advection terms. North of 35[degrees]S, in the SWSIG, phytoplankton growth is limited by nutrients supply throughout the year. However, deeper stratification, enhanced cross-frontal transport and higher detritus remineralization explain the simulated higher concentrations of phytoplankton found in winter in the SWSIG. The region between 35[degrees] and 40[degrees]S constitutes a transition zone between the SCZ and the oligotrophic subtropical province. Horizontal advection is the main process bringing nutrients for phytoplankton growth. The front at 34[degrees]S represents a dynamical barrier to an extension further to the north of this advection of nutrients. Within the SCZ, primary production is high during spring and summer. This high productivity depletes the nutrient standing stock built up during winter time. In winter, nutrients supply in the convergence zone is indeed large, but the deep mixing removes phytoplankton from the euphotic zone and inhibits photosynthesis, yielding lower surface chlorophyll a concentrations. Waters south of the Subantarctic Front have a summer biomass close to that of frontal waters and higher than for subtropical waters. However, these simulated concentrations are slightly higher than the observed ones suggesting that limitation by iron and/or silica may play a role. Author Affiliation: (a) Laboratoire d'Etudes en Geophysique et Oceanographie Spatiales, CNRS, UMR5566, 18, Avenue E. Belin, 31401 Toulouse cedex 9, France (b) Institut fur Meereskunde an der Universitat Kiel, Dusternbrooker Weg 20, 24105, Kiel, Germany (c) Department of Oceanography, University of Cape Town, 7700 Rondebosch, South Africa

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.dsr.2005.01.008 Byline: Heather Bouman (a)(b), Trevor Platt (b), Shubha Sathyendranath (c)(b), Venetia Stuart (c) Abstract: Using data collected in the Arabian Sea and on the Nova Scotian Shelf we examined the relationships between temperature, phytoplankton taxonomic composition (indexed by pigment composition) and the size structure (indexed by chlorophyll-specific absorption coefficient at 676nm), Chlorophyll-a biomass and the light-saturated photosynthesis parameter P.sub.m.sup.B. Our results show that changes in phytoplankton community structure for the Scotian Shelf closely follow changes in temperature. In the Arabian Sea the relationship between phytoplankton community structure and temperature was less striking and fluctuations in phytoplankton pigment composition were strongly related to Chlorophyll-a biomass. The light-saturated photosynthesis parameter P.sub.m.sup.B was correlated with temperature for the Scotian Shelf. When we compared data collected on the Scotian Shelf with the temperature-dependent function of Eppley (1972. Fishery Bulletin 70, 1063-1085), the model fitted the data remarkably well. For the Arabian Sea data, however, only a weak temperature dependence in P.sub.m.sup.B was observed, which may be a result of a strong negative correlation between ambient nitrate concentration and temperature. Our results also show that for both the Scotian Shelf and the Arabian Sea, diatom-dominated waters had similarly low P.sub.m.sup.B values even though the temperatures of the two systems were markedly different. The absorptive characteristics of phytoplankton on the Scotian Shelf were well correlated with P.sub.m.sup.B, thus providing another potential predictor of P.sub.m.sup.B that may, in the future, be routinely accessible by remote sensing. The contrasting relationships among community structure, temperature, and primary production observed in the two study regions suggest that primary production algorithms incorporating such information could be developed and applied on a domain-specific basis. These algorithms should be centred on knowledge of the relationships between physical forcing, community structure and phytoplankton photophysiology. Author Affiliation: (a) Biology Department, Dalhousie University, Halifax, Nova Scotia, Canada B3H 4J1 (b) Bedford Institute of Oceanography, Dartmouth, Nova Scotia, Canada B2Y 4A2 (c) Oceanography Department, Dalhousie University, Halifax, Nova Scotia, Canada B3H 4J1 Article History: Received 13 February 2004; Revised 16 September 2004; Accepted 18 January 2005

Cellulose (β-1,4-glucan) microfibrils provide strength and flexibility to plant tissues and are also of great importance to wood, paper, textile, and chemical industries. Genetic evidence implicates plant CesA genes, homologous [...], Cellulose synthesis in plants requires β-1,4-glucan chain initiation, elongation, and termination. The process of chain elongation is likely to be distinct from the process of chain initiation. We demonstrate that a CesA glucosyltransferase initiates glucan polymerization by using sitosterol-β-glucoside (SG) as primer. Cotton fiber membranes synthesize sitosterol-cellodextrins (SCDs) from SG and uridine 5-'diphosphate-glucose (UDP-Glc) under conditions that also favor cellulose synthesis. The cellulase encoded by the Korrigan (Kor) gene, required for cellulose synthesis in plants, may function to cleave SG from the growing polymer chain.