Download or read book The Photosynthetic Acclimation Response of Lolium Perenne to Four Years Growth in a Free air CO sub 2 Enrichment FACE Facility written by and published by . This book was released on 1996 with total page 87 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this study, the photosynthetic responses of field grown Lolium perenne to ambient (354?mol mol−1) and elevated (600?mol mol−1) C{sub a} were measured. The experiment utilized the FACE facility at Eschikon, Switzerland; here the L. Perenne swards had been grown at two nitrogen treatments, with six cuts per year, for 4 years. The study revealed a significant decrease in Rubisco activity (Vcmax) in the low nitrogen FACE plots; this is consistent with the theories of source-sink imbalance resulting in feedback inhibition and down-regulation. Such negative acclimation was not wholly supported by diurnal investigations which revealed an average stimulation of 53.38% and 52.78% in the low and high nitrogen, respectively. However, light response curves and AI investigations also suggested down-regulation, especially in the low nitrogen. SI is expected to decrease in response to elevated C{sub a}, if any change is seen. This was indeed observed in the high nitrogen plots but for the low nitrogen a significant increase was found. Conclusions drawn from this project center around the implications of negative acclimation to future crop productivity. For instance, inter-specific differences in response to elevated C{sub a} may result in ecosystem changes and new management techniques may be necessary. However, real predictions cannot be made from leaf level studies alone as these may not represent the overall changes at the whole plant level.

Download or read book The Photosynthetic Acclimation Response of Lolium Perenne to Four Years Growth in a Free air CO2 Enrichment FACE Facility written by and published by . This book was released on 1996 with total page 87 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this study, the photosynthetic responses of field grown Lolium perenne to ambient (354 [mu]mol mol−1) and elevated (600 [mu]mol mol−1) C{sub a} were measured. The experiment utilized the FACE facility at Eschikon, Switzerland; here the L. Perenne swards had been grown at two nitrogen treatments, with six cuts per year, for 4 years. The study revealed a significant decrease in Rubisco activity (Vcmax) in the low nitrogen FACE plots; this is consistent with the theories of source-sink imbalance resulting in feedback inhibition and down-regulation. Such negative acclimation was not wholly supported by diurnal investigations which revealed an average stimulation of 53.38% and 52.78% in the low and high nitrogen, respectively. However, light response curves and AI investigations also suggested down-regulation, especially in the low nitrogen. SI is expected to decrease in response to elevated C{sub a}, if any change is seen. This was indeed observed in the high nitrogen plots but for the low nitrogen a significant increase was found. Conclusions drawn from this project center around the implications of negative acclimation to future crop productivity. For instance, inter-specific differences in response to elevated C{sub a} may result in ecosystem changes and new management techniques may be necessary. However, real predictions cannot be made from leaf level studies alone as these may not represent the overall changes at the whole plant level.

Download or read book The Photosynthetic Acclimation of Lolium Perenne in Response to Three Years Growth in a Free air CO sub 2 Enrichment FACE System written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Pure stands of Ryegrass were in their third year of growth in the field, exposed to either ambient (355[mu]mol mol[sup -1]), or elevated (600[mu]mol mol[sup -1]) atmospheric CO[sub 2] concentration. A Free-Air CO[sub 2] Enrichment (FACE) system was used to maintain the elevated CO[sub 2] concentration whilst limiting experimental constraints on the field conditions. The theoretically predicted increase in the net rates of CO[sub 2] uptake per unit leaf area (A[mu]mol mol[sup -1]) as a consequence, primarily, of the suppression of photorespiration by CO[sub 2] a competitive inhibitor of RubP oxygenation by Rubisco, was observed for the Lolium perenne studied. Also observed was a general decline in leaf evapotranspiration (E) consistent with observations of increased water use efficiency of crops grown in elevated CO[sub 2]. Enhancement of leaf A in the FACE grown L. perenne ranged from 26.5 1% to 44.95% over the course of a diurnal set of measurements. Whilst reductions in leaf E reached a maximum of 16.61% over the same diurnal course of-measurements. The increase in A was reconciled with an absence of the commonly observed decline in V[sub c][sub max] as a measure of the maximum in vivo carboxylation capacity of the primary carboxylasing enzyme Rubisco and J[sub max] a measure of the maximum rate of electron transport. The manipulation of the source sink balance of the crop, stage of canopy regrowth or height in the canopy had no effect on the observation of a lack of response. The findings of this study will be interpreted with respect to the long term implications of C[sub 3] crops being able to adapt physiologically to maximize the potential benefits conferred by growth in elevated CO[sub 2].

Download or read book The Photosynthetic Acclimation of Lolium Perenne Growing in a Free air CO2 Enrichment FACE System written by and published by . This book was released on 1994 with total page 31 pages. Available in PDF, EPUB and Kindle. Book excerpt: Stands of Ryegrass (Lolium perenne L. cv. Bastion) were grown in the field at ambient or elevated (600[mu]mol/mol) CO2 concentration, high (560Kg/ha) or low (140Kg/ha) nitrogen addition and with a frequent (every 4 weeks) or infrequent (every 8 weeks) cutting regime. Plants were in the second year of a 3 year experiment. Exposure to elevated CO2 was carried out with a Free-Air CO2 Enrichment (FACE) system which provides the most {open_quote}realistic{close_quote} system of CO2 fumigation currently available. Elevated CO2 increased diurnal CO2 assimilation by between 34 and 88% whilst reducing rates of stomatal conductance by between 1 and 42%. However, analysis of the A vs. Ci response showed considerable acclimation of the photosynthetic apparatus in response to elevated CO2 - Vc{sub max} as an in vivo measure of RubisCO activity, decreased by between 29 and 35% in high CO2, whilst J{sub max}, as a measure of the RubP regeneration capacity, showed no significant change. Two out of three additional perennial grassland species studied showed similar acclamatory behavior to Ryegrass. Diurnal assimilation rate, J{sub max} and, in most cases, Vc{sub max}, increased significantly directly after cutting of Ryegrass stands, but nitrogen treatment had little effect on any of these parameters. Neither stomatal density, stomatal index nor stomatal pore length of Ryegrass were significantly altered by growth in elevated CO2. The results are discussed in terms of the limitation imposed on maximizing photosynthetic and growth responses of Ryegrass at elevated CO2, by the ability of perennial species to increase long-term sink capacity under these conditions.

Download or read book The Photosynthetic Acclimation of Lolium Perenne Growing in a Free air CO sub 2 Enrichment FACE System written by and published by . This book was released on 1994 with total page 31 pages. Available in PDF, EPUB and Kindle. Book excerpt: Stands of Ryegrass (Lolium perenne L. cv. Bastion) were grown in the field at ambient or elevated (600?mol/mol) CO2 concentration, high (560Kg/ha) or low (140Kg/ha) nitrogen addition and with a frequent (every 4 weeks) or infrequent (every 8 weeks) cutting regime. Plants were in the second year of a 3 year experiment. Exposure to elevated CO2 was carried out with a Free-Air CO2 Enrichment (FACE) system which provides the most {open_quote}realistic{close_quote} system of CO2 fumigation currently available. Elevated CO2 increased diurnal CO2 assimilation by between 34 and 88% whilst reducing rates of stomatal conductance by between 1 and 42%. However, analysis of the A vs. Ci response showed considerable acclimation of the photosynthetic apparatus in response to elevated CO2 - Vc{sub max} as an in vivo measure of RubisCO activity, decreased by between 29 and 35% in high CO2, whilst J{sub max}, as a measure of the RubP regeneration capacity, showed no significant change. Two out of three additional perennial grassland species studied showed similar acclamatory behavior to Ryegrass. Diurnal assimilation rate, J{sub max} and, in most cases, Vc{sub max}, increased significantly directly after cutting of Ryegrass stands, but nitrogen treatment had little effect on any of these parameters. Neither stomatal density, stomatal index nor stomatal pore length of Ryegrass were significantly altered by growth in elevated CO2. The results are discussed in terms of the limitation imposed on maximizing photosynthetic and growth responses of Ryegrass at elevated CO2, by the ability of perennial species to increase long-term sink capacity under these conditions.

Download or read book Australian Journal of Plant Physiology written by and published by . This book was released on 2000 with total page 552 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Proceedings of the International Grassland Conference written by and published by . This book was released on 2001 with total page 1130 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Anais do Congresso Internacional de Pastagens written by and published by . This book was released on 2001 with total page 1124 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Mycorrhiza in Tropical and Neotropical Ecosystems written by Mohamed Hijri and published by Frontiers Media SA. This book was released on 2018-10-19 with total page 139 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mycorrhizal symbiosis is a mutualistic association of plant roots and fungi that plays a major role in ecosystem function and diversification, as well as its stability and productivity. It also plays a key role in the biology and ecology of forest trees, affecting growth, water and nutrient absorption and protection against soil-borne pathogens. However, the mycorrhizal research in tropical and neotropical ecosystems remains largely unexplored despite its importance in tropical and neotropical ecosystems. These ecosystems represent more than 0.6% of the total land ecosystems and they have a crucial role in the Earth’s biogeochemical cycling and climate. Threats to tropical forest biodiversity should therefore encourage investigations and inventories of mycorrhizal diversity, function and ecology in tropical latitudes because they concern ecologically and economically important plant species. This Research Topic aims to provide an overview of the knowledge of mycorrhizal symbioses in tropical and neotropical ecosystems. For this Research Topic, we welcome articles that address the diversity, ecology and function of mycorrhiza associated with plants, the impacts of mycorrhiza on plant diversity and composition, the regeneration and dynamics of ecosystems, and biomass production in ecosystems.

Download or read book Arbuscular Mycorrhizas written by Yoram Kapulnik and published by Springer Science & Business Media. This book was released on 2013-03-09 with total page 369 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent years have brought an upsurge of interest in the study of arbuscular mycorrhizal (AM) fungi, partly due to the realization that the effective utilization of these symbiotic soil fungi is likely to be essential in sustainable agriculture. Impressive progress has been made during the last decade in the study of this symbiosis largely as a result of increasing exploitation of molecular tools. Although early emphasis was placed on the use of molecular tools to study physiological processes triggered by the symbiosis, such as expression of symbiosis-specific polypeptides and modulation of host defences, other applications await. It was obvious to us that gathering leaders in the field to summarize these topics and point out research needs was necessary if we were to understand the physiology and function of AM fungi at a molecular level. In addition, we have taken the opportunity to present these reviews in a logical sequence of topics ranging from the initiation of the life cycle of the fungus to its functions in plant growth and in the below ground ecosystem. It was a challenge to limit this flood of information to the confines of one text. This is a very exciting time for mycorrhiza biologists and it is our hope that some of this excitement is conveyed to our readers.

Download or read book Phosphorus in Agriculture 100 Zero written by Ewald Schnug and published by Springer. This book was released on 2016-06-14 with total page 357 pages. Available in PDF, EPUB and Kindle. Book excerpt: The title ‘Phosphorus in Agriculture: 100 % Zero’ is synonymous for make-or-break. And it stands up to the promise. This book sends an important message as it delivers background information, intrinsic hypotheses, validation approaches and legal frameworks, all for balanced phosphorus fertilization in agriculture. This implies firstly that the phosphorus requirement of crop is fully satisfied by applying exclusively fertilizers which contain the nutrient in completely available form. Secondly, environmental demands through eutrophication and hazardous contaminants must not be compromised. The book identifies equally knowledge gaps and deficits in the transformation and implementation of research into practice. Bottom line is that research delivers the tools for a sustainable phosphorus management while legal frameworks are insufficient.

Download or read book Biochemical Models of Leaf Photosynthesis written by Susanna Von Caemmerer and published by CSIRO PUBLISHING. This book was released on 2000 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt: Increasing concerns of global climatic change have stimulated research in all aspects of carbon exchange. This has restored interest in leaf-photosynthetic models to predict and assess changes in photosynthetic CO2 assimilation in different environments. This is a comprehensive presentation of the most widely used models of steady-state photosynthesis by an author who is a world authority. Treatments of C3, C4 and intermediate pathways of photosynthesis in relation to environment have been updated to include work on antisense transgenic plants. It will be a standard reference for the formal analysis of photosynthetic metabolism in vivo by advanced students and researchers.

Download or read book Grasslands and Climate Change written by David J. Gibson and published by Cambridge University Press. This book was released on 2019-03-21 with total page 363 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive assessment of the effects of climate change on global grasslands and the mitigating role that ecologists can play.

Download or read book Respiration and Crop Productivity written by Jeffrey S. Amthor and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 227 pages. Available in PDF, EPUB and Kindle. Book excerpt: Respiration is a large and important component of the carbon economy of crops. There are already several good books dealing with the biochemistry and physiol ogy of plant respiration, but there are none I know of that are devoted to the rela tionship between respiration and crop productivity, although this relationship is more and more frequently being studied with both experiment and simulation. Crop physiology books do cover respiration, of course, but the treatment is limited. The purpose of the present book is to fill this void in the literature. The approach taken here is to use the popular two-component functional model whereby respiration is divided between growth and maintenance components. Mter thoroughly reviewing the literature, I came to the conclusion that at present this is the most useful means of considering respiration as a quantitative compo nent of a crop's carbon economy. This functional distinction is used as the frame work for describing respiration and assessing its role in crop productivity. Discussions and critiques of the biochemistry and physiology of respiration serve primarily as a means of more fully understanding and describing the functional approach to studying crop respiration. It is assumed that the reader of this book is familiar with the fundamentals of plant physiology and biochemistry. The research worker in crop physiology should find this an up-to-date summary of crop respiration and the functional model of respiration. This book is not, however, a simple review of existing data.

Download or read book Grasp the Nettle written by Peter Proctor and published by Penguin Random House New Zealand Limited. This book was released on 2012-12-01 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: The expert guide to biodynamic farming and gardening. In this revised and updated edition of Grasp the Nettle Peter Proctor tells the reader how to apply biodynamic methods of farming and gardening to a wide range of conditions in New Zealand and in other countries. The book provides practical observations and techniques, and relates these to the spiritual scientific knowlege upon which that biodynamic practice is based. Peter gives tips on how to recognise healthy soil and pasture, and on how to make your own biodynamic preparations. He also gives examples of farms that are successfully using biodynamic methods. This book aims to assist biodynamic farmers and gardeners to observe the processes of life and growth, and to understand how these processes are governed by cosmic forces, so they can use this knowlege in applying their practical skills. Peter Proctor, past national field advisor for the NZ Bio Dynamic Farming and Gardening Association, now teaches and advises farmers on biodynamic methods around the world.

Download or read book Advances in Carbon Dioxide Effects Research written by L. H. Allen and published by . This book was released on 1997 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Rhizosphere written by Zoe G. Cardon and published by Elsevier. This book was released on 2011-04-28 with total page 235 pages. Available in PDF, EPUB and Kindle. Book excerpt: Below the soil surface, the rhizosphere is the dynamic interface among plant roots, soil microbes and fauna, and the soil itself, where biological as well as physico-chemical properties differ radically from those of bulk soil. The Rhizosphere is the first ecologically-focused book that explicitly establishes the links from extraordinarily small-scale processes in the rhizosphere to larger-scale belowground patterns and processes. This book includes chapters that emphasize the effects of rhizosphere biology on long-term soil development, agro-ecosystem management and responses of ecosystems to global change. Overall, the volume seeks to spur development of cross-scale links for understanding belowground function in varied natural and managed ecosystems. - First cross-scale ecologically-focused integration of information at the frontier of root, microbial, and soil faunal biology - Establishes the links from extraordinarily small-scale processes in the rhizosphere to larger-scale belowground patterns and processes - Includes valuable information on ecosystem response to increased atmospheric carbon dioxide and enhanced global nitrogen deposition - Chapters written by a variety of experts, including soil scientists, microbial and soil faunal ecologists, and plant biologists