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 Government Reports Announcements Index written by and published by . This book was released on 1995-07 with total page 708 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Managed Ecosystems and CO2 written by Josef Nösberger and published by Springer Science & Business Media. This book was released on 2006-08-18 with total page 480 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides an up-to-date review of the effects of increasing atmospheric carbon dioxide on agroecosystems, forests, and grasslands. It summarizes the main findings from 13 experiments with annual crops, permanent pastures and plantation forests at 11 sites throughout the world during the past ten years. The results significantly alter our perception of how rising CO2 will directly affect these managed ecosystems.
Download or read book Ecophysiology of Tropical Plants written by Sachchidanand Tripathi and published by CRC Press. This book was released on 2023-10-03 with total page 640 pages. Available in PDF, EPUB and Kindle. Book excerpt: Plants in tropical regions are coping with enormous challenges of physiological stresses owing to changing environmental and climatic conditions. Rapid growth of human population and rampant exploitation of fossil fuels and other developmental activities are actively contributing to such perturbations. The Intergovernmental Panel on Climate Change has projected a sustained increase in carbon dioxide (CO2) emissions and thereby a rise in global temperature in the coming decades. The resultant changes in precipitation patterns are now evident across the globe due to intensication of hydrological cycle. Moreover, gaseous and particulate pollutants are also an immense challenge for tropical plants. Such vagaries in environmental conditions have signicant impacts on the ecophysiological traits of plants, resulting from altered interactions of tropical plants with each other, as well as other biotic and abiotic components within the ecosystem. Books available in the market that particularly focus on ecophysiological responses of tropical plants to abiotic and biotic environmental factors under climate change are limited. This book intends to fill this knowledge gap and provides a detailed analysis on ecophysiological responses of tropical plants to these environmental challenges, as well as suggesting some approachable measures for plant adaptations to these challenges. The book is equally applicable to undergraduate and postgraduate students, researchers, teachers and forest managers, and policy makers. Salient features of the book are: 1. A comprehensive discussion on adaptive mechanisms of plants through their ecophysiological responses to various biotic and abiotic stresses. 2. Elaboration on the recent techniques involved in ecophysiological research. 3. A detailed account of evolutionary responses of plants to changing climate. 4. Discussion of recent research results and some pointers to future advancements in ecophysiological research. 5. Presentation of information in a way that is accessible for students, researchers, and teachers practicing in plant physiology and ecology.
Download or read book Inter and Intra specific Variation in Photosynthetic Acclimation Response to Long Term Exposure of Elevated Carbon Dioxide written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The response of intra and interspecific variation in photosynthetic acclimation to growth at elevated atmospheric CO[sub 2] concentration (600[micro]mol mol-l) in six important grassland species was investigated. Plants were grown in a background sward of Lolium perenne and measurements were made after four years of growth at elevated C[sub a]. Elevated CO[sub 2] was maintained using a FACE (Free-Air Carbon Enrichment) system. Significant intra and interspecific variation in acclimation response was demonstrated. The response of adaxial and abaxial stomatal conductance to elevated CO[sub 2] was also investigated. The stomatal conductance of both the adaxial and abaxial leaf surfaces was found to be reduced by elevated C[sub a]. Significant asymmetric responses in stomatal conductance was demonstrated in D. glomerata and T. pratense. Analysis of stomatal indices and densities indicated that the observed reductions in stomatal conductance were probably the result of changes in stomatal aperture.
Download or read book Annual Review of Plant Biology written by Deborah P. Delmer and published by . This book was released on 2004-06 with total page 760 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Crop Stress Management and Global Climate Change written by José Luis Araus and published by CABI. This book was released on 2011 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: Agriculture has shaped our planet into the world we know, but its continued success is threatened by changing weather patterns. Climate change is a diverse, multifactorial phenomenon and the agronomic strategies we employ to combat its effects need to be case-specific, with significant regional differences. With two major sections, the first explaining the challenges posed by climate change and the second reviewing the current research avenues employed, this book combines detailed discussion of physiological plant responses with practical experience on crop stress management and breeding. Using a number of illustrative case studies, it discusses how the stresses resulting from climate change could be overcome by assessing, measuring and predicting environmental changes and stresses, and identifying opportunities for adapting to multifactorial change. A global effort to combine climate change science with policy is desperately needed. Climate change will continue to pose many challenges to agriculture in the future but by taking an integrative approach to predicting and adapting to change, this book will inspire researchers to turn those challenges into opportunities.
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 Energy Research Abstracts written by and published by . This book was released on 1995 with total page 598 pages. Available in PDF, EPUB and Kindle. Book excerpt: Semiannual, with semiannual and annual indexes. References to all scientific and technical literature coming from DOE, its laboratories, energy centers, and contractors. Includes all works deriving from DOE, other related government-sponsored information, and foreign nonnuclear information. Arranged under 39 categories, e.g., Biomedical sciences, basic studies; Biomedical sciences, applied studies; Health and safety; and Fusion energy. Entry gives bibliographical information and abstract. Corporate, author, subject, report number indexes.
Download or read book Carbon Water Nitrogen Processes and Mechanisms of Agricultural and Forest Ecosystems under Future Climate Change written by Yunpu Zheng and published by Frontiers Media SA. This book was released on 2024-05-23 with total page 137 pages. Available in PDF, EPUB and Kindle. Book excerpt: It is well known that agricultural and forest ecosystems are the most important carbon sinks in terrestrial ecosystems, and therefore understanding the key processes and potential mechanisms of agricultural and forest ecosystems in response to climate change is critical for accurately estimating the carbon sinks in agriculture and forests. However, the response and adaptation of carbon-water-nitrogen processes in agricultural and forest ecosystems to climate change remain unclear. These knowledge gaps create significant uncertainties in future projections, and fully exploring the potential mechanisms and processes of agriculture and forests to climate change is pivotal to projecting the potential risk of climate change on global grain yield and forest carbon sequestrations.
Download or read book Dissertation Abstracts International written by and published by . This book was released on 2003 with total page 784 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Effects on Photosynthetic CO sub 2 Assimilation to Long term Elevation of Atmospheric CO sub 2 Concentration An Assessment of the Response of Trifolium Repens L Cv Blanca Grown at F A C E written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding how photosynthetic capacity acclimates to elevated CO[sub 2] concentrations is vital in predicting the response of important grassland species such as Trifolium repens. Previous studies of acclimatization have been carried out in artificial experimental conditions, such as acrylic greenhouses or controlled environment chambers. The advent of FACE technology has enabled a large area of crop to be fumigated in the field, providing more realistic growing conditions. Pure stands of Trifolium repens L. cv. Blanca grown at either 355 or 600[mu]mol mol[sup -1] CO[sub 2] were examined, and their photosynthetic response to elevated Ca determined via gas exchange studies. Rates of photosynthesis of young, fully expanded leaves were increased between 21 and 36% when grown and measured at elevated CO[sub 2]. This increase in A corresponded to a decrease in g[sub S] of between 18 and 52%. No acclimation effect was observed in the most frequently cut stands, whilst the response of stands clipped only 4 times per year was more variable. When down regulation of V[sub cmax] did occur, this was not nearly as marked as that which occurred in 3 other temperate species (Chrysanthemum leucanthemum, Ranunculus friesianus, Plantago lanceolata (L.) J. & C. Presl.), at similar growth regimes. No acclimation of stomatal frequency, SI or pore length was found to occur in the enriched clover stands.
Download or read book Bibliography of Agriculture written by and published by . This book was released on 1999 with total page 582 pages. Available in PDF, EPUB and Kindle. Book excerpt:
