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Berlin Brandenburg

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  • 1
    Language: English
    In: New Phytologist, Feb, 2011, Vol.189, p.659(19)
    Description: To authenticate to the full-text of this article, please visit this link: http://dx.doi.org/10.1111/j.1469-8137.2010.03576.x Byline: Jorg Kruse (1), Heinz Rennenberg (1), Mark A. Adams (2) Keywords: acclimatization; Arrhenius kinetics; Q-model; respiration; temperature response Abstract: Contents Summary Temperature crucially affects the speed of metabolic processes in poikilotherm organisms, including plants. The instantaneous temperature responses of O.sub.2-reduction and CO.sub.2-release can be approximated by Arrhenius kinetics, even though respiratory gas exchange of plants is the net effect of many constituent biochemical processes. Nonetheless, the classical Arrhenius equation must be modified to account for a dynamic response to measurement temperatures. We show that this dynamic response is readily explained by combining Arrhenius and Michaelis-Menten kinetics, as part of a fresh appraisal of metabolic interpretations of instantaneous temperature responses. In combination with recent experimental findings, we argue that control of mitochondrial electron flow is shared among cytochrome oxidase and alternative oxidase under in vivo conditions, and is continuously coordinated. In this way, upstream carbohydrate metabolism and downstream electron transport appear to be optimized according to the demand of ATP, TCA-cycle intermediates and anabolic reducing power under differing metabolic states. We provide a link to the 'Growth and Maintenance Paradigm' of respiration and argue that respiratory temperature responses can be used as a tool to probe metabolic states of plant tissue, such that we can learn more about the mechanisms that govern longer-term acclimatization responses of plant metabolism. Author Affiliation: (1)Institute of Forest Botany, Chair of Tree Physiology, Albert-Ludwigs-University Freiburg, Georges-Koehler-Allee 53-54, D-79110 Freiburg, Germany (2)Faculty of Agriculture, Food and Natural Resources, The University of Sydney, Sydney, NSW 2006, Australia Article History: Received: 6 July 2010, Accepted: 29 October 2010 Article note: Author for correspondence:, Jorg Kruse, Tel: +49 (0) 761 203 8300, Fax: +49 (0) 761 203 8302, Email: joerg.kruse@ctp.uni-freiburg.de
    Keywords: Carbohydrate Metabolism -- Physiological Aspects ; Cytochrome Oxidase -- Physiological Aspects
    ISSN: 0028-646X
    Source: Cengage Learning, Inc.
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  • 2
    Language: English
    In: New Phytologist, Feb, 2011, Vol.189, p.659(19)
    Description: To authenticate to the full-text of this article, please visit this link: http://dx.doi.org/10.1111/j.1469-8137.2010.03576.x Byline: Jorg Kruse (1), Heinz Rennenberg (1), Mark A. Adams (2) Keywords: acclimatization; Arrhenius kinetics; Q-model; respiration; temperature response Abstract: Contents Summary Temperature crucially affects the speed of metabolic processes in poikilotherm organisms, including plants. The instantaneous temperature responses of O.sub.2-reduction and CO.sub.2-release can be approximated by Arrhenius kinetics, even though respiratory gas exchange of plants is the net effect of many constituent biochemical processes. Nonetheless, the classical Arrhenius equation must be modified to account for a dynamic response to measurement temperatures. We show that this dynamic response is readily explained by combining Arrhenius and Michaelis-Menten kinetics, as part of a fresh appraisal of metabolic interpretations of instantaneous temperature responses. In combination with recent experimental findings, we argue that control of mitochondrial electron flow is shared among cytochrome oxidase and alternative oxidase under in vivo conditions, and is continuously coordinated. In this way, upstream carbohydrate metabolism and downstream electron transport appear to be optimized according to the demand of ATP, TCA-cycle intermediates and anabolic reducing power under differing metabolic states. We provide a link to the 'Growth and Maintenance Paradigm' of respiration and argue that respiratory temperature responses can be used as a tool to probe metabolic states of plant tissue, such that we can learn more about the mechanisms that govern longer-term acclimatization responses of plant metabolism. Author Affiliation: (1)Institute of Forest Botany, Chair of Tree Physiology, Albert-Ludwigs-University Freiburg, Georges-Koehler-Allee 53-54, D-79110 Freiburg, Germany (2)Faculty of Agriculture, Food and Natural Resources, The University of Sydney, Sydney, NSW 2006, Australia Article History: Received: 6 July 2010, Accepted: 29 October 2010 Article note: Author for correspondence:, Jorg Kruse, Tel: +49 (0) 761 203 8300, Fax: +49 (0) 761 203 8302, Email: joerg.kruse@ctp.uni-freiburg.de
    Keywords: Carbohydrate Metabolism -- Physiological Aspects ; Cytochrome Oxidase -- Physiological Aspects
    ISSN: 0028-646X
    Source: Cengage Learning, Inc.
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  • 3
    Language: English
    In: Proceedings of the National Academy of Sciences of the United States of America, 11 October 2016, Vol.113(41), pp.E5993-E5995
    Description: Author contributions: M.A.A., H.R., and J.K. designed research; J.K. performed research; M.A.A. and J.K. analyzed data; and M.A.A., H.R., and J.K. wrote the paper.
    Keywords: Plant Leaves ; Temperature
    ISSN: 00278424
    E-ISSN: 1091-6490
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  • 4
    Language: English
    In: Plant and Soil, 2010, Vol.332(1), pp.387-403
    Description: The root/shoot-ratio is a simple parameter to describe the systemic response of plants to alterations of their nutritional status, as indicated by the C/N-balance of leaves. The ‘functional equilibrium hypothesis’ holds that leaf growth is limited by the supply of nitrogen from the roots, whereas root growth depends on the carbon supply from leaves. The nature of the systemic control that balances root and shoot growth is not fully understood. Previous experiments have shown that root growth of transformed tobacco plants, which lack functional root nitrate reductase, was severely impeded, when plants were grown on NO 3 − as the sole N-source. In these experiments, the root/shoot-ratio was correlated with the Glutamate/Glutamine-ratio of roots. In the present study we tested the hypothesis that high internal Glu contents (in relation to Gln) inhibit root growth. Wild type and transformed tobacco plants were given access to both NH 4 and NO 3 , and were cultivated at ambient and elevated p CO 2 in order to vary carbon availability. The uptake and assimilation of NH 4 + by the root was significantly higher in transformed than in wild type tobacco, in particular at elevated p CO 2 . Consequently, the Glu/Gln-ratio in the root of transformants was significantly lower than in NO 3 − -grown plants, and was, in the present study, not different from the wild type. However, we failed to observe a correlation between plant architecture and the Glu/Gln-ratio of roots, suggesting that signals arising from the immediate products of nitrate reduction (nitrite) are involved in the systemic control of root growth. Furthermore the synthesis of root-derived signals, which affect N-turnover, starch re-mobilization and the growth of leaves, appears to be associated with root nitrate reduction. This enzymatic step seems to be indispensable for the systemic control of biomass partitioning, and plays a crucial role for the integration of carbon and nitrogen metabolism at the whole plant level.
    Keywords: Systemic control ; C/N-balance ; Root: shoot ratio ; Nitrate reduction ; Ammonium assimilation ; Glutamate signalling
    ISSN: 0032-079X
    E-ISSN: 1573-5036
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  • 5
    Language: English
    In: Forest Ecology and Management, 01 December 2012, Vol.285, pp.227-238
    Description: ► δ C- and δ O- signatures of tree-rings were used to assess forest management. ► One site showed pronounced differences in δ C between early- and latewood. ► Here, greater productivity was related to greater flexibility in water use efficiency. ► δ O-signatures acted as a proxy record of Vapor Pressure Deficit (VPD). ► The slope of the correlation between δ O and WUE indicated stomatal sensitivity to VPD. Foresters frequently lack sufficient information about site quality to optimize plantation management and logwood production to local conditions. In the present study we explored the potential of δ C- and δ O-signatures of tree-rings to provide such information. We studied stem disks collected from two plantations in south-eastern Australia that had been thinned or treated with fertilizer. Estimated from tree-ring δ C, the sites differed markedly in intrinsic water use efficiency of photosynthesis (WUE = / ). Stem disks from one site (Lyons) showed pronounced differences in δ C between early- and latewood, depending on stand density. Fertilizer application subsequent to thinning transiently increased foliage-N concentrations, without additional effects on and δ C. Thinning (and fertilization) at the other site (Daylesford) had little effect on δ C-variation between early- and late wood. Greater productivity at Lyons is seemingly related to greater flexibility in WUE such that fluctuating water supply was more efficiently exploited. Current theory suggests δ O-signatures in wood at this site acted as a proxy record of Vapor Pressure Deficit (VPD), and the slope of the correlation between δ O and WUE (as an indicator of stomatal sensitivity to VPD) helped identify growth limiting resources and conditions. In general, δ O and WUE were positively correlated and WUE seemed mainly under stomatal control. Employing a General Linear Model, we identified additional influences on WUE . The slope, and closeness of fit of the correlation between δ O and WUE depended on stand density, wood type (early- or late wood), and individual trees. These traits were not correlated in early wood immediately after planting, suggesting WUE was driven by biochemical demand for CO in photosynthesis. Conversely, enhanced competition for soil water after canopy closure resulted in positive correlations between δ O and WUE , indicating enhanced importance of stomatal resistance to CO -diffusion. We discuss the limitations to the use of δ C- and δ O analysis of bulk wood for determining the balance between demand- and supply-driven control of WUE .
    Keywords: Pinus Radiata ; Plantation Management ; Thinning ; Fertilization ; Stable Isotopes ; Δ13c and Δ18o ; Forestry ; Biology
    ISSN: 0378-1127
    E-ISSN: 1872-7042
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  • 6
    In: New Phytologist, July 2012, Vol.195(1), pp.149-163
    Description: • Respiratory acclimation to growth temperature differs between species, but underlying mechanisms are poorly understood. In the present study, we tested the hypothesis that respiratory acclimation of CO2 release is a consequence of growth regulation such that growth rates of young foliage of Eucalyptus spp. are similar at contrasting growth temperatures. Further, we tested whether such a response is affected by adaptation of Eucalyptus to different thermal environments via growth at different altitudes in the Australian Alps. • We employed calorimetric methods to relate rates of CO2 release (mainly from substrate oxidation) and rates of O2 reduction to conservation of energy. Temperature responses of these processes provided insight into mechanisms that control energy conservation and expenditure, and helped define ‘instantaneous enthalpic growth capacity’ (CapG). • CapG increased with altitude, but was counteracted by other factors in species adapted to highland habitats. The acclimation response was partly driven by changes in respiratory capacity (), and partly by more pronounced dynamic responses of CO2 release to measurement temperature. We observed enhanced temperature sensitivity of O2 reduction at higher altitudes. • Adaptation to growth temperature included differences in respiration and growth capacities, but there was little evidence that Eucalyptus species vary in metabolic flexibility.
    Keywords: Calorimetry ; Growth Capacity ; Growth Regulation ; Respiration ; Temperature Response
    ISSN: 0028-646X
    E-ISSN: 1469-8137
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  • 7
    Language: English
    In: The New phytologist, February 2011, Vol.189(3), pp.659-77
    Description: Temperature crucially affects the speed of metabolic processes in poikilotherm organisms, including plants. The instantaneous temperature responses of O(2)-reduction and CO(2)-release can be approximated by Arrhenius kinetics, even though respiratory gas exchange of plants is the net effect of many constituent biochemical processes. Nonetheless, the classical Arrhenius equation must be modified to account for a dynamic response to measurement temperatures. We show that this dynamic response is readily explained by combining Arrhenius and Michaelis-Menten kinetics, as part of a fresh appraisal of metabolic interpretations of instantaneous temperature responses. In combination with recent experimental findings, we argue that control of mitochondrial electron flow is shared among cytochrome oxidase and alternative oxidase under in vivo conditions, and is continuously coordinated. In this way, upstream carbohydrate metabolism and downstream electron transport appear to be optimized according to the demand of ATP, TCA-cycle intermediates and anabolic reducing power under differing metabolic states. We provide a link to the 'Growth and Maintenance Paradigm' of respiration and argue that respiratory temperature responses can be used as a tool to probe metabolic states of plant tissue, such that we can learn more about the mechanisms that govern longer-term acclimatization responses of plant metabolism.
    Keywords: Carbohydrate Metabolism ; Energy Metabolism ; Temperature ; Acclimatization -- Physiology ; Plants -- Metabolism ; Stress, Physiological -- Physiology
    ISSN: 0028646X
    E-ISSN: 1469-8137
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  • 8
    In: New Phytologist, December 2008, Vol.180(4), pp.841-852
    Description: •  Correlation methods originating in the growth and maintenance paradigm (GMP) are traditionally used to calculate a ‘growth coefficient’ (g) or the ‘growth potential’ (1/g) of entire plants. The enthalpy balance approach is usually applied to plant organs and relies on determination of both CO2 release and O2 reduction to provide a measure of instantaneous rates of enthalpic growth (RSGΔHB). •  Aspects of both the approaches to explore physiological mechanisms that govern enthalpic growth (variation in rates of CO2 release versus rates of O2 reduction) were combined. •  Respiration and growth rates of apical buds of Pinus radiata were affected strongly by canopy position, and moderately by branching order. A linear relation between enthalpic growth and CO2 respiration explained 69% of the observed variation. Despite faster rates of growth, enthalpic growth potential (1/gH) was comparatively low in the upper canopy. Low enthalpic growth potential entailed comparatively low enthalpy conversion efficiency (ηH, ratio of RSGΔHB to ; proportional to CO2:O2 and to carbon conversion efficiency ɛ) at large RSGΔHB. Maximizing enthalpic growth requires a large capacity for O2 reduction. •  Relations between RSGΔHB and ηH could be described by hyperbolae using two parameters. One parameter, P1, is equivalent to enthalpic growth potential (1/gH).
    Keywords: Enthalpy Balance ; Growth And Maintenance Paradigm Gmp ; Growth ; Pinus Radiata ; Respiration
    ISSN: 0028-646X
    E-ISSN: 1469-8137
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  • 9
    In: Global Change Biology, June 2008, Vol.14(6), pp.1233-1251
    Description: Scaling of respiration from the leaf to the canopy level currently depends on identification of physiological parameters that are tightly linked to respiration and that can readily be determined. Several recent studies have helped provide guides to predicting whole canopy respiration on the basis of foliar nitrogen (N). This approach is potentially powerful owing to the well‐described patterns of allocation of N that follow interception of radiation. In the present study, we investigated the sensitivity of the N–respiration correlation to environmental and developmental factors, in order to evaluate its usage for attempts to scale respiration to the organism and ecosystem level. We studied fully expanded, 1 and 2‐year‐old, and current‐year needles from canopies of that had been treated (unthinned, thinned and thinned+fertilized treatments) in ways likely to induce a wide range of growth and respiratory responses. We examined respiration in detail during the growth period in spring and again at the end of summer, using calorespirometric methods (combined measurements of CO and heat rates) to determine the respiration rates , instantaneous enthalpic growth rates (Δ, a measure of the conservation of electrons in anabolic products) and the enthalpy conversion efficiency () of needles differing in age. A general linear model revealed that was positively correlated with needle N, but this correlation was strongly dependent on the season and the needle age – indicating an important physiological difference between expanding young needles and fully expanded old needles. Furthermore, the strength of the correlation between needle N and respiration was comparatively weak for the current year, expanding foliage, indicating that factors other than foliage N significantly influenced the respiration of young needles. The analysis of instantaneous growth rates revealed two general processes. Older, nonexpanding foliage showed considerable rates of enthalpic growth (increases in enthalpy) that was mainly caused by the increment of lignin during secondary growth. Secondly, canopy development appeared dynamic and to be optimized according to environmental drivers and constraints – such as light and water availability. In late spring, needle extension slowed in the upper, but not the lower canopy, because the upper canopy appeared to be affected first by the onset of drought stress in late spring. Growth rates were reduced in the upper canopy despite greater rates of respiration, indicating higher demand of ATP for the maintenance of protein and for export of sugars. Consequently, the enthalpy conversion efficiency and enthalpic N productivity (enthalpic growth per unit N) were comparatively poor indicating advanced development of needles in the upper canopy. We suggest that the growth and maintenance paradigm of respiration is, at best, only moderately useful when applied to whole trees, and is not valid at the cellular level or that of the plant organ. A different concept, namely that of respiratory efficiency, seems a more suitable way to represent respiration in carbon (C) balance models and should help provide a better mechanistic understanding of how respiration affects the C conversion efficiency of plants, and ultimately the net primary productivity of ecosystems.
    Keywords: Enthalpy Conversion Efficiency ; Instantaneous Growth Rate ; Nitrogen ; Pinus ; Respiration
    ISSN: 1354-1013
    E-ISSN: 1365-2486
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  • 10
    Language: English
    In: Oecologia, 2014, Vol.174(3), pp.839-851
    Description: Plant carnivory represents an exceptional means to acquire N. Snap traps of Dionaea muscipula serve two functions, and provide both N and photosynthate. Using 13 C/ 15 N-labelled insect powder, we performed feeding experiments with Dionaea plants that differed in physiological state and N status (spring vs. autumn plants). We measured the effects of 15 N uptake on light-saturated photosynthesis ( A max ), dark respiration ( R D ) and growth. Depending on N status, insect capture briefly altered the dynamics of R D / A max , reflecting high energy demand during insect digestion and nutrient uptake, followed by enhanced photosynthesis and growth. Organic N acquired from insect prey was immediately redistributed, in order to support swift renewal of traps and thereby enhance probability of prey capture. Respiratory costs associated with permanent maintenance of the photosynthetic machinery were thereby minimized. Dionaea’s strategy of N utilization is commensurate with the random capture of large prey, occasionally transferring a high load of organic nutrients to the plant. Our results suggest that physiological adaptations to unpredictable resource availability are essential for Dionaea’s success with regards to a carnivorous life style.
    Keywords: Plant carnivory ; Cost/benefit ; Photosynthetic efficiency ; Respiration ; Nitrogen uptake
    ISSN: 0029-8549
    E-ISSN: 1432-1939
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