The effect of aqueous transport of CO2 in xylem sap on gas exchange in woody plants

Levy, Peter; Meir, Patrick; Allen, S. J.; Jarvis, P. G.

doi:10.1093/treephys/19.1.53

Cited by 134 publications

(142 citation statements)

References 18 publications

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“…(4) Sapflow could transport part of the CO 2 respired by the stem [12,23,30,33] and it could release it in the upper parts of the stem. However, Edwards and Wullschleger [11] and Ceschia [7] found little evidence of the effect of the sapflow on stem respiration.…”

Section: Introductionmentioning

confidence: 99%

Spatial and seasonal variations in stem respiration of beech trees (Fagus sylvatica)

et al. 2002

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-Stem respiration of adult beech (Fagus sylvatica L.) trees was measured in the field in eastern France at several levels in the crown and along the stem. Strong variations in respiration rates throughout the season and within the trees were mainly caused by gradients in stem temperature, growth rates and distribution of living cells. The higher respiration rates, were measured in the upper crown. During the non-growing season, maintenance respiration ranged between 7.2 and 528 µmol m -3 s -1 at breast height and in the upper crown, respectively. Q 10 increased along the stem from 1.

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Section: Introductionmentioning

confidence: 99%

Spatial and seasonal variations in stem respiration of beech trees (Fagus sylvatica)

et al. 2002

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“…Furthermore, most studies of plant metabolic scaling have been based on the aboveground parts and have ignored respiration of the roots, which is very difficult to measure (23). Furthermore, the flow of dissolved CO 2 in the sap brings into question the accuracy of estimating whole-tree respiration based on measuring small portions of large trees using the standard clamp-on chambers that are commercially available (16,(27)(28)(29)(30).Given the methodological difficulties inherent in whole-plant physiological studies, it is not surprising that there have thus far been no empirical measurements of complete whole-plant respiration, including roots, that have a reasonable sample size and encompass a wide range of plant sizes (2,22,26,(31)(32)(33)(34). Accurate and efficient methods using whole-plant chambers to measure respiration rates have recently been developed (5,18,19,(24)(25)(26) and can be applied to assess metabolic scaling (Fig.…”

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confidence: 99%

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confidence: 99%

Mixed-power scaling of whole-plant respiration from seedlings to giant trees

Mori

Yamaji

Ishida

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

187

259

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The scaling of respiratory metabolism with body mass is one of the most pervasive phenomena in biology. Using a single allometric equation to characterize empirical scaling relationships and to evaluate alternative hypotheses about mechanisms has been controversial. We developed a method to directly measure respiration of 271 whole plants, spanning nine orders of magnitude in body mass, from small seedlings to large trees, and from tropical to boreal ecosystems. Our measurements include the roots, which have often been ignored. Rather than a single power-law relationship, our data are fit by a biphasic, mixed-power function. The allometric exponent varies continuously from 1 in the smallest plants to 3/4 in larger saplings and trees. The transition from linear to 3/4-power scaling may indicate fundamental physical and physiological constraints on the allocation of plant biomass between photosynthetic and nonphotosynthetic organs over the course of ontogenetic plant growth.allometry | metabolic scaling | mixed-power function | whole-plant respiration | simple-power function F rom the smallest seedlings to giant trees, the masses of vascular plants span 12 orders of magnitude in mass (1). The growth rates of most plants, which are generally presented in terms of net assimilation rates of CO 2 , are believed to be controlled by respiration (2, 3). Furthermore, many of the CO 2 -budget models of plant growth and carbon dynamics in terrestrial ecosystems are based on whole-plant respiration rates in relation to plant size (2, 4-7). Thus far, however, there have been few studies of wholeplant respiration over the entire range of plant size from tiny seedlings to large trees. The purpose of the present study was to quantify the allometric scaling of metabolism by directly measuring whole-plant respiration over a representative range of sizes.For the past century, the scaling of metabolic rate with body size has usually been described using an allometric equation, or simple power function, for the form (8-17)where Y is the respiratory metabolic rate (μmol s −1 ), F is a constant (μmol s −1 kg -f ), M is the body mass (kg), and f is the scaling exponent. The exponent f has been controversial, and various values have been reported based on studies of both animals and plants (15). Recently, it was suggested that f = 1 for relatively small plants, based on data for a 10 6 -fold range of body mass (16), including measurements using a whole-plant chamber (18,19). If f = 1, this means that whole-plant respiration scales isometrically with body mass, which may be reasonable in the case of herbaceous plants and small trees because nearly all of their cells, even those in the stems, should be active in respiration. However, it was suggested that f = 3/4 based originally on empirical studies of animal metabolism (8). This idea is consistent with the mechanistic models of resource distribution in vascular systems (10, 11), including the pipe model (20, 21) and models based on space-filling, hierarchical, fractal-like networks of br...

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“…These values are corresponding well with results from other studies from various trees. Levy et al (1999) reported efflux rates between 6.0 (day time) and 3.5 (night time) μmol m -2 s -1 in a Combretum micranthum G. Don shrub in Cameroon, whereas maximum values of 9.9 μmol m -2 s -1 are also known for Schima superba Gardner & Champ. trees in the subtropics of southern China (Zhu et al 2011).…”

Section: Resultsmentioning

confidence: 99%

“…One study using continuous measurements with open dynamic chambers was conducted in a Schima superba Gardner & Champ. plantation, in the subtropics of southern China (Zhu et al 2011), and another in a subtropical Combretum micranthum G. Don shrub growing in Cameroon (Levy et al 1999). These studies generally found a positive relation between xylem sap fl ux and CO 2 effl ux, but the fi ndings regarding the overall effect of the water transport were quite controversial compared to the results with trees from temperate and boreal forests.…”

Section: Introductionmentioning

confidence: 98%

Effects of xylem water transport on CO2 efflux of woody tissue in a tropical tree, Amazonas State, Brazil

Kunert

Cárdenas

2012

Hoehnea

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-(Effects of xylem water transport on CO 2 effl ux of woody tissue in a tropical tree, Amazonas State, Brazil). We assessed the effect of xylem sap fl ux on radial CO 2 effl ux of woody tissue of a tropical trees species growing in the Center of Manaus (Amazonas State, Brazil). An open chamber system was used to constantly measure diurnal changes in CO 2 effl ux over several days. Xylem sap fl ux was monitored additionally. We found a strong relationship between temperature and woody tissue respiration rates during night time. CO 2 effl ux rates were reduced up to 35% during daytime most probably due to vertical water uptake within the tree trunks. The results suggest a distinct daytime depression of the CO 2 effl ux compared with a night time temperature relationship. Xylem sap fl ux appears to be a major infl uence on CO 2 effl ux rates. The reductions in CO 2 effl ux will become most distinct during periods with a high evaporative demand and predictions of CO 2 effl ux by the temperature/fl ux relation are critical during these periods. Key words: daytime depression, sap fl ux, temperature dependency, woody tissue respiration RESUMEN -(Efectos del transporte de agua por el xilema en la afl uencia de CO 2 en el tejido leñoso de un árbol tropical, Estado del Amazonas, Brasil). Evaluamos el efecto del fl ujo de la savia del xilema en la afl uencia del CO 2 radial en tejidos leñosos de una especie de árbol tropical en el centro de Manaos (Amazonas, Brasil). Un sistema de cámara abierta fue usado constantemente para medir cambios diarios en la afl uencia del CO 2 durante varios días. Al mismo tiempo, se midió el fl ujo de la savia del xilema. Encontramos una fuerte relación entre las tazas de temperatura y la respiración del tejido leñoso durante el periodo nocturno. Las tazas de afl uencia de CO 2 se redujeron hasta un 35% durante el día, probablemente debido a la absorción vertical del agua dentro de los troncos. Los resultados sugieren una depresión de la afl uencia del CO 2 específi ca durante el día comparada con la relación de la temperatura durante la noche. El fl ujo de la savia del dilema parece tener una infl uencia más fuerte en las tazas de afl uencia del CO 2 . Las reducciones en la afl uencia del CO 2 serán más marcadas durante periodos con una alta demanda de evaporación y las predicciones de la afl uencia del CO 2 dadas por la relación de temperatura/fl ujo son críticas durante dichos periodos. Palabras-clave: dependencia en la temperatura, depresión diurna, fl ujo de savia, respiración de tejido leñoso 1.

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The effect of aqueous transport of CO2 in xylem sap on gas exchange in woody plants

Cited by 134 publications

References 18 publications

Spatial and seasonal variations in stem respiration of beech trees (Fagus sylvatica)

Spatial and seasonal variations in stem respiration of beech trees (Fagus sylvatica)

Mixed-power scaling of whole-plant respiration from seedlings to giant trees

Effects of xylem water transport on CO2 efflux of woody tissue in a tropical tree, Amazonas State, Brazil

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