Does turgor limit growth in tall trees?

Woodruff, David R.; Bond, Barbara J.; Meinzer, F. C.

doi:10.1111/j.1365-3040.2003.01141.x

Cited by 247 publications

(234 citation statements)

References 40 publications

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“…It is well known that low xylem water potentials cause detrimental effects on plant function by inducing xylem conduit embolism and turgor reduction in living cells (e.g. Tyree, 2003;Woodruff et al, 2004). This study suggested that decreasing xylem water potentials also limits sugar transport for a given phloem structure as water is held more tightly in the xylem (see Eq.…”

Section: Accepted Manuscript 26mentioning

confidence: 84%

Linking phloem function to structure: Analysis with a coupled xylem–phloem transport model

Hölttä

Mencuccini

Nikinmaa

2009

Journal of Theoretical Biology

202

188

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Cite this article as: T. Hölttä, M. Mencuccini and E. Nikinmaa, Linking phloem function to structure: Analysis with a coupled xylem-phloem transport model, Journal of Theoretical Biology (2009Biology ( ), doi:10.1016Biology ( /j.jtbi.2009 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. We carried out a theoretical analysis of phloem transport based on Münch hypothesis by developing a coupled xylem-phloem transport model. Results showed that the maximum sugar transport rate of the phloem was limited by solution viscosity and that transport requirements were strongly affected by prevailing xylem water potential. The minimum number of xylem and phloem conduits required to sustain transpiration and assimilation, respectively, were calculated. At its maximum sugar transport rate, the phloem functioned with a high turgor pressure difference between the sugar sources and sinks but the turgor pressure difference was reduced if additional parallel conduits were added or solute relays were introduced. Solute relays were shown to decrease the number of parallel sieve tubes needed for phloem transport, leading to a more uniform turgor pressure and allowing faster information transmission within the phloem. Because xylem water potential affected both xylem and phloem transport, the conductance of the two systems was found to be coupled such that large structural investments in the xylem reduced the need for investment in the phloem and vice versa.

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Section: Accepted Manuscript 26mentioning

confidence: 84%

Linking phloem function to structure: Analysis with a coupled xylem–phloem transport model

Hölttä

Mencuccini

Nikinmaa

2009

Journal of Theoretical Biology

202

188

View full text Add to dashboard Cite

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“…Todas estas respuestas tienen como consecuencia la disminución del crecimiento global de la planta y, por ende, una disminución en la acumulación de biomasa. El transporte de agua en la planta es una parte integral del proceso de crecimiento, ya que una variedad de procesos relacionados con el crecimiento, incluyendo la formación y expansión de células vegetales, son dependientes de la presión de turgencia y el volumen celular (Woodruff et al 2004). Por tanto, las relaciones existentes entre las variables hídricas, fotosíntesis y conductancia estomática son aspectos clave en la comprensión del proceso de tolerancia al estrés (Dickson y Tomlinson 1996), lo cual determina a su vez el crecimiento, reproducción, distribución y composición de especies vegetales.…”

Section: Introductionunclassified

Respuesta fisiológica y de crecimiento en plantas de Quillaja saponaria y Cryptocarya alba sometidas a restricción hídrica

et al. 2011

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Respuesta fisiológica y de crecimiento en plantas deChile is characterized by a Mediterranean Climate. Some of the tree species that grows in this zone (e.g. Quillaja saponaria (quillay) and Cryptocarya alba (peumo)) have developed physiological mechanisms to tolerate drought periods during the summer. The aim of this study was to quantify physiological and growth parameters in two-year-old quillay and peumo saplings, maintained under controlled water restricted conditions during one summer season. The plants were assigned to two different experimental treatments: well watered (control-WW) and restricted irrigation (RI). Saplings in RI had an average predawn water potential (ψ pd ) near to -3.5 MPa. At the end of the water restriction period, plant gas exchange parameters were determined and biomass distributions in leaves, branches, stems and roots were analyzed. During the period of high water deficit, quillay did not showed a clear mechanism of adjustment to water deficit, but a reduction in 55 % of leaf biomass decreased the evapotranspiration rate. Peumo showed an osmotic adjustment. Net photosynthesis, stomatal conductance and transpiration rate of quillay and peumo plants were significantly reduced in the RI treatment when compared to control saplings. Quillay saplings showed a significant reduction in the above/below biomass ratio under the restricted irrigation treatment (2.3 to 1.4). In contrast peumo saplings did not change significantly this ratio (1.3).Key words: Quillaja saponaria, Cryptocarya alba, water potential, gas exchange, biomass distribution. RESUMENLa zona central de Chile presenta un clima mediterráneo donde las especies arbóreas como Quillaja saponaria (quillay) y Cryptocarya alba (peumo) han desarrollado mecanismos fisiológicos que le permiten tolerar la falta de agua durante el verano. Se desarrolló un ensayo con plantas de dos años de quillay y peumo, que fueron sometidas a condiciones de restricción hídrica, en el periodo estival. Un grupo de plantas fue regado diariamente a capacidad de campo (tratamiento testigo) y otro grupo fue sometido a riego restringido hasta llegar a un potencial hídrico a pre-alba cercano a -3,5 MPa. Finalizado el período de restricción hídrica, las plantas se rehidrataron. Durante el estudio se midieron variables hídricas y de crecimiento. Al finalizar el periodo de restricción hídrica se determinaron tasas de intercambio gaseoso, así como la distribución de biomasa en hojas, ramas, fuste y raíces. En el periodo de mayor restricción hídri-ca, quillay no presentó un mecanismo claro de ajuste al déficit hídrico, pero redujo su biomasa foliar en 55 % para reducir la pérdida hídrica. Mientras que peumo presentó ajuste osmótico. Quillay y peumo presentaron una reducción significativa de la fotosíntesis neta, conductancia estomática y transpiración de frente a riego restringido. La relación parte aérea/parte radical no se modificó en peumo (1,3), y se redujo significativamente en quillay, de 2,3 a 1,4 para el tratamiento de restricción hídrica.Palabras clave: Qu...

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“…Lower A at the same g s for tall versus short trees could also result from reduced g i . Thus, while hydraulics per se appear to play a direct role in driving diel gas exchange patterns, longer term impacts of hydraulics on g i or leaf [N] appear to also be critical (see also Le Roux et al 2001;Woodruff et al 2004;Lloyd et al 2009). Foliar D and p a − p c results for all seven Nothofagus sites showed evidence of lower p c as h increased (Table 10.1, Fig.…”

Section: The Response Of Leaf-level Gas Exchange and D To H In Nothofmentioning

confidence: 99%

“…This relationship sets boundaries on physiological properties that impact D. First, it sets an upper limit on foliar water potential during expansion, causing increasing leaf mass per unit area with increasing h (Marshall and Monserud 2003;Woodruff et al 2004;Koch et al 2004;Cavaleri et al 2010), which may subsequently influence g i and p c via shifts in mesophyll surface area (Terashima et al 2005;Oldham 2008). Second, as maximum xylem water potential declines with increasing h, the potential range of xylem water potential must also decline (unless the trees are anisohydric with h, which is rarely observed, allows only a few tenths MPa shift, and has consequences for xylem conductance and leaf area, Yoder et al 1994;McDowell et al 2002a).…”

Section: Why Does D Decline Linearly With Increasing H?mentioning

confidence: 99%

“…This morphological response is commonly thought to be adaptive to the light environment, although it also driven by the gravitational constraint on leaf water potential (0.01 MPa m −1 ) and subsequent impacts on turgor during leaf expansion (e.g. Marshall and Monserud 2003;Woodruff et al 2004;Cavaleri et al 2010;Woodruff and Meinzer 2011). Foliar nitrogen content may increase with light availability within crowns Duursma and Marshall 2006;Lloyd et al 2009), which could increase A and hence reduce D via increased photosynthetic capacity.…”

Section: Introductionmentioning

confidence: 99%

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Relationships Between Tree Height and Carbon Isotope Discrimination

et al. 2011

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Understanding how tree size impacts leaf-and crown-level gas exchange is essential to predicting forest yields and carbon and water budgets. The stable carbon isotope ratio (d 13 C) of organic matter has been used to examine the relationship of gas exchange to tree size for a host of species because it carries a temporally integrated signature of foliar photosynthesis and stomatal conductance. The carbon isotope composition of leaves reflects discrimination against 13 C relative to 12 C during photosynthesis and is the net result of the balance of change in CO 2 supply and demand at the sites of photosynthesis within the leaf mesophyll. Interpreting the patterns of changes in d 13 C with tree size are not always clear, however, because multiple factors that regulate gas exchange and carbon isotope discrimination (D) co-vary with height, such as solar irradiance and hydraulic conductance. Here we review 36 carbon isotope datasets from 38 tree species and conclude that there is a consistent, linear decline of D with height. The most parsimonious explanation of this result is that gravitational constraints on maximum leaf water potential set an ultimate boundary on the shape and sign of the relationship. These hydraulic constraints are manifest both over the long term through impacts on leaf structure, and over diel periods via impacts on stomatal conductance, photosynthesis and leaf hydraulic conductance. Shading induces a positive offset to the linear decline, consistent with light limitations reducing carbon fixation and increasing partial pressures of CO 2 inside of the leaf, p c at a given height. Biome differences between tropical and temperate forests were more important in predicting D and its relationship to height than wood type associated with being an angiosperm or gymnosperm. It is not yet clear how leaf internal conductance varies with leaf mass area, but some data in particularly tall, temperate conifers suggest that photosynthetic capacity may not vary dramatically with height when compared between tree-tops, while stomatal and leaf internal conductances do decline in unison with height within canopy gradients. It is also clear that light is a critical variable low in the canopy, whereas hydrostatic constraints dominate the relationship between D and height in the upper canopy. The trend of increasing maximum height with decreasing minimum D suggests that trees that become particularly tall may be adapted to tolerate particularly low values of p c .

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Does turgor limit growth in tall trees?

Abstract: ABSTRACT

Cited by 247 publications

References 40 publications

Linking phloem function to structure: Analysis with a coupled xylem–phloem transport model

Linking phloem function to structure: Analysis with a coupled xylem–phloem transport model

Respuesta fisiológica y de crecimiento en plantas de Quillaja saponaria y Cryptocarya alba sometidas a restricción hídrica

Relationships Between Tree Height and Carbon Isotope Discrimination

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