New evidence for a role of vessel‐associated cells and phloem in the rapid xylem refilling of cavitated stems of <i>Laurus nobilis</i> L.

Salleo, Sebastiano; Gullo, M. A. Lo; Trifilò, Patrizia; Nardini, Andrea

doi:10.1111/j.1365-3040.2004.01211.x

Cited by 235 publications

(256 citation statements)

References 57 publications

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“…Salleo et al, 2004;Salleo et al, 2006). A theoretical study by Hölttä et al (2006b) showed that water released by sugar unloading from the phloem may induce xylem embolism refilling in certain conditions.…”

Section: Solute Relaysmentioning

confidence: 99%

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: Solute Relaysmentioning

confidence: 99%

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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“…Boyer (1989) argued that drying of the soil may result in the collapse of the water potential gradient between xylem and actively-dividing cells. When roots were severed, Salleo et al (2000Salleo et al ( , 2004 showed that plants closed their stomata to reduce the occurrence of cavitation and to prevent the decrease in Ψ L . The apparent recovery in Ψ L after root severing observed here (Fig.…”

Section: Nature Of the Root Signalmentioning

confidence: 99%

Stomatal Responses in Rainfed Lowland Rice to Partial Soil Drying ; Evidence for Root Signals

Siopongco

Sekiya

Yamauchi

et al. 2008

Plant Production Science

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“…This common, even daily, event (2-4) can lead to complete failure of the hydraulic system if runaway embolism occurs (5). Two of the three attributes by which plants' negative-pressure flow systems can be protected against failure, resistance and reparability, have been subjects of active research during the last decade (2)(3)(4)(6)(7)(8)(9)(10). The third attribute, redundancy, has received much less attention as an important drought adaptation but is emerging as a focus of research (11)(12)(13)(14).…”

mentioning

confidence: 99%

Hydraulic integration and shrub growth form linked across continental aridity gradients

Schenk

Espino

Goedhart

et al. 2008

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

156

154

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Both engineered hydraulic systems and plant hydraulic systems are protected against failure by resistance, reparability, and redundancy. A basic rule of reliability engineering is that the level of independent redundancy should increase with increasing risk of fatal system failure. Here we show that hydraulic systems of plants function as predicted by this engineering rule. Hydraulic systems of shrubs sampled along two transcontinental aridity gradients changed with increasing aridity from highly integrated to independently redundant modular designs. Shrubs in humid environments tend to be hydraulically integrated, with single, round basal stems, whereas dryland shrubs typically have modular hydraulic systems and multiple, segmented basal stems. Modularity is achieved anatomically at the vessel-network scale or developmentally at the whole-plant scale through asymmetric secondary growth, which results in a semiclonal or clonal shrub growth form that appears to be ubiquitous in global deserts.plant hydraulic systems ͉ wood anatomy ͉ hydraulic redundancy ͉ xylem structure and function I n engineering terms, the hydraulic system of a plant is a negative-pressure flow system. This type of hydraulic system, whether natural or man-made, is prone to fail when air bubbles (emboli) are introduced, because under strong negative pressure a single embolism can lead to breakage of the water column unless the air bubble is isolated in a branch or pipe. Both drought and freezing can cause embolisms in plants (1).Drought-induced embolisms form under negative pressure, when air is pulled into a water-filled conduit from adjacent air-filled spaces or cells, a process known as ''air seeding.'' This common, even daily, event (2-4) can lead to complete failure of the hydraulic system if runaway embolism occurs (5). Two of the three attributes by which plants' negative-pressure flow systems can be protected against failure, resistance and reparability, have been subjects of active research during the last decade (2-4, 6-10). The third attribute, redundancy, has received much less attention as an important drought adaptation but is emerging as a focus of research (11)(12)(13)(14). Attributes of redundancy in hydraulic systems of vessel-bearing angiosperms include the numbers of vessels (14), the vessel network topology (12), the number and sizes of pits between adjacent vessels (13,15,16), and the division of whole plants into independent hydraulic units (17).A basic rule of reliability engineering states that the level of independent redundancy should increase with increasing risk of fatal system failure (18); hydraulic engineers routinely increase the safety of man-made pressure-flow systems by designing them to be redundant (19). Redundancy in hydraulic systems (Fig. 1) can vary from a high degree of inter-connectedness (i.e., integrated redundancy) to complete, independent compartmentation (i.e., modular redundancy). In a negative-pressure flow system, integrated redundancy allows alternate water transport pathways around blockage...

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New evidence for a role of vessel‐associated cells and phloem in the rapid xylem refilling of cavitated stems of Laurus nobilis L.

Cited by 235 publications

References 57 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

Stomatal Responses in Rainfed Lowland Rice to Partial Soil Drying ; Evidence for Root Signals

Hydraulic integration and shrub growth form linked across continental aridity gradients

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