Roles of Aquaporins in Root Responses to Irrigation

Vandeleur, Rebecca K.; Niemietz, Christa; Tilbrook, Joanne; Tyerman, Stephen D.

doi:10.1007/s11104-004-8070-z

Cited by 77 publications

(46 citation statements)

References 145 publications

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“…Such gating of an Arabidopsis aquaporin by changes in pH was recently confirmed in studies of proteoliposomes (Verdoucq et al 2008). Vandeleur et al (2005) hypothesised that gating of aquaporins in roots experiencing O 2 -deficit might be a mechanism by which water uptake is re-directed to other roots in more favourable regions of the soil (e.g. from O 2 -deficient deeper roots, to those in surface layers with access to some O 2 ).…”

Section: Soil Waterlogging -Short Durationmentioning

confidence: 87%

Flooding tolerance: suites of plant traits in variable environments

Colmer

Voesenek

2009

Functional Plant Biol.

688

538

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Abstract.Flooding regimes of different depths and durations impose selection pressures for various traits in terrestrial wetland plants. Suites of adaptive traits for different flooding stresses, such as soil waterlogging (short or long duration) and full submergence (short or long duration -shallow or deep), are reviewed. Synergies occur amongst traits for improved internal aeration, and those for anoxia tolerance and recovery, both for roots during soil waterlogging and shoots during submergence. Submergence tolerance of terrestrial species has recently been classified as either the Low Oxygen Quiescence Syndrome (LOQS) or the Low Oxygen Escape Syndrome (LOES), with advantages, respectively, in short duration or long duration (shallow) flood-prone environments. A major feature of species with the LOQS is that shoots do not elongate upon submergence, whereas those with the LOES show rapid shoot extension. In addition, plants faced with long duration deep submergence can demonstrate aspects of both syndromes; shoots do not elongate, but these are not quiescent, as new aquatictype leaves are formed. Enhanced entries of O 2 and CO 2 from floodwaters into acclimated leaves, minimises O 2 deprivation and improves underwater photosynthesis, respectively. Evolution of 'suites of traits' are evident in wild wetland species and in rice, adapted to particular flooding regimes.

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Section: Soil Waterlogging -Short Durationmentioning

confidence: 87%

Flooding tolerance: suites of plant traits in variable environments

Colmer

Voesenek

2009

Functional Plant Biol.

688

538

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“…In general PIP1s have little or no water channel activity in vitro, whereas the PIP2s show high water permeability when expressed in Xenopus laevis oocytes (Chaumont et al, 2000). Water permeability of aquaporins can be regulated by cytosolic pH and pCa (Gerbeau et al, 2002;Alleva et al, 2006), phosphorylation (Maurel et al, 1995;Johansson et al, 1998), large pressure pulses (Wan et al, 2004), and osmotic solutes (Ye et al, 2004;Vandeleur et al, 2005). It has been demonstrated that PIP1 and PIP2 members may interact either within the membrane or by targeting to the plasma membrane (Fetter et al, 2004;Zelazny et al, 2007).…”

mentioning

confidence: 99%

The Role of Plasma Membrane Intrinsic Protein Aquaporins in Water Transport through Roots: Diurnal and Drought Stress Responses Reveal Different Strategies between Isohydric and Anisohydric Cultivars of Grapevine

et al. 2008

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We report physiological and anatomical characteristics of water transport across roots grown in soil of two cultivars of grapevine (Vitis vinifera) differing in response to water stress (Grenache, isohydric; Chardonnay, anisohydric). Both cultivars have similar root hydraulic conductances (L o ; normalized to root dry weight) that change diurnally. There is a positive correlation between L o and transpiration. Under water stress, both cultivars have reduced minimum daily L o (predawn) attributed to the development of apoplastic barriers. Water-stressed and well-watered Chardonnay had the same diurnal change in amplitude of L o , while water-stressed Grenache showed a reduction in daily amplitude compared with well-watered plants. Hydraulic conductivity of root cortex cells (L pcell ) doubles in Chardonnay but remains unchanged in Grenache. Of the two most highly expressed plasma membrane intrinsic protein (PIP) aquaporins in roots (VvPIP1;1 and VvPIP2;2), only VvPIP2;2 functions as a water channel in Xenopus laevis oocytes. VvPIP1;1 interacts with VvPIP2;2 to induce 3-fold higher water permeability. These two aquaporins are colocated in the root from in situ hybridization and immunolocalization of VvPIP1 and VvPIP2 subfamily members. They occur in root tip, exodermis, root cortex (detected up to 30 mm), and stele. VvPIP2;2 mRNA does not change diurnally or with water stress, in contrast to VvPIP1;1, in which expression reflects the differences in L o and L pcell between cultivars in their responses to water stress and rewatering. VvPIP1;1 may regulate water transport across roots such that transpirational demand is matched by root water transport capacity. This occurs on a diurnal basis and in response to water stress that corresponds to the difference in drought tolerance between the cultivars. Root hydraulic conductance is usually lowest within the liquid component of the soil-plant-air continuum. The hydraulic conductance of roots can be highly variable in both time and space, which will affect soilwater extraction and shoot water status (Steudle and Peterson, 1998;Steudle, 2000aSteudle, , 2000b. Steudle (2000aSteudle ( , 2000b explains variation in root hydraulic conductivity (L p ; hydraulic conductance normalized to root surface area) in terms of the composite transport model based on the composite anatomical structure of roots, where water can move radially toward the xylem along three pathways: the apoplastic, symplastic, and transcellular. The symplastic and transcellular pathways are difficult to separate experimentally and are collectively considered as the cell-to-cell pathway (Steudle, 2000b). The extent to which water flow predominates in either pathway varies according to the relative hydraulic conductances of the pathways and the relative magnitude of hydrostatic versus osmotic gradients (Steudle, 2000a; Bramley et al., 2007b). Apoplastic flow can be altered irreversibly by anatomical changes, including Casparian bands and suberin lamellae (Steudle and Peterson, 1998). The conductance of the cell...

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“…These resistances are regulated by the physics of conduits (e.g. size and density of vessels), by some physiological traits, such as aquaporin-induced changes of membrane permeability, and depend on the time scale considered (Vandeleur et al, 2005). Directly, through absorption and transport, exceeding part of the cellular barriers, or indirectly, exploring a bigger soil volume and interstices between little agglomerates, the hyphae increase the water flow potentially available to plants.…”

Section: Hydraulic Conductivitymentioning

confidence: 99%