The leaf economics spectrum (LES) describes consistent correlations among a variety of leaf trait... more The leaf economics spectrum (LES) describes consistent correlations among a variety of leaf traits that reflect a gradient from conservative to acquisitive plant strategies. So far, whether the LES holds in wetland plants at a global scale has been unclear. Using data on 365 wetland species from 151 studies, we find that wetland plants in general show a shift within trait space along the same common slope as observed in non-wetland plants, with lower leaf mass per area, higher leaf nitrogen and phosphorus, faster photosynthetic rates, and shorter leaf life span compared to non-wetland plants. We conclude that wetland plants tend to cluster at the acquisitive end of the LES. The presented global quantifications of the LES in wetland plants enhance our understanding of wetland plant strategies in terms of resources acquisition and allocation, and provide a stepping-stone to developing trait-based approaches for wetland ecology.
Soil waterlogging impedes gas exchange with the atmosphere, resulting in low P(O2) and often high... more Soil waterlogging impedes gas exchange with the atmosphere, resulting in low P(O2) and often high P(CO2). Conditions conducive to development of high P(CO2) (5-70 kPa) during soil waterlogging and flooding are discussed. The scant information on responses of roots to high P(CO2) in terms of growth and metabolism is reviewed. P(CO2) at 15-70 kPa has been reported for flooded paddy-field soils; however, even 15 kPa P(CO2) may not always be reached, e.g. when soil pH is above 7. Increases of P(CO2) in soils following waterlogging will develop much more slowly than decreases in P(O2); in soil from rice paddies in pots without plants, maxima in P(CO2) were reached after 2-3 weeks. There are no reliable data on P(CO2) in roots when in waterlogged or flooded soils. In rhizomes and internodes, P(CO2) sometimes reached 10 kPa, inferring even higher partial pressures in the roots, as a CO2 diffusion gradient will exist from the roots to the rhizomes and shoots. Preliminary modelling predicts ...
Page 1. Letter The respiratory down-regulation debate Over the past decade there have been severa... more Page 1. Letter The respiratory down-regulation debate Over the past decade there have been several claims of sensor-operated respiratory down-regulation in plants at O2 pressures greatly in excess of the critical O2 pressure ...
... The experiments were conducted at 26±2 ◦ C, unless stated otherwise. Here we report ex-perime... more ... The experiments were conducted at 26±2 ◦ C, unless stated otherwise. Here we report ex-periments on Musa spp. cv. ... (1985). The discrep-ancy may reflect the inclusion of more mature tissue in the longer banana segments. ...
Akagare and Akiochi are diseases of rice associated with sulfide toxicity. This study investigate... more Akagare and Akiochi are diseases of rice associated with sulfide toxicity. This study investigates the possibility that rice reacts to sulfide by producing impermeable barriers in roots. Root systems of rice, Oryza sativa cv. Norin 36, were subjected to short-term exposure to 0.174 mm sulfide (5.6 ppm) in stagnant solution. Root growth was monitored; root permeability was investigated in terms of polarographic determinations of oxygen efflux from fine laterals and the apices of adventitious roots, water uptake, anatomy and permeability to Fe2+ using potassium ferricyanide. Both types of root responded rapidly to the sulfide with immediate cessation of growth, decreased radial oxygen loss (ROL) to the rhizospheres and reduced water uptake. Profiles of ROL measured from apex to basal regions of adventitious roots indicated that more intense barriers to ROL than normal were formed around the apices. Absorption of Fe2+ appeared to be impeded in sulfide-treated roots. In adventitious roo...
Claims that submerged roots of alder and other wetland trees are aerated by pressurized gas flow ... more Claims that submerged roots of alder and other wetland trees are aerated by pressurized gas flow generated in the stem by a light-induced thermo-osmosis have seemed inconsistent with root anatomy. Our aim was to seek a verification using physical root-stem models, stem segments with or without artificial roots, and rooted saplings. Radial O2 loss (ROL) from roots was monitored polarographically as the gas space system of the models, and stems were pressurized artificially. ROL and internal pressurization were also measured when stems were irradiated and the xylem stream was either CO2 enriched or not. Stem photosynthesis and respiration were measured polarographically. Stem and root anatomy were examined by light and fluorescence microscopy. Pressurizing the models and stems to <or=10 kPa, values much higher than those reportedly generated by thermo-osmosis, created only a negligible density-induced increase in ROL, but ROL increased rapidly when ambient O2 concentrations were ra...
Oil pollution of wetlands is a world-wide problem but, to date, research has concentrated on its ... more Oil pollution of wetlands is a world-wide problem but, to date, research has concentrated on its influences on salt marsh rather than freshwater plant communities. The effects of water-borne light oils (liquid paraffin and diesel) were investigated on the fresh/brackish wetland species Phragmites australis in terms of routes of oil infiltration, internal gas transport, radial O(2) loss (ROL), underwater gas films and bud growth. Pressure flow resistances of pith cavities of nodes and aerenchyma of leaf sheaths, with or without previous exposure to oil, were recorded from flow rates under applied pressure. Convective flows were measured from living excised culms with oiled and non-oiled nodes and leaf sheaths. The effect of oil around culm basal nodes on ROL from rhizome and root apices was measured polarographically. Surface gas films on submerged shoots with and without oil treatment were recorded photographically. Growth and emergence of buds through water with and without an oil ...
The leaf economics spectrum (LES) describes consistent correlations among a variety of leaf trait... more The leaf economics spectrum (LES) describes consistent correlations among a variety of leaf traits that reflect a gradient from conservative to acquisitive plant strategies. So far, whether the LES holds in wetland plants at a global scale has been unclear. Using data on 365 wetland species from 151 studies, we find that wetland plants in general show a shift within trait space along the same common slope as observed in non-wetland plants, with lower leaf mass per area, higher leaf nitrogen and phosphorus, faster photosynthetic rates, and shorter leaf life span compared to non-wetland plants. We conclude that wetland plants tend to cluster at the acquisitive end of the LES. The presented global quantifications of the LES in wetland plants enhance our understanding of wetland plant strategies in terms of resources acquisition and allocation, and provide a stepping-stone to developing trait-based approaches for wetland ecology.
Soil waterlogging impedes gas exchange with the atmosphere, resulting in low P(O2) and often high... more Soil waterlogging impedes gas exchange with the atmosphere, resulting in low P(O2) and often high P(CO2). Conditions conducive to development of high P(CO2) (5-70 kPa) during soil waterlogging and flooding are discussed. The scant information on responses of roots to high P(CO2) in terms of growth and metabolism is reviewed. P(CO2) at 15-70 kPa has been reported for flooded paddy-field soils; however, even 15 kPa P(CO2) may not always be reached, e.g. when soil pH is above 7. Increases of P(CO2) in soils following waterlogging will develop much more slowly than decreases in P(O2); in soil from rice paddies in pots without plants, maxima in P(CO2) were reached after 2-3 weeks. There are no reliable data on P(CO2) in roots when in waterlogged or flooded soils. In rhizomes and internodes, P(CO2) sometimes reached 10 kPa, inferring even higher partial pressures in the roots, as a CO2 diffusion gradient will exist from the roots to the rhizomes and shoots. Preliminary modelling predicts ...
Page 1. Letter The respiratory down-regulation debate Over the past decade there have been severa... more Page 1. Letter The respiratory down-regulation debate Over the past decade there have been several claims of sensor-operated respiratory down-regulation in plants at O2 pressures greatly in excess of the critical O2 pressure ...
... The experiments were conducted at 26±2 ◦ C, unless stated otherwise. Here we report ex-perime... more ... The experiments were conducted at 26±2 ◦ C, unless stated otherwise. Here we report ex-periments on Musa spp. cv. ... (1985). The discrep-ancy may reflect the inclusion of more mature tissue in the longer banana segments. ...
Akagare and Akiochi are diseases of rice associated with sulfide toxicity. This study investigate... more Akagare and Akiochi are diseases of rice associated with sulfide toxicity. This study investigates the possibility that rice reacts to sulfide by producing impermeable barriers in roots. Root systems of rice, Oryza sativa cv. Norin 36, were subjected to short-term exposure to 0.174 mm sulfide (5.6 ppm) in stagnant solution. Root growth was monitored; root permeability was investigated in terms of polarographic determinations of oxygen efflux from fine laterals and the apices of adventitious roots, water uptake, anatomy and permeability to Fe2+ using potassium ferricyanide. Both types of root responded rapidly to the sulfide with immediate cessation of growth, decreased radial oxygen loss (ROL) to the rhizospheres and reduced water uptake. Profiles of ROL measured from apex to basal regions of adventitious roots indicated that more intense barriers to ROL than normal were formed around the apices. Absorption of Fe2+ appeared to be impeded in sulfide-treated roots. In adventitious roo...
Claims that submerged roots of alder and other wetland trees are aerated by pressurized gas flow ... more Claims that submerged roots of alder and other wetland trees are aerated by pressurized gas flow generated in the stem by a light-induced thermo-osmosis have seemed inconsistent with root anatomy. Our aim was to seek a verification using physical root-stem models, stem segments with or without artificial roots, and rooted saplings. Radial O2 loss (ROL) from roots was monitored polarographically as the gas space system of the models, and stems were pressurized artificially. ROL and internal pressurization were also measured when stems were irradiated and the xylem stream was either CO2 enriched or not. Stem photosynthesis and respiration were measured polarographically. Stem and root anatomy were examined by light and fluorescence microscopy. Pressurizing the models and stems to <or=10 kPa, values much higher than those reportedly generated by thermo-osmosis, created only a negligible density-induced increase in ROL, but ROL increased rapidly when ambient O2 concentrations were ra...
Oil pollution of wetlands is a world-wide problem but, to date, research has concentrated on its ... more Oil pollution of wetlands is a world-wide problem but, to date, research has concentrated on its influences on salt marsh rather than freshwater plant communities. The effects of water-borne light oils (liquid paraffin and diesel) were investigated on the fresh/brackish wetland species Phragmites australis in terms of routes of oil infiltration, internal gas transport, radial O(2) loss (ROL), underwater gas films and bud growth. Pressure flow resistances of pith cavities of nodes and aerenchyma of leaf sheaths, with or without previous exposure to oil, were recorded from flow rates under applied pressure. Convective flows were measured from living excised culms with oiled and non-oiled nodes and leaf sheaths. The effect of oil around culm basal nodes on ROL from rhizome and root apices was measured polarographically. Surface gas films on submerged shoots with and without oil treatment were recorded photographically. Growth and emergence of buds through water with and without an oil ...
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