TY - JOUR

T1 - Submergence tolerance in Hordeum marinum

T2 - dissolved CO2 determines underwater photosynthesis and growth

AU - Pedersen, Ole

AU - Malik, Al I.

AU - Colmer, Timothy D.

PY - 2010

Y1 - 2010

N2 - Floodwaters differ markedly in dissolved CO(2), yet the effects of CO(2) on submergence responses of terrestrial plants have rarely been examined. The influence of dissolved CO(2) on underwater photosynthesis and growth was evaluated for three accessions of the wetland plant Hordeum marinum Huds. All three accessions tolerated complete submergence, but only when in CO(2) enriched floodwater. Plants submerged for 7 days in water at air equilibrium (18 mM CO(2)) suffered loss of biomass, whereas those with 200 mM CO(2) continued to grow. Higher underwater net photosynthesis at 200 mM CO(2) increased by 2.7- to 3.2-fold sugar concentrations in roots of submerged plants, compared with at air equilibrium CO(2). Leaf gas films enhancing gas exchange with floodwater, lack of a shoot elongation response conserving tissue sugars and high tissue porosity (24-31% in roots) facilitating internal O(2) movement, would all contribute to submergence tolerance in H. marinum. The present study demonstrates that dissolved CO(2) levels can determine submergence tolerance of terrestrial plants. So, submergence experiments should be conducted with defined CO(2) concentrations and enrichment might be needed to simulate natural environments and, thus, provide relevant plant responses

AB - Floodwaters differ markedly in dissolved CO(2), yet the effects of CO(2) on submergence responses of terrestrial plants have rarely been examined. The influence of dissolved CO(2) on underwater photosynthesis and growth was evaluated for three accessions of the wetland plant Hordeum marinum Huds. All three accessions tolerated complete submergence, but only when in CO(2) enriched floodwater. Plants submerged for 7 days in water at air equilibrium (18 mM CO(2)) suffered loss of biomass, whereas those with 200 mM CO(2) continued to grow. Higher underwater net photosynthesis at 200 mM CO(2) increased by 2.7- to 3.2-fold sugar concentrations in roots of submerged plants, compared with at air equilibrium CO(2). Leaf gas films enhancing gas exchange with floodwater, lack of a shoot elongation response conserving tissue sugars and high tissue porosity (24-31% in roots) facilitating internal O(2) movement, would all contribute to submergence tolerance in H. marinum. The present study demonstrates that dissolved CO(2) levels can determine submergence tolerance of terrestrial plants. So, submergence experiments should be conducted with defined CO(2) concentrations and enrichment might be needed to simulate natural environments and, thus, provide relevant plant responses

KW - aerenchyma

KW - elevated CO(2)

KW - flooding tolerance

KW - sea barleygrass

KW - tissue porosity

KW - tissue sugars

KW - Triticeae

KW - waterlogging tolerance

KW - wetland plant

KW - wild Hordeum

KW - RADIAL OXYGEN LOSS

KW - INORGANIC CARBON

KW - ROOT AERATION

KW - WATER PLANTS

KW - RICE

KW - DYNAMICS

KW - O-2

KW - FLOODWATER

U2 - 10.1071/FP09298

DO - 10.1071/FP09298

M3 - Journal article

VL - 37

SP - 524

EP - 531

JO - Australian Journal of Plant Physiology

JF - Australian Journal of Plant Physiology

SN - 1445-4408

IS - 6

ER -