Submergence-induced leaf acclimation in terrestrial species varying in flooding tolerance.
Earlier work on the submergence-tolerant species Rumex palustris revealed that leaf anatomical and morphological changes induced by submergence enhance underwater gas exchange considerably. Here, the hypothesis is tested that these plastic responses are typical properties of submergence-tolerant species. Submergence-induced plasticity in leaf mass area (LMA) and leaf, cell wall and cuticle thickness was investigated in nine plant species differing considerably in tolerance to complete submergence. The functionality of the responses for underwater gas exchange was evaluated by recording oxygen partial pressures inside the petioles when plants were submerged. Acclimation to submergence resulted in a decrease in all leaf parameters, including cuticle thickness, in all species irrespective of flooding tolerance. Consequently, internal oxygen partial pressures (pO(2)) increased significantly in all species until values were close to air saturation. Only in nonacclimated leaves in darkness did intolerant species have a significantly lower pO(2) than tolerant species. These results suggest that submergence-induced leaf plasticity, albeit a prerequisite for underwater survival, does not discriminate tolerant from intolerant species. It is hypothesized that these plastic leaf responses may be induced in all species by several signals present during submergence; for example, low LMA may be a response to low photosynthate concentrations and a thin cuticle may be a response to high relative humidity.
Mommer
Liesje
L
Department of Experimental Plant Ecology, Institute for Water and Wetland Research, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, the Netherlands.|Present address: Nature Conservation & Plant Ecology, Wageningen University, PO Box 47, 6700 AA, Wageningen, the Netherlands.
Wolters-Arts
Mieke
M
Department of Experimental Botany, Institute for Water and Wetland Research, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, the Netherlands.
Andersen
Charlotte
C
Freshwater Biological Laboratory, Helsingørsgade 51, DK-3400, Hillerød, Denmark.
Visser
Eric J W
EJW
Department of Experimental Plant Ecology, Institute for Water and Wetland Research, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, the Netherlands.
Pedersen
Ole
O
Freshwater Biological Laboratory, Helsingørsgade 51, DK-3400, Hillerød, Denmark.
D000064:Acclimatization; D010100:Oxygen / Q000378:metabolism; D010313:Partial Pressure; D010788:Photosynthesis; D063245:Plant Development; D018515:Plant Leaves / Q000254:growth & development / Q000378:metabolism* / Q000502:physiology; D010944:Plants / Q000378:metabolism; D013045:Species Specificity; D014867:Water / Q000378:metabolism*
D014867:Water; D010100:Oxygen