ISSN:
1432-1939
Keywords:
Littorella uniflora
;
Terrestrial isoetids
;
Carbon uptake
;
Sediment CO2 utilization
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary Submerged macrophytes of the isoetid life form derive the majority of their CO2 for photosynthesis from the sediment. The experiments described here were designed to test the hypothesis that root uptake of CO2 is important also in the terrestrial form of Littorella uniflora. The results of 14CO2 experiments showed that sediment CO2 contributed 56% of the total fixation at 0.1mm CO2 in the rhizosphere, 83% at 0.5mm and 96% at 2.5mm. Sediment CO2 in emergent Littorella stands ranged from 0.1 to 1.0mm and averaged 0.5mm. Measurements of the net CO2 exchange over the leaves showed an even higher dependence of the sediment as CO2 source. Littorella leaves had no stomata at the base and densities (ca. 100 mm−2) typical of terrestrial plants at the tip, allowing sediment-derived CO2 to be supplied along the length of the leaf. The stomata permit supply of CO2 from the air during periods of reduced sediment CO2 concentrations (e.g. if the sediment dries up) and regulate transpiration.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00320820
