Photosynthetic Properties and Root Chilling Responses of Altitudinal Ecotypes of Typha Latifolia L.

Photosynthetic characteristics of two low—altitude and two high—altitude populations of the broad—leaved cattail (Typha latifolia L.) were compared. Light—saturation characteristics and light—saturated rates in normal air were identical. Although carbon dioxide saturation characteristics were similar, photosynthetic rates at high CO2 concentrations (<350 ppm in air) were higher in high—altitude ecotypes. Carbon dioxide compensation concentrations of the populations were similar over a wide range of temperatures. The effects of root chilling on water and phosphorus uptake were also compared in a low—altitude and a high—altitude ecotype. Root chilling reduced leaf water content and phosphorus uptake more in the low—altitude ecotype. The phosynthetic differences between the ecotypes seem to have minor ecological significance, but reductions in water and nutrient uptake upon root chilling suggest strong natural selection in the high—altitude site for ability to function efficiently in cold soils.