Photosynthetic pigments and efficiencies of two Phragmites australis stands in different nitrogen availabilities

Two contrasting ecotypes of Phragmites australis adapted to high (Lake Temp liner See: Templ) and low (Lake Parsteiner See: Par1) N supply were investi gated regarding the leaf content of photosynthetic pigments. Pigment conten ts were greatest in middle leaves compared to uppermost (still developing) and lowest leaves (already senescent). The highest content was always yield ed by chlorophyll a followed by chlorophyll b > lutein > beta -carotene > n eoxanthin > violaxanthin > zeaxanthin > antheraxanthin. Pigment patterns we re similar when comparing both stands, However, the contents per leaf area (and per dry weight) of all pigments were up to three-fold higher at Templ versus Par1. Differences in N supply are most likely the cause. Although, t he productivity of Templ reed was about 10-fold higher than that of Par1, t he latter showed a two-fold higher biomass gain per chlorophyll a content ( 60.8 versus 31.3 g dry weight g(-1) chlorophyll a). This reflects the highe r efficiency of the Par1 reed adapted to N-limited growth. It is concluded that site conditions, especially N availability, were determining stand-spe cific variations in content of photosynthetic pigments. (C) 2001 Elsevier S cience B.V. All rights reserved.