Low levels of reserve carbohydrates in reed (Phragmites australis) stands of Kis-Balaton, Hungary

Seasonal dynamics of concentrations of reserve carbohydrates (starch, sucro se, glucose, fructose and their sum denoted as total non-structural carbohy drates, TNC) were followed in five reed stands of Kis-Balaton wetland area in Hungary. The stands included three stands of tall and robust reed, situa ted in the Ingoi area, and two stands of short and subtle reed situated in the downstream part. While both the seasonal pattern and the proportions of single carbohydrate species corresponded to findings for other sites, the absolute concentrations were markedly lower as compared to other European r eed stands except lake Ferto in Hungary. The seasonal minimum values ranged from 54 to 87 mg g(-1) dry weight. During the seasonal minimum, glucose re ached the lowest concentrations (down to 0.01 mg g(-1) dry weight) of all c arbohydrates measured. The seasonal maximum concentrations of TNC reached 1 60-270 mg g(-1) dry weight. Maximum TNC standing stock ranged from 240 to 5 20 g m(-2), and was depleted by 60-80% during the period of spring shoot gr owth. It is proposed that the remaining TNC pool may not suffice to support complete recovery after a subsequent catastrophic event. (C) 2001 Elsevier Science B.V. All rights reserved.