Az Eszterházy Károly Tanárképző Főiskola Tudományos Közleményei. 2004. Sectio Biologiae. (Acta Academiae Paedagogicae Agriensis : Nova series ; Tom. 25)

Makrai, L., Dulai, S., Polyánka, H., Ertli, T. and Lehoczki, E.: Monitoring of the Functional State of Beds of Common Reed (Phragmites australis) in Shallow Lake Balaton (Hungary) by Means of Chlorophyll Fluorescence Studies

Acta Acad. Paed. Agriensis, Sectio Biologiae XXV (2004) 139-12

6 Monitoring of the Functional State of Beds of Common Reed (Phragmites australis) in Shallow Lake Balaton (Hungary) by Means of Chlorophyll Fluorescence Studies Makrai, L.\ Dulai, S.

2, Polyánka, H.

1, Ertli, T.

1 and Lehoczki, E.

1,

3 1 Department of Botany, Faculty of Science, University of Szeged, H-6701 Szeged, Hungary " Department of Plant Physiology, Eszterházy Károly College, H-3301 Eger, Hungary 3 Corresponding author, e-mail: lehoczki@bio.u-szeged.hu Abstract: Comparative measurements of chlorophyll fluorescence induction were performed to study the functional status of reed-stands (Phragmites australis (Cav.) Trin.ex Steud.) along the shores of Lake Balaton. Over 4000 measurements a year of fast and slow chlorophyll fluorescence induction were made on reed leaf samples collected from July until the middle of August during 1996, 1997 and 1998.. The most marked and indicative differences were observed for the ratio of fluorescence decrease (Rfd) values, determined from the slow fluorescence induction measurements. The mean value of Rfd for the overall reed population of Lake Balaton in these three years was around 1.55±0.28, which indicates that the physiological state of the reeds was moderate. However, Rfd values of above 3 or of around 1.2 were also found for some reed-stands. The Rfd values monitored for the reed population of the northern shore in 1996 and 1997 (1.85 and 1.63) were significantly higher than those on the southern side in this period (between 1.58 and 1.44). The mean Rfd values for the southern and northern sides in 1998 were roughly the same, because of the deterioration of the functional state on the northern side. It was also found that the Rfd parameters relate directly to the maximum CO? assimilation rates in reed beds of Lake Balaton, and can be taken as an indication of the physiological state of these beds.