Kulturverfahren zur Bestimmung der Salz- und Über-flutungsverträglichkeit vonPuccinellia spp. (Gramineae)

Abstract

In the ecology ofPuccinellia species (P. maritima, P. distans, P. retroflexa andP. limosa of the German flora described to date) two environmental factors seem to be very important: the salinity of the soil or of the tidal sea water and, especially in regard toP. maritima, the periodical inundation during the tidal cycle. The latter species forms an important community (Puccinellietum maritimae) a few decimetres above the middle tide level. The other species seem to be specialized to localities of higher levels. Some 450 natural localities covered withP. maritima on the western coasts of Schleswig-Holstein (W. Germany) have been analysed with respect to the type of plant community, dominance ofP. maritima, frequency of inundations, level above or below middle tide level, and soil factors (for instance: Cl-ion content, electrical conductivity, pH, clay content, etc.). Physiological experiments have been carried out in greenhouses, experimental grounds, and culture-rooms to test the effects onP. maritima (number 57 from the optimal level within the Puccinellietum maritimae of the banks of the River Eider) of soil composition, light intensity and daylength, temperature, inundation, etc.P. maritima grows with long creeping stolons at daylengths of 16 hrs and more; it forms a caespitose tufted plant at daylengths of 12 hrs and less (light intensity: 10,000 lux and more). Optimal growth occurs between 17° and 23° C and under conditions of artificial flooding up to soil surface twice a day (for about 10 minutes) by artificial sea water of 25 ‰ S. Two culture techniques have been developed for testing growth and survival after 8 weeks under greenhouse conditions (20° C or more; 10,000 lux or more; 15 hrs daylength or more, after comparable pre-cultivation over 8 weeks under 12 hrs day and artificial light conditions; sand + 3 % peat). The first technique has been used for testing salt tolerances between 0 and 60 ‰ S (artificial sea water), the second for testing inundation tolerances (0–2.5 hrs inundation twice a day; artificial sea water of 25 ‰ S). Considering different proveniences ofPuccinellia species on German coasts, it became clear thatPuccinellia exhibits broader ecological and morphological than taxonomical variabilities. WithinP. maritima, for example, several ecological types can be separated. This finding indicates the possibility of isolating different ecological types for specific localities in land reclamation areas.

Zusammenfassung

1. Kulturverfahren zur Ermittlung der Salz- und Überflutungsverträglichkeit vonPuccinellia-Arten wurden auf Grund von etwa 450 Standortanalysen an Standorten vonP. maritima und eingehenden Vorversuchen ausgearbeitet. Hiernach ergeben sich fürP. maritima (Sort. Nr. 57) folgende Optimalbedingungen: (a) Temperatur: 17–23° C; (b) Lichtintensität: 10 000 Lux und mehr; (c) Tageslänge: Langtag von 16 Std. und mehr (Ausläuferentwicklung); (d) überflutung: 2mal täglich (alle 12 Std.) bis 1 cm über Bodenoberfläche; (e) Boden: Hirschauer-Quarzsand + 3 % Flora-Torf; (f) Nährlösung: 1,1 ‰ Grundnährlösung bis 5 ‰ künstliches Meerwasser.

2. Die Kulturverfahren basieren auf einer stufenweisen Kultur mit künstlichem Meerwasser von 0–60 ‰ bzw. auf einer stufenweisen Überflutungszeit von 0 bis 2,5 Std. im Abstand von 12 Std. und werden in einem Gewächshaus durchgeführt.

3. Die Methoden (bzw. Fehlerquellen und Übertragbarkeit auf die natürlichen Standortverhältnisse) werden diskutiert.