L. Lőkös szerk.: Studia Botanica Hungarica 27-28. 1996-97 (Budapest, 1978)

Csontos, Péter: Seed bank behaviour of Verbascum L. species

Studia bot. hung. 27-28, pp. 117-121, 1996-97(1998) SEED BANK BEHAVIOUR OF VERBASCUM L. SPECIES P. CSONTOS Ecological Modelling Research Group Dept. of Plant Taxonomy and Ecology, L. Eötvös University H-1083 Budapest, Ludovika tér 2, Hungary Seed bank behaviour of Verbascum austriacum Schott and V. lychnitis L., two native mulleins of Hungary, were studied in a burial experiment. Both species germinated in every year of the experiment. Following four years of burial 7% and 41% germination were observed, respectively. Considering reports on earlier investigations as well as the results of our studies it seems that long term seed viability and maintenance of persistent seed banks are characteristic of the genus Verbascum. Key words: burial experiment, mullein, seed bank, seed longevity, Verbascum austriacum, Verbascum lychnitis INTRODUCTION Practically all the flowering plants have certain type of seed bank. With lack of it very few examples can be found like some viviparous species or hybrids that reproduce by vegetative means only. However, there are extreme differences regarding seed bank behaviour and seed longevity of species. Some of them maintain seed viability for extraordinary long time (RAMSBOTTOM 1942, LERMAN and ClGLIANO 1971, HARRINGTON 1972, PRIESTLEY and POSTHUMUS 1982, BAKER 1989), while others lose germinability soon (HARRINGTON 1972, THOMPSON and GRIME 1979, MlLBERG 1993, CSONTOS etal. 1998). For characterizing seed bank types of species THOMPSON and GRIME (1979) suggested a classification with four categories. More recently a threegrouped typification was also established focusing more on the time span of seed bank survival (THOMPSON 1993). In the light of earlier studies mullein species maintain large persistent seed banks (type IV. in THOMPSON and GRIME 1979), and retain germinability for long time ("long-term persistent" according to THOMPSON 1993). 0DUM (1965, 1974, 1978) observed germination of Verbascum nigrum L., V. thapsiforme Schrad. and V. thapsus L. from excavated soil samples. Verbascum thapsus seeds germinated from soils of four pine plantations (25, 37, 41 and 80 years old) in Massachusetts (LIVINGSTONE and ALLESSIO 1968) as well as from soils of Douglas fir and larch stands (both were 20 years old) in south-west