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Comparison of seed longevity for thirty forest, grassland and weed species of the Central European flora: results of a seed burial experiment

100%

Csontos P. , Kalapos T. , Tomas J.

tom 64

nr 3

We compared seed longevity of herbaceous species in three habitat types differing in stability. We hypothesized that seed longevity is the lowest for forest species (living in stable habitat), the highest for weeds, while species of xerothermic grasslands take an intermediate value. Ten species were selected from each of the three habitats with balanced representation of plant families among habitats. Seeds of the 30 species were deep buried at 65 cm depth, then replicates recovered after 1, 2, 3, 4 and 6 years, and germinated in an unheated greenhouse. Weeds expressed the highest germination rate (36.1% in average) exceeding forest (14.4%) and grassland species (10.2%) which did not differ significantly. The number of species with transient, short-term persistent and long-term persistent seed bank, respectively, was 1, 7 and 2 for grasslands; 1, 3 and 6 for forests; and 0, 1 and 9 for weeds. As expected, weeds possessed the highest seed longevity. Contrary to our assumption, low seed longevity was not the norm among forest understorey species, and seed longevity of xerothermic grassland species was not intermediate but the shortest one. Ecological background of differences between hypotheses and experimental results are discussed. First record on seed bank type is reported here for 12 species: Dianthus pontederae, Digitalis grandiflora, Ferula sadleriana, Hieracium sylvaticum, Inula ensifolia, Jurinea mollis, Lychnis coronaria, Saponaria officinalis, Scorzonera austriaca, Secale sylvestre, Stipa borysthenica, Verbascum lychnitis.

Seed longevity and recruitment of seedlings in xerothermic grassland

80%

Czarnecka J.

Polish Journal of Ecology

2004

tom 52

nr 4

The aim of the study was to check which of the xerothermic grassland species create persistent seed bank and what type of germination characteristics they exhibit. The following features of diaspores and the seed bank were taken into consideration: 1) relation between the annual seed production and the seed bank; 2) keeping the germination ability longer than one year, despite the soil samples being kept in the conditions promoting germination; 3) presence in the deeper layers of soil; 4) permanent abundance in soil, also between seed germination and seed shedding time. Carex flacca Schreb., C. transsilvanica Schur, Linum flavum L., Origanum vulgare L. and Scabiosa ochroleuca L. create persistent seed bank, Senecio macrophyllus M. Bieb., Aster amellus L. and Brachypodium pinnatum (L.) Beauv. have the transient type of the bank. Germination time for the grassland species is spring and additionally, in a few cases, early autumn when the most favourable temperature and moisture conditions prevail in the studied plant community. Taking into consideration the changes in the percentage of germinating seeds during the year we can distinguish three types of annual dormancy cycle: Linum flavum pattern – germination occurs exclusively in spring; Salvia verticillata L. pattern – the germination peak in spring; yet, the seedlings are detected during the rest of the season; Senecio macrophyllus pattern – the species with two germination peaks: one in spring, the other in autumn.