COMPARATIVE GERMINATION RESPONSES OF 28 TEMPERATE GRASSLAND SPECIES

The comparative germination biology of 28 perennial species native to the temperate grasslands of southern Victoria was tested using a singl e temperature regime (20/10 degrees C) in either constant darkness or 12 h diurnal white-light conditions. This temperature regime was chose n because it corresponds to the temperature found to produce substanti al or optimal germination in other germination studies of grassland pl ants. Four germination attributes-time to the beginning of germination (germination lag), time taken to achieve 50% of final germination (ge rmination speed -t(50)), percentage germination in diurnal light condi tions and percentage germination in continuous darkness-were calculate d for each species and correlated to three plant attributes: plant fam ily, life form and seed weight. Germination lag was short for many spe cies: 50% had a lag of less than 7 days, whilst 96% of species had beg un germinating within 28 days. Germination speed was moderately fast f or most species: 75% of species had a t(50) of less than 28 days. Tota l percentage germination in diurnal light or continuous darkness was v ariable (0-98%), but many species (64%) germinated readily (> 50%) in at least one treatment. Twenty-four percent of species had germination substantially inhibited by darkness (i.e. Acaena echinata, Bulbine bu lbosa, Eryngium ovinum, Podolepis sp. aff. jaceoides, Velleia paradoxa and Wahlenbergia luteola). No species had its germination promoted by darkness. Few correlations between plant and germination attributes w ere detected. Seed weight was not correlated with any of the three ger mination attributes, nor was life form or plant family correlated with germination speed or percentage germination in the light or dark. Ger mination lag, however, was significantly associated with plant family and, in a related way, with life form: species from the Liliaceae (geo phytes) took longer to begin germination than species from the Asterac eae (hemicryptophytes). The ecological implications of the observed ge rmination biology on the potential formation of persistent soil seed b anks and seedling recruitment dynamics are discussed.