Zur Keimungsbiologie von zwölf ausgewählten Xerothermrasen-, Saum- und Waldarten - Teil 6: Lamiaceae

Abstract

Partzsch, M.: Germination biology of twelve xerothermic grassland, fringe and wood species - Part 6:
Lamiaceae. - Hercynia N. F. 49 (2016): 27 – 45.

Germination is an important functional trait which might explain structure and dynamic of plant communities,
but there is still lack of comparable data. Therefore, with the present study the series on investigation
of germination behavior under standardized conditions should be proceeding. Seed germination
of the following twelve species of the family Lamiaceae was studied: Acinos arvensis, Ajuga reptans,
Betonica officinalis, Clinopodium vulgare, Galeopsis tetrahit, Origanum vulgare, Prunella vulgare, Salvia
nemorosa, S. pratensis, Teucrium botrys, T. chamaedrys and Thymus serpyllum.
The germination experiments were carried out under three temperature-light regimes (8 / 4 °C, 20 /
10 °C, 32 / 20 °C; 12 h light : 12 h darkness; 45 days), simulating climate conditions in spring, summer
and autumn. The collected seeds were divided into two parts. Germination experiment of half of the
seeds was carried out in the year of harvest. The other half was buried in soil from November till March,
to ensure hibernation until the next experimental phase in following spring. Seed viability was tested
before and after the experiments.
The results show that germination percentages of six of the species (Betonica officinalis, Clinopodium
vulgare, Origanum vulgare, Prunella vulgaris, Salvia nemorosa, Teucrium botrys) were >50 %, whereas
seeds of the others (Acinos arvensis, Ajuga reptans, Galeopsis tetrahit, Salvia pratensis, Teucrium
chamaedrys, Thymus serpyllum) germinated badly. Clinopodium vulgare and Salvia nemorosa showed a
significant optimum of germination under warm conditions, and Prunella vulgaris and Thymus serpyllum
under hot conditions, whereas the other species germinated in a broad range of temperature between
warm und hot conditions. There was almost no germination under cold conditions. Germination was
promoted after hibernation only in the therophytes Galeopsis tetrahit and Teucrium botrys (cold germinators).
Most species were characterized by an asynchronous germination (expect from Origanum
vulgare and Teucrium botrys), where only part of the seeds germinate. The test of seed viability following
the experiment showed that non-germinating seeds are still viable. Their germination behavior and
literature references indicate that the investigated diaspores of the Lamiaceae possess physiological and
physical dormancy and build up a longterm-persistent diaspore bank in the soil.