Zur Keimungsbiologie acht ausgewählter kurzlebiger Ruderal- und Segetalarten

Abstract

Partzsch, M.: Germination biology of eight short-living ruderal and segetal species – Hercynia N. F.
43 (2010): 149 –166.
Knowledge on the germination behaviour of plant species allows to draw conclusions to be drawn on
their associated regeneration capacity. Open field observations indicate that short-living species often
produce high numbers of seedlings. For this study we collected samples from eight species (Berteroa
incana, Camelina microcarpa, Lepidium campestre, Medicago lupulina, Microrrhinum minus, Odontites
vulgaris, Thlaspi arvense and Trifolium arvense) which commonly occur throughout a climatic dry
region in central Germany in the vicinity of Halle/S. to investigate their germination behaviour under
different temperature and light conditions.
A proportion of the mature seeds collected was used for an initial germination experiment while the
rest were buried in soil to ensure hibernation until the following experiment phase under similar conditions
the following spring. The germination experiments were carried out under cold (8/4 °C), regular
(20/10 °C) and hot (32/20 °C) temperature conditions and under an alternating light-dark regime (12h :
12h). Thirty or forty batches of seeds (n = 4) were placed on filter paper in Petri dishes and kept permanently
moist with de-ionized water. All germinated seeds (radicula being visible) were counted every
two to three days. The experiments lasted 45 days and, after each experiment, the remaining seeds were
tested for viability.
In general, the germination percentage and velocity of the investigated species was highest under warm
temperature conditions, which corresponds with the optimum development period in any year. However,
with the exception of Berteroa incana, germination in the year of harvest was surprisingly low. The
seeds of Berteroa incana were not dormant and germinated equally well after harvest and after hibernation.
Berteroa incana belongs to the transient seed bank type. The dormancy of Camelina microcarpa,
Lepidium ruderale and Microrrhinum minus was broken after hibernation, whereas Medicago lupulina,
Odontites vulgaris, Thlaspi arvense and Trifolium arvense remained dormant. The first three species
germinated between 50 and 94 % at 32/20 °C in the second year and built up a short-term persistent seed
bank. Germination of the four latter species was very low (approx. 40 % or lower), and after hibernation,
their dormancy was not significantly broken, rendering their seed bank of the long-term persistence.
Key words: Germination, dormancy, natural stratification, seed bank type, viability