Zur Keimungsbiologie von zehn ausgewählten Ruderal- und Xerothermrasenarten - Teil 4: Fabaceae

Abstract

Partzsch, M.: Germination biology of ten ruderal and xerothermic grassland species - Part 4:Fabaceae. - Hercynia N. F. 45 (2012): 125 – 144.Germination is one of the most important processes in the life-cycle of a plant species. With the presentstudy the series on investigation of germination biology of rare species from xerothermic grasslands anddry, ruderal influenced habitats should be proceeded. The following species of the family Fabaceae wereinvestigated: Anthyllis vulneraria, Genista tinctoria, Hippocrepis comosa, Lotus corniculatus, L. maritimus,Onobrychis arenaria, Securigera varia,Vicia hirsuta, V. tenuifolia and V. tetrasperma.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, summerand autumn. The collected seeds were divided in two parts. Germination experiment of the first part wascarried out in the year of harvest. The second part of diaspores was buried in soil from November tillMarch, to ensure hibernation until the next experimental phase in following spring. Seed viability wastested before and after the experiments. The results show that, with exception of Onobrychis arenaria, all species had a strong dormancy, whichwas not or only marginally broken by natural stratification of hibernation. Anthyllis vulneraria, Hippocrepiscomosa, Securigera varia and Vicia tetrasperma were nearly fully dormant, while Genista tinctoria, Lotuscorniculatus, L. maritimus, Vicia hirsuta and V. tenuifolia had between ca. 70 and 90 % dormant seeds. Thegermination success was equally low in the year of harvest as after hibernation, only the commencementof germination was earlier after hibernation. The change of temperature had no or less significant effect ongermination percentage and velocity; the species germinated on a broad range of temperature from cold towarm and hot conditions but with low germination rates. Significant interactions between temperature andhibernation were only found in Genista tinctoria, Vicia hirsuta and V. tenuifolia.A correlation between germination behaviour and life-time of the species was not found, but there weresignificant positive interactions between germination percentage and velocity and the size and mass ofthe diaspores of the species of the family Fabaceae. However, without the data of Onobrychnis arenaria,the correlations were not significant.Germination behaviour and dormancy indicate a long-term persistent seed bank type of the investigatedspecies. An exception is Onobrychis arenaria, which germinated in the year of harvest as well as afterhibernation nearly completely under all three temperature-light-regimes. This species assigns to thetransient seed bank type.Results suggest that it needs long-term investigation for restoration of grasslands by seed addition andexperiments with the functional group of legumes because of the low germination of most species of thefamily Fabaceae.Key words: Germination, dormancy, natural stratification, seed size, seed bank type, viability