engleski

Seed germination of eight Hypericum L. taxa

Seed germination is the first critical stage of plant development and the key factor of reproductive biology. Germination is crucial for successful establishment of wild communities as well as in efficient gardening. Investigation of seed germination is still of great importance, especially in botanic gardens devoted to preserve the world’s plant diversity. Botanical garden F. Kušan of Faculty of Pharmacy and Biochemistry has cultivated more than 20 taxa of the genus Hypericum L. Apart from medicinal plant H. perforatum L. and several endemics, germination of Hypericum has not been studied yet. In order to increase knowledge of germination biology of Hypericum as well as to test seed viability in garden conditions, germination of 8 Hypericum taxa was investigated (H. androsaemum L., H. delphicum Boiss & Heldr, H. densiflorum Pursh., H. hircinum L., H. kouytchense H.Lév, H. olympicum L., H. patulum Thunb. ex Murray and H. pseudohenryi N. Robson). Seeds were collected over two years. Tests were carried out following the International Rules for Seed Testing protocols, and defined by the final germination percentage and the germination rate. The effect of prechilling (7 days/8° C) and the influence of gibberellic acid (0, 025%) were also tested. Final germination percentages were highly variable depending on the taxa, ranging from 11% (H. densiflorum) to 90% (H. pseudohenryi). Similarly, germination rate varied from 6 days (H. hircinum, H. patulum) to 23 days (H. androsaemum). For the most of the taxa, seeds collected in different years germinated at the similar percentage. However, the exceptions were seeds of H. androsaemum and H. olympicum which seem to be highly dormant since observed lesser germination of younger seeds. Prechilling had no effect on germination, while gibberellic acid significantly enhanced the germination of the most taxa, except in the case of H. hircinum and H. patulum. Germination of H. androsaemum and H. densiflorum seeds was very low (20-41% ; 11-12%), and was promoted significantly by gibberellic acid up to three times. Seeds of the Chinese H. pseudohenryi displayed the most efficient germination (85-90%).

Hypericum; germiination percentage; germination rate; prechilling; gibberellic acid

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