Allelopathy effect of aqueous lichen extract on germination of conifers
Martin Pizňak 1
Martin Bačkor 1
1 Univerzita Pavla Jozefa Šafárika, Katedra Botaniky, Košice, Slovensko
|Section:||Ecology and Environmental Sciences|
Lichens are globally widespread organisms playing an important role in diverse ecosystems. They produce secondary metabolites, unique compounds, which play many important ecological and biological roles, including their effects on other plants, through allelopathy.
Many of them also inhibit the growth of higher plants (1). Brown and Mikola (2) mentioned negative lichen allelopathy effects on the germination and development of conifer trees, whereas Stark and Hyvarinen (3) and Kytoviita and Stark (4) documented neutral, no allelopathic effect of lichens on conifer trees. On the other hand, the negative influence was achieved when the plant species naturally not co-occurring with lichens were laboratory treated with usnic acid, one of the lichen secondary metabolite. Such species include tomato (5), wheat and sunflower (6) and red clover (7). Lichen secondary metabolites are soluble the most in organic solvents. However, aqueous extracts of certain lichens species possessed cytotoxicity effects on meristematic cells of lettuce and maize (8). Particularly H. physodes synthesize depsidones and depsides, such as protocetraric acid, physodalic acid and atranorin (9).
Our aim was to measure total germination of Picea abies, Pinus sylvestris and Pinus mugo in the presence of aqueous lichen extracts. The extracts were made from lichens (Hypogymnia physodes, Parmelia sulcata, Physcia adscendens, Pseudevernia furfuracea) collected from fallen branches. For experiment we macerated dried lichens for 24 (1 day) and 72 hours (3 day) in rain water (1:10 mg/ml). We analysed total anion and cation content and pH in rain water and extracts. Besides we monitored secondary metabolites and sugars soluted in the extracts by HPLC.
We conclude that aqueous lichen extracts from particular species naturally growing on trees can be considered as a source of nutrients for young emerging conifers from the same habitat. The extracts contained much more anions and cations than pure rain water. Assumpted low solubility (10) of lichen secondary metabolites and sugars in water was confirmed. Our observations show that P. sylvestris is more sensitive than P. mugo and P. abies. Only 3 day extract, which contained the greatest amount of nutrients, significantly (P < 0.05) stimulated germination of P. sylvestris and therefore overtook possible negative allelopathy effect showed by 1 day extract treatment
(2) Brown RT, Mikola P (1974) The influence of fruticose soil lichens upon the mycorrhizae and seedling growth of forest trees. Acta Forestalia Fennica 141:1-23
(3) Stark S, Hyvärinen M (2003) Are phenolics leaching from the lichen Cladina stellaris sources of energy rather than allelopathic agents for soil microorganisms? Soil Biol Biochem 35:1381-1385
(4) Kytöviita MM, Stark S (2009) No allelopathic effect of the dominant forest-floor lichen Cladonia stellaris on pine seedlings. Funct Ecol 23:435–441
(5) Latkowska E, Bialczyk J, Lechowski Z, Czaja-Prokop U (2008) Responses in tomato roots to stress caused by exposure to (+) usnic acid. Allelopathy Journal 21:239-252
(6) Lascève G, Gaugain F (1990) Effects of usnic acid on sunflower and maize plantlets. J Plant Physiol 136:720–727
(7) Nieves JA, Acevedo LJ, Valencia-Islas NA, Rojas JL, Dávila R (2012) Fitotoxicidad de extractos metanólicos de los líquenes Everniastrum sorocheilum, Usnea roccellina y Cladonia confusa. Glalia 4:96
(8) Campos JMS, Davide LC, Soares GLG, Viccini LF (2008) Mitodepressive and clastogenic effects of aqueous extracts of the lichens Myelochroa lindmanii and Canoparmelia texana (Lecanorales, Parmeliaceae) on meristematic cells in plant bioassays. Genet Mol Biol 31:141–145
(9) Molnár K, Farkas E (2011) Depsides and depsidones in population of the lichen Hypogymnia physodes and its genetic diversity. Ann. Bot. Fenn. 48: 473–482.
(10) Huneck S, Yoshimura I (1996) Identification of Lichen Substances, Berlin: Springer.