Resumo

PANDO-MORENO, Marisela; MOLINA, Víctor; JURADO, Enrique  e  FLORES, Joel. Effect of biological soil crusts on the seed germination of three plant species under laboratory conditions. Bot. sci [online]. 2014, vol.92, n.2, pp.273-279. ISSN 2007-4476.

Semiarid grasslands in northeastern Mexico contain endemic plants and animals, and are an important refuge for resident and migratory animals. Here, as in other semiarid areas, biological soil crusts (BSC) are a key component of the ecosystem. However, findings about their effect on the germination of vascular plants are contradictory. We asked whether seed germination of some native plant species would be inhibited by the presence of BSC as it has been found in other studies; in turn, we evaluated the effect of five lichens (Endocarpon pusillum Hedw., Placidium sp., Psora cerebriformis W.A.Weber, Psora decipiens (Hedw.) Hoffm., Xanthoparmelia chlorochroa (Tuck.) Hale), one cyanobacteria (Nostoc commune Vauch.), and one hepatic (Oxymitra sp.), from the dominant BSC of the area on the germination percentage (germinability) and speed of germination (t₅₀) of three native plant species: Frankenia gypsophila I.M.Johnst., Muhlenbergia arenicola Buckl., and Sartwellia mexicana A.Gray. Germination tests were carried out in an environmental chamber at 26 °C and at a constant humidity of 60% with 12:12 hours light and darkness. BSC did not affect germination percentage of the three evaluated plant species when compared to bare soil. Speed of germination ranged between 3.5 and 5 days and there were no differences between substrates.

Palavras-chave : Endocarpon pusillum; northeastern Mexico; Nostoc commune; Placidium; semiarid grasslands.

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