Resumo

CARDONA-MEDINA, Edison  e  MURIEL RUIZ, Sandra B. SEED GERMINATION AND PLANT DEVELOPMENT IN Escobedia grandiflora (OROBANCHACEAE): EVIDENCE OF OBLIGATE HEMIPARASITISM?. Acta biol.Colomb. [online]. 2015, vol.20, n.3, pp.133-140. ISSN 0120-548X.  https://doi.org/10.15446/abc.v20n2.43776.

Root parasitic plants can be facultative or obligate. Facultative parasites are able to complete their life cycle and their seeds can germinate without a host. Escobedia grandiflora is a poorly studied species in spite of its ancestral importance as dye of foods and medicinal use. The present study evaluates the states of seed, seedlings and mature plants, under presence and absence of possible hosts, for inferring the type of parasitism exhibited by E. grandiflora. Seeds were evaluated using two conditions each of light (12 and 0 hours) and temperature (20 °C and 25 °C); percentage germination, and germination speed were determined. The seeds did not require a host to germinate, as is typical of facultative parasitic plants. Percentage of germination varied between 66 % and 85.3 % and was not affected by light or temperature although germination speed was greater at 25 °C. Larger seeds had a higher percentage of germination and produced larger seedlings. The seedlings planted without a host did not survive, while those planted with Paspalum notatum had a 45 % survival rate, demonstrating that this is a critical stage of development, even with a host. Escobedia grandiflora plants sowed with grasses began the reproductive stage at the 28^th week, and those planted with Pennisetum purpureum showed better performance, expressed in more haustoria, higher dry matter of total plant, rhizome and aerial stems. Plants sowed alone lived for more than six months, but they did not produce flowers or fruits. According to the behavior of seedlings and plants, E. grandiflora is an obligate parasite.

Palavras-chave : Escobedia; obligate hemiparasite; parasitic plant; root parasitism; seed germination.

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