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Applied and Environmental Soil Science
Volume 2011, Article ID 107159, 8 pages
http://dx.doi.org/10.1155/2011/107159
Research Article

Mycoflora in Exhumed Seeds of Opuntia tomentosa and Its Possible Role in Seed Germination

1Instituto de Ecología, Universidad Nacional Autónoma de México, 04510 México, D. F, Mexico
2Facultad de Ciencias, Universidad Nacional Autónoma de México, 04510 México, D. F, Mexico

Received 15 March 2011; Revised 20 June 2011; Accepted 8 July 2011

Academic Editor: Ismail Saadoun

Copyright © 2011 María Esther Sánchez-Coronado et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The funicular cover of the Opuntia tomentosa seed limits imbibition; germination occurs only when the funicle is weakened or the funicular valve is removed. We investigated the role of fungi in funicular weakening and seed germination. Seeds that had been either buried in one of two sites or stored in the laboratory were germinated with and without a valve. Disinfected or nondisinfected seeds and their naked embryos were cultivated on agar or PDA. None of the 11 identified fungal genera grew on the disinfected control seeds or the embryos. The mycoflora present on disinfected and nondisinfected exhumed seeds suggest that the fungal colonization occurred in the soil and differed between the burial sites. Exhumed seeds with and without a valve germinated in high percentages, whereas only the control seeds without a valve germinated. Scanning electron micrographs showed that the hyphae penetrated, cracked, and eroded the funicular envelope of exhumed seeds.