Do soil microbes and abrasion by soil particles influence persistence and loss of physical dormancy in seeds of tropical pioneers?

• DOI: 10.3389/fpls.2014.00799
• Publication Date: 2015-01-13T09:24:56Z
• Authors: Paul-Camilo Zalamea; Carolina Sarmiento; A. Elizabeth Arnold; Adam S. Davis; James W. Dalling
• Keywords: Persistence (discontinuity)

Germination from the soil seed bank (SSB) is an important determinant of species composition in tropical forest gaps, with persistence SSB allowing trees to recruit even decades after dispersal. The capacity form a persistent often associated physical dormancy, where coats are impermeable at time literature speculates, without empirical evidence, that dormancy-break physically dormant seeds result microbial action and/or abrasion by particles. We tested microbial/soil hypothesis four widely distributed neotropical pioneer tree (Apeiba membranacea, Luehea seemannii, Ochroma pyramidale, and Cochlospermum vitifolium). Seeds were buried five common gardens lowland Panama, recovered 1, 3, 6, 12 months burial. Seed permeability, infection, coat thickness, germination measured. Parallel experiments compared fraction fresh aged contact, as function permeability. Contrary proportion permeable seeds, infected cultivable microbes, decreased burial duration. Furthermore, stored dark dry conditions for 2 years showed higher than identical conditions. determined A. membranacea O. pyramidale had cracks chalazal area or lacked plug, whereas all surfaces intact. Our results inconsistent dormancy loss instead suggest existence multiple phenotypes, each cohort dispersed state germinates immediately, while accounts SSB. Thus, we conclude fluctuations temperature absence infection sufficient break on trees.