Seed storage-mediated dormancy alleviation in Fabaceae from campo rupestre

Abstract

We studied the effects of seed storage on germination and dormancy alleviation in three species of Fabaceae endemic to campo rupestre in southeastern Brazil. Fresh seeds of Collaea cipoensis, Mimosa maguirei and Mimosa foliolosa were set to germinate and germination of seeds after four, five and 13 years of storage was tested. Seed viability was maintained for all species after the full storage period. Seed storage significantly increased germination percentage and decreased germination time for C. cipoensis and M. foliolosa, suggesting the alleviation of physical dormancy with storage. However, we did not find evidence of dormancy alleviation in M. maguirei since stored seeds showed a decrease in germination in comparison to that of fresh seeds. Our data indicate species-specific storage-mediated dormancy alleviation, which will have important implications for restoration of campo rupestre. . KeywordsAlthough the short-term effects of seed storage on seed viability are well-known (Rokich et al. 2000), the long-term storage effects on dormancy alleviation have not been tested in Neotropical legumes. Here, we artificially stored seeds of three Fabaceae species for different periods and tested for storage-mediated dormancy alleviation. Despite the fact that natural field conditions differ from those under controlled laboratory conditions, ex situ seed storage may provide useful data to advance our capacity to identify proper species for ecological restoration and germplasm banking.Dry dehiscent pods (n> 30 individuals/species) were collected in campo rupestre vegetation at Serra do Cipó (19°17'S, 43°35'W), southeastern Brazil (Tab. 1). The campo rupestre is a species-rich altitudinal grassland highly threatened by cattle breeding, invasive species, uncontrolled fires, and particularly by quarries and opencast mining (Le Stradic et al. 2014). These communities establish on extremely nutrient-poor, quartzite-derived or ironstone soils, and harbour hundreds of endemic and/or threatened species (Giulietti et al. 1997). All study species are endemic from campo rupestre and have been recommended for ecological restoration ( Negreiros et al. 2009;Le Stradic et al. 2014;Silveira et al. 2014). Seeds were collected from a single population for each species and were stored for different periods ranging from 48-144 months depending on seed availability (Tab. 1).Fresh apparent viable seeds (seeds with no signs of predation by beetles) were sterilized with a 1% sodium hypochlorite solution for five minutes and then washed with tap water for 10 minutes. Seeds were placed in Petri dishes layered with double sheet of filter paper and moistened 446 Naïla Nativel, Elise Buisson and Fernando Augusto Oliveira Silveira Acta bot. bras. 29(3): 445-447. 2015.with distilled water whenever necessary. Apparent viable seeds were stored in 100mL opaque, closed glass pots at laboratory conditions in which temperature ranged between 13 and 29°C and moisture from 54 to 79%. To overcome PY, we mechanically scarified the seed coats of both...

Environmental factors affecting germination of Mimosa ephedroides (Fabaceae), an endemic shrub from Monte Desert, Argentina

“…These results match with those found by other authors for other species of Mimosoideae, where seeds stored at room temperature remain viable for several years (20). For some species of Mimosa, storage at room temperature for long periods can increase germination or reduce MGT (32,36,47). These differences are probably due to physical dormant seeds of some species that may become permeable to water after long storage periods (2,36).…”

Ecology and evolution of plant diversity in the endangered campo rupestre: a neglected conservation priority

“…Smallsized seeds have increased probabilities of burial, and thus light dependency is critical for seedling establishment (Milberg et al 2000). In situ experimental studies testing seed longevity, important to understand vegetation recovery after disturbances, have shown that seed persistence in the soil is variable and phylogeneticallyconserved, but most species are able to build persistent soil seed banks (Gomes et al 2001;Munné-Bosch et al 2011;Cheib and Garcia 2012;Garcia et al 2012Garcia et al , 2014Nativel et al 2015). Exceptions include seeds of Eremanthus (Asteraceae) (Velten and Garcia 2007), and graminoids (Le Stradic 2012), which persist in soil for less than a year.…”