Variation between three Eremanthus (Asteraceae) species in their ability to form a seed bank

Abstract

-(Variation between three Eremanthus (Asteraceae) species in their ability to form a seed bank)-Knowledge on seed bank function is fundamental for understanding the species regeneration patterns. This investigation was carried out to compare the ability of Eremanthus elaeagnus (Mart. ex DC.) Schultz-Bip, E. glomerulatus Less., and E. incanus (Less.) Less. to form a soil seed bank. Seeds (aquenes) of each of these three species were collected, stored in the laboratory and subsequently buried in the same area where they were collected, inside nylon bags. The bags were collected monthly or bimonthly for germination tests under continuous light and also in darkness at 20 °C (E. elaeagnus e E. glomerulatus) and at 25 °C (E. incanus). After 12 months, a further series of tests compared the germination of achenes that had been buried in soil and compared with those stored in the laboratory at 15, 20, 25, 30, 35, and 40 °C. After three months of burial, the seeds of E. elaeagnus and E. glomerulatus failed to germinate, whereas the seeds of E. incanus, even after burial for 18 months, retained germination percentage of between 1% and 30%. After one year stored in laboratory, the seeds of E. glomerulatus were no longer viable and seeds of E. elaeagnus e E. incanus had a germination percentage below that of newly collected seeds. The results showed that E. elaeagnus and E. glomerulatus do not form seed banks while E. incanus may form a small and persistent soil seed bank.

Arbuscular mycorrhizal colonization and growth of Eremanthus incanus Less. in a highland field

“…incanus was shown to form a persistent soil seed bank, showing higher potential for regeneration in habitats subjected to disturbance (Velten and Garcia 2007), and the additional fact that E. incanus plants are AM-dependent in natural and restored highland field ecosystem supplies important information for restoration programs.…”

“…This arboreal species which reaches 3 to 5 m in height is common in Minas Gerais highland fields. This plant is presumed to be a threatened species and attempts to study its characteristics are important for conservation and management because this species is subject to intense exploratory pressure (Velten and Garcia 2007).…”

Mountain biodiversity in Brazil

“…Benites et al 2007, Ribeiro et al 2007). However, most mountain biodiversity research in Brazil is concentrated in elevations within the "cerrado" biome ("campos rupestres"; e.g., Coelho et al 2007, Figueira & Del Sarto 2007, Medina & Fernandes 2007, Velten & Garcia 2007, and in the "campos de altitude" of the Atlantic Rainforest biome (Martinelli 1996, Porembski et al 1998, Safford 1999, Safford & Martinelli 2000, Caiafa & Silva 2007, Ribeiro et al 2007). This pattern repeats itself in the present special issue: none of the studies published here are set in the Brazilian Amazon, and most concentrate within the "cerrado" and the Atlantic forest biomes.…”

Rock outcrop vegetation in Brazil: a brief overview

“…Therefore, in this special issue, it is the only study set in rock outcrops inserted in the "caatinga" biome (for a list of northeastern mountains and inselbergs, see Martinelli 2007). The type of rock here is quartzite-sandstone, such as in the studies of this issue located at "Serra do Cipó", Minas Gerais, within the "cerrado" biome (Coelho et al 2007, Figueira & Del Sarto 2007, Medina & Fernandes 2007, Velten & Garcia 2007. Despite the insertion of these rock outcrops in the "caatinga" biome, Conceição et al (2007) show that the general pattern of monocot dominance (particularly of families such as Velloziaceae, Bromeliaceae, Orchidaceae, Asteraceae and Poaceae), common to other Brazilian rock outcrops in the southeast region and/or on granitegneiss, repeats itself also in this part of the northeast region.…”

“…Several papers in this special issue were particularly interested on the relationship between soil and vegetation (Benites et al 2007, Conceição et al 2007, Gröger & Huber 2007, Medina & Fernandes 2007, Velten & Garcia 2007. This was quite surprising and welcome given the relative scarcity of papers covering this topic from an ecological or botanical viewpoint.…”