Influence of shrub cover on germination, dormancy and viability of buried and unburied seeds of Piptochaetium napostaense (Speg.) Hackel

Effect of environmental heterogeneity on field germination of Opuntia tomentosa (Cactaceae, Opuntioideae) seeds

“…Nonetheless, full germination was not observed in any treatment or site, which suggests that the seeds may either remain dormant even longer than two rainy seasons, thus forming part of the seed bank, or die from continuous exposure to adverse environment as in Piptochaetium napostaense (Mayor et al, 2007). All these observations indicate that morphological (in the thickness of the funicular envelope) and physiological heterogeneity (in the depth of dormancy and germination requirements) of the seed population may spread germination across the years.…”

“…Field mean temperatures included this wide variation, due to that the temperatures that inhibit field germination were lower than the constant temperature at which Opuntia seeds are known to germinate in the laboratory (!25 C, Reyes-Agü ero et al, 2006). Additionally, because temperature and soil moisture are inversely related in the field (as temperature increases soil moisture decreases (Lakshmi et al, 2003), either one of them may inhibit germination or damage seeds placed in the field (Mayor et al, 2007).…”

The TTC-technique might not appropriately test the physiological stage of plant tissues

“…Twenty seeds were sampled from each bag and immersed in distilled water during 24 h previous to their cutting. Seeds of this species have innate dormancy imposed by their glumes [19]. They were removed from the seeds, which were cut longitudinally under a stereo scopic microscope.…”

Ubiquitous germination among common perennial species in response to facilitated and unfacilitated microhabitats

“…With the exception of L. tridentata, all of the focal species present aggregated patches at the study site (Miriti, 2007;Miriti et al, 1998), but our results suggest that these patterns are not the result of germination responses. Studies of benefactor effects on germination are rare, and biased towards germination of annuals (but see Mayor et al, 2007;Thompson and Huenneke, 1996). These studies show that patterns of benefactor effects on germination vary among beneficiary species (Sotomayor et al, 2014;Tielb€ orger and Kadmon, 1995), and can show temporal variation in the relative importance of microsite variables (Yu et al, 2009).…”