Germination of Styrax camporum Pohl. seeds in response to substrate types, moisture contents and the seed morphology

Abstract

This study evaluated the contributions of Styrax camporum seed morphology (size of seeds, presence or absence of endocarp attached to the seed), different substrates (filter paper, vermiculite, sand and the soils of cerrado s. str., cerradão and a riparian forest), different water potentials (0, -0.1, -0.2, -0.3, -0.4 and -0.5 MPa), light and temperature to seed germination. Seed size did not affect the germination percentage when seeds were sown on vermiculite. Seeds were affected by small variations in the moisture content of the tested substrates, showing a significant decrease in germination under water potentials lower than -0.1 MPa, close to the field capacity of cerrado s. str. soils. At the temperatures of 15 and 20°C, a significant decrease in germination was observed. Thus, the availability of water in cerrado soils associated to temperature modulate the distribution of germination in this species. Seed morphology contributes to the maintenance of seeds in the soil, and the lack of synchrony in seed germination spreads the distribution of germination in time. These peculiarities allow the emergency of seedlings at different time periods and establishment conditions, an adaptative response of S. camporum to the cerrado environment.

Seed germination performances of Styrax species help understand their distribution in Cerrado areas in Brazil

“…Seeds of each of the three species exhibited well-distributed germination over time (Figure 2), and this behavior was also confirmed for S. camporum seeds (Simão et al, 2013). The slow and non-synchronized seed germination may represent a strategy, which is suitable for unpredictable environments or seasonal climates, since this behavior…”

“…The number of germinated seeds was monitored every other day until 90 days after sowing (DAS) for S. camporum and S. ferrugineus, and until 60 DAS for S. pohlii. We did not monitor seeds under green light because seeds of these three species are aphotoblastic, being such behavior confirmed for S. camporum seeds (Simão et al, 2013). Protrusion of roots with 2 mm in length was used as evidence of germination.…”

Distinct germination responses may contribute to the distribution pattern of two Moquiniastrum species in different phytophysiognomies from the Brazilian savanna

“…Considering that micro-climatic conditions tend to be more unstable and limiting at typical savanna (Salazar et al, 2012), the strategy of spreading germination through time may increase the chances of seedling survival and establishment, when conditions become suitable. This trait was reported in other typical savanna species (Kissmann and Habermann, 2013;Mendes-Rodrigues et al, 2011;Ribeiro and Borghetti, 2014;Simão et al, 2013). This strategy would also help seedling survival at the beginning of the rainy season (dispersal time of M. barrosoae), when rainfall varies in intensity and frequency in the Cerrado region (Oliveira, 2008).…”

“…Germination response to water limitation varies among Cerrado species. In Styrax camporum germination was affected by −0.1 MPa solutions (Simão et al, 2013); Bowdichia virgilioides had germination affected by −0.3 MPa, and its tolerance limit was between −0.6 and −0.9 MPa (Silva et al, 2001). In Zygophyllum xanthoxilum, a species from arid environments, seed germination was more sensitive to water limitation than in other species from less dry environments, and this strategy was proposed as an adaptive germination mechanism of native xerophytes, which can reduce seedling mortality after short-term rainfall events (Zeng et al, 2010).…”

Do fruit morphology and scarification affect germination and predation rates of Babassu seeds?

“…These results corroborated those reported by Lorenzi et al (2010), who estimated that this species would require from 6 to 8 months to germinate in the field. Neves et al (2013) and Simão et al (2013) stressed the importance of abiotic effects on palm germination, especially temperature (Labouriau & Agudo 1987) and humidity. Neves et al (2013) found that A. vitrivir seeds that did not attain 25 % humidity did not germinate.…”