Variability in the germination of spores among and within natural populations of the endangered tree fern Dicksonia sellowiana Hook. (Xaxim)

Lehmann

Braz. arch. biol. technol.

et al. 2010

Self Cite

Section: Discussionsupporting

confidence: 59%

Spore germination of Gleichenella pectinata (Willd.) Ching (Polypodiopsida-Gleicheniaceae) at different temperatures, levels of light and pH

Lehmann

Braz. arch. biol. technol.

et al. 2010

Self Cite

Tropical Conservation Science

“…However, tree ferns produce billions of spores (Large & Braggins, 2004); D . sellowiana , for example, produces approximately 4 billion spores per kilogram (Gomes et al, 2006), which facilitates the formation of spore banks (Fiilippini et al, 1999). Moreover, it has been suggested that in general they are able to disperse even over distances greater than 3000 km (Tryon, 1970; Tryon & Tryon, 1982).…”

Section: Discussionmentioning

confidence: 99%

Diversity and Genetic Structure of Dicksonia navarrensis (Dicksoniaceae) Populations in the Mexican Sierra Madre Oriental

Reyes-Ortiz

Octavio‐Aguilar

López–Mata

et al. 2022

Background and Research Aims Dicksonia navarrensis is a species of tree fern at risk of extinction, distributed in the montane cloud forest (MCF) of the Americas from the central region of Mexico to Ecuador. In Mexico, populations of this species grow in primary vegetation of the MCF, in a matrix with a high degree of fragmentation and under threat of disappearance. Methods In the present study, the diversity and genetic structure of seven populations of D. navarrensis that are distributed in the cloud forest of the Sierra Madre Oriental were evaluated, with both standard laboratory and statistical analysis techniques, using 11 microsatellites developed for the genus Dicksonia. Results A total of 33 alleles were found. Genetic diversity differed between populations, and some presented low heterozygosity. Using assignment tests, three genetic groups were identified, associated with the geographical distribution of the populations; those from the north maintain connectivity with each other but diverge highly from the populations in the south, probably due to processes of isolation by distance (local environment), genetic drift, and natural selection. Conclusion The northernmost population, which is more isolated from the rest, has a broader genetic reservoir, which can be useful for maintaining the genetic diversity of the species. In the other populations, with less genetic diversity, the introduction of individuals and/or the dispersion of spores is important, to maintain and increase the genetic variability that they still possess, but which could disappear in a short time if their habitat continues to deteriorate at a high degree. Implications for Conservation The results obtained provide basic information that can be used in management and conservation plans, because the populations with the greatest genetic diversity and the possible processes that are influencing the genetic structure of the species were identified.

“…Germination and establishment are crucial stages in the life cycle of a plant [13,14] especially for the bryophytes which must survive an array of habitat conditions mainly on only one set of chromosomes. Germination of bryophyte spores has been reported to be limited by habitat pH.…”

Section: Discussionmentioning

confidence: 99%

Effects of pH, Photoperiod, and Nutrient on Germination and Growth of Calymperes erosum C. Muell. Gemmaling

et al. 2014

Effects of pH, photoperiod, and substrate nutrient concentration on the rate of germination of the gemmae and primary protonema growth of Calymperes erosum C. Muell. were studied. There was a statistically significant difference in germination of C. erosum gemmae and protonema growth among the different substrate pH levels, photoperiod treatments, and substrate nutrient conditions, respectively (P<0.01). Gemmae germination and protonemal growth peaked at pH 4 and 5. Protonemal growth was retarded at pH 2, 3, 6, and 7. No germination was observed in continuous darkness. Germination and protonema growth increased significantly (P<0.01) within the first 3 and 6 hours of daylight but not again until after 9 and 12 hours of exposure, respectively. No statistical (P>0.05) increase in germination and protonemal growth was observed when the nutrient concentration was increased from 25% to 200%. Results indicate the moss is adapted to low nutrients and that it may germinate well at substrate pH as low as 2 howbeit the probability of establishment will remain limited until pH levels improve to 4 or 5. Furthermore, the moss is able to achieve net photosynthetic carbon gain during morning hours. Recovery from photoinhibition is likely by evening.