33 research outputs found
Factors influencing epiphytic bryophyte and lichen species richness at different spatial scales in managed temperate forests
The effect of management related factors on species richness of epiphytic
bryophytes and lichens was studied in managed deciduous-coniferous mixed
forests in Western-Hungary. At the stand level, the potential explanatory
variables were tree species composition, stand structure, microclimate and
light conditions, landscape and historical variables; while at tree level host
tree species, tree size and light were studied. Species richness of the two
epiphyte groups was positively correlated. Both for lichen and bryophyte plot
level richness, the composition and diversity of tree species and the abundance of shrub layer were the most influential positive factors. Besides, for
bryophytes the presence of large trees, while for lichens amount and
heterogeneity of light were important. Tree level richness was mainly
determined by host tree species for both groups. For bryophytes oaks, while for lichens oaks and hornbeam turned out the most favourable hosts. Tree size
generally increased tree level species richness, except on pine for bryophytes
and on hornbeam for lichens.
The key variables for epiphytic diversity of the region were directly
influenced by recent forest management; historical and landscape variables
were not influential. Forest management oriented to the conservation of
epiphyte s should focus on: (i) the maintenance of tree species diversity in
mixed stands; (ii) increment the proportion of deciduous trees (mainly oaks);
(iii) conserving large trees within the stands; (iv) providing the presence of
shrub and regeneration layer; (v) creating heterogeneous light conditions. For
these purposes tree selection and selective cutting management seem more
appropriate than shelterwood system
Variation in rates of spontaneous male production within the nematode species Pristionchus pacificus supports an adaptive role for males and outcrossing
Extremely low genetic diversity in the European clade of the model bryophyte Anthoceros agrestis
The hornwort Anthoceros agrestis is emerging as a model system for the study of symbiotic interactions and carbon fixation processes. It is an annual species with a remarkably small and compact genome. Single accessions of the plant have been shown to be related to the cosmopolitan perennial hornwort Anthoceros punctatus. We provide the first detailed insight into the evolutionary history of the two species. Due to the rather conserved nature of organellar loci, we sequenced multiple accessions in the Anthoceros agrestisâA. punctatus complex using three nuclear regions: the ribosomal spacer ITS2, and exon and intron regions from the single-copy coding genes rbcS and phytochrome. We used phylogenetic and dating analyses to uncover the relationships between these two taxa. Our analyses resolve a lineage of genetically near-uniform European A. agrestis accessions and two non-European A. agrestis lineages. In addition, the cosmopolitan species Anthoceros punctatus forms two lineages, one of mostly European accessions, and another from India. All studied European A. agrestis accessions have a single origin, radiated relatively recently (less than 1 million years ago), and are currently strictly associated with agroecosystem habitats
Stepâbyâstep protocol for the isolation and transient transformation of hornwort protoplasts
Premise: A detailed protocol for the protoplast transformation of hornwort tissue is not yet available, limiting molecular biological investigations of these plants and comparative analyses with other bryophytes, which display a gametophyteâdominant life cycle and are critical to understanding the evolution of key land plant traits.
Methods and Results: We describe a detailed protocol to isolate and transiently transform protoplasts of the model hornwort Anthoceros agrestis. The digestion of liquid cultures with Driselase yields a high number of viable protoplasts suitable for polyethylene glycol (PEG)âmediated transformation. We also report early signs of protoplast regeneration, such as chloroplast division and cell wall reconstitution.
Conclusions: This protocol represents a straightforward method for isolating and transforming A. agrestis protoplasts that is less laborious than previously described approaches. In combination with the recently developed stable genome transformation technique, this work further expands the prospects of functional studies in this model hornwort
Step-by-step protocol for the isolation and transient transformation of hornwort protoplasts.
PREMISE: A detailed protocol for the protoplast transformation of hornwort tissue is not yet available, limiting molecular biological investigations of these plants and comparative analyses with other bryophytes, which display a gametophyte-dominant life cycle and are critical to understanding the evolution of key land plant traits. METHODS AND RESULTS: We describe a detailed protocol to isolate and transiently transform protoplasts of the model hornwort Anthoceros agrestis. The digestion of liquid cultures with Driselase yields a high number of viable protoplasts suitable for polyethylene glycol (PEG)-mediated transformation. We also report early signs of protoplast regeneration, such as chloroplast division and cell wall reconstitution. CONCLUSIONS: This protocol represents a straightforward method for isolating and transforming A. agrestis protoplasts that is less laborious than previously described approaches. In combination with the recently developed stable genome transformation technique, this work further expands the prospects of functional studies in this model hornwort
Faunistical data on the Croatian Orthoptera with four species newly recorded in the country
Balance between inbreeding and outcrossing in a nannandrous species, the moss Homalothecium lutescens.
Epiphytic dwarf males on the females present a possible solution to the problem of short fertilization distances in mosses. However, leptokurtic spore dispersal makes dwarf males likely to be closely related to their host shoot, with an accompanying risk of inbreeding. The capacity of a female to harbour a high number of different dwarf males suggests that there may be mechanisms in place that counteract inbreeding, such as polyandry and post-fertilization selection. We have genotyped sporophytes, female host shoots and dwarf males in four populations of the moss Homalothecium lutescens. We found no evidence of selective sporophyte abortion based on level of heterozygosity. The occurrence of entirely homozygous sporophytes together with significantly positive inbreeding coefficients in three of the populations (mean FIS between 0.48 and 0.64) suggest frequent mother-son mating events. However, 23% of all sampled sporophytes had a higher level of heterozygosity compared with the mean expected heterozygosity at the population level. Polyandry was frequent, on average 59% of the sporophytes on a female shoot were sired by distinct fathers. In conclusion, sporadic fertilizations by dwarf males originating from nonhost female shoots appear to counteract strong inbreeding.Heredity advance online publication, 2 September 2015; doi:10.1038/hdy.2015.79