Age and sex-specific rates of leaf regeneration in the Mojave Desert moss Syntrichia caninervis

The extremely skewed female-biased sex ratio in the desert moss Syntrichia caninervis was investigated by assessing the regeneration capacity of detached leaves. Juvenile, green, yellow-green, and brown leaves equating to approximately 0, 2, 6, and 12 yr of age, respectively, were detached from individuals of S. caninervis collected from 10 field populations and grown in a growth chamber for 58 d at a light intensity of 33–128 µmol · m–2 · s–1. Younger leaves (0–2 yr old) tended to have a greater viability, regenerate more quickly, extend their protonemal filaments farther, produce shoots (gametophores) more quickly, produce more shoots, and accumulate a greater biomass than older leaves (6 and 12 yr old). Among younger leaf classes, regenerating female leaves were more likely to produce a shoot than male leaves and produced more shoots than male leaves. The sexes did not differ significantly in time until protonemal emergence, linear extension of protonemata, or rate of biomass accumulation. However, protonemata of male leaves tended to emerge more quickly and produce a greater total biomass, ultimately consisting mostly of protonemata, than did female leaves. The more rapid proliferation of shoots by female leaf regenerants may help to explain the rarity of males in this species

Sporophyte and Gametophyte Generations Differ in their Thermotolerance Response in the Moss Microbryum

• Background and Aims Actively growing post-embryonic sporophytes of desert mosses are restricted to the cooler, wetter months. However, most desert mosses have perennial gametophytes. It is hypothesized that these life history patterns are due in part to a reduced thermotolerance for sporophytes relative to gametophytes

Gender Differences and a New Adult Eukaryotic Record for Upper Thermal Tolerance in the Desert Moss Syntrichia Caninervis

1.Two Competing Hypotheses Relating to Thermostress Were Proposed to Understand Skewed Sex Ratios in Syntrichia Caninervis, a Reproductive Investment Hypothesis and a Wildfire Selection Hypothesis.2.Nearly All Shoots from Both Sexes Remained Viable (Regenerated in Culture) Following Exposure to 120 °C for 30 Min, Thus Setting a New Upper Thermotolerance Record for Adult Eukaryotic Organisms for a Minimum 30 Min Exposure Time.3.Males Regenerated Faster Than Females, Produced More Biomass, and Suffered Less Fungal Attack Than Females. Findings Support the Wildfire Selection Hypothesis. © 2008 Elsevier Ltd

Does selection for gamete dispersal and capture lead to a sex difference in clump water holding capacity?

For methods please see:<div><br></div><div>Moore, J. D., L. M.  Kollar, and D. N. McLetchie. Does selection for gamete dispersal and capture lead to a sex difference in clump water- holding capacity? American Journal of Botany. <i>in press</i>.</div

Marchantia inflexa fluctuating sexual dimorphism

This item includes data on recovery from dehydration treatment for the dehydration tolerant tropical liverwort <i>Marchantia inflexa</i>. Data characterizing the environmental conditions at field sites are also included

Sex Ratio and Sex Expression in an Urban Population of the Silver Moss, Bryum argenteum Hedw

Introduction. A well-supported pattern among dioicous bryophytes is male rarity. However, few assessments of bryophyte sex ratios have been made across environmental gradients to assess the role of environment in shaping population sex ratios. Methods. We systematically surveyed 200 shoots from a 20 m2 urban population of Bryum argenteum, and regenerated each shoot apex until sex expression occurred (up to 315 days). Key results. Female shoots outnumbered male shoots 132 to 68, giving a sex ratio of 1.94♀: 1♂. The female bias was found in two transects in higher light environments but not in the third transect, which had a lower light level and an equal sex ratio. Female shoots took longer than male shoots to reach gametangial induction (122 vs. 60 days) and longer to produce 5 inflorescences (120 vs. 80 days). Male shoots produced an average of 10× the total number of inflorescences compared to female shoots (34 vs. 3.5 inflorescences). Despite producing more inflorescences, male plants also produced more regenerant shoots, thus contradicting the prediction that a higher prefertilisation reproductive effort in males trades off with vegetative proliferation. Female plants harboured significantly more associated microbes than male plants. Conclusions. Our results support the role of light in influencing sex ratios in this species, suggest that trade-offs between reproduction and vegetative growth may not be strong for males, and indicate a potential role of a sex-specific microbiome in influencing sex ratios