New Fossil Liverworts from the Lower Cretaceous of Western Liaoning, China

Sixteen liverwort specimens collected from the Lower Cretaceous Yixian Formation of Huangbanjigou Village, Liaoning Province, China are studied in this work. The plants are thalloid and preserved in brown arenaceous mudstone as impressions. Based on examinations, the liverworts are assigned to two new genera and five new species： Riccardiothallus palmata sp. nov., Pallaviciniites stricta sp. nov., Pellites latithallus gen. et sp. nov., Conocephalumites hexagonites gen. et sp. nov. and Metzgerites multifidus sp. nov., belonging to five families and five genera. The fossil research indicates that the divergence of families, Aneuraceae and Metzgeriaceae, Pallaviciniaceae and Hymenophytaceae,Pelliaceae and Fossombroniaceae, was in the Lower Cretaceous（125 Ma）. The research provides significant additions to the fossil liverwort records in Western Liaoning and offers fossil evidence for studying the classification and evolution of extant liverworts.

Deadly oasis:Recurrent annihilation of Cretaceous desert bryophyte colonies;the role of solar,climate and lithospheric forcing

Many oases(wet interdunes)are sedimentary systems characterized by high-frequency water-level oscillations,marked changes in salinity and intense biological activity at their margins.They are considered to be one of the most challenging environments on Earth for ecosystem development.These dynamic,depositional settings are usually unfavourable for fossilization and subsequent preservation of vegetal remains.This paper describes bryophyte(liverwort)assemblages occurring in three successive horizons interpreted to represent(i)recurrent early successional phases of biological soil crust colonization of wet interdune margins or(ii)exceptional preservation of floating or riparian liverworts in oasis pond waters associated with a progressive fall of the interdune water level.The record of in situ colonization surfaces characterized by delicate(e.g.lignin-free)three-dimensional structures represents an exceptional type of preservation herein associated with a rapid variation in phreatic interdune water level and the subsequent establishment of anoxic and reducing conditions.The occurrence of exceptionally preserved liverwort colonies coincides with the sedimentary record of,at least,three seismite levels in the oasis.Data gathered from the site suggests that the water table of the oasis was controlled by a combination of(i)a positive creation of accommodation space due to subsidence associated with movement on syn-sedimentary extensional faults,and(ii)the rise and fall of the oasis water table controlled by the oscillations of the groundwater system due to orbital changes which appear to drive the variability of the climate system.Rising groundwater levels flooded the oasis soil crusts and lead to the exceptional recurrent preservation of liverwort colonies at the oasis margins.Alternatively,considering the hypothesis of floating or riparian liverworts in the oasis pond waters,the fall in the level of the oasis water table placed the floating liverworts in contact with the oasis bottom sediments.This fall in the level of the oasis water table could indicate a cessation of accommodation space by syn-sedimentary extensional faults and/or a regional lowering of the groundwater system level associated with drought periods.Preliminary results indicate that oasis lamination between liverwort colonies records decadal and sub-decadal cyclicity,related with 11-year Schwabe sunspot and sub-decadal NAO cyclicities,conferring for every sedimentary cycle between liverwort colonies a duration of approximately 200 years,that otherwise matches the expected recurrence period for the De Vries cycle of solar activity.

<i>Conocephalum conicum</i>(L.) Dumort: A Case of Unique Reproductive Biology

This paper reports spore-elater ratio per capsule in three populations of Conocephalum conicum collected from different regions of Jammu and Kashmir (Doda, Ladakh and Bhaderwah). Spore-elater ratio came out to be 0.40-0.43:1, far less than expected for Marchantialian taxa. The ratios thus obtained were compared with that present in herbarium specimen collected in 1958 from Kyushu. The ratios have remained constant since many decades, thereby indicating that the sex-ual reproduction has lesser role to play in the propagation of this species.

Studies on the Associates of <i>Conocephalum conicum</i>L. (Dumort.) and <i>Dumortiera hirsuta</i>Sw. (Nees)

Paper includes information on association of 46 populations of Conocephalum conicum L. (Dumort.) and 25 of Dumortiera hirsuta Sw. (Nees) with diverse organisms, including fungi, bryophytes, pteridophytes, gymnosperms, angiosperms and an insect.

A New Epi‑neoverrucosane‑type Diterpenoid from the Liverwort Pleurozia subinfata in Borneo

New bioactive 13-epi-neoverrucosane diterpenoid,5β-acetoxy-13-epi-neoverrucosanic acid(1)along with three known secondary metabolites,13-epi-neoverrucosan-5β-ol(2),chelodane(3)and(E)-β-farnesene(4)were isolated from the MeOH extract of east Malaysia’s liverwort Pleurozia subinfata.The chemical structure of new compound was elucidated by the analyses of its spectroscopic data(FTIR,NMR and HR-ESI-MS).These epi-neoverrucosane-type compounds seem to be notable chemosystematic markers for P.subinfata in Borneo.Compound 3 was widespread in marine sponges however this is the frst record for 3 to be found in liverwort.These metabolites were tested for their antifungal potentials against selected fungi from the marine environment.Compound 1 exhibited efective antifungal activity against Lagenidium thermophilum.

<i>Conocephalum conicum</i>(L.) Dumort. (Snake Liverwort) Threatened in Bhaderwah (J &K) due to Environmental Shock

Paper includes information on population status of Conocephalum conicum collected from diverse habitats in Bhader-wah (J & K state). Taxon exhibits tremendous diversity in morphoanatomical details of various gametophytic charac-ters. Isozyme analysis was performed to find out whether variability in the taxon is only environmental or has genetic basis as well.

Rearranged 19-nor-7,8-seco-labdane diterpenoids and Diels-Alder cycloadducts from the Chinese liverwort Pallavicinia ambigua:Structural elucidation,photoinduced rearrangement,and cytotoxic activity

Two distinctive rearranged 19-nor-7,8-seco-labdane diterpenoids(1 and 2)with a novel tetracyclo[5.2.1.0^(2,5.)0^(4,10)]decane skeleton,a derivative of the open tetrahydrofuran ring(7),three dimeric compounds(8-10),and four revised homologs(3-6)were obtained from Chinese liverwort Pallavicinia ambigua.Their structures were identified via combined analysis of their spectroscopic data,single-crystal X-ray diffraction patterns,and ECD calculations.The light-driven conversion of compound 5 to compounds 1-4 demonstrated that photochemically induced postmodification involved in biosynthesis is an important way to diversify natural structures.A preliminary cytotoxicity assay revealed that compound 5 showed significant inhibition in the human prostate cancer(PC-3)cell line via an apoptotic pathway.

Reinvestigation on species richness and environmental correlates of bryophytes at a regional scale in China

Aims The aim of this article is 4-fold:(i)to update species richness of bryophytes for each of the Chinese provinces based on the most current knowledge on distributions of bryophytes in China,(ii)to provide a set of analyses based on the updated species richness data and the environmental variables used in a recent article on species richness of bryophytes in China,(iii)to expand the analysis presented in the recent article by relating species richness of bryophytes to over 15 additional climatic variables and(iv)to determine the degree to which the relationships between bryophyte species richness and environmental variables that were reported in the recent article might have been biased.Methods Over 180 literatures with national,provincial and local species lists of bryophytes in China were used in this study.Taxonomy and nomenclature of bryophytes in China were standardized according to The Plant List.Correlation and regression analyses were used to examine the relationships between species richness or species density of bryophytes in Chinese provinces and environmental variables.Important Findings On average,each Chinese province possesses 700.6 species of bryophytes,which is 112.1 species more than previously reported.With the updated species richness data reported in this study,stronger relationships between species richness of bryophytes and environmental variables have been found,compared with those found in a recently published study for China.When single environmental variables were considered,precipitation-related variables were,on average,more strongly correlated with species richness and species density than were temperature-related variables.Environmental variables were on average correlated more strongly with species density than with species richness of bryophytes at the regional scale in China.Our study showed that measures quantifying the average and variation of environmental conditions within each Chinese province explained 82.7%and 71.1%of the variation in species richness of liverworts and mosses,respectively,and explained 86.5%and 70.7%of the variation in species density of liverworts and mosses,respectively.

Scapaundulin C,a novel labdane diterpenoid isolated from Chinese liverwort Scapania undulate,inhibits acetylcholinesterase activity

In the present study, scapaundulin C(1), a new labdane diterpenoid, and four related known compounds scapaundulin A(2), 5?, 8?, 9?-trihydroxy-13E-labden-12-one(3), 5?, 8?-dihydroxy-13E-labden-12-one(4), and(13S)-15-hydroxylabd-8(17)-en-19-oic acid(5), were isolated from the Chinese liverwort Scapania undulate(L.) Dum., using column chromatography. The structures of these compounds were determined on the basis of 1D- and 2D-NMR analyses. The acetylcholinesterase(Ach E) inhibitory activity was evaluated using a bioautographic TLC assay and the cytotoxic activity was evaluated by the MTT method. All the compounds were reported for the first time to exhibit moderate Ach E inhibitory activity with minimal inhibitory quantities ranging from 250 to 500 ng. All the compounds were tested for their cytotoxicity against five human tumor cell lines, A549, K562, A2780, Hela, and HT29, and compounds 3 and 4 exhibited moderate inhibitory effects on the growth of A2780 cells.