A Whole Plant Herbaceous Angiosperm from the Middle Jurassic of China

In contrast to woody habit with secondary growth, truthful herbaceous habit lacking secondary growth is restricted to angiosperms among seed plants. Although angiosperms might have occurred as early as in the Triassic and herbaceous habit theoretically may have been well adopted by pioneer angiosperms, pre-Cretaceous herbs are missing hitherto, leaving the origin of herbs and evolution of herbaceous angiosperms mysterious. Here we report Juraherba bodae gen. et sp. nov, a whole plant herbaceous angiosperm, from the Middle Jurassic （〉164 Ma） at Daohugou Village, Inner Mongolia, China, a fossil Lagerst^itten that is worldwide famous for various fossil finds. The angiospermous affinity of Juraherba is ensured by its enclosed ovules/seeds. The plant is small but complete, with physically connected hairy root, stem, leaves, and fructifications. The Middle Jurassic age recommends Juraherba as the earliest record of herbaceous seed plants, demanding a refresh look at the evolutionary history of angiosperms.

Genome size evolution of the extant lycophytes and ferns

Ferns and lycophytes have remarkably large genomes.However,little is known about how their genome size evolved in fern lineages.To explore the origins and evolution of chromosome numbers and genome size in ferns,we used flow cytometry to measure the genomes of 240 species(255 samples)of extant ferns and lycophytes comprising 27 families and 72 genera,of which 228 species(242 samples)represent new reports.We analyzed correlations among genome size,spore size,chromosomal features,phylogeny,and habitat type preference within a phylogenetic framework.We also applied ANOVA and multinomial logistic regression analysis to preference of habitat type and genome size.Using the phylogeny,we conducted ancestral character reconstruction for habitat types and tested whether genome size changes simultaneously with shifts in habitat preference.We found that 2 C values had weak phylogenetic signal,whereas the base number of chromosomes(x)had a strong phylogenetic signal.Furthermore,our analyses revealed a positive correlation between genome size and chromosome traits,indicating that the base number of chromosomes(x),chromosome size,and polyploidization may be primary contributors to genome expansion in ferns and lycophytes.Genome sizes in different habitat types varied significantly and were significantly correlated with habitat types;specifically,multinomial logistic regression indicated that species with larger 2 C values were more likely to be epiphytes.Terrestrial habitat is inferred to be ancestral for both extant ferns and lycophytes,whereas transitions to other habitat types occurred as the major clades emerged.Shifts in habitat types appear be followed by periods of genomic stability.Based on these results,we inferred that habitat type changes and multiple whole-genome duplications have contributed to the formation of large genomes of ferns and their allies during their evolutionary history.

Development of genomic resources for Wenchengia alternifolia(Lamiaceae)based on genome skimming data

Wenchengia alternifolia(Lamiaceae),the sole species of the genus Wenchengia is extremely rare and is currently listed as Critically Endangered(CR) on the IUCN Red List. The species had long been considered endemic to Hainan Island,China and was once believed to be extinct until a small remnant population was rediscovered at the type locality in 2010.Four more populations were later found on Hainan and in Vietnam.In order to develop genomic resources for further studies on population genetics and conservation biology of this rare species,we identified infraspecific molecular markers in the present study,using genome skimming data of five individuals collected from two populations on Hainan Island and three populations in Vietnam respectively.The length of plastome of the five individuals varied from 152,961 bp to 150,204 bp,and exhibited a typical angiosperm quadripartite structure.Six plastid hotspot regions with the Pi> 0.01(trnH-psbA,psbA-trnK,rpl22,ndhE,ndhG-ndhI rps15-ycf1),and 1621 polymorphic gSSRs,as well as 1657 candidate SNPs in 237 variant nuclear genes were identified,thereby providing important information for further genetic studies.

Insights into cryptic speciation of quillworts in China

Cryptic species are commonly misidentified because of high morphological similarities to other species.One group of plants that may harbor large numbers of cryptic species is the quillworts(Isoetes spp.),an ancient aquatic plant lineage.Although over 350 species of Isoetes have been reported globally,only ten species have been recorded in China.The aim of this study is to better understand Isoetes species diversity in China.For this purpose,we systematically explored the phylogeny and evolution of Isoetes using complete chloroplast genome(plastome)data,spore morphology,chromosome number,genetic structure,and haplotypes of almost all Chinese Isoetes populations.We identified three ploidy levels of Isoetes in Chinaddiploid(2n=22),tetraploid(2n=44),and hexaploid(2n=66).We also found four megaspore and microspore ornamentation types in diploids,six in tetraploids,and three in hexaploids.Phylogenetic analyses confirmed that I.hypsophila as the ancestral group of the genus and revealed that Isoetes diploids,tetraploids,and hexaploids do not form monophyletic clades.Most individual species possess a single genetic structure;however,several samples have conflicting positions on the phylogenetic tree based on SNPs and the tree based on plastome data.All 36 samples shared 22 haplotypes.Divergence time analysis showed that I.hypsophila diverged in the early Eocene(~48.05 Ma),and most other Isoetes species diverged 3-20 Ma.Additionally,different species of Isoetes were found to inhabit different water systems and environments along the Yangtze River.These findings provide new insights into the relationships among Isoetes species in China,where highly similar morphologic populations may harbor many cryptic species.

An edible fruit from the Jurassic of China

Frugivory is an important ecological tie between animals and angiosperms.It plays an important role in the evolution of food webs and energy flow networks in the ecosystem.However,little is known about how old this relationship can be due to lack of relevant fossil evidence.Here,the authors report a fossil fruit,Jurafructus gen.nov.,a putative angiosperm from the Middle-Late Jurassic(>164 Ma)of Daohugou Village,Inner Mongolia,China,which provides the currently earliest evidence of frugivory.The fossil is a more or less three-dimensionally preserved coalified drupe that has been damaged by animals in two different ways.The pericarp,in addition to the seed coat surrounding parenchyma seed contents,is suggestive of an angiospermous affinity,as such a 3+3 structure is distinct from a three-layered seed coat in gymnosperms.The seed possesses a distal micropyle,attached on the base of the pericarp,suggestive of a former orthotropous ovule in the gynoecium.The damaged pericarp of Jurafructus suggests that firugivory can be dated back to the Middle-Late Jurassic.Apparently,the ecological relationship between angiosperms and animals extends deep into the fossil record.

Conservation and reintroduction of the rare and endangered orchid Paphiopedilum armeniacum

Paphiopedilum armeniacum is a rare and endangered lady’s slipper orchid in China.It is distributed around the mid-elevations of the Nu Mountains in southwest China.Due to over-harvest,habitat loss,and degradation,wild populations of P.armeniacum has declined drastically.A combination of approaches involving biotechnology,habitat restoration,and interspecific relationship reconstruction was used to carry out the reintroduction of the species.Integrated conservation program for this species included in-situ protection,ex-situ conservation,and reintroduction,which helped to rebuild a harmonious relationship between local farmers and P.armeniacum.The sustainable utilization of native plant resources in poor areas can promote regional sustainable development which is compatible with species protection.

Ceratopteris chunii and Ceratopteris chingii(Pteridaceae),two new diploid species from China,based on morphological,cytological,and molecular data

Understanding how natural hybridization and polyploidizations originate in plants requires identifying potential diploid ancestors.However,cryptic plant species are widespread,particularly in Ceratopteris(Pteridaceae).Identifying Ceratopteris cryptic species with different polyploidy levels is a challenge because Ceratopteris spp.exhibit high degrees of phenotypic plasticity.Here,two new cryptic species of Ceratopteris,Ceratopteris chunii and Ceratopteris chingii,are described and illustrated.Phylogenetic analyses reveal that each of the new species form a well-supported clade.C.chunii and C.chingii are similar to Ceratopteris gaudichaudii var.vulgaris and C.pteridoides,respectively,but distinct from their relatives in the stipe,basal pinna of the sterile leaf or subelliptic shape of the fertile leaf,as well as the spore surface.In addition,chromosome studies indicate that C.chunii and C.chingii are both diploid.These findings will help us further understand the origin of Ceratopteris polyploids in Asia.