On the selective advantage of coloniality in staghorn ferns (Platycerium bifurcatum, Polypodiaceae).

The staghorn fern (Platycerium bifurcatum, Polypodiaceae) is an epiphyte from Australasia that displays many life history characteristics commonly associated with eusocial animals. Here, I hypothesize about the selective advantage of living in cooperative groups by comparing the morphological characteristics of colonies to their solitary congeners.

Developmental analyses of divarications in leaves of an aquatic fern Microsorum pteropus and its varieties.

Plant leaves occur in diverse shapes. Divarication patterns that develop during early growths are one of key factors that determine leaf shapes. We utilized leaves of Microsorum pteropus, a semi-aquatic fern, and closely related varieties to analyze a variation in the divarication patterns. The leaves exhibited three major types of divarication: no lobes, bifurcation, and trifurcation (i.e., monopodial branching). Our investigation of their developmental processes, using time-lapse imaging, revealed localized growths and dissections of blades near each leaf apex. Restricted cell divisions responsible for the apical growths were confirmed using a pulse-chase strategy for EdU labeling assays.

Studies on ontogeny and reproductive behaviour of Lepisorus nudus (Hook.) Ching (Polypodiaceae).

In-vitro studies of the ontogeny and mating system of the gametophytes of Lepisorus nudus were carried out through multispore and isolate cultures lasting 23 weeks. Spore germination begins early, on day 5-6. Spore germination pattern was Vittaria type and the germination percentage reached 82.69% (± 3.20%). Filamentous gametophyte did not branch and never produce separate prothalli. Occasionally the branching and separate prothalli were produced from mature and cordate gametophytes. Prothallial development was Drynaria type (cordate gametophytes with notched apex) contrary to other known species of Lepisorus, where gametophyte development was Kaulinia type (strap gametophytes without apical notch). Gametophyte production in multispore cultures reached up-to 75.6% (± 18.85%). All isolates initially produced archegonia and antheridia only after a prolonged cessation of production in archegonia. In contrast, only 37.2% (±12.63%) of individuals in multispore culture exhibited the same pattern with 29.8% (±7.56%) developing as males that did not produce archegonia by the end of the study. Only 37.2% (±12.63%) of archegoniate gametophytes developed antheridia by the end of the study and only once archegonia had degenerated; i.e., a temporal gap existed in expression of female and male gametangia. In multispore culture, only 26.21% (±5.70%) sporophytes developed on 160th day by fusion of female and male gametes that were derived from matings between sib gametophytes. In contrast, isolated gametophytes did not produce sporophytes. In isolate gametophytes, mature archegonia could not take delivery of male gametangia because antheridia were produced sequentially. This study suggests that the sequential expression of gametangia and absence of the intragametophytic selfing may also be a possible cause of reproductive barriers. Lepisorus nudus promotes inter-gametophytic selfing as an adaptive mechanism for reproductive success in multispore culture. This study presents a detailed account on reproductive biology of the taxa whose population is decreasing at distressing rate.

Cytological and Proteomic Analyses of Osmunda cinnamomea Germinating Spores Reveal Characteristics of Fern Spore Germination and Rhizoid Tip Growth.

Fern spore is a good single-cell model for studying the sophisticated molecular networks in asymmetric cell division, differentiation, and polar growth. Osmunda cinnamomea L. var. asiatica is one of the oldest fern species with typical separate-growing trophophyll and sporophyll. The chlorophyllous spores generated from sporophyll can germinate without dormancy. In this study, the spore ultrastructure, antioxidant enzyme activities, as well as protein and gene expression patterns were analyzed in the course of spore germination at five typical stages (i.e. mature spores, rehydrated spores, double-celled spores, germinated spores, and spores with protonemal cells). Proteomic analysis revealed 113 differentially expressed proteins, which were mainly involved in photosynthesis, reserve mobilization, energy supplying, protein synthesis and turnover, reactive oxygen species scavenging, signaling, and cell structure modulation. The presence of multiple proteoforms of 25 differentially expressed proteins implies that post-translational modification may play important roles in spore germination. The dynamic patterns of proteins and their encoding genes exhibited specific characteristics in the processes of cell division and rhizoid tip growth, which include heterotrophic and autotrophic metabolisms, de novo protein synthesis and active protein turnover, reactive oxygen species and hormone (brassinosteroid and ethylene) signaling, and vesicle trafficking and cytoskeleton dynamic. In addition, the function skew of proteins in fern spores highlights the unique and common mechanisms when compared with evolutionarily divergent spermatophyte pollen. These findings provide an improved understanding of the typical single-celled asymmetric division and polar growth during fern spore germination.

Heavy metal accumulation in Pyrrosia flocculosa (D. Don) Ching growing in sites located along a vehicular disturbance gradient.

Monitoring of environment is a key contemporary issue that has necessitated search for bio-indicators. The very fact that epiphytes do not have a direct contact with soil and absorb nutrients from the environment puts them among the best indicators of environmental conditions. We, therefore, selected Pyrrosia flocculosa (D. Don) Ching-an epiphytic fern that commonly occurs in the Himalaya for this study. The study focused on analyzing heavy metal concentrations in the fronds of P. flocculosa growing along a disturbance gradient. For this, three sites representing different levels of disturbance viz., least disturbed, moderately disturbed, and highly disturbed, were identified in Kangra district of Himachal Pradesh. From each site, fronds of P. flocculosa were collected, categorized into three growth stages (juvenile, young, and mature), and brought to the laboratory for analyses. After drying and powdering, the samples were analyzed for Pb, Cd, Fe, Ni, Cu, Mn, and Zn using atomic absorption spectrophotometer. The results obtained were statistically compared using the software package Statistica. As expected, concentration of the metals varied among the sites and also among the identified growth stages of the species. In general, concentration of the metals was in the order Fe (639.28 ± 81.63) > Ni (56.03 ± 4.97) > Mn (7.54 ± 0.69) > Zn (6.51 ± 0.36) > Cd (4.01 ± 0.86) > Cu (1.93 ± 0.74). Barring Mn, concentration of all the metals increased with disturbance and was positively correlated to it. However, except for Cd and Fe, none of the metals reported higher than threshold values. Effective monitoring of the environment can thus be done using P. flocculosa.

[Photosynthetic characteristics of Drynaria fortunei and its relation to environmental factors].

OBJECTIVE: To have a better utilization of diurnal photosynthetic variation of Drynaria fortunei in three light environments and provide theoretical basis for its artificial cultivation. METHODS: Diurnal photosynthetic variation of Drynaria fortunei were determinated by portable photosynthesis analysis system (Li-6400), and correlation between physiological and environmental factors was further analysed. RESULTS: The diurnal net photosynthetic rate (NPR) exhibited a single peak curve, with the peak value of NPR occurring at 15:30. The mean diurnal Pn of D. fortunei in three environments followed a tread of tree epiphytes > shine > shade. WUE had significantly positive correlation with NPR. Air temperature (Ta), ambient CO2 concentration (Ca) and relative humidity (RH) were the main environmental factors for NPR of D. fortunei. CONCLUSION: The optimum cultivation condition of D. fortunei is 32 degrees C, RH around 40%, and appropriate shade is recommended.

[Identification of foliumn pyrrosiae from different habitats and species by HPLC fingerprint].

OBJECTIVE: To establish HPLC fingerprint of Folium Pyrrosiae for identification. METHODS: The HPLC method was developed with Diamonsil C18 column (250 mm x 4.6 mm, 5 microm),and a mixture liquid of acetonitrile-0.8% acetic acid solution as mobile phase in a gradient elution. HPLC fingerprints of44 samples were analyzed by similarity, cluster and principal component analysis. RESULTS: The HPLC fingerprint common pattern of Pyrrosia petiolosa, Pyrrosia lingua and common pattern of Pyrrosia sheareri were set up separately. Samples from different species were classified based on the result of cluster and principal component analysis. Fingerprints of Pyrrosia sheareri and Pyrrosia lingua have high degree of similarity, but were different from Pyrrosia petiolosa, while Pyrrosia calvata and Pyrrosia assimlis were classified as adulterants with their dissimilar fingerprints. CONCLUSION: The method is stable and reliable with a good reproducibility and provides a reference standard for identifying Folium Pyrrosiae from different habitats and species.

Gametophyte morphology of Platycerium andinum Baker and Platycerium wandae Racif.

This paper describes the morphology of the sexual phase and spores of Platycerium andinum and Platycerium wandae. Spores were sown in Thompson's media and the cultures were kept at 24-25 degrees C, with 12h light/darkness photoperiod. Developmental phases were fixed in FAA and processed for observation with the scanning electron microscope. Spores of both species are monolete; Vittaria-type germination and Aspidium-type prothallial development were observed. In the phase of development, the gametophytes develop unicellular secretory and as they mature, develop bifurcated or branched pluricellular trichomes, both in the cushion and near the meristematic zone. Adult gametophytes in culture are cordiform-spatulate to cordiform-reniform, most are unisexual and a few are bisexual. Gametangia belong to the leptosporangiate fern type. Archegonial morphology is uniform, with an elongate, thin neck curved toward the base of the gametophyte. Antheridia have a basal cell, an annular cell and an undivided opercular cell. Three hundred days after the spores were sown, sporophytes still had not developed. In both species, some spores germinate inside the sporangial capsule (intra-sporangial germination). We provide new information on morphogenesis in the genus Platycerium.

Developmental morphology of strap-shaped gametophytes of Colysis decurrens: a new look at meristem development and function in fern gametophytes.

BACKGROUND AND AIMS: The gametophytes of most homosporous ferns are cordate-thalloid in shape. Some are strap- or ribbon-shaped and have been assumed to have evolved from terrestrial cordate shapes as an adaptation to epiphytic habitats. The aim of the present study was to clarify the morphological evolution of the strap-shaped gametophyte of microsoroids (Polypodiaceae) by precise analysis of their development. METHODS: Spores of Colysis decurrens collected in Kagoshima, Japan, were cultured and observed microscopically. Epi-illuminated micrographs of growing gametophytes were captured every 24 h, allowing analysis of the cell lineage of meristems. Light microscopy of resin-sections and scanning electron microscopy were also used. KEY RESULTS: Contrary to previous assumptions that strap-shaped Colysis gametophytes have no organized meristem, three different types of meristems are formed during development: (1) apical-cell based - responsible for early growth; (2) marginal - further growth, including gametophyte branching; and (3) multicellular - formation of cushions with archegonia. The cushion is two or three layers thick and intermittent. The apical-cell and multicellular meristems are similar to those of cordate gametophytes of other ferns, but the marginal meristem is unique to the strap-shaped gametophyte of this fern. CONCLUSIONS: The strap-shaped gametophytes of C. decurrens may have evolved from ancestors with a cordate shape by insertion of the marginal meristem phase between the first apical-cell-based meristem and subsequent multicellular meristem phases. Repeated retrieval of the marginal meristem at the multicellular meristem phase would result in indefinite prolongation of gametophyte growth, an ecological adaptation to epiphytic habitats.

[Gametophyte morphogenesis of Mexican species of Pleopeltis (Polypodiaceae, subfamily Pleopeltoideae)]. / Morfogénesis de los gametofitos de especies mexicanas de Pleopeltis (Polypodiaceae, subfamilia Pleopeltoideae).

The development and morphology of the gametophytes of seven species of ferns from genus Pleopeltis are described and compared. The spore germination is Vittaria-type in P. astrolepis, P. crassinervata, P. macrocarpa, P. polylepis and P. revoluta. For P. angusta and P. mexicana it was proposed a new germination pattern is Pleopeltis-type. The prothallial development is Drynaria-type in P. astrolepis, P. crassinervata, P. macrocarpa, P. polylepis and P. revoluta and Ceratopteris-type for P. angusta and P. mexicana. The gametangia are typical of the leptosporangiate ferns, sporophytes after six and a half months in culture did not appeared.