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Pteris (Pteridaceae) spores are usually trilete and can be distinguished by the perine ornamentation. The systematic value of spore morphology in Pteris is unclear, especially based on the renewed infrageneric classification of Pteris. In the present study, we used scanning electron microscopy (SEM) to understand spore characters in 57 Pteris species, one Onychium species, and two Astrolepis species; 40 species are reported here for the first time. The observed spore characters combined with published spore data, totaling 100 species from 16 sections of Pteris, were mapped onto a reconstructed phylogenetic tree. Seven characters (five proposed in previous studies), including an equatorial flange, laesural ridges, proximal ridges, distal ridges, tubercula on distal faces, coarse reticula on distal faces, and a row of extervermiculi between the distal face and equatorial flange, were analyzed to investigate spore morphology evolution in Pteris. However, the results showed no synapomorphies with other genera in Pteridaceae. Most of the characters were found to have arisen independently several times in different lineages or were even frequently reversed. Equatorial flanges and tubercula on distal faces are plesiomorphies and present in most Pteris species. Overall, the application of spore morphology in section circumscription is limited. Thus, we suggest combining spore morphology with leaf characters for Pteris infrageneric classification.

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BACKGROUND AND AIMS: Pteris (Pteridaceae), comprising over 250 species, had been thought to be a monophyletic genus until the three monotypic genera Neurocallis, Ochropteris and Platyzoma were included. However, the relationships between the type species of the genus Pteris, P. longifolia, and other species are still unknown. Furthermore, several infrageneric morphological classifications have been proposed, but are debated. To date, no worldwide phylogenetic hypothesis has been proposed for the genus, and no comprehensive biogeographical history of Pteris, crucial to understanding its cosmopolitan distribution, has been presented. METHODS: A molecular phylogeny of Pteris is presented for 135 species, based on cpDNA rbcL and matK and using maximum parsimony, maximum likelihood and Bayesian inference approaches. The inferred phylogeny was used to assess the biogeographical history of Pteris and to reconstruct the evolution of one ecological and four morphological characters commonly used for infrageneric classifications. KEY RESULTS: The monophyly of Pteris remains uncertain, especially regarding the relationship of Pteris with Actiniopteris + Onychium and Platyzoma. Pteris comprises 11 clades supported by combinations of ecological and morphological character states, but none of the characters used in previous classifications were found to be exclusive synapomorphies. The results indicate that Pteris diversified around 47 million years ago, and when species colonized new geographical areas they generated new lineages, which are associated with morphological character transitions. CONCLUSIONS: This first phylogeny of Pteris on a global scale and including more than half of the diversity of the genus should contribute to a new, more reliable infrageneric classification of Pteris, based not only on a few morphological characters but also on ecological traits and geographical distribution. The inferred biogeographical history highlights long-distance dispersal as a major process shaping the worldwide distribution of the species. Colonization of different niches was followed by subsequent morphological diversification. Dispersal events followed by allopatric and parapatric speciation contribute to the species diversity of Pteris.

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The Pteris cadieri complex displays extensive morphological variation and seems to have originated through hybridization. However, the members of this complex reproduce by apogamy, which usually limits genetic variation. To evaluate the hypotheses of hybrid origins, the pattern of evolution in this species complex is reconstructed. Multiple methodologies were used. Diploids, triploids, and tetraploids were identified by chromosome counts and flow cytometry. Nuclear DNA markers (cytosolic phosphoglucose isomerase gene, PgiC) were used, together with chloroplast DNA markers (atpB-rbcL spacer and rbcL gene) to infer the biparental and maternal lineages of the Pteris cadieri complex. The three cpDNA haplotype groups and five PgiC alleles found in this study indicate that the evolution of the Pteris cadieri complex has been extremely reticulate. Up to 11 taxa belonging to eight morphs were identified. By comparing genetic variation in the Pteris cadieri in two independent areas, Hainan and Taiwan, we inferred that hybridization has occurred independently in different areas. Furthermore, we found evidence for phenological divergence (evergreen and deciduous) within Taiwan. We propose that the Pteris cadieri complex originated from different genetic lineages through multiple hybridizations in different geographical areas, leading to its present morphological diversity.

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The pantropical fern genus Pteris L. has about 250 species of which 60 occur in the American continent. We studied the morphogenesis of the gametophyte, and the morphology of the young sporophytes of four species: P. cretica, P. ensiformis, P. multifida and P. vittata, together with a palynological analysis that includes the ability of spores to germinate. Gametophytes were obtained trough in vitro culture techniques with agar-gellified Knudson medium. Young sporophytes were placed in earth-sand (3:1) sterile substrate. We used light and SEM microscopy. Triletes spores predominate, but monolete, tetralete, and other types of apertura are often found. The viability of spores is not affected by the variation, so the term spore polymorphism is applied to the condition occurring among these species. Spore polymorphism is similar in P. cretica and P. multifida. Germination occurs following the Vittaria type, 3-7 days after the sowing. Filamentous, 3-5 celled gametophytes were found in P. cretica, P. multifida and P. vittata, and 7-9 celled in P. ensiformis. Development of gametophytes takes place following Adiantum type and Ceratopteris type. The symmetry of the laminae differ in gametophytes, those of P. ensiformis and P. multifida are similar and differ from the other two species, P. cretica and P. vittata. Gametophytes of P. ensiformis, P. multifida and P. vittata are bisexual and protandric, while male gametophytes were found in P. cretica. Antheridia correspond to the common leptosporangiate type; they are cylindric in P. vittata and ovoid in the other three species. Archegonia necks have 4 rows of 4 cells each. The sporophytes complete their development 3 months after sowing, and have indument close to the adult plants. P. cretica shows obligated apogamy.

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Gametophytes and young sporophytes of four species of the fern genus Pteris (Pteridaceae) naturalized in the American continent. The pantropical fern genus Pteris L. has about 250 species of which 60 occur in the American continent. We studied the morphogenesis of the gametophyte, and the morphology of the young sporophytes of four species: P. cretica, P. ensiformis, P. multifida and P.vittata, together with a palynological analysis that includes the ability of spores to germinate. Gametophytes were obtained trough in vitro culture techniques with agar-gellified Knudson medium. Young sporophytes were placed in earth-sand (3:1) sterile substrate. We used light and SEM microscopy. Triletes spores predominate, but monolete, tetralete, and other types of apertura are often found. The viability of spores is not affected by the variation, so the term spore polymorphism is applied to the condition occurring among these species. Spore polymorphism is similar in P. cretica and P. multifida. Germination occurs following the Vittaria type, 3-7 days after the sowing. Filamentous, 3-5 celled gametophytes were found in P. cretica, P. multifida and P. vittata, and 7-9 celled in P. ensiformis. Development of gametophytes takes place following Adiantum type and eratopteris type. The symmetry of the laminae differ in gametophytes, those of P. ensiformis and P. multifida are similar and differ from the other two species, P. cretica and P. vittata. Gametophytes of P. ensiformis, P. multifida and P. vittata are bisexual and protandric, while male gametophytes were found in P. cretica. Antheridia correspond to the common leptosporangiate type; they are cylindric in P. vittata and ovoid in the other three species. Archegonia necks have 4 rows of 4 cells each. The sporophytes complete their development 3 months after sowing, and have indument close to the adult plants. P. cretica shows obligated apogamy. Rev. Biol. Trop. 58 (1): 89-102. Epub 2010 March 01.

El género pantropical Pteris L. tiene 250 especies de la cuales 60 están en el continente Americano. Se estudió la morfogénesis de los gametófitos, y la morfología de los esporófitos jóvenes de cuatro especies: P. cretica, P. ensiformis, P. multifida y P.vittata, junto con un análisis palinológico que incluye la capacidad de las esporas de germinar. Los gametófitos se obtuvieron mediante técnicas de cultivo in vitro. Los esporófitos jóvenes se trasladaron a sustrato estéril de tierra y arena (3:1). Se usó el microscopio de luz y el de barrido (SEM). Se encontraron esporas con diferentes tipos de aperturas. La germinación ocurre entre 3-7 días y corresponde al tipo Vittaria. Se encontraron gametófitos filamentosos formados por 3-5 células en P. cretica, P. multifida y P. vittata y por 7-9 células en P. ensiformis. El desarrollo gametofítico ocurre de dos formas: tipo Adiantum y tipo Ceratopteris. Los gametófitos de P. ensiformis, P. multifida y P. vittata son monoicos y protándricos. P. cretica desarrolla gametófitos anteridiados. Los anteridios corresponden al tipo común de los helechos leptosporangiados, son cilíndricos en P. vittata y ovoides en las otras tres especies. Los cuellos de los arquegonios tienen 4 hileras con 4 células cada una. Los esporófitos se desarrollan después de los 3 meses de su siembra y su indumento es semejante a las plantas adultas. P. cretica presenta apogamia obligada.

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To better understand the mechanisms of plant tolerance to high concentration of arsenic, we characterized two antioxidant enzymes, glutathione reductase (GR) and catalase (CAT), in the fronds of Pteris vittata, an arsenic-hyperaccumulating fern, and Pteris ensiformis, an arsenic-sensitive fern. The induction, activation and apparent kinetics of GR and CAT in the plants upon arsenic exposure were investigated. Under arsenic exposure (sodium arsenate), CAT activity in P. vittata was increased by 1.5-fold, but GR activity was unchanged. Further, GR was not inhibited or activated by the arsenic in assays. No significant differences in K(m) and V(max) values of GR or CAT were observed between the two ferns. However, CAT activity in P. vittata was activated by 200 microM arsenate up to 300% compared to the control. Similar but much smaller increases were observed for P. ensiformis and purified bovine liver catalase (133% and 120%, respectively). This research reports, for the first time, the activation of CAT by arsenic in P. vittata. The increased CAT activities may allow P. vittata to more efficiently mediate arsenic-induced stress by preparing the fern for the impeding production of reactive oxygen species resulting from arsenate reduction to arsenite in the fronds.

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A new compound, 4-caffeoyl quinic acid 5-O-methyl ether (2), together with 12 known compounds--identified as (2R,3R)-pterosin L 3-O-beta-D-glucopyrannoside (3), beta-sitosterol beta-D-glucopyranoside (4), apigenin 7-O-beta-D-glucopyranoside (5), luteolin 7-O-beta-D-glucopyranoside (6), sucrose (7), caffeic acid (8), pterosin C 3-O-beta-D-glucopyranoside (9), pteroside C (10), 4,5-dicaffeoyl quinic acid (11), pteroside A (12), wallichoside (13) and (2S)-5,7,3',5'-tetrahydroxyflavanone (14)--were isolated from Pteris multifida. The structure of the new compound was determined by means of physical, chemical and spectroscopic evidence. Compounds 5 and 6 were the main constituents of the plant, with yields of 0.19% and 0.16%, respectively. The cytotoxic activities of 2, 3, and 9-13 were evaluated against a human cell line (KB cells). Among the isolated compounds, pterosin C 3-O-beta-D-glucopyrannoside (9) and 4,5-dicaffeoylquinic acid (11) showed a significant selective cytotoxicity (IC(50) 2.35 and 5.38, respectively), while moderate activity was observed for compound 2 (IC(50) 12.3). The chemosystematics of Pteris species is also discussed.

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OBJECTIVE: To determine the content of 5F in Pteris semipinnata L. from various origins. METHODS: 5F was determined by TLC-Scanning. RESULTS: The linear relationship was in range of 0. 504 - 2. 520 microg. The mean recovery was 96. 68% and RSD = 1.24% (n = 5). CONCLUSION: The method is available with a good reproducibility, and pretreatment is simple and easy to operate.

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The new fern species Pteris herrerae A. Rojas & M. Palacios, endemic to Costa Rica, is described. It differs from P. decurrens C. Presl in basal segments reduced to 1/5-1/2 of the next segment (vs. 2/3-3/4), basal pinnae not bifurcated (vs. bifurcated), pinnae apex mucronate (vs. acuminate) and segment apex undulate (vs. dentate). It differs from Pteris consanguinea in the elliptic pinnae (vs. oblong), two segments reduced on the base (vs. lack), segments entire to undulate (vs. dentate), basal pinnae without basiscopic lobes (vs. with basiscopic lobes) and segment apex entire to undulate (vs. dentate).

Se describe Pteris herrerae A. Rojas & M. Palacios, endémica de Costa Rica. Esta es diferente de P. decurrens C. Presl por segmentos basales reducidos a 1/5-1/2 del tamaño de los siguientes (vs. 2/3-3/4), pinnas basales no bifurcadas (vs. bifurcadas), ápice de las pinnas mucronado (vs. acuminado) y ápice de los segmentos ondulado (vs. dentado). También es diferente de Pteris consanguinea Mett. ex Kuhn por pinnas deltado-lanceoladas (vs. oblongas), con un par de segmentos reducidos en la base (vs. sin ellos), pinnas basales sin lóbulos basicópicos alargados (vs. con lóbulos basiscópicos) y segmentos enteros a ondulados (vs. dentados).

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The new fern species Pteris herrerae A. Rojas & M. Palacios, endemic to Costa Rica, is described. It differs from P. decurrens C. Presl in basal segments reduced to 1/5-1/2 of the next segment (vs. 2/3-3/4), basal pinnae not bifurcated (vs. bifurcated), pinnae apex mucronate (vs. acuminate) and segment apex undulate (vs. dentate). It differs from Pteris consanguinea in the elliptic pinnae (vs. oblong), two segments reduced on the base (vs. lack), segments entire to undulate (vs. dentate), basal pinnae without basiscopic lobes (vs. with basiscopic lobes) and segment apex entire to undulate (vs. dentate).

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To identify and compare the main peaks of HPLC-APCI-MS FP of the diterpenoids in Pteris semipinnata collected from different region and time, a quadrupole mass spectrometer coupled with atmospheric pressure chemical ionization interface was employed as a detector for HPLC to establish total ion chromatography. HPLC retention time and MS spectrum were used to identify comprehensively. 4F, 5F and 6F were identified from the chromatography comparing with their standards. The saturated state of 6F and glycoside of 4F and 5F were inferred. The content of 5F in samples collected from region of Guangzhou or in Nov. and Dec. were comparatively higher. This method is highly effective and fast,which can be applied to research and develop for diterpenoids in Pteris semipinnata L as new antitumor drug resource.

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