A remarkable new species of Liparis (Orchidaceae) from China and its phylogenetic implications.

 0  7  6  2017-02-01 15:19:57 Report infringing document
A Remarkable New Species of Liparis (Orchidaceae) from China and Its Phylogenetic Implications Lin Li, Haifei Yan* Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China Abstract In the present study, we formally describe Liparis pingxiangensis as a new species from Guangxi, China on the basis of morphological and molecular phylogenetic analyses. It is easily distinguished from closely related species by strongly curved column without column wings, and broadly rhombic-elliptic lip with 2 uncinate calli at the base. In particular, it differs most markedly from its congeners in possessing two pollinia attached by long and prominent caudicles (not stipes), to a distinct sticky disc. This type of pollinarium, as far as we know, is not found in any other species of Liparis, and is also unique among the orchids with waxy pollinia. We then proceeded to a phylogenetic analysis to ascertain the systematic position of this enigmatic species. Molecular study based on nuclear ribosomal ITS and plastid matK DNA sequence data supports L. pingxiangensis as a distinct species, which forms an independent lineage sister to L. nervosa and its allies (93% BS, 1.00 BPP). In the light of previous work, the findings have important implications for a better understanding of the wellsupported pattern mainly based on vegetative features in Malaxideae. Citation: Li L, Yan H (2013) A Remarkable New Species of Liparis (Orchidaceae) from China and Its Phylogenetic Implications. PLoS ONE 8(11): e78112. doi:10.1371/journal.pone.0078112 Editor: Simon Joly, Montreal Botanical Garden, Canada Received June 20, 2013; Accepted August 26, 2013; Published November 13, 2013 Copyright: ß 2013 Li, Yan. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: This study was financially supported by the National Natural Science Foundation of China (31100149) and Doctoral Fund for Scientific Research of South China Botanical Garden, CAS (201007). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: The authors have declared that no competing interests exist. * E-mail: yanhaifei@scbg.ac.cn Introduction As currently understood, the genus Liparis Rich. in the tribe Malaxideae (Epidendroideae, Orchidaceae) [1] is relatively large and cosmopolitan, consisting of approximately 350 species, with the majority occurring in tropical and subtropical regions, with some representatives extending to the temperate regions [2,3,4]. Liparis species are terrestrial, epiphytic or rarely lithophytic. Generally, it is readily characterized by floral morphology, such as resupinate flowers which usually have narrow linear petals; 2parted lip (forming the hypochile and the epichile), most common bearing a basal bilobed callus; elongate, slender, curved, and slightly winged column lacking a foot [3,4,5]. A previous molecular phylogenetic study indicated that Liparis in the traditional broad sense is polyphyletic [6]. The taxonomy of the genus is complicated and controversial. In spite of clear and distinct differences, Liparis has been divided differently by different authors in the past [7,8,9,10,11]. Some clades are well resolved and can be diagnosed morphologically, others less so, requiring more data to see clear evidence of interrelationships among the tribe [1]. Before the establishment of the robust classification schemes, the traditional recognition of Liparis s.lato is employed in this paper. In China, the genus Liparis is represented by approximately 63 species (20 endemic) [12]. During a recent field trip to Guangxi, China, a terrestrial species was collected by one of the authors. At first glance the plants appeared to resemble the ordinary Liparis species, but a closer study revealed that its most striking feature was the pollinarium structure, which we had never seen before. This unusual specimen has two specialized waxy pollinia, with two long and prominent caudicles, attached to a terminal viscidium. Another unusual character is its column, which is strongly curved without column wings. Molecular phylogenetic study using nuclear ribosomal ITS and plastid matK sequences was initiated to ascertain its systematic position. Our thorough morphological comparison and phylogenetic analysis indicated that it represents an unknown species, which is described and illustrated here for the first time. Materials and Methods Ethics statement The collecting location reported in this work is not protected in any way. The species collected here are currently not included in the Chinese Red Data Book. No specific permits are required for the present study. Nomenclature The electronic version of this article in Portable Document Format (PDF) in a work with an ISSN or ISBN will represent a published work according to the International Code of Nomenclature for algae, fungi, and plants, and hence the new names contained in the electronic publication of a PLOS ONE article are effectively published under that Code from the electronic edition alone, so there is no longer any need to provide printed copies. In addition, new names contained in this work have been submitted to IPNI, from where they will be made available to the Global Names Index. The IPNI LSIDs can be resolved and the PLOS ONE | www.plosone.org 1 November 2013 | Volume 8 | Issue 11 | e78112 A New Orchid Species from China associated information viewed through any standard web browser by appending the LSID contained in this publication to the prefix http://ipni.org/. The online version of this work is archived and available from the following digital repositories: PubMed Central, LOCKSS. Morphological observations Morphological description of the new species was based on examination of fresh and pressed specimens. Details of the flowers, particularly the gynostemium and pollinarium were examined and photographed under a stereomicroscope (Olympus MD-90). The morphological comparison with other species of Malaxideae was based on study of live plants in the field and in cultivation, herbarium specimens, and information gathered in the literature searches. The specimens examined have been deposited in the herbarium of South China Botanical Garden, Chinese Academy of Sciences (IBSC). Taxon sampling We downloaded 74 sequences for 54 species from GenBank. In addition, we sequenced four species including three samples of the new taxon for this work. The ingroup included a total of 80 sequences of 58 species, representing all of the major clades in the tribe Malaxideae sensu Pridgeon et al. [1]. Three representative species of Acanthephippium Bl. ex Endl., Collabium Bl., and Eria Lindl. were selected as outgroups following previous phylogenetic studies [13]. GenBank accession numbers for all the DNA sequences and voucher information are given in Table S1. Molecular markers We analyzed the nucleotide sequences of the nuclear ribosomal internal transcribed spacers (nrITS), as well as the plastid matK, which have demonstrated their utility for inferring phylogenetic relationships at various taxonomic levels among the Malaxideae and other members in Orchidaceae [6,14,15,16,17]. Extraction, amplification and sequencing of genomic DNA were carried out from fresh leaf tissue using the modified 26 CTAB method after leaf tissue was ground in liquid nitrogen [18]. The nrITS region (ITS1-5.8S-ITS2) was amplified via a polymerase chain reaction (PCR) with the primers 17SE and 26SE of Sun et al. [19]. The matK gene region was amplified and sequenced using the primers as described by Whitten et al. [20] and Cameron [6]. Sequence alignment and phylogenetic analysis DNA sequences were initially aligned with the computer program CLUSTAL X version 1.83 [21] with minor subsequent manual adjustment using the software Se-Al verion 2.0a11 [22]. To evaluate congruence between different DNA regions, we analyzed each dataset (nrITS and matK) separately to see if they produced a similar topology. We also conducted the incongruence length difference (ILD) test [23] with 500 replicates of the heuristic search in PAUP* verion 4.0b10 [24]. The 1% level of significance was chosen as described in [25]. The ILD value in this study was 0.23, suggesting congruence between the two regions. We therefore analyzed these two datasets in combination. Separate and combined phylogenetic analyses were carried out using maximum parsimony (MP) and Bayesian inference (BI) as implemented in PAUP* [24] and MrBayes verion 3.1.2 [26], respectively. MP analyses were performed using heuristic searches with 1,000 replicates of random taxon addition, and tree rearrangements using tree bisection-reconnection (TBR) branch swapping, and MULTREES option in effect, and simple addition and ACCTRAN optimization. All characters were treated as unordered and had equal weights, gaps considered as missing data. Internal support for clades was assessed by non-parametric bootstrapping (BS) with 1,000 bootstrap replicates [27]. The best-fitting model of sequence evolution in Bayesian analyses was chosen for each marker using ModelTest 3.7 [28]. The Akaike information criterion was implemented. Evolutionary models that best fitted the ITS and matK were GTR+I+G and TVM+I+G, respectively. BI analyses settings were: the Markov chain Monte Carlo (MCMC) algorithm was run for 2 million generations, and sampled every 200 generations. A conservative burn-in (25%) was applied after checking for stability on the loglikelihood curves and split variances being ,0.01. A majority rule consensus tree was calculated from the remaining samples. Branch support was determined by Bayesian Posterior Probabilities (BPP). Results Phylogenetic analysis The length of aligned matrix of nrITS was 970 bp, of which 516 (53%) were variable and 410 (42%) were parsimony-informative. The aligned matK matrix consisted of 1470 characters, of which 409 (28%) were variable and 266 (18%) were parsimonyinformative. There was no significant difference in topographies between nrITS and matK (see Figure S1). For the combined data, the heuristic search found 1932 MPTs with a length of 2280 steps, consistency index (excluding uninformative characters) = 0.53 and retention index = 0.89. The topologies from the MP and Bayesian analyses were congruent. The strict consensus tree based on combined data (with BS and BPP) is shown in Figure 1. Taxonomic treatment Liparis pingxiangensis. L. Li & H. F. Yan, sp. nov. [urn:lsid:ipni.org: names: 77131431-1] (Figs. 2, 3A–D, G). Type: — CHINA. Guangxi: Pingxiang, mixed deciduous forests, terrestrial in moist and shady grassy slopes, rare, collected 23 June 2011, flowered and pressed from plant cultivated in an experimental greenhouse of SCBG, 2 Apr 2012, L. Li 151 (HOLOTYPE: IBSC). Species affinis L. nervosae (Thunb.) Lindl., a qua labiis late rhombico-ellipticus, callis uncinnatis praeditis, columnis arcuatis sine alis, polliniis duobus caudiculis longis affixis cum viscidio magno recedit. Terrestrial herb, up to 20 cm in height. Pseudobulbs cylindric, tapering, enveloped by 3–4 clasping basal foliaceous sheaths that fall away and bares the bulbs before the new growth arises; old leafless pseudobulbs usually covered with several membranous sheaths at internodes, 8–10 cm long, 2.5–3 cm in diameter. Leaves 3–4, basal, amplexicaul, blade elliptic-lanceolate to ovate-elliptic, plicate, membranous or herbaceous, base slightly oblique and contracted into petioles, margin wavy or undulating, apex acute, 14–16 cm long, 5–8 cm wide; petiole sheathlike, 3– 5 cm long, not articulate. Inflorescence terminal, racemose, 24– 33 cm long; peduncle ridged, ebracteate; rachis 16–20 cm with many well-spaced flowers. Floral bracts ovate-triangular, carinate on the abaxial surface, dark purple, 3–3.5 mm long. Ovary ridged and grooved, greenish brown, 1.0–1.3 cm long. Flowers resupinate, spreading, 1.2–1.3 cm across, yellowish-green with dull purple markings, column greenish-yellow. Dorsal sepal broadly linear-oblong, 3-veined, 8–8.5 mm long, 1.3–1.5 mm wide, obtuse at apex, often recurved or reflexed, margins revolute, dull purple; lateral sepals broader than the dorsal sepal, ovate-elliptic, slightly oblique, 6–7 mm long, 2–2.5 mm wide, 5-veined, obtuse at apex, recurved or reflexed, upside dull purple, lower side greenish yellow. Petals linear, more or less falcate, 7.5–8 mm long, 0.7– PLOS ONE | www.plosone.org 2 November 2013 | Volume 8 | Issue 11 | e78112 A New Orchid Species from China PLOS ONE | www.plosone.org 3 November 2013 | Volume 8 | Issue 11 | e78112 A New Orchid Species from China Figure 1. Phylogenetic tree. Strict consensus tree of the 1932 most parsimonious trees obtained from sequences of the combined nrITS and plastid matK DNA sequence data (2280 steps, CI = 0.53, RI = 0.89), showing the position of Liparis pingxiangensis. Parsimony bootstrap proportions higher than 50% and Bayesian posterior probabilities (BPP) more than 0.95 are shown above and below branches, respectively. doi:10.1371/journal.pone.0078112.g001 0.9 mm wide, 1-veined, margins revolute, brownish purple, tinged with greenish yellow. Lip entire, broadly rhomboid-elliptic, slightly fleshy, concave in the middle, base abruptly contracted, with a pair of subulate, somewhat uncinate calli, curved downward or reflexed back near the middle, apex emarginate, margin slightly erose, greenish yellow, with conspicuous dark brownish blotch on each side, 4.0–4.2 long, 4.5–5.6 mm wide. Column elongated, strongly incurved or arcuate near apex, 5–5.8 mm long, column wings absent. Stigma transverse, concave, subquadrate. Rostellum protruding, approximately triangular, apex obtuse, whitish. Anther terminal, 2-celled, persistent, oblong-ovoid, ca. 1.0 mm long. Pollinarium ca. 1.0 mm long, formed by 2 pollinia, more or less, but not completely cleft, elongate-obovoid, bilaterally flattened, somewhat club-shaped, hard, waxy, darker yellow or orange, provided with two distinctly long caudicles, ca. 0.3 mm long, hyaline, with light yellow tinges, attached to the rostellum by a terminal, rounded viscidium, white to transparent, thick. Distribution, habitat and ecology. Liparis pingxiangensis is terrestrial, forming more or less scattered colonies on shady and damp areas with small ravines, in wet to most soils and humus, on Figure 2. Liparis pingxiangensis. A. habit, B. flower, frontal view, C. flower, lateral view, D. bract, E. dorsal sepal, F. petal, G. lateral sepal, H. lip, I. column, lateral view, J. column without anther cap, ventral view, K. anther cap, L. pollinarium. Drawn by Yun-Xiao Liu. doi:10.1371/journal.pone.0078112.g002 PLOS ONE | www.plosone.org 4 November 2013 | Volume 8 | Issue 11 | e78112 A New Orchid Species from China Figure 3. Morphology of Liparis pingxiangensis (A–D, G) and allied species L. nervosa (E–F). A. inflorescence, B. flower, front view, C. flower, lateral view, D. gynostemium including anther, clinandrium and viscidium attached to apex of rostellum, lateral view, E. two pairs of close pollinia, F. two pairs of separate pollinia, G. pollinarium including pollinia, caudicles and viscidium. Scale bars, 3 mm (B–C); 1 mm (D); 0.3 mm (E–G). doi:10.1371/journal.pone.0078112.g003 the steeper slopes, at elevations of around 800 m in the mixed deciduous forest of southwest China’s Guangxi Zhuang Autonomous Region. Flowering occurs in early spring, from early until late April. Up to now, it has not been observed in fruits. Conservation status. A rare species occurs in a rather small population (no more than 10 individuals). As far as we can currently observe, it is known only from the type collection and a neighboring population. The forest has been experiencing a continuing decline in quality of habitat due to deforestations. Using the World Conservation Union Red List Categories and Criteria [29], L. pingxiangensis should be treated as critically endangered due to its rarity and the threat of disturbance. More studies at the two nearby localities may shed light on this enigmatic species. Etymology. The species is named after the site of its first discovery, Pingxiang, Guangxi province, China. Species recognition. Liparis pingxiangensis is very distinctive among species in the genus. It is the only species with two pollinia, through distinctly long and prominent caudicles, attached to a thick viscidium (Figs. 2-L, 3-G). As we all know, this pollinarium type has not been discovered in any other group of orchids. It is morphologically similar to L. nervosa (Thunb.) Lindl., a widespread terrestrial species with plicate leaves, but it can be easily distinguished from the latter by having strongly curved column without column wings, broadly rhombic-elliptic lip with 2 uncinate calli at the base. Two pollinia are also found in L. fissipetala Finet, but this is an epiphytic plant with ovoid pseudobulbs, strongly crisped-margined leaves, deeply bilobed or Y-shaped petals, and two pollinia with much shorter caudicles, without a true viscidium [30]. Our molecular results based on nrITS and matK DNA sequence data support L. pingxiangensis as a distinct species. It clearly and precisely indicates that the individuals of L. pingxiangensis form a monophyletic clade (100% BS, 1.00 BPP), being strongly supported as sister to L. nervosa and its allies (93% BS, 1.00 BPP). Discussion Orchids are well known for specialized floral morphology. Most orchids (Orchidoideae and Epidendroideae) develop pollinia, which are often accompanied by appendages, known as pollinaria [31,32]. The morphological features of pollinaria are equilibrium value of MeCpG steps (,+14 deg.) [31,44]. In comparison, methylation has a significantly lower stability cost when happening at major groove positions, such as 211 and 21 base pair from dyad (mutations 9 and 12), where the roll of the nucleosome bound conformation (+10 deg.) is more compatible with the equilibrium geometry of MeCpG steps. The nucleosome destabilizing effect of cytosine methylation increases with the number of methylated cytosines, following the same position dependence as the single methylations. The multiple-methylation case reveals that each major groove meth- PLOS Computational Biology | www.ploscompbiol.org 3 November 2013 | Volume 9 | Issue 11 | e1003354 DNA Methylation and Nucleosome Positioning ylation destabilizes the nucleosome by around 1 kJ/mol (close to the average estimate of 2 kJ/mol obtained for from individual methylation studies), while each minor groove methylation destabilizes it by up to 5 kJ/mol (average free energy as single mutation is around 6 kJ/mol). This energetic position-dependence is the reverse of what was observed in a recent FRET/SAXS study [30]. The differences can be attributed to the use of different ionic conditions and different sequences: a modified Widom-601 sequence of 157 bp, which already contains multiple CpG steps in mixed orientations, and which could assume different positioning due to the introduction of new CpG steps and by effect of the methylation. The analysis of our trajectories reveals a larger root mean square deviation (RMSD) and fluctuation (RMSF; see Figures S2– S3 in Text S1) for the methylated nucleosomes, but failed to detect any systematic change in DNA geometry or in intermolecular DNA-histone energy related to methylation (Fig. S1B, S1C, S4–S6 in Text S1). The hydrophobic effect should favor orientation of the methyl group out from the solvent but this effect alone is not likely to justify the positional dependent stability changes in Figure 2, as the differential solvation of the methyl groups in the bound and unbound states is only in the order of a fraction of a water molecule (Figure S5 in Text S1). We find however, a reasonable correlation between methylation-induced changes in hydrogen bond and stacking interactions of the bases and the change in nucleosome stability (see Figure S6 in Text S1). This finding suggests that methylation-induced nucleosome destabilization is related to the poorer ability of methylated DNA to fit into the required conformation for DNA in a nucleosome. Changes in the elastic deformation energy between methylated and un-methylated DNA correlate with nucleosomal differential binding free energies To further analyze the idea that methylation-induced nucleosome destabilization is connected to a worse fit of methylated DNA into the required nucleosome-bound conformation, we computed the elastic energy of the nucleosomal DNA using a harmonic deformation method [36,37,44]. This method provides a rough estimate of the energy required to deform a DNA fiber to adopt the super helical conformation in the nucleosome (full details in Suppl. Information Text S1). As shown in Figure 2, there is an evident correlation between the increase that methylation produces in the elastic deformation energy (DDE def.) and the free energy variation (DDG bind.) computed from MD/TI calculations. Clearly, methylation increases the stiffness of the CpG step [31], raising the energy cost required to wrap DNA around the histone octamers. This extra energy cost will be smaller in regions of high positive roll (naked DNA MeCpG steps have a higher roll than CpG steps [31]) than in regions of high negative roll. Thus, simple elastic considerations explain why methylation is better tolerated when the DNA faces the histones through the major groove (where positive roll is required) that when it faces histones through the minor groove (where negative roll is required). Nucleosome methylation can give rise to nucleosome repositioning We have established that methylation affects the wrapping of DNA in nucleosomes, but how does this translate into chromatin structure? As noted above, accumulation of minor groove methylations strongly destabilizes the nucleosome, and could trigger nucleosome unfolding, or notable changes in positioning or phasing of DNA around the histone core. While accumulation of methylations might be well tolerated if placed in favorable positions, accumulation in unfavorable positions would destabilize the nucleosome, which might trigger changes in chromatin structure. Chromatin could in fact react in two different ways in response to significant levels of methylation in unfavorable positions: i) the DNA could either detach from the histone core, leading to nucleosome eviction or nucleosome repositioning, or ii) the DNA could rotate around the histone core, changing its phase to place MeCpG steps in favorable positions. Both effects are anticipated to alter DNA accessibility and impact gene expression regulation. The sub-microsecond time scale of our MD trajectories of methylated DNAs bound to nucleosomes is not large enough to capture these effects, but clear trends are visible in cases of multiple mutations occurring in unfavorable positions, where unmethylated and methylated DNA sequences are out of phase by around 28 degrees (Figure S7 in Text S1). Due to this repositioning, large or small, DNA could move and the nucleosome structure could assume a more compact and distorted conformation, as detected by Lee and Lee [29], or a slightly open conformation as found in Jimenez-Useche et al. [30]. Using the harmonic deformation method, we additionally predicted the change in stability induced by cytosine methylation for millions of different nucleosomal DNA sequences. Consistently with our calculations, we used two extreme scenarios to prepare our DNA sequences (see Fig. 3): i) all positions where the minor grooves contact the histone core are occupied by CpG steps, and ii) all positions where the major grooves contact the histone core are occupied by CpG steps. We then computed the elastic energy required to wrap the DNA around the histone proteins in unmethylated and methylated states, and, as expected, observed that methylation disfavors DNA wrapping (Figure 3A). We have rescaled the elastic energy differences with a factor of 0.23 to match the DDG prediction in figure 2B. In agreement with the rest of our results, our analysis confirms that the effect of methylation is position-dependent. In fact, the overall difference between the two extreme methylation scenarios (all-in-minor vs all-in-major) is larger than 60 kJ/mol, the average difference being around 15 kJ/ mol. We have also computed the elastic energy differences for a million sequences with CpG/MeCpG steps positioned at all possible intermediate locations with respect to the position (figure 3B). The large differences between the extreme cases can induce rotations of DNA around the histone core, shifting its phase to allow the placement of the methylated CpG steps facing the histones through the major groove. It is illustrative to compare the magnitude of CpG methylation penalty with sequence dependent differences. Since there are roughly 1.5e88 possible 147 base pairs long sequence combinations (i.e., (4n+4(n/2))/2, n = 147), it is unfeasible to calculate all the possible sequence effects. However, using our elastic model we can provide a range of values based on a reasonably large number of samples. If we consider all possible nucleosomal sequences in the yeast genome (around 12 Mbp), the energy difference between the best and the worst sequence that could form a nucleosome is 0.7 kj/mol per base (a minimum of 1 kJ/mol and maximum of around 1.7 kJ/mol per base, the first best and the last worst sequences are displayed in Table S3 in Text S1). We repeated the same calculation for one million random sequences and we obtained equivalent results. Placing one CpG step every helical turn gives an average energetic difference between minor groove and major groove methylation of 15 kJ/ mol, which translates into ,0.5 kJ/mol per methyl group, 2 kJ/ mol per base for the largest effects. Considering that not all nucleosome base pair steps are likely to be CpG steps, we can conclude that the balance between the destabilization due to CpG methylation and sequence repositioning will depend on the PLOS Computational Biology | www.ploscompbiol.org 4 November 2013 | Volume 9 | Issue 11 | e1003354 DNA Methylation and Nucleosome Positioning Figure 3. Methylated and non-methylated DNA elastic deformation energies. (A) Distribution of deformation energies for 147 bplong random DNA sequences with CpG steps positioned every 10 base steps (one helical turn) in minor (red and dark red) and major (light and dark blue) grooves respectively. The energy values were rescaled by the slope of a best-fit straight line of figure 2, which is 0.23, to por la lectura a través de la lectura de la prensa. La educación en los medios las fuerzas dispersas en función de los soportes mediáticos y orientarse más hacia la educación en medios que al dominio adquiere pleno derecho y entidad en la sección sexta titulada «competencias sociales y cívi- técnico de los aparatos. cas» que indica que «los alum- nos deberán ser capaces de juz- gar y tendrán espíritu crítico, lo que supone ser educados en los las programaciones oficiales, ya que, a lo largo de un medios y tener conciencia de su lugar y de su influencia estudio de los textos, los documentalistas del CLEMI en la sociedad». han podido señalar más de una centena de referencias a la educación de los medios en el seno de disciplinas 4. Un entorno positivo como el francés, la historia, la geografía, las lenguas, Si nos atenemos a las cifras, el panorama de la las artes plásticas : trabajos sobre las portadas de educación en medios es muy positivo. Una gran ope- prensa, reflexiones sobre temas mediáticos, análisis de ración de visibilidad como la «Semana de la prensa y publicidad, análisis de imágenes desde todos los ángu- de los medios en la escuela», coordinada por el CLE- los, reflexión sobre las noticias en los países europeos, MI, confirma año tras año, después de 17 convocato- información y opinión rias, el atractivo que ejerce sobre los profesores y los Esta presencia se constata desde la escuela mater- alumnos. Concebida como una gran operación de nal (2 a 6 años) donde, por ejemplo, se le pregunta a complementariedad entre la escuela y los profesiona- los niños más pequeños si saben diferenciar entre un les de los medios, alrededor del aprendizaje ciudada- periódico, un libro, un catálogo, a través de activida- no de la comunicación mediática, este evento moviliza des sensoriales, si saben para qué sirve un cartel, un durante toda una semana un porcentaje elevado de periódico, un cuaderno, un ordenador si son capa- centros escolares que representan un potencial de 4,3 ces de reconocer y distinguir imágenes de origen y de millones de alumnos (cifras de 2006). Basada en el naturaleza distintas. Podríamos continuar con más voluntariado, la semana permite desarrollar activida- ejemplos en todos los niveles de enseñanza y práctica- des más o menos ambiciosas centradas en la introduc- Páginas 43-48 ción de los medios en la vida de la escuela a través de la instalación de kioscos, organización de debates con profesionales y la confección por parte de los alumnos de documentos difundidos en los medios profesionales. Es la ocasión de dar un empujón a la educación en medios y de disfrutarlos. Los medios –un millar en 2006– se asocian de maneras diversas ofreciendo ejemplares de periódicos, acceso a noticias o a imágenes, proponiendo encuentros, permitiendo intervenir a los jóvenes en sus ondas o en sus columnas Esta operación da luz al trabajo de la educación en medios y moviliza a los diferentes participantes en el proyecto. 5. La formación de los docentes La formación es uno de los pilares principales de la educación en los medios. Su función es indispensable ya que no se trata de una disciplina, sino de una enseñanza que se hace sobre la base del voluntariado y del compromiso personal. Se trata de convencer, de mostrar, de interactuar. En primer lugar es necesario incluirla en la formación continua de los docentes, cuyo volumen se ha incrementado desde 1981 con la aparición de una verdadera política de formación continua de personal. Es difícil dar una imagen completa del volumen y del público, pero si nos atenemos a las cifras del CLEMI, hay más de 24.000 profesores que han asistido y se han involucrado durante 2004-05. 5.1. La formación continua En la mayoría de los casos, los profesores reciben su formación en contextos cercanos a su centro de trabajo, o incluso en este mismo. Después de una política centrada en la oferta que hacían los formadores, se valora más positivamente la demanda por parte del profesorado, ya que sólo así será verdaderamente fructífera. Los cursos de formación se repartieron en varias categorías: desde los formatos más tradicionales (cursos, debates, animaciones), hasta actividades de asesoramiento y de acompañamiento, y por supuesto los coloquios que permiten un trabajo en profundidad ya que van acompañados de expertos investigadores y profesionales. Citemos, por ejemplo en 2005, los coloquios del CLEMI-Toulouse sobre el cine documental o el del CLEMI-Dijon sobre «Políticos y medios: ¿connivencia?». Estos coloquios, que forman parte de un trabajo pedagógico regular, reagrupan a los diferentes participantes regionales y nacionales alrededor de grandes temas de la educación en medios y permiten generar nuevos conocimientos de aproximación y una profundización. Páginas 43-48 Hay otro tipo de formación original que se viene desarrollando desde hace menos tiempo, a través de cursos profesionales, como por ejemplo, en el Festival Internacional de Foto-periodismo «Visa para la imagen», en Perpignan. La formación se consolida en el curso, da acceso a las exposiciones, a las conferencias de profesionales y a los grandes debates, pero añade además propuestas pedagógicas y reflexiones didácticas destinadas a los docentes. Estas nuevas modalidades de formación son también consecuencia del agotamiento de la formación tradicional en las regiones. Los contenidos más frecuentes en formación continua conciernen tanto a los temas más clásicos como a los cambios que se están llevando a cabo en las prácticas mediáticas. Así encontramos distintas tendencias para 2004-05: La imagen desde el ángulo de la producción de imágenes animadas, el análisis de la imagen de la información o las imágenes del J.T. La prensa escrita y el periódico escolar. Internet y la información en línea. Medios y educación de los medios. 5.2 La formación inicial La formación inicial está aun en un grado muy ini- cial. El hecho de que la educación en medios no sea una disciplina impide su presencia en los IUFM (Institutos Universitarios de Formación de Maestros) que dan una prioridad absoluta a la didáctica de las disciplinas. En 2003, alrededor de 1.400 cursillistas sobre un total de 30.000 participaron en un momento u otro de un módulo de educación en medios. Estos módulos se ofrecen en función del interés que ese formador encuentra puntualmente y forman parte a menudo de varias disciplinas: documentación, letras, historia-geografía Estamos aún lejos de una política concertada en este dominio. La optativa «Cine-audiovisual» ha entrado desde hace muy poco tiempo en algunos IUFM destinada a obtener un certificado de enseñanza de la opción audiovisual y cine. Internet tiene cabida también en los cursos de formación inicial, recientemente con la aparición de un certificado informático y de Internet para los docentes, dirigido más a constatar competencias personales que a valorar una aptitud para enseñarlos. 6. ¿Y el futuro? El problema del futuro se plantea una vez más por la irrupción de nuevas técnicas y nuevos soportes. La difusión acelerada de lo digital replantea hoy muchas cuestiones relativas a prácticas mediáticas. Muchos Comunicar, 28, 2007 47 Comunicar, 28, 2007 Enrique Martínez-Salanova '2007 para Comunicar 48 trabajos que llevan el rótulo de la educación en medios solicitan una revisión ya que los conceptos cambian. La metodología elaborada en el marco de la educación en medios parece incluso permitir la inclinación de la sociedad de la información hacia una sociedad del conocimiento, como defiende la UNESCO. En Francia, se necesitaría unir las fuerzas dispersas en función de los soportes mediáticos y orientarse más hacia la educación en medios que al dominio técnico de los aparatos. Los avances recientes en el reconocimiento de estos contenidos y las competencias que supondrían podrían permitirlo. Referencias CLEMI/ACADEMIE DE BORDEAUX (Ed.) (2003): Parcours médias au collège: approches disciplinaires et transdisciplinaires. Aquitaine, Sceren-CRDP. GONNET, J. (2001): Education aux médias. Les controverses fécondes. Paris, Hachette Education/CNDP. SAVINO, J.; MARMIESSE, C. et BENSA, F. (2005): L’éducation aux médias de la maternelle au lycée. Direction de l’Enseignement Scolaire. Paris, Ministère de l’Education Nationale, Sceren/CNDP, Témoigner. BEVORT, E. et FREMONT, P. (2001): Médias, violence et education. Paris, CNDP, Actes et rapports pour l’éducation. – www.clemi.org: fiches pédagogiques, rapports et liens avec les pages régionales/académiques. – www.ac-nancy-metz.fr/cinemav/quai.html: Le site «Quai des images» est dédié à l’enseignement du cinéma et de l’audiovisuel. – www.france5.fr/education: la rubrique «Côté profs» a une entrée «education aux médias». – www.educaunet.org: Programme européen d’éducation aux risques liés à Internet. dResedfeleexliobnuetsacón Páginas 43-48
123dok avatar

Ingressou : 2016-12-29

Documento similar

A remarkable new species of Liparis (Orchidac..