:: M.-A. SELOSSE Letters to the twenty-first century botanist: “What is a flower?” (3) The flower as an evolutionary arms race: was Linnaeus’s choice misleading? Paru dans Botany Letters, 2016, 163 (3), pp. 231-235. Anglais :: A. P. SUKHORUKOV & M. V. NILOVA A new species of Arthrocnemum (Salicornioideae: Chenopodiaceae-Amaranthaceae) from West Africa, with a revised characterization of the genus Paru dans Botany Letters, 2016, 163 (3), pp. 237-250. Anglais Abstract A new species Arthrocnemum franzii Sukhor. is described from the Republic of Cape Verde (Sal, Maio and Boa Vista islands). The species is recognized as distinct from Arthrocnemum macrostachyum (Moric.) K.Koch based on differences in the perianth shape, length of the anthers and style, and seed-coat ornamentation. No seed heteromorphism is observed within individuals of either species, despite differences in the size of the central and lateral flowers within each cyme (heteroanthocarpy). The North American Arthrocnemum subterminale (Parish) Standl. (syn. Salicornia subterminalis Parish) is morphologically distant from Eurasian Arthrocnemum or Salicornia/Sarcocornia group and should be excluded from these genera. The genus Arthrocnemum now comprises only two species (A. macrostachyum and A. franzii), distributed in the Mediterranean area, Macaronesia, West Tropical Africa and the Saharo-Arabian region. A generic description is here elaborated, clearly delimiting Arthrocnemum from morphologically similar species of Sarcocornia. A list of current species previously considered as Arthrocnemum is provided. It is argued that the taxonomic status of Salicornia mucronata Lag. (1817), mentioned in some references as a synonym of Salicornia macrostachya Moric. (1820) [≡Arthrocnemum macrostachyum (Moric.) K.Koch], is indeed a new synonym of Anabasis articulata (Forssk.) Moq. (subf. Salsoloideae). Both names merged with Arthrocnemum macrostachyum – Salicornia virginica Forssk. and Arthrocnemum glaucum (Delile) Ung.-Sternb. var. fasciculatum Sennen were lectotypified. The typification of the genus Arthrocnemum has so far been lacking and requires a special proposal with a conserved type.
:: O. KAYGUSUZ, K. GEZER & M. ŞEKER Four new records of Pluteus Fr. from interesting habitats in the Aegean region of Turkey Paru dans Botany Letters, 2016, 163 (3), pp. 251-259. Anglais Abstract Pluteus hispidulus, Pluteus kovalenkoi, Pluteus semibulbosus and Pluteus shikae of the family Pluteaceae (Basidiomycota: Agaricales) collected in the Aegean region of Turkey are new records for the Turkish mycota. In addition, this is the first report of these taxa growing in the forests under domination of Laurus nobilis and the relict endemic Liquidambar orientalis. Photographs, drawings, detailed descriptions and information about locality and habitat of the taxa are given.
:: A. DANIN, F. BULDRINI, M. BANDINI MAZZANTI, G. BOSI, M. CARMELA CARIA, D. DANDRIA, E. LANFRANCO, S. MIFSUD & S. BAGELLA Diversification of Portulaca oleracea L. complex in the Italian peninsula and adjacent islands Paru dans Botany Letters, 2016, 163 (3), pp. 261-272. Anglais Abstract There is an increasing interest in the taxonomy and distribution of the forms of the Portulaca oleracea complex. The information accruing from specimens collected in the Italian peninsula and surrounding islands (Sicily, Sardinia, Corsica and Malta) is here described. Eleven morphotypes were recorded: ‘P. cypria’, ‘P. granulatostellulata’, ‘P. nitida’, ‘P. oleracea’, ‘P. papillatostellulata’, ‘P. rausii’, ‘P. sardoa’, ‘P. sativa’, ‘P. sicula’, ‘P. trituberculata’, ‘P. zaffranii’ and a still unclear form Portulaca oleracea f. Three occur in almost all the Italian peninsula and adjacent islands; three are scattered in the Italian peninsula and in the adjacent islands; the remnant have a distribution restricted to the islands such as Sicily and Sardinia. The morphotypes can be divided into two main categories: seeds smooth, without ornamentations; seeds with ornamentations. The morphotypes with ornamentations are more widespread than smooth ones, probably because seed ornamentations play an important role in seed dispersal, which is perhaps mainly anthropochorous given that P. oleracea is a synanthropic species that can tolerate mechanical disturbance. There are cases of multiple occurrence, as evidenced by the presence of different morphotypes in some of the sites. Such populations can count up to five morphotypes growing together. Seven morphotypes were here recorded from Malta; they are all hexaploid, even those which in other areas are tetraploid.
:: C. HENRY, J.-F. RAIVOARISOA, A. RAZAFIMAMONJY, H. RAMANANKIERANA, P. ANDRIANAIVOMAHEFA, M. DUCOUSSO & M.-A. SELOSSE. Characterization of ectomycorrhizal communities of Asteropeia mcphersonii seedlings spontaneously growing in natural forest and in open disturbed areas Paru dans Botany Letters, 2016, 163 (3), pp. 273-279. Anglais Abstract Forest ecosystem disturbances generate changes including soil changes, generally with loss of topsoil and loss of much of the diversity of microorganisms, which are usually replaced by others that are more adapted to the new conditions. We describe the effect of rainforest clearcutting in Madagascar, with stripping of surface soil horizons among ectomycorrhizal fungal communities associated with natural Asteropeia mcphersonii seedlings. An experimental device was placed on four sites, each including an undisturbed plot with litter and a plot in clear-cut areas on a soil composed of a homogeneous mineral substrate. On each of these eight plots the ectomycorrhizal infection rate was determined and root tips were collected to sequence the internal transcribed spacer. 219 sequences grouped into 59 operational taxonomic units (OTUs) were obtained. The main taxonomic groups were Russulaceae, Boletales and Thelephoraceae. Marked spatial aggregation was observed for OTUs. The disturbance significantly affected the ectomycorrhizal infection rate of A. mcphersonii seedlings and the OTU composition of mycorrhizal communities. However, some OTUs were found in both types of environments. We discuss the effect of the disturbance on mycorrhizal communities associated with natural ectomycorrhizal A. mcphersonii seedlings, particularly in view of its application to ecological restoration of disturbed forest environments.
:: M. TARHOUNI, F. BEN SALEM, A. TLILI, A. OULED BELGACEM, M. NEFFATI & M. LOUHAICHI Measurement of the aboveground biomass of some rangeland species using a digital non-destructive technique Paru dans Botany Letters, 2016, 163 (3), pp. 281-287. Anglais Abstract Plant biomass is usually assumed to be positively correlated with canopy cover. Measurements of canopy cover can now be easily and precisely made through image processing of high-resolution digital photography. This study aims to determine rapid, accurate and non-destructive ecological measurements of the aboveground biomass of selected plant species of the dry rangelands of southern Tunisia. The digital vegetation charting technique was used to estimate the canopy cover of three plant species: Artemisia herba-alba Asso., Rhanterium suaveolens Desf. and Stipa tenacissima L. Biomass of the selected species was also determined to develop regression models and correlation equations with the relative canopy cover. The main result was a strong correlation between canopy cover and dry biomass: coefficients of determination of 0.46 and 0.96 for A. herba-alba during the springs of 2014 and 2015, respectively; and correspondingly 0.9 and 0.97 for R. suaveolens and 0.69 and 0.97 for S. tenacissima. This digital charting technique offers a non-destructive, accurate and rapid means for monitoring and assessment of rangeland productivity dynamics as well as an efficient tool for developing range management strategies in dry areas.
:: A. NABIL BENGHANEM, N. BOUCHENEB, S. BENHOUHOU, B. O’HANRAHAN & F. MÉDAIL Acacia tortilis var. raddiana communities in the northwestern Algerian Sahara Paru dans Botany Letters, 2016, 163 (3), pp. 289-306. Anglais Abstract The aim of this work is the phytoecological study of the Acacia tortilis var. raddiana desert savanna in the northwestern Algerian Sahara. Sixty-seven relevés were collected for this habitat from an area extending from the northern boundary of Béchar to the southern part of Kerzaz, a latitudinal gradient of 250 km. A detrended correspondence analysis identified two communities represented by 35 and 32 relevés. Canonical correspondence analysis highlighted the topography and the nature of the substratum as the main environmental factors explaining the distribution of the two groups. The most frequent community corresponded to the Acacia tortilis var. raddiana, Panicum turgidum and Foleyola billotii association Quézel 1965. It is associated with large wadi-beds and alluvial plains. This association presents two facies: a saxicolous one characterized by Farsetia occidentalis and Trichodesma calcaratum and a sandy facies with Kickxia aegyptiaca and Brocchia cinerea. The second community corresponds to the Acacia tortilis var. raddiana and Rhus tripartita association Quézel 1965, typical of narrow wadi-beds with rocky substrates. The floristic composition reveals fewer taxa of tropical origin and a reduced list of characteristic species is proposed. Details of the range of the two syntaxa identified are provided. They are compared with the other Acacia tortilis var. raddiana associations described for the Algerian central Sahara.
:: M. TERZI, R. DI PIETRO & J.-P. THEURILLAT Nomenclature of the class Festuco-Brometea in Italy and remarks on the interpretation of articles 1 and 2b ICPN Paru dans Botany Letters, 2016, 163 (3), pp. 307-319. Anglais Abstract The class Festuco-Brometea includes the dry grassland and the steppe vegetation extending over most of Europe and part of Asia. Many high-rank syntaxa regarding the central and southern Europe grasslands are currently classified under the Festuco-Brometea and several of these concern the Italian Peninsula. According to the most recent and influential checklist of the Italian vegetation, the Vegetation Prodrome of Italy by Biondi and colleagues, the Italian Festuco-Brometea grasslands are to be distributed within five orders, two suborders and eighteen alliances. The names of these syntaxa, however, are often cited incorrectly in the phytosociological literature, and some of these errors are to be found in the Vegetation Prodrome of Italy. Therefore, owing to the importance of using correct names for the stabilization of the syntaxonomic nomenclature, this paper aims to resolve these inconsistencies in following the rules of the International Code of Phytosociological Nomenclature (ICPN). As a result, 15 names are corrected, a new suborder (Bromenalia erecti) is described and six names are typified (Festucetalia Soó 1940, Stipo capillatae-Poion xerophilae Braun-Blanquet & Richard 1950, Diplachnion serotinae Braun-Blanquet 1961, Mesobrometum erecti W. Koch 1926, Festuco-Bromion erecti Barbero & Loisel 1972, Xerobromion erecti [Braun-Blanquet & Moor 1938] Zoller 1954). In addition, it is proposed that three names are to be conserved (Festucetalia valesiacae Braun-Blanquet & Tüxen ex Braun-Blanquet 1950, Festucion valesiacae Klika 1931, Mesobromion erecti [Braun-Blanquet & Moor 1938] Zoller 1954) and three to be rejected (Festucetalia Soó 1940, Festucetalia valesiacae Soó 1947, Bromion erecti W. Koch 1926). Due to the fact that the revised names are referred to in the literature with different authors’ citations, their revision is preceded by a discussion about divergent interpretations of what constitutes a ‘publication’ and the ‘date of a publication’ in the sense of article 1 of ICPN for works issued in several parts, often in relationship with a ‘sufficient diagnosis’ in the sense of article 2b. A proposal is made in this respect.
:: L. VEIGA-BARBOSA, C. RUIZ, E. C. CORREA & F. PÉREZ-GARCÍA Dormancy imposed by a tough seed coat in Malvella sherardiana (Malvaceae), a highly threatened species of Spain Paru dans Botany Letters, 2016, 163 (3), pp. 321-327. Anglais Abstract Malvella sherardiana (L.) Jaub & Spach (Malvaceae) is a perennial herbaceous plant listed as Vulnerable in the Red List of threatened plant species for Spain. The germination characteristics under controlled conditions of light and temperature of M. sherardiana seeds were studied. Mechanical scarification, cold stratification, liquid nitrogen, freezing, hot water, dry heat, sulphuric acid, soaking in distilled water and soaking in gibberellic acid were used as pre-sowing treatments applied for enhancing germination. The untreated seeds showed a high dormancy at all temperature regimens tested and sulphuric acid scarification drastically improved final germination percentage and germination rate. Germination of seeds soaked in concentrated sulphuric acid arithmetically increased as soaking time increased (from 5 min to 3 h), but seeds soaked in acid for more than 4 h failed to germinate. The application of a gibberellic acid solution (1000 mg l−1) increased the germination percentages for all tested soaking times in sulphuric acid. However, it was only significantly effective for the soaking time of 3 h. The other pre-sowing treatments resulted in some germination, but none resulted in greater germination than sulphuric acid. As embryos are fully developed and the seed coat is water ermeable, we conclude that M. sherardiana seeds present physiological dormancy. The main conclusion of the study is that dormancy of M. sherardiana seeds is attributed to mechanical restriction of the embryo caused by the tough seed coat. This is the first report on germination requirements of the Malvella genus.
:: E. PIPINIS, E. MILIOS, K. KITIKIDOU & K. RADOGLOU Treatments for seed germination improvement in Prunus azorica, Frangula azorica and Morella faya, three native species of Azores Islands Paru dans Botany Letters, 2016, 163 (3), pp. 329-335. Anglais Abstract The aim of this study was to determine the best treatment to maximize seed germination of three native species of the Azores islands (Prunus azorica, Frangula azorica and Morella faya). In all three species the effect of gibberellic acid (GA3) application and cold stratification on seed germination under controlled conditions (light and temperature) was investigated. In particular, seeds of all three species were treated with 500 and 1000 mg L–1 GA3 for 24 hours and were subsequently cold stratified at 3–5°C for 0, 1 and 2 months. In addition, seeds from each species were only cold stratified for 0, 1 and 2 months and also seeds with the endocarp (stones) of P. azorica only were subjected to outdoor stratification from 1 October 2014 up to 28 February 2015. Untreated seeds of all three species exhibited a very low germination percentage, indicating that the seeds of all three species were dormant. For all three species, the germination of seeds untreated with GA3 significantly increased as the cold stratification period increased whereas GA3 application was more effective in improving germination in P. azorica and F. azorica than M. faya seeds. Furthermore, stones of P. azorica that were subjected to outdoor stratification and then transferred to germinate under controlled standard conditions exhibited high and rapid germination.
:: L. POULET, J.-P. FONTAINE & C.-G. DUSSAP Plant’s response to space environment: a comprehensive review including mechanistic modelling for future space gardeners Paru dans Botany Letters, 2016, 163 (3), pp. 337-347. Anglais Abstract The study of higher plant growth in space started in the 1950s both on the Russian and the American sides. The first experiments were intended to assess whether plants could grow outside Earth and to determine what differences there were between spaceflight-grown and Earth-grown plants. As plant-growth hardware started to adapt to spaceflight, more opportunities for plant experiments in space became available. Direct microgravity effects started being differentiated from confinement effects and Earth orbit started to become a laboratory where plants could be grown without the influence of Earth gravity. Experiments have shown that, with adapted ventilation, plant growth in space is similar to plant growth on Earth in 1 g, except for some morphological traits. However, only small-scale experiments on plant growth were performed in Earth orbit, which provided insufficient data on crop yield for reduced gravity environments. Challenges remain to grow plants in space, in terms of nutrient delivery, lighting and ventilation, but also on the choice of plant species and traits to favour. Additionally, significant effort must be made on mechanistic modelling of plant growth to reach a more thorough understanding of the intricate and combined physical, biochemical, and morphological phenomena involved, which is necessary to accurately control and predict plant growth in life-support systems. This review intends to list the main spaceflight effects to take into account for plant growth in space, as well as to give an overview of the current state of plant-growth hardware while stressing the challenges associated with their development.
:: B. DE FOUCAULT Guide des Characées de France méditerranéenne Paru dans Botany Letters, 2016, 163 (3), pp. 349-350. Anglais Abstract Book analysis