The stigma plays several roles such as pollen hydration and selection, and pollen tube nutrition. In the Ficus-fig wasp mutualism, stigmata have an additional, almost unknown, function by representing a physical interface for both plant and wasp reproduction. We used light and electron microscopy to compare the detailed morphology of the stigmata of nine Ficus species of different sections and with different pollination modes and sexual expressions. Figs were collected at the stage when the stigmata were receptive for pollination. Stigmata in actively pollinated monoecious species have well developed papillae concentrated on the adaxial surface exposed towards the fig cavity. Conversely, the passively pollinated monoecious species have the whole surface of the stigmata covered by somewhat smaller papillae. In both actively and passively pollinated monoecious species these features are consistent, irrespective of style length. In all actively pollinated gynodioecious species, the stigmata of pistillate flowers were tubular or infundibuliform whereas in almost all actively pollinated monoecious species (except F. racemosa) the stigmata were filiform, with one branch or two asymmetric branches. In gynodioecious species the short-styled flowers in "male" figs show a limited receptive surface with small papillae, while the stigmata of long-styled flowers in "female" figs are covered by papillae that extend down the sides of the style, increasing the stigmatic surface. In actively pollinated species, stigmata are cohesive, forming a common surface for pollen tube germination (= synstigma). The synstigma arrangement was quite variable: lax, cohesive or very cohesive, with entanglement by stigmatic papillae and stylar trichomes. Entanglement by stylar trichomes is common in gynodioecious species. The synstigma arrangement did not correlate with phylogeny or breeding system. This study is the first to report a very loose synstigma in actively pollinated monoecious Ficus species. Our analyses revealed that, in Ficus, the synstigma is functionally analogous to an extra-gynoecial compitum. Comparative studies will be required to test further hypotheses about the evolutionary determinants of such variation.
-(Leaf anatomy with taxonomic implications in "ipê" species). By considering that Brazilian species of Ipês are hardly identifi ed when in vegetative stage, the present study aims to research foliar anatomic characters that might allow recognize medicinal ipê species. Leaves of six species of Handroanthus (yellow fl owers: H. chrysotrichus, H. ochraceus and H. serratifolius; white fl owers: H. roseo-albus; purple fl owers: H. heptaphyllus and H. impetiginosus) and one species of Tabebuia (yellow fl owers: T. aurea) were prepared to be observed with light microscopy (free-hand cuts), and scanning electronic microscopy (surface analysis). Foliar anatomical characters allow recognizing Ipê species. The better ones provided by foliar lamina were the number of epidermic layers, the stomata position in relation to the other epidermic cells, the occurrence of domatia, the parechymatic cell wall thickening in the margin, the mesophyll type and the presence of paraveinal parenchyma; in the petiole, we can cite the petiole shape, the epidermic cell shape and the occurrence of inner phloematic fi bers. Key words: Bignoniaceae, diagnostic character, Handroanthus, Tabebuia RESUMO -(Anatomia foliar com implicações taxonômicas em espécies de ipês). Tendo em vista a difi culdade de identifi cação dos ipês brasileiros em estado vegetativo, este trabalho objetivou levantar caracteres que possibilitassem reconhecê-los pela anatomia foliar (lâmina foliar e pecíolo). Folhas de seis espécies de Handroanthus (ipês amarelos: H. chrysotrichus, H. ochraceus e H. serratifolius; ipê branco: H. roseo-albus; ipês roxos: H. heptaphyllus e H. impetiginosus) e de uma espécie de Tabebuia (ipês amarelo: T. aurea) foram preparadas para observação em microscopias de luz (exame histológico) e eletrônica de varredura (exame de superfície). Caracteres provenientes da anatomia foliar possibilitaram a diagnose dos ipês, sendo mais relevantes na lâmina foliar, o número de camadas da epiderme, a posição dos estômatos em relação às demais células epidérmicas, a presença de domácias, a presença de espessamento de parede das células parenquimáticas na margem, o tipo de mesofi lo e a presença de parênquima paravenal; no pecíolo, destacaram-se seu formato, a forma das células epidérmicas e a presença de fi bras na região interna do fl oema.
The synstigma is a structure formed by clusters of two to several stigmas, whether in the same or between different flowers. Although rare in angiosperms, synstigmas are found in c. 500 out of the c. 750 Ficus spp. (Moraceae). This floral structure is associated with fig-fig wasp pollinating mutualism. The synstigma structure and pollen tube pathways were studied in six Ficus spp. from Ficus section Americanae to test the hypothesis that the synstigma allows pollen grains deposited on a stigma to emit pollen tubes that can grow laterally and fertilize surrounding flowers. Syconia containing recently pollinated stigmas were collected and dissected, and the stigmas were processed for analyses with light and scanning and transmission electron microscopy. The arrangement of the synstigmas across species can be spaced or congested, with the number of stigmas per synstigma ranging from two to 20. Contact between the stigmas in a synstigma occurs by the intertwining of the stigmatic branches and papillae; their union is firm or loose. The pollen tube grows through live cells of the transmitting tissue until reaching the ovule micropyle. Curved pollen tubes growing from one stigma to another were observed in five out of the six species studied. The curvilinear morphology of pollen tubes probably results from competition by pollen between the stigmas composing a synstigma via chemotropic signals. The synstigma appears to be a key adaptation that ensures seed production by flowers not exploited by the fig wasps in actively pollinated Ficus spp.
The flower has always aroused great interest of researchers because it is considered the key innovation in the evolution of plants, featuring a very special group, the Angiosperms. It is conceptualized as a specialized stem apex or as a lateral branch with shortened internodes and appendices hypothetically homologous to leaves, modified for reproductive functions in sepals, petals, stamens and carpels. The predominance of angiosperm species on Earth is due probably to the success of the appearance of the flower, which enabled more effective ways in interbreeding. This fact is closely related to pollinators, which, along with the flowers, have diversified, becoming sometimes specialized in the pollination of a single plant species. A group of well‐known plants, the urticalean rosids, composed of Cannabaceae, Moraceae, Ulmaceae and Urticaceae, surprises by displaying a flower of unusual morphology: small, inconspicuous, diclinous (= single‐sex), perianth single or none , androecium with few stamens (1‐5) arranged in one whorl, pseudomonomerous gynoecium, a single functional ovule inserted in different ways, in addition to a stigma with various forms. Thus, this flower, if compared to that of other rosids (Rosaceae, for example), can be considered reduced. Although morphological features of the flower of urticalean rosids are recorded since a long time (about 150 years), comprehensive studies on floral development, which could elucidate how this floral reduction takes place in this group are missing. This study aims to show how the ontogeny can explain the variations in flower structure of urticalean rosids. Flower morphology and pollination syndrome are also addressed. Our interpretations are based on data from at least 20 species obtained by analyses of surface in scanning electron microscopy and of histology in conventional light microscopy. The main points we raised are summarized in: (A) The condition perianth single (Fig. 1) or none (Fig. 2) results from the absence of the corolla organs or of both calyx and corolla organs from the inception. The interspecific variation in the calyx number of organs is also due to the absence of organs from the inception and not by organ abortion throughout the development. (B) The synorganization can be congenital (rare) (Fig. 3) or postgenital in the perianth and congenital in the gynoecium and androecium (rare). (C) Male and female flowers result of stamen and carpel abortion (Fig. 4) in most cases. Thus female flowers bear a pistillode and the male flowers a staminode. (D) The ontogeny of pseudomonomerous gynoecium deserves to be highlighted: one primordium arises in the center of the floral meristem, divides into two, but only one forms an ovule, although the other also participates in the style and stigma structure. (E) The arrangement of floral organs and pollination syndrome is strongly related in some species of Urticaceae (anemophily) and Moraceae (anemophily and entomophily). The inflate pistillode together with the anthers arrested by sepals in the staminate flowers of Urticaceae, for example, compose an explosive mechanism of pollen release which is then transported by the wind to a pistillate flower. In the few genera of Moraceae with entomophilous species, the union of several stigmas of different flowers within the inflorescence (fig), forming platforms ( Ficus ), or the offer of pollen and various exudates to pollinator insects ( Artocarpus, Castilla, Dorstenia ) ensures the formation of seeds. We conclude that the floral reduction in urticalean rosids takes place by different ontogenetic pathways, even among members of the same family. This finding contradicts the current paradigm which predicts that the floral ontogeny is conserved in related groups. Floral specializations, observed late in development, appear as responses to selection pressures exerted by different pollinators observed in the urticalean rosids.
We present a list of vascular plants found in Legado das Águas, Reserva Votorantim, a private reserve having an area of approximately 35,000 ha that spans the municipalities of Tapiraí, Miracatú, and Juquiá, in the state of São Paulo, Brazil. The reserve is part of a complex of state-protected areas including Alto Ribeira Touristic State Park, Intervales State Park , Carlos Botelho State Park, Jurupará State Park, and Serra do Mar State Park. Together, these form an important and large area of continuous and well-preserved forest. Our study, which involved two main floristic surveys in March/April 2013 and April 2014, recorded 768 species, representing 131 families and 432 genera. The majority of species were angiosperms (619) representing 106 families and 370 genera. There were also two species of gymnosperms belonging to two genera in separate families; 147 species of ferns and lycophytes belonging to 23 families and 60 genera. In demonstrating the presence of almost 800 species of plants, of which 16 are threatened, our study highlights the importance of floristic surveys and the critical role of private protected areas in managing and preserving native flora.
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