Histological changes of Berberis mikuna pollen grains in relation to viability and germinability

Berberis mikuna is a spontaneous shrub grown in the Tucuman-Bolivian subtropical jungle area and its fruits were highly prized as food by diaguitas and calchaquies who were local populations. Fruits are rich in phenolic compounds which would be responsible for the beneficial properties for health. Pollen preservation in gene banks should be implemented as standard procedures since pollen is a useful source of diverse alleles within a gene pool. Therefore, the aim of this work was to study the histological and ultrastructural changes of pollen grains after 45 days of conservation at different temperatures. Berberis mikuna pollen grain germination and viability decreased significantly after 45 days of its collection. Germination and viability decreased with increasing storage temperature, although the viability in T45 Ref and T45 Fr was similar. Ultrastructure studies revealed differences in the fibrillar structure of the intine, as well as the decrease in starch reserve in pollen grains stored at 5 °C andat room temperature.Fil: Radice, Silvia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Moron. Facultad de Agronomia y Ciencias Agroalimentarias. Laboratorio de Investigaciones En Fisiología Vegetal; ArgentinaFil: Galati, Beatriz Gloria. Universidad de Buenos Aires. Facultad de Agronomía. Cátedra de Botánica General; ArgentinaFil: Zarlavsky, Gabriela Elena. Universidad de Buenos Aires. Facultad de Agronomía. Cátedra de Botánica General; ArgentinaFil: Arena, Miriam Elisabet. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Moron. Facultad de Agronomia y Ciencias Agroalimentarias. Laboratorio de Investigaciones En Fisiología Vegetal; Argentin

Nectary ultrastructure of Cabomba caroliniana Gray (Cabombaceae)

Cabomba Aubl. is a genus considered as a potential genetic model for studies of early angiosperm evolution, accordingly, it is important to expand the knowledge of it. This paper reports the study of the anatomy and the ultrastructure of the nectary of Cabomba caroliniana Gray using bright-field microscope, scanning and transmission electron microscope in order to understand its secretion mechanism. C. caroliniana has protoginous flowers and the anthesis lasts two days. Nectaries of C. caroliniana are located in two basal lobes or yellow auricles of each white petal. Most nectar is observed in the area above the pronounced auricles. The secretion is released mainly by the four-cellular trichomes or hydropotens present in both nectary epidermis. The cellular ultrastructure indicates that the nectary is active during the two days of the anthesis. This agrees with the fact that in both anthesis days the fertile structures of the flower (first the stigmata and then the anthers) are disposed above the nectaries. The nectar secretion mechanism is discussed in relation to the present knowledge. The results of this study are related to what has been described for other basal angiosperms.Fil: Galati, Beatriz Gloria. Universidad de Buenos Aires. Facultad de Agronomía. Cátedra de Botánica General; ArgentinaFil: Gotelli, Marina María. Universidad de Buenos Aires. Facultad de Agronomía. Cátedra de Botánica General; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Fabbri, Liliana Teresa. Universidad de Buenos Aires. Facultad de Agronomía. Cátedra de Botánica General; ArgentinaFil: Rosenfeldt, Sonia. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; ArgentinaFil: Zarlavsky, Gabriela Elena. Universidad de Buenos Aires. Facultad de Agronomía. Cátedra de Botánica General; Argentin

Pollen development and anther morphology in 14 species of Rhamnaceae

Microsporogenesis, microgametogenesis, and anther structure of 14 species belonging to Rhamneae (Rhamnoids clade), Paliureae, Pomaderreae, Colletieae, and Gouanieae (Ziziphoids clade) of the Rhamnaceae family were analyzed using bright-field, scanning, and transmission electron microscopy. The aim is to look for morphological characters that have systematic value on a suprageneric level within the family. The character states of the number of nuclei in tapetal cells, the endothecial thickening pattern, and the number of endothecial layers are consistent on tribal level. Tribes were previously delineated based on molecular phylogenetic evidence. On the other hand, pollen morphology does not seem to have systematic value at tribal level in Rhamnaceae. The presence or absence of orbicules and their morphology vary within tribes. It seems that for Rhamnaceae, the anatomy of the reproductive sporophytic structures could have more systematic value than the gametophytic structures. However, more studies are needed to confirm this.Fil: Gotelli, Marina María. Universidad de Buenos Aires. Facultad de Agronomía. Cátedra de Botánica General; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario; ArgentinaFil: Galati, Beatriz Gloria. Universidad de Buenos Aires. Facultad de Agronomía. Cátedra de Botánica General; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario; ArgentinaFil: Zarlavsky, Gabriela Elena. Universidad de Buenos Aires. Facultad de Agronomía. Cátedra de Botánica General; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario; Argentin

Morphology, anatomy, and ultrastructure of the floral nectary of Alphitonia excelsa (Rhamnaceae) in relation to its taxonomic position

Alphitonia excelsa (Fenzl) Reissek ex Benth. is a tree endemic to Australia. The study of floral characteristics can provide information that helps clarify the taxonomic position of the genus at the tribal level within Rhamnaceae, since it has not yet been determined. In this study, the morphology, anatomy and ultrastructure of the floral nectary were carried out with bright field, scanning and transmission electron microscopes. Alphitonia excelsa presents a structural nectary, with well-located and histologically differentiated areas. The epidermis has a single layer of cells, with a cuticle with undulations and striations, and sunken nectarostomas. The nectariferous tissue is formed by several layers of isodiametric cells, with a dense cytoplasm, large nuclei, small vacuoles, presence of plastids with several starch grains, numerous mitochondria, dictyosomes and rough endoplasmic reticulum. Cytoplasmic density decreases at the end of anthesis until this tissue is no longer differentiated from the subnectariferous parenchyma in post-anthesis. The subnectariferous tissue is formed by the third and last stratum of the nectary and is vascularized by boundless with abundant phloem. It is concluded that the annular type nectary, with sunken stomata, striated cuticle and absence of trichomes could represent a synapomorphy between Alphitonia excelsa (Tribe unknown), Gouania ulmifolia (Gouanieae Tribe), Ziziphus mucronata and Ziziphus jujuba (Paliureae Tribe). More studies should be done in order to confirm this position between or within the Gouanieae or Paliureae tribes of the Ziziphoids clade.Fil: Nicolau, Magali. Universidad de Buenos Aires. Facultad de Agronomía. Cátedra de Botánica General; ArgentinaFil: Gotelli, Marina María. Universidad de Buenos Aires. Facultad de Agronomía. Cátedra de Botánica General; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario; ArgentinaFil: Zarlavsky, Gabriela Elena. Universidad de Buenos Aires. Facultad de Agronomía. Cátedra de Botánica General; ArgentinaFil: Galati, Beatriz. Universidad de Buenos Aires. Facultad de Agronomía. Cátedra de Botánica General; Argentin

Pollen and microsporangium development in Hovenia dulcis (Rhamnaceae): a different type of tapetal cell ultrastructure

Despite that there is some literature on pollen morphology of Rhamnaceae, studies addressing general aspects of the microsporogenesis, microgametogenesis, and anther development are rare. The aim of this paper is to describe the ultrastructure of pollen grain ontogeny with special attention to tapetum cytology in Hovenia dulcis. Anthers at different stages of development were processed for transmission and scanning electron microscopy, bright-field microscopy, and fluorescence microscopy. Different histochemical reactions were carried out. The ultrastructural changes observed during the development of the tapetal cells and pollen grains are described. Large vesicles containing carbohydrates occur in the tapetal cell cytoplasm during the early stages of pollen development. Its origin and composition are described and discussed. This is the first report on the ontogeny and ultrastructure of the pollen grain and related sporophytic structures of H. dulcis.Fil: Gotelli, Marina María. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario; Argentina. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Recursos Naturales y Ambiente. Cátedra de Botánica Agrícola; Argentina. Comisión Nacional de Investigación Científica y Tecnológica; ChileFil: Galati, Beatriz Gloria. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario; Argentina. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Recursos Naturales y Ambiente. Cátedra de Botánica Agrícola; ArgentinaFil: Zarlavsky, Gabriela Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario; Argentina. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Recursos Naturales y Ambiente. Cátedra de Botánica Agrícola; ArgentinaFil: Medan, Diego. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario; Argentina. Comisión Nacional de Investigación Científica y Tecnológica; Chile. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Recursos Naturales y Ambiente. Cátedra de Botánica Agrícola; Argentin

Agricultural land management negatively affects pollination service in Pampean agro-ecosystems

Agricultural land management modify environments in such a way that ecosystem functions are impaired. The establishment of exotic plants, favoured by agricultural land management, may alter the foraging behaviour of native floral visitors and consequently the pollination service they provide. To determine whether agricultural land management affects the pollination service provided by floral visitors for the most abundant plant species in a Pampean grassland ecosystem, we compared the pollination service of native and exotic entomophilous plants in landscape fragments with or without current agricultural usage. Both the quantity (number of conspecific pollen grains deposited on stigmas) and quality (proportion of heterospecific pollen grains deposited on stigmas) of the pollination service was estimated for three to nine entomophilous plants in each landscape fragment. Agricultural land management reduced the quality of the pollination service due to an increase in the deposition of heterospecific pollen on stigmas.Fil: Marrero, Hugo Javier. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Recursos Naturales y Ambiente. Cátedra de Botánica Agrícola; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Provincia de Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Universidad Nacional de Cuyo. Instituto Argentino de Investigaciones de las Zonas Áridas; ArgentinaFil: Medan, Diego. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Recursos Naturales y Ambiente. Cátedra de Botánica Agrícola; ArgentinaFil: Zarlavsky, Gabriela Elena. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Recursos Naturales y Ambiente. Cátedra de Botánica Agrícola; ArgentinaFil: Torretta, Juan Pablo. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Recursos Naturales y Ambiente. Cátedra de Botánica Agrícola; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Structure of the style and pollen tube pathway in the Ziziphoid and Rhamnoid clades of Rhamnaceae

The ultrastructure of the style and pollen tube pathway before, during and after anthesis were studied in 13 species belonging to the tribes Pomaderreae, Paliureae, Colletieae and Gouanieae (Ziziphoid clade) and Rhamneae (Rhamnoid clade) using light microscopy and transmission electron microscopy. The aim of this study is to provide new morphological characters useful for phylogenetic analysis at suprageneric level in Rhamnaceae. The patterns of pollen tube growth and the ultrastructural changes undergone by cells of the style were also described. Species of Rhamneae (Scutia buxifolia and Condalia buxifolia) have a solid style, with the transmitting tissue forming three independent strands (S. buxifolia) or a central, single horseshoe-shaped strand as seen in transversal section (C. buxifolia) which could derive from the fusion of formerly independent strands. In contrast, Pomaderreae, Gouanieae and Paliureae showed semi-solid styles, while in Colletieae, as previously reported, the style is hollow with two or three stylar canals. The style anatomy and the ultrastructure of the pollen tube pathway show that there is a tendency towards a solid style with a single strand of transmitting tissue within the family. The three-canalled hollow style could be the plesiomorphic state of the character “type of style” in the family, the semi-solid style the synapomorphic state and the solid style with three strands of transmitting tissue the apomorphic state, with the solid style with a single strand of transmitting tissue as the most derived state. Therefore, Colletieae would be the most basal tribe of the Ziziphoid clade.Fil: Gotelli, Marina María. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Recursos Naturales y Ambiente; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Galati, Beatriz Gloria. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Recursos Naturales y Ambiente; ArgentinaFil: Zarlavsky, Gabriela Elena. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Recursos Naturales y Ambiente; ArgentinaFil: Medan, Diego. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Recursos Naturales y Ambiente; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Developmental and ultrastructural characters of the pollen grains and tapetum in species of Nymphaea subgenus Hydrocallis

Variations in pollen characters and tapetum behavior were recently acknowledged in the early-divergent family Nymphaeaceae and even within the genus Nymphaea, which probably is not monophyletic; some traits such as infratectum and tapetum type are also a matter of different interpretations. In this study, developmental characters of the pollen grains and tapetum in Nymphaea subgenus Hydrocallis are provided for the first time. Observations were made in N. amazonum, N. gardneriana, and N. prolifera using light, scanning, and transmission electron microscopy. Tapetum is of the secretory type and produces orbicules. At microspore and pollen grain stages, the distal and proximal walls differ considerably. This result supports the operculate condition of the aperture in Hydrocallis, and such aperture might be plesiomorphic for Nymphaeoideae. The infratectum is intermediate, composed of inter-columellae granular elements, robust columellae consisting of agglomerated granules, complete columellae, and fused columellae. Narrow microchannels are present and persist until the mature pollen grain stage. The membranous granular layer is often present in the pollen grains of Nymphaeaceae. In N. gardneriana, this layer is most probably a component of the intine because it is lost after acetolysis. Orbicules in the Nymphaeaceae are characterized as spherical or subspherical, with a smooth sporopolleninic wall that surrounds an electron-lucent core and with individual orbicules that usually merge to give irregular aggregations. The aperture, pollen wall ultrastructure, and the tapetum of the studied species are discussed in an evolutionary and systematic context, and these characters are also compared with those of other angiosperm lineages.Fil: Zini, Lucia Melisa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; ArgentinaFil: Galati, Beatriz Gloria. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Recursos Naturales y Ambiente. Cátedra de Botánica Agrícola; ArgentinaFil: Zarlavsky, Gabriela Elena. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Recursos Naturales y Ambiente. Cátedra de Botánica Agrícola; ArgentinaFil: Ferrucci, María Silvia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; Argentin

Localization, morphology, anatomy and ultrastructure of osmophores in species of Rhamnaceae

Although the presence of scent was described for several species of Rhamnaceae, localization, morphology and structure of osmophores were unknown. We studied different species of the tribes Rhamneae (Rhamnoids clade), Pomaderreae, Colletieae, Paliureae (Ziziphoids clade) and the species Alphitonia excelsa (unknown tribe, Ziziphoids clade). We expect to have a better comprehension of these structures and provide information on which morphological and anatomical characters may support the phylogeny of the family. We localized the osmophores in the margins and top of the sepals using neutral red. Histochemical tests were made on transverse hand-cut sections of fresh sepals. Observations were made with stereoscopic and bright field microscopes, scanning and transmission electron microscopes. Papillae were observed in the zones with positive reaction to reagents. Different kinds of hairs are present in the sepal epidermis besides papillae. Epidermal cells present a striate cuticle with canals and cavities. Druses are abundant in most species. The ultrastructure of epidermal and subepidermal cells shows high metabolic activity: there are vesicles, mitochondria, endoplasmic reticulum, dictyosomes, plastids with lipids and starch. The vascularization is well developed and reaches the top of the sepal where the principal area of volatile components production is localized. The location and abundance of papillae are the most important traits that allow us recognize and characterize the osmophores in Rhamnaceae. There are no clear anatomical and morphological features exclusive of one clade or tribe. Therefore, in contrast to other sporophytic structures of this family, osmophores do not seem to have any systematic value.Fil: Gotelli, Marina María. Universidad de Buenos Aires. Facultad de Agronomía. Cátedra de Botánica General; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario; ArgentinaFil: Galati, Beatriz Gloria. Universidad de Buenos Aires. Facultad de Agronomía. Cátedra de Botánica General; ArgentinaFil: Zarlavsky, Gabriela Elena. Universidad de Buenos Aires. Facultad de Agronomía. Cátedra de Botánica General; ArgentinaFil: Nicolau, Magalí. Universidad de Buenos Aires. Facultad de Agronomía. Cátedra de Botánica General; ArgentinaFil: Reposi, Sofía. Universidad de Buenos Aires. Facultad de Agronomía. Cátedra de Botánica General; Argentin

Colleters, osmophores, and nectaries in the species Ceropegia lenewtonii: a sapromyiophilous stapeliad (Asclepiadoideae, Apocynaceae)

Ceropegia lenewtonii (Plowes) Bruyns (=Huernia keniensis), currently belonging to the Huernia section of the genus Ceropegia, is a stapeliad species distributed in Africa and the Arabian Peninsula; but it is widely cultivated as ornamental in most parts of the world. This species of stapeliad presents “carrion flowers” associated with a sapromyophilous pollination syndrome since the flowers emit an unpleasant odor. In this work, we describe the floral morphology and anatomy of the calyx, corolla, and corona of this species based on bright-field and scanning electron microscope techniques. We detected the presence of diverse floral secretor tissues, and based on different histochemical tests, the principal component of the secreted substance was identified. We interpret the functions of the glands and compare with other related species of stapeliads. Our results indicate that flowers of C. lenewtonii present colleters in sepals, osmophores in corolla, and primary and secondary nectaries in corona. All these floral glands have specific functions that involve the processes of pollination and reproduction of this species, as well as protection and defense mechanisms.Fil: Aliscioni, Sandra Silvina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentina. Universidad de Buenos Aires. Facultad de Agronomía. Cátedra de Botánica General; ArgentinaFil: Gotelli, Marina María. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario; Argentina. Universidad de Buenos Aires. Facultad de Agronomía. Cátedra de Botánica General; ArgentinaFil: Galati, Beatriz Gloria. Universidad de Buenos Aires. Facultad de Agronomía. Cátedra de Botánica General; ArgentinaFil: Zarlavsky, Gabriela Elena. Universidad de Buenos Aires. Facultad de Agronomía. Cátedra de Botánica General; ArgentinaFil: Torretta, Juan Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario; Argentina. Universidad de Buenos Aires. Facultad de Agronomía. Cátedra de Botánica General; Argentin