Stamens Research Articles

НОВЫЙ ВИД РОГОЗА (TYPHA L., TYPHACEAE) С ЮЖНОГО САХАЛИНА

The results of a comparative morphological analysis of Typha sakhalinica Krasnova et Efremov are pre-sented. It was found that the morphological characters of the reproductive organs do not correspond to T. latifolia from the European part of Russia. The species is distinguished by staminate flowers with narrow membran-ous anthers, large and solitary pollen, degraded flowers in bunches of three. Plants are smaller, cauline leaves with axils and membranous auricles directed downwards. It is believed T. sakhalinica is a Pleistocene species that emerged from the isolation of Sakhalin Island from the mainland North-Eastern Asia.

A comparative approach reveals diversity of floral developmental processes in Urticaceae

Abstract Most species of Urticaceae, the nettle family, have small and inconspicuous, diclinous flowers, in which the perianth, androecium and gynoecium tend to vary in number. Our objective was to study the morphology of the developing flowers of seven species of Urticaceae to understand the pathways that lead to the different patterns of floral reduction and the complex development of pseudomonomerous gynoecia. Buds and flowers were prepared for electron and light microscopy. Vascularization was studied via high resolution X-ray computed tomography micro-CT. Only one whorl of perianth organs is initiated, except for Phenax sonneratii, the flower of which is achlamydeous; variation in perianth merosity results from absence of organs from inception; dicliny results from the absence of stamens from inception (pistillate flowers) and from pistil abortion at intermediate developmental stages (staminate flowers). The gynoecium results from a primordium that divides partially forming two congenitally united primordia (most species) or from a single primordium that apparently does not divide. The gynoecium is served by a single (four species), or two vascular bundles. This second condition is expected for a pseudomonomerous gynoecium. Pistillode or rudimentary carpels occur in staminate flowers. The comparison among species shows that the developmental processes acting in the floral construction in Urticaceae is diverse.

Integrative Analyses of Transcriptomics and Metabolomics in Sex Differentiation of Mulberry Flowers.

Sex determination and sex differentiation of plants are important physiological processes of plant development. Mulberry (Morus indica L.) is an important economic tree being cultivated in sericulture countries, and mulberry leaf is commonly used for sericulture. The transcriptomic and metabolomic differences between the staminate flowers (SFs) and pistillate flowers (PFs) of mulberry were investigated by RNA sequencing and ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Overall, we uncovered 4,230 genes and 209 metabolites are significantly differentially expressed between the SFs and PFs of mulberry. The combined transcriptomic and metabolomic analysis revealed these differentially expressed genes (DEGs) and differentially expressed metabolites (DEMs) are involved in flavonoid biosynthesis, galactose metabolism, plant–pathogen interaction, and starch and sucrose metabolism, and these detected DEGs and DEMs may be associated with sex differentiation of mulberry through the regulation of the enrichment pathways, such as the MAPK pathway, flavonoid biosynthesis, galactose metabolism, plant–pathogen interaction, and starch and sucrose metabolism. This study will provide a rich source for the analysis of the molecular mechanism of mulberry sex differentiation processes.

Inflorescence and floral development of Dipteronia sinensis (Sapindaceae): Demonstration of developmental constraints in the shaping of the flower

The inflorescence, floral structure and ontogeny, and breeding system of the relict woody species Dipteronia sinensis was investigated to understand the developmental basis for its floral Bauplan, more particularly the octandrous androecium, dimerous gynoecium and the occurring flower symmetry in comparison with Sapindaceae.The functionally unisexual flowers arise in thyrses. Structural floral dimorphism was clearly observed in the different lengths of style and filaments and in the presence or absence of fructifications. Functionally pistillate flowers are found in a terminal position of each cincinnus maturing before the functionally staminate flowers. Petals are initiated unidirectionally and there is a time overlap with stamens. No common petal-stamen primordium was observed. There are two empty stamen positions, always opposite the first initiated petal, between sepals 1 and 3, and opposite the second petal between sepals 2 and 4; subsequently stamens are displaced to accommodate to the available space. Two median carpels are almost apocarpous in early stages and produce two parallel ovules each that become later superposed. Floral dimorphism develops as a late event when pollen and ovules are formed.Empty stamen positions are inversely correlated with the sequence of initiation and delayed growth of the petals, suggesting that a subtle heterochronic shift is responsible for the balance between petal and stamen initiation. Although the flower is initially polysymmetric to weakly monosymmetric, the bicarpellate gynoecium causes a shift to disymmetry during the mid-developmental stage as in the sister genus Acer, differently from tricarpellate Sapindaceae. Floral development demonstrates the flexibility in building symmetry in Sapindaceae, which is linked with available space and subtle changes in the sequence of initiation, rate of development and reduction of floral organs. This study underlines the importance of analyzing developmental constraints responsible for the floral diversity of Sapindaceae and provides further support for a monosymmetric ancestry in Sapindaceae.

Begonia xenos—a new species and an updated checklist of Begonia in Laos

This study provides an updated list of Begonia occurring in Laos, and a new species is added to the checklist. The new taxon, Begonia xenos C.W.Lin, Phonep. & Rahm is similar to B. sinofloribunda Dorr in habit and leaf shape, but the new species differs in its staminate flowers having 4 tepals (vs. 2) with slightly crenulate (vs. entire) margins, pistillate flowers with 5 tepals (vs. 2 or 3) and a 2-locular (vs. 3-locular) ovary.

Production and Postharvest Assessment of Tropical Pumpkin Flowers Harvested for Consumption

Consumption of staminate (male) flowers of squash and pumpkin (Cucurbita sp.) has generally been limited to summer squash (Cucurbita pepo), a species of temperate regions or highland tropical environments. In the lowland tropics of the Caribbean Basin, tropical pumpkin (Cucurbita moschata) is better adapted and more widely grown. We evaluated flower production in Lajas, Puerto Rico, and postharvest attributes (shelf life, chemical and nutritional properties, sensory quality) of flowers of four tropical pumpkin and two summer squash cultivars. Tested cultivars varied slightly among experiments. Passive and active modified atmosphere packaging (MAP) were compared. For passive MAP, packages were sealed without further intervention. Under active MAP, packages were adjusted to 6% to 7% oxygen (O2) and 12% to 13% carbon dioxide (CO2) during sealing. Sensory quality of fresh and canned tropical pumpkin flowers was evaluated by panelists. Production ranged from 1.8 to 4.0 flowers/plant per day. Flower weight and length were up to 50% greater in tropical pumpkin compared with summer squash. Packaged flowers turned more orange but with less color saturation as they aged. In active MAP packages, decreases in O2, and increases in CO2 observed after 5 days were small or not significant compared with initially established atmospheres at day 0. Storage temperature generally had no effect on changes in O2 and CO2. Packaged flowers lost about 27% of their initial weight after 5 days. Type of MAP had no consistent effect on the appearance of packaged flowers. Storing flowers at 5 °C often improved appearance compared with storage at 10 °C. The rate of deterioration was slower in packaged flowers of tropical pumpkin compared with summer squash, but by day 6 the poor appearance of flowers of all cultivars made them unmarketable. Compared with fresh flowers, packaged flowers stored for 5 days exhibited a decrease in soluble solids, total acidity, ascorbic acid, antioxidant capacity, and total phenolics, and generally an increase in pH. Beta-carotene often increased in stored flowers although this varied by cultivar. Storage temperature and type of MAP had inconsistent effects on chemical attributes of stored flowers. Panelists rated fresh flowers as “like moderately” to “like very much” for texture, taste, and overall acceptability, whereas canned flowers were rated as “like moderately” for overall acceptability. Male flowers of tropical pumpkin are suitable for human consumption but deterioration after 5 days of storage limits their market potential unless better packaging methods are developed. Canned tropical pumpkin flowers may be an alternative to packaged flowers.

Use of the staminate flowers of ‘Saijo’ persimmon

Use of the staminate flowers of ‘Saijo’ persimmon

Begonia ngocbonii (sect. Petermannia, Begoniaceae), a new species from North Vietnam

Begonia ngocbonii, a new species from North Vietnam is here described and illustrated. It resembles B. pellionioides Y.M.Shui & W.H.Chen, but is distinguishable by its hairy (vs. glabrous) stem, shorter inflorescence up to 1 cm (vs. ca. 5 cm or longer), 2-tepaled staminate and pistillate flowers (vs. 4-tepaled staminate flowers and 5-tepaled pistillate flowers), glabrous tepals (vs. spiny pilose on abaxial surface of outer tepals) and unilamellate placenta (vs. bilamellate).

Study of Various Floral Types on Different Plants of Garcinia indica (Thouars) Choisy and Correlation of Its Functionality in Sexual Reproduction

ABSTRACT Genus Garcinia shows high diversity of sexual systems; most of them are dioecious in nature. The other reported sexual systems of Garcinia include gynodioecious, androdioecious, monoecious, and andromonoecious. Garcinia indica (Thouars) Choisy was reported as facultative apomictic polygamodioecious species. There is a large diversity in floral types. Hence, a detailed study of various floral types found on different types of plants of G. indica and to correlate its functionality with sexual reproduction was undertaken. The study at Kokum Plot, BSSKVV, Dapoli, revealed that the male plants could be categorized into four types – androecious, functional males, andromonoecious, and hermaphrodites. The female plants displayed large variation in number and viability of stamens/staminodes. Each category showed significant difference in phenology, floral morphology and pollen types. In December, the percentage of staminate flowers (79.13 ± 2.93%) in androecious trees was significantly higher than functional males (58.61 ± 8.60%) or andromonoecious trees (56.36 ± 2.77%) (p ≤ .01). As female plants started flowering, all male morphotypes bore significantly higher numbers of staminate flowers and carpellate flowers were significantly reduced. Pollen viability was highest in androecious flowers at 90.11 ± 1.10% and lowest at 64.70 ± 2.09% in hermaphrodite trees. Earlier studies reported female flowers bore well-developed female gametophyte, but the embryo development was not observed. Thus, the fruit formation might be apomictic, but in present embryological investigation; more than 60% of female and andromonoecious flowers, a well-developed embryo was formed between 8 and 24 h after anthesis. Thus, the embryo formation might be sexual or apomictic. Floral types favoring sexual reproduction are essential for conservation of highly endemic species.

Unraveling the development behind unisexual flowers in Cylindropuntia wolfii (Cactaceae)

BackgroundIn certain unisexual flowers, non-functional sexual organs remain vestigial and unisexuality can be overlooked leading to the ambiguous description of the sexual systems. Therefore, to accurately describe the sexual system, detailed morphological and developmental analyses along with experimental crosses must be performed. Cylindropuntia wolfii is a rare cactus endemic to the Sonoran Desert in southern California and northern Baja California that was described as gynodioecious by morphological analysis. The aims of our project include accurately identifying the sexual system of C. wolfii using histological and functional studies and characterizing the developmental mechanisms that underlie its floral development.MethodsHistological analyses were carried out on different stages of C. wolfii flowers and controlled crosses were performed in the field.ResultOur results identified C. wolfii to be functionally dioecious. The ovule and anther development differed between staminate and pistillate flowers. In vivo pollen germination tests showed that the pollen of staminate and pistillate flowers were viable and the stigma and style of both staminate and pistillate flowers were receptive. This suggests that there are no genetic or developmental barriers in the earlier stages of pollen recognition and pollen germination.ConclusionsDespite being functionally dioecious, we observed that functionally pistillate individuals produced fruits with a large number of aborted seeds. This implies that not only does this species have low reproductive success, but its small population sizes may lead to low genetic diversity.

Flower differentiation and fruiting dynamics in olive trees (Olea europaea): Eco-physiological analysis in the Mediterranean basin

The formation of flowers in sufficient number and quality is a prerequisite for a successful subsequent fruit set. Despite the abundant flowering, olive trees (Olea europea) are characterized by a very low fruit set, and a very severe yield alteration leading to market fluctuation over time. The goal of this paper is to explore and analyze eco-physiological driving factors behind the poor fruit set in Mediterranean olive groves. The key mechanisms causing floral differentiation and extreme yield alternate are functional of plant genetic variability, nutrient competition, and some ecological aspects as a response to climate change. Additionally, olive inflorescence architecture appears to be complex and can vary between cultivars; the olive flower differentiation results in a variable proportion of hermaphrodite, pistillate and staminate flowers among olive cultivars as well as across canopy positions and branches, enhancing nutrient competition between flowers. Self-pollination could be one of the limiting factors for increasing early fruit abscission and extreme alternate fruit-bearing. Hormonal treatments to reduce alternate production in olive trees should be explored. The current review analysis shall help to improve olive grove management, but also for breeding new cultivars more suitable for Mediteranean agro-ecological constraints. Ovule viability and fertilisation, and embryo sac development abnormalities should all be further investigated.

Mixed pollination system and floral signals of Paepalanthus (Eriocaulaceae): insects and geitonogamy ensure high reproductive success.

Eriocaulaceae exhibit a great variety of floral traits associated with insect (e.g. nectariferous structures) and wind pollination (unisexual flowers, exposed sexual organs and small pollen grains), as well as the 'selfing syndrome' (small flowers, short distance between stigma and anthers, and temporal overlap of male and female phases). Paepalanthus bifidus, P. subtilis and P. tortilis are related species that differ in form, size and colour of floral structures. We aimed to investigate the pollination and reproductive biology of these three species. We analysed the floral biology, floral visitors, pollinator behaviour, and the contribution of insects, wind and spontaneous geitonogamy to fruit set. We also evaluated the floral colour and scent of the species. Colour reflectance of capitula of each species was measured and plotted in models of insect vision. Floral scent samples were extracted and the compounds were compared to vegetative scent samples. In all species, the staminate and pistillate flowers are arranged in alternating cycles with a temporal overlap between these phases. Ants were the most frequent floral visitors and were effective pollinators in P. bifidus and P. tortilis, while flies were occasional pollinators in P. tortilis. Floral visitors were not observed in P. subtilis. In all species, fruits were produced by spontaneous geitonogamy, with no evidence of wind pollination. According to the models of insect vision, the colours of the capitula of P. bifidus and P. subtilis are the most inconspicuous for ants and flies. We found no difference between the emission of volatiles of inflorescences and vegetative structures. This study suggests that ant pollination might be more widespread in Eriocaulaceae than currently assumed. Furthermore, for small monocarpic plants, mixed mating strategies are most favourable, by ensuring reproduction either by outcrossing when pollinators are abundant or by spontaneous geitonogamy when pollinations are scarce/absent.

Embryology of some flowers of the Gardenieae complex (Rubiaceae).

Different breeding systems occur in the Gardenieae complex (Rubiaceae), from homoecy to dioecy which is present in two tribes, Gardenieae and Cordiereae. As part of a broad project focused on the reproductive anatomy of the species of these two tribes, we described the structural and functional differences of the gynoecium in the different floral morphs and determined the degree of gynoecium development in the staminate flowers. We conducted a comparative anatomical study focused on the gynoecium of one homoecious species (Tocoyena formosa, with perfect flowers) and three dioecious species (Genipa americana, Randia calycina, and Randia heteromera) of Gardenieae and one dioecious species (Cordiera concolor) of Cordiereae. The dioecious species have flowers that are morphologically perfect and functionally unisexual. Flowers in successive stages of development were collected, photographed, and fixed in formalin-acetic acid-alcohol. The material was examined using light microscopy and scanning electron microscopy. The anatomy of the ovary, style, and stigma was analyzed, and megasporogenesis and megagametogenesis were studied. The results achieved in this study, together with previously obtained data of the androecium, show that dioecy originated from homoecy in these species, since the unisexual flowers conserve some characteristics of the perfect flowers. In addition, a new type of ovule for the Rubiaceae family is described.

Intersexual flower differences in an andromonoecious species: small pollen-rich staminate flowers under resource limitation.

Andromonoecy, the presence of perfect and staminate flowers in the same individual, has evolved repeatedly in angiosperms. The staminate flowers are generally smaller than the perfect flowers in species that produce staminate flowers plastically when resources are limited. The smaller staminate flowers are expected to be less attractive to pollinators and have reduced size-matching with pollinators than perfect flowers. We hypothesized that these potential disadvantages of staminate versus perfect flowers facilitate the evolution of sex-specific floral morphology, such as allometric relationship between flower size and male reproductive organ. We compared six floral morphology traits, pollen production, pollinator visits and pollen removal from anthers between staminate and perfect flowers in several natural Commelina communis populations. Nectarless and zygomorphic C. communis flowers have polymorphic stamens with attracting, feeding and pollinating anthers and were visited by diverse pollinators. Staminate flowers were significantly smaller than perfect flowers, despite a large overlap in size between sexes. The lengths of pollinating stamens did not differ between staminate and perfect flowers, and staminate flowers produced significantly more pollen. We observed significantly more pollinator visits to perfect flowers than to staminate flowers. By contrast, pollen removal from pollinating stamens was significantly higher in staminate flowers than in perfect flowers. There is sexual dimorphism in flower morphology in C. communis. Staminate flowers with smaller attraction organs, similar pollinating stamens and higher pollen production assure higher pollen donor success relative to perfect flowers. Our results suggest that the morphological changes in staminate flowers enhance pollination success, even with limited resources.

Floral Aromatics of Ptelea: Chemical Identification and Human Response

Many members of the citrus family (Rutaceae) are valued for the aromatic compounds emitted by their flowers. Ptelea species are unusually cold-hardy members of the Rutaceae, but conflicting descriptions of the fragrance of their unisexual flowers may discourage the use of these trees. We analyzed floral volatiles and human response to these chemicals to test the hypothesis that the fragrance of staminate and pistillate flowers of these species differs. Gas chromatography and mass spectrometry showed that most volatile chemicals emitted by flowers of Ptelea trifoliata and Ptelea crenulata are monoterpenes, sesquiterpenes, and esters. Most volatiles were emitted from flowers of both sexes, but ethyl benzoate and estragole were emitted only from pistillate flowers. When concentrations of aromatics differed between sexes, they were higher for pistillate flowers, except for cis-3-hexenyl butanoate and an unidentified terpene. For P. crenulata and P. trifoliata, respectively, 81% and 77% of survey responses were from volunteers who liked the fragrance. Panelists most frequently described the scent of flowers of P. crenulata of both sexes with the words citrus, lime, and sweet. Panelists distinguished between pistillate and staminate flowers of P. trifoliata, describing the odor of pistillate flowers most frequently with the words damp-earthy, spicy, and sweet; staminate flowers were perceived as light, fresh, grassy, and pleasant. This work represents the first analysis of floral volatiles of P. crenulata and resolves conflicting prior reports regarding the floral fragrance of P. trifoliata. We conclude that differences among people rather than the sex of flowers account for conflicting prior reports of floral fragrance. The scents of flowers of P. crenulata and P. trifoliata appeal to most people and are horticultural assets of these trees.

Андромоноэция и протандрия у Oenanthe aquatica (Apiaceae)

The paper studies the synflorescence structure and flowering biology of the biennial monocarpic wetland plant Oenanthe aquatica. This species has a set of adaptations to prevent self-pollination, including generation of a pseudanthium, andromonoecy, intra- and interfloral protandry, and a specific sequence of flowering within its umbels. The synflorescence of O. aquatica is a panicle of umbels. The size of perfect and male flowers consistently decreases as the order of synflorescence axes grows. The size-related differences between perfect and staminate flowers on axes of the same branching order consist only in the length of their calyx abaxial teeth, corolla diameter, width of abaxial petals, length and width of anthers, and length and height of stylopodium. We have identified two arrangements of staminate flowers in O. aquatica: male flowers are located at the periphery or in the center of the umbellets. The share of staminate flowers in umbels increases as an axis order grows. The female phase of flowers on axes of one order occurs simultaneously within entire synflorescences with the male phase of flowers on axes of the next order, which might mean geitonogamy. Perfect flowers live for five to seven days, while staminate flowers function for no more than one day. The article contains 4 Figures, 2 Tables, 32 References. The Authors declare no conflict of interest.

Clusia falcata (Clusiaceae), an endangered species with exceptionally narrow leaves endemic to Chiapas, Mexico

SummaryClusia falcata (Clusiaceae), a new species from Chiapas, Mexico, is described and illustrated. This new taxon is distinctive for its leaves, among the narrowest of all known species, having lanceolate to oblong laminas that are mostly 10 – 15 × 2 – 2.5 cm. The flowers have a quadrangular perianth with succulent petals, and a non-resiniferous androecium and gynoecium. Staminate flowers have a quadrangular androphore bearing 18 – 24 short stamens. Pistillate flowers have 4 pairs of staminodia, with each pair born on an androphore. The species is endemic to montane forests of the Northern and Eastern highlands of Chiapas in Mexico and is currently considered to be endangered.

FLORAL BIOLOGY AND BEEKEEPING POTENTIAL OF Croton heliotropiifolius KUNTH (EUPHORBIACEAE) AT SEMI ARID REGION, BRAZIL1

ABSTRACT The aim of the present study was to determine the beekeeping potential of Croton heliotropiifolius Kunth (Euphorbiaceae) based on flowering strategy, floral characteristics, available floral resources, and the individuals frequencies and foraging activities of Apis mellifera L. on its flowers in Fazenda Ingazeira, Brazil. Each C. heliotropiifolius plant possessed inconspicuous diclinous flowers clustered into 560 ± 60 dense terminal inflorescences containing 59 ± 12 pistillate and 160 ± 26 staminate flowers. Although both types of flowers produced nectar (pistillate: 2.8 ± 0.8 μL ; staminate: 0.3 ± 0.06 μL ), A. mellifera workers mostly visited staminate flowers (98%) during the peak visitation period (08:00-11:00 h). Moreover, during the foraging period, each plant produced approximately 5.376 × 10 8 pollen grains, ensuring approximately 33 visitation cycles from a colony of A mellifera workers that picked up an average of 405 pollen grains per visit per flower. Further, C. heliotropiifolius showed an annual cornucopia flowering strategy with high flower production for five months, which is an important characteristic that ensures floral resource availability in the environment. These findings suggest that C. heliotropiifolius has a great potential for apiculture in this region.

Differential reward in “male” versus “female” pollen of functionally dioecious Solanum

PremiseFive to six percent of angiosperm species exhibit a dioecious sexual system, with unisexual “male” or “female” flowers borne on separate plants. The consequent need for inter‐individual pollen exchange is a special challenge for taxa where pollen is the sole pollinator reward. Dioecious Australian Solanum assure visits from pollen‐foraging bees via production of inaperturate pollen in functionally female (morphologically bisexual) flowers. Biochemical composition of pollen from Australian Solanum has not been assessed nor compared to porate pollen from staminate flowers to reveal whether these flowers differ in their pollinator reward potential.MethodsPorate pollen from male flowers and inaperturate pollen from functionally female flowers of two functionally dioecious Australian species were compared for protein and amino acid content. We also assessed pollen from bisexual and staminate flowers of a closely related andromonoecious species, in which all pollen is porate, as a comparison across co‐occurring sexual systems.ResultsIn both functionally dioecious species, porate pollen grains from staminate flowers had significantly higher levels of proteins and amino acids than inaperturate pollen grains from functionally female flowers. Levels of proteins and amino acids were highest in bisexual and staminate flowers of the andromonoecious species.ConclusionsHigher levels of proteins and amino acids in porate pollen of “male” flowers in our functionally dioecious Solanum species suggests a greater nutritive reward for bees foraging on “male” plants than for those foraging on functionally “female” plants. Greater reward in porate pollen (including andromonoecious species) may be connected to the potential to generate a pollen tube.

Begonia lanuzaensis (sect. Petermannia, Begoniaceae) a new species from Surigao del Sur, Mindanao Island, Philippines

Begonia lanuzaensis from Mt. Nabuywang, Lanuza, Surigao del Sur, is described as a new species endemic to the Philippines. B. lanuzaensis is allied to B. mindanaensis and B. agusanensis in having oblanceolate leaves with short petioles and four-tepalled staminate flowers but is distinct in having glabrous stems and petioles; bigger, triangular and glabrous stipules and larger leaves.