Pistillate Flowers Research Articles

A new endemic Begonia species (sect. Knesebeckia, Begoniaceae) from the south-western montane forest remnants of Ecuador

Begonia jocotocoi is a new species described from the Buenaventura Reserve in El Oro Province, south-west Ecuador. The new species morphologically resembles Begonia serotina, but differs by its minutely bullate leaf lamina (vs. smooth), the dense red long trichomes that cover the petioles and the lower surface of the leaf lamina, the latter of which distinctly become purple at maturity (vs. usually glabrous or occasionally with an indument of minute glandular white hairs and pale green below), presence of a pair of bracteoles directly beneath the pistillate flowers (vs. bracteoles absent), and the pedicels and also sometimes the abaxial surfaces of most floral whorls having a sparse cover of glandular hairs (vs. glabrous to puberulous). Photos of the new species and a distribution map are provided. Relationships with other species are discussed and the species’ preliminary conservation status is assigned as critically endangered (CR).

Variability of the sexual reproductive part in stinging nettle Urtica dioica L. (Urticaceae): From flower to genet

AbstractStinging nettle, Urtica dioica L., is a widely distributed subdioecious long‐rhizomatous plant. Within a single population growing in the territory of the Zvenigorod Biological Station of Lomonosov Moscow State University, eight plots were selected in stinging nettle thickets to study the variability of the sexual reproductive part in U. dioica depending on internal and external factors. As monoecious ramets are relatively common in the studied population, four gender forms were distinguished based on the ratio of male and female flowers. On 156 ramets of different gender forms and 36 genets, it was shown that predominantly male plants are shorter, while predominantly female plants have larger and more widely spread inflorescences compared to other gender forms. The pubescence type (spreading or appressed unicellular hairs) shows the greatest repeatability within the merigenet. True monoecy in stinging nettle is widespread: male and female flowers of different gender forms were found in 10 out of 36 genets. The most common inflorescence architecture types in the studied population were proxigynous and basigynous. Both normal pistillate and normal staminate flowers, as well as flowers with morphological abnormalities formed based on flowers of different sexes can be found on the same ramet, which suggests the presence of paradioecious lability.

How pollen and ovule development underlay dioecy in Chloroluma gonocarpa (Sapotaceae).

Previous studies have determined that Chloroluma gonocarpa (Sapotaceae), is a species that has cryptic dioecy. This type of sexual system is characterized by flowers that are morphologically perfect (both sexual whorls are present) but functionally pistillate or staminate (in each type of flower one of the sexual whorls is non-functional). In C. gonocarpa the pistillate flowers present well-developed stigma, functional ovules, and staminodes, while the staminate flowers present a poorly developed stigma, collapsed ovules, and pollen-producing anthers. In angiosperms, the abortion of sexual organs can occur at different stages of development (from pre-meiosis to post-meiosis), that is why we conducted an anatomical analysis of both flower types at various developmental stages. Using light microscopy, we described the processes of sporogenesis and gametogenesis to establish when the staminate flowers lose their pistillate function. To achieve this, we collected, fixed, and processed the flowers following conventional anatomical techniques for observation under a light microscope. Our findings reveal that pollen development occurs only in staminate flowers, while ovule development begins in both types of flowers but ceases in staminate flowers due to post-meiosis abortion. In contrast, normal development continues in pistillate flowers. These results suggest that dioecy in C. gonocarpa may have arisen from a gynodioecious pathway.

Species delimitation in Xanthium sect. Acanthoxanthium (Heliantheae, Asteraceae) and the neglected species Xanthium argenteum

AbstractXanthium is a genus of annual herbaceous plants that stands out within Asteraceae for being wind‐pollinated, diclinous monoecious, and bearing solitary pistillate flowers in peculiar spiny structures (burs). Xanthium sect. Acanthoxanthium is native to South America and characterized by the presence of trifurcate spines at the base of the leaves. Past taxonomic treatments of the section have been contradictory, some recognising up to six species, others reducing all to a single polymorphic species. Altogether, 42 samples of X. sect. Acanthoxanthium were analysed, the vast majority taken from herbarium specimens between 20 and 160 years old. We sampled multiple specimens of X. spinosum from throughout its broad range as well as those taxa with narrower distributions, covering the whole range of morphological variation in the section. When possible, we included types and original material. We used Hyb‐Seq techniques to obtain information from about 1000 single‐copy nuclear genes and complete plastomes. Phylogenomic data were submitted to coalescent‐based species delimitation approaches (SPEEDEMON). Additionally, we performed geometric morphometric analysis of leaf outlines. The results strongly support the identification of four lineages in the section favouring the acceptance of four of the hitherto described species, i.e., X. ambrosioides, X. argenteum, X. catharticum, and X. spinosum. These results were to some extent corroborated by morphometric analyses. While X. ambrosioides was well distinct from X. spinosum based on leaf morphology, such difference was not observed between X. spinosum and X. catharticum. However, X. catharticum differs from X. spinosum in its ecological requirements, being a species rather adapted to high‐mountain environments of the Neotropics. Intriguingly, X. argenteum – a taxon described from a single herbarium collection – was also inferred as a species.

Putting the puzzle together: the relationship between floral characters and pollinator morphology determines pollination mode in the fig-fig wasp mutualism.

The diversification of angiosperms has largely been attributed to adaptive radiation of their pollination and mating systems, which are relevant drivers of the macroevolution processes. The fig (Ficus, Moraceae) and fig wasp (Agaonidae, Hymenoptera) interaction is an example of obligate mutualism. Passive and active pollination modes have been associated with morphological traits in both partners. However, more information is required to assess the relationship between floral traits and pollination modes, particularly in Neotropical Ficus species. This study evaluates the morphological traits of figs and fig wasps regarding pollination modes in species belonging to Neotropical Ficus sections (three species each of Americanae and Pharmacosycea). Pollination mode was identified by floral morphology, anther/ovule ratio, and specialized structures fig wasps use for pollen transport (pollen pocket and coxal combs). Fig species in sect. Americanae are actively pollinated because pistillate flowers form a synstigma, present anther/ovule ratios <0.11, and their pollinator Pegoscapus fig wasps have pollen pockets and coxal combs. In contrast, species in sect. Pharmacosycea have free pistillate flowers, with anther/ovule ratios >0.27; they are pollinated by Tetrapus wasps, which lack specialized structures to carry pollen. Each species of Ficus was associated with a single morphospecies of fig wasp. The results support previous contributions that consider reciprocal morphological traits between fig species and their pollinating wasps as evidence of a close co-evolutionary history.

Floral morphology and development reveal extreme diversification in some species of Croton (Euphorbiaceae).

Floral diversity of Croton, the second largest genus in Euphorbiaceae, is currently under-explored. Several clades demonstrate an unusual floral morphology, e.g., lower or higher stamen number, bilateral symmetry and reduced ovary, but have never been investigated in a comparative study with typical Croton. This study examined morphology and ontogeny of flowers in nine Croton species from different clades within the genus with light and scanning microscopy, resin sectioning and micro-computed tomography. In staminate flowers, great variations of stamen number and arrangement are observed. The ancestral androecium likely consisted of two or more whorls with the outermost antepetalous stamen whorl developing centrifugally. Modification by reduction of the antepetalous whorl resulted in an outer alternipetalous stamen whorl in Croton section Moacroton, subgenus Quadrilobi. Several species in the subgenus Geiseleria show an independent reduction of stamen numbers by absence of a centrifugal development with the antepetalous whorl the first whorl to develop. Petal losses are observed in the distantly related C. setiger and C. dioicus. Chaotic stamen arrangement is found in C. celtidifolius (subgenus Adenophylli) as a result of a secondary stamen increase. In pistillate flowers, reduction of carpel numbers happened three times in the subgenus Geiseleria. C. monanthogynus has a bicarpellate ovary, while in C. setiger and C. michauxii the ovary is monocarpellate. Reduction of carpel number is linked with merism change and perianth reduction. The ovary in C. michauxii has basal placentation which is unique among all Croton. Moreover, strong bilateral sepals and nectaries are observed in species from section Julocroton. Therefore, the floral diversity of some species in the genus Croton could be explained by developmental modification of an ancestral form via reduction, rearrangement of stamen whorls, and symmetry shifts.

Sugar-conditioned honey bees can be biased towards a nectarless dioecious crop

The targeted pollination strategy has shown positive results in directing honey bees to crop flowers offering nectar along with pollen as reward. Kiwifruit is a functionally dioecious species, which relies on bees to transport pollen from staminate to pistillate nectarless flowers. Following the targeted pollination procedures recently validated, we first developed a mimic odor (KM) based on kiwifruit floral volatiles for which bees showed the highest level of generalization to the natural floral scent, although the response towards pistillate flowers was higher than towards staminate flowers. Then, in the field, feeding colonies KM-scented sucrose solution resulted in higher amounts of kiwifruit pollen collected by honey bees compared to control colonies fed unscented sucrose solution. Our results support the hypothesis that olfactory conditioning bees biases their foraging preferences in a nectarless crop, given the higher visitation to target flowers despite having provided the mimic odor paired with a sugar reward.

Cooler Is Better: The Role of Temperature in the Reproductive Biology of Persian Walnut (Juglans regia L.) Studied in a Hungarian-Bred Cultivar

The aim was to determine the growth of pollen tubes throughout the transmitting tissue and the process of fertilization in open, optimal and over pollination on the 3rd, 6th and 9th day after pollination of pistillate flowers, together with apomixis. The experiment was carried out over 2 years in Lovasberény, Fejér district, Hungary, which differed in temperature conditions. The average number of pollen tubes in the locule of the ovary was significantly higher in 2017 (1.3%) than in 2019 (1%). A higher percentage of fruit set was recorded in 2017 compared to 2019. The percentage of apomictic fruits from variant of unpollination was higher in 2017 (10%) than in 2019 (3.7%). Based on these results it can be concluded that pollen tube growth and post-fertilization processes together with apomixis of cultivar ‘AK’ are better adaptable to lower temperatures. These findings may help us to move walnut production to the north or to higher altitudes, where the climate is more continental.

Contrasting Phenological Patterns and Reproductive Strategies in Closely Related Monoecious Fig Tree Species.

Understanding the ecological and evolutionary aspects of mutualistic interactions is essential for predicting species responses to environmental changes. This study aimed to investigate the phenological patterns and reproductive strategies in two closely related fig tree species, Ficus citrifolia and Ficus eximia. We monitored 99 F. citrifolia and 21 F. eximia trees weekly from January 2006 to April 2011 in an area close to the southern edge of the tropical region in Brazil. Our results revealed contrasting phenological patterns between the two species, with F. citrifolia displaying an annual flowering pattern (1.4 episodes per tree per year) and F. eximia a supra-annual pattern (0.5 episodes per tree per year). We also found significant differences in reproductive strategies, with F. eximia producing more pistillate flowers and, consequently, more seeds and pollinating wasps per fig than F. citrifolia, likely as an adaptation to overcome limitations of low population density by maximizing the gene flow. As the shorter-lived organism, the fig wasp was found to influence critical processes associated with the success and stability of mutualism, such as fig development and ripening. Our findings emphasize the importance of understanding the intricate interactions between mutualistic partners and their adaptive responses to environmental conditions in shaping fig tree populations' reproductive strategies and genetic structure.

Principal component and correlation analyses study on fruit yield in cucumber (Cucumis sativus L.) genotypes

The degree of association between yield and its components can be identified using correlation and Principal Component Analyses (PCA). PCA also reveals key characteristics that explain most of the differences between genotypes. A study was formulated to evaluate the relationship between yield and its contributing traits in cucumber. The experiment was conducted with 16 cucumber genotypes in a Randomized Complete Block Design, with three replications. The correlation analysis revealed a strong and statistically significant relationship in number of pistillate flowers (r = 0.58**), number of branches (r = 0.43**), vine length (r = 0.69**), number of leaves (r = 0.73**), leaf area (r = 0.70**), number of fruits (r = 0.91**), fruit length (r = 0.40**), fruit girth (r = 0.39**), and fruit weight (r = 0.74**) with fruit yield. PCA revealed that PC1 accounted for 51.53% of the total variation, while PC2 explained 13.91% of the total variability. This study demonstrated that choosing traits such as number of pistillate flowers, number of branches, vine length, number of leaves, leaf area, number of fruits, fruit length, fruit girth, and fruit weight that have a strong positive correlation with fruit yield could be given priority in selection for yield improvement.

Biometric variability of inflorescence and flower traits among ex situ accessions of the neotropical oilseed palm Acrocomia Mart.

The oilseed palm genus Acrocomia is suitable for sustainable oil production in South America. The high phenotypic diversity of wild populations poses a challenge for the delimitation of the genus. Comparing the inflorescence architecture, a first-order panicle, and staminate and pistillate flower traits could be a valuable tool in resolving the taxonomic disarray. Thus, this study aims to characterize the differences in the inflorescence architecture and floral structures of three common and economically significant Acrocomia species: A. aculeata, A. totai, and A. intumescens. Biometric traits of the inflorescence architecture and floral structures of various Acrocomia accessions in an ex situ germplasm collection in Brazil were assessed. The unweighted pair group method with arithmetic mean (UPGMA) cluster analysis based on the Gower distance was used to measure dissimilarities between the individual plants of the accessions. To our best knowledge, this study provides the first evidence of the presence of second-order rachillae in the genus Acrocomia. Evaluated traits showed a high level of variation within and between accessions, emphasizing the phenotypic diversity of the genus. The accessions of A. totai were distinguishable from those of the other two species by their inflorescence architecture and flower traits. The dissimilarities between A. aculeata and A. intumescens were not sufficient to differentiate both. In conclusion, the quantitative assessment of inflorescence and floral traits is a valuable tool for taxonomic resolution of the genus.

Characterization of YABBY transcription factors in Osmanthus fragrans and functional analysis of OfYABBY12 in floral scent formation and leaf morphology

BackgroundThe plant-specific YABBY transcription factor family plays important roles in plant growth and development, particularly leaf growth, floral organ formation, and secondary metabolite synthesis.ResultsHere, we identified a total of 13 OfYABBY genes from the Osmanthus fragrans genome. These 13 OfYABBY genes were divided into five subfamilies through phylogenetic analysis, and genes in the same subfamily showed similar gene structures and conserved protein motifs. Gene duplication promoted the expansion of the OfYABBY family in O. fragrans. Tissue-specific expression analysis showed that the OfYABBY family was mainly expressed in O. fragrans leaves and floral organs. To better understand the role of OfYABBY genes in plant growth and development, OfYABBY12 was selected for heterologous stable overexpression in tobacco, and OfYABBY12-overexpressing tobacco leaves released significantly fewer volatile organic compounds than wild-type tobacco leaves. Overexpression of OfYABBY12 led to the downregulation of NtCCD1/4 and decreased β-ionone biosynthesis. Correspondingly, a dual-luciferase assay showed that OfYABBY12 negatively regulated the expression of OfCCD4, which promotes β-ionone synthesis. Furthermore, tobacco leaves overexpressing OfYABBY12 were curled and wrinkled and had significantly reduced leaf thickness and leaf inclusions and significantly extended flower pistils (styles).ConclusionOverall, the results suggest that the OfYABBY gene family may influence the biosynthesis of the floral scent (especially β-ionone) in O. fragrans and may regulate leaf morphogenesis and lateral organs.

Phyllanthus novofriburgensis and P. pedrosae, two new species of Phyllanthus subsect. Clausseniani (Phyllanthaceae) from Southeastern Brazil

Phyllanthus novofriburgensis J.C.R.Mendes, J.M.A.Braga &amp; Fraga sp. nov. and P. pedrosae J.C.R.Mendes, J.M.A.Braga &amp; Fraga sp. nov. are new species of Phyllanthaceae described from the Brazilian Atlantic Forest and Brazilian Cerrado, respectively. Phyllanthus novofriburgensis resembles P. acutifolius Poir. ex Spreng., P. hypoleucus Müll.Arg. and P. lilliputianus J.C.R.Mendes, J.M.A.Braga &amp; Fraga, sharing ovate, elliptical, and lanceolate leaf blades. However, it can be distinguished by its pendulous habit, often with sinuous branches and lanceolate leaf blades with characteristically revolute margins. Phyllanthus pedrosae exhibits morphological similarities with P. claussenii Müll.Arg. due to its subshrubby and prostrate habit. It is distinghuished by the unisexual inflorescence with cymules composed of one or two staminate flowers proximally positioned in the axil of the branches and solitary pistillate flowers distally situated, and the 5-merous calyx in the staminate and pistillate flowers. Both new species are classified in Phyllanthus subgen. Phyllanthus sect. Phyllanthus subsect. Clausseniani G.L.Webster, primarily due to the deeply emarginate anthers. Notes on their geographical distribution and habitat are provided, as well as a key to the species of Phyllanthus from Southeastern Brazil.

Correlation Coefficient and Path Analysis of Yield and It’s Components Analysis in Pumpkin (Cucurbita moschata Duch ex. Poir)

The current experiment was designed to evaluate the correlation coefficient and path analysis of yield and its components in pumpkin (Cucurbita moschata Duch ex. Poir) among various genotypes. The study involved 35 distinct genotypes, including a control, to measure both quantitative and qualitative traits. It was conducted in a randomized block design with three replications at Acharya Narendra Deva University of Agriculture and Technology, Kumarganj, Ayodhya, during the summer of 2021. Observations included the node number at first staminate and pistillate flower anthesis, days to anthesis of both flower types, days to first fruit harvest, fruit polar length, fruit equatorial circumference, flesh thickness, number of fruits per plant, average fruit weight, and total fruit yield per plant. The genotypes were assessed for yield through correlation coefficients and path analysis, indicating promising breeding values as supported by the analysis of variance. Among the 35 genotypes, four yielded significantly more than the highest-performing control, Narendra Agrim.

Nymphanthus namkadingensis, a new species of Phyllanthaceae from Laos

A new species of Nymphanthus (Phyllanthaceae), N. namkadingensis from Bolikhamxai Province, central Laos, is described and illustrated, along with its vernacular name and preliminary conservation status. The new species is similar to N. rubescens, but distinguished by having larger stipules, longer pedicels, and connate annular disc glands (vs. free disc glands) of pistillate flowers.

Observations on the Pollination in &lt;I&gt;Nechamandra alternifolia&lt;/I&gt; (Roxb.) Thw.

While studying the ecology of low lying lands in and around Calcutta, some observations were made on the mechanism of pollination in Nechamandra alternifolia, a common aquatic herb of Hydrocharitaceae. The mode of pollination in this plant indicates that the phenomenon is little influenced by the surface depression formed by tepals of the pistillate flowers. It takes place by the direct contact of the anthers of the floating male flowers on a calm surface of water with die stigmatic lobes of the female flower.

A new species of Croton sect. Geiseleria (Euphorbiaceae) from Brazil, supported by macro- and micromorphological data

Taxonomic studies on the genus Croton in the Midwest region of Brazil enabled the analysis of about 700 collections from all over the country. Three of these collections were identified as a new species, Croton piriquetifolius, which is described and illustrated here. We also give a preliminary evaluation of its conservation status, provide data on flowering and fruiting seasons, geographic distribution environmental preferences, as well as its systematic position. The new species is compared macro- and micromorphologically with C. adamantinus, C. glandulosus and C. eremophilus, with which it resembles or has been confused in herbaria. Morphological (e.g., presence, shape, and location of the acropetiolar nectaries, presence, and distribution of glands on stipules, presence, and size of pedicel on pistillate flower, integrity of styles, type, and location of trichomes) and anatomical (e.g., disposition of the stomata, contour of petiole and midrib, organization of vascular bundles, type of mesophyll, and types of trichomes) characters serve to differentiate the species studied.

Clusia salicifolia (Clusiaceae), a new hemiepiphyte species from Costa Rica and Panama

SummaryWe describe and illustrate Clusia salicifolia (Clusiaceae) a new species from Central America. This new species is different to all related species for its hemiepiphytic habit, narrow leaves with acute to acuminate apex, reticulate resin canals, staminate flowers with quadrangular androecium with 30 – 47 free stamens, and pistillate flowers with 4 stigmas and 4 pairs of stamen-like staminodia. The species is known from a limited number of localities in lowland wet forests in Costa Rica and Panama and is here assessed as endangered under the IUCN criteria.

Managed honeybee hives negatively affect the reproduction of native plants in a dryland nature reserve

Abstract The honeybee, Apis mellifera, stands out for its positive image due to its contribution to crop pollination and honey production, which facilitated its widespread distribution. However, large apiaries resulting in high honeybee densities could increase pollination frequency while increasing competition for floral resources, ultimately affecting native plant fitness. We studied the impact of managed honeybee hives on pollination and reproductive success of native plants in Villavicencio Nature Reserve, Mendoza, Argentina. During the flowering peak, we studied pollination and reproduction of three native plant species (Larrea divaricata, L. cuneifolia and Zuccagnia punctata) near and far from the hives. We estimated pollen deposition on flower stigmas, pollen tubes developed in flower pistils, fruit set, seed set and seed viability. We found that the honeybee hives had a positive effect on the reproduction of the self‐compatible species, L. divaricata. For the self‐incompatible species, results differed among species: Hives had positive effects on the pollination and negative effects on the reproduction of L. cuneifolia, while they had negative effects on the reproduction of Z. punctata. Synthesis and applications. Beekeeping is increasingly turning to natural areas in search of better quality honey; however, increased honeybee abundance in the field could influence the reproduction of native plants. Our results show that the introduction of managed hives negatively affected the reproduction of self‐incompatible native plants. This result allows us to make several recommendations for conservation and management actions concerning beekeeping in natural areas, regarding the among‐year rotation of the location of hives, the number of hives per site, and the need to monitor the reproduction of self‐incompatible species.

Studies on floral morphology and fruit diversity in wild melon (Cucumis melo L.ssp. agrestis (Naudin) Pangalo var. agrestis Naudin)

Floral morphology and fruit diversity are two essential attributes of a plant to establish mutualistic association with pollinators. Pollinators will have a direct influence on fruit setting and yield. The present paper represents the floral morphology and fruit diversity of six wild melon genotypes (Cucumis melo ssp. agrestis). The staminate and pistillate flowers were analysed for their size, sepal and petal colour and pedicel length. It was observed that female flowers of wild genotypes were longer than male flowers, however male flowers possessed larger diameter, longer pedicel length and corolla length over female flowers. Among the six genotypes studied, HUB-13 produced maximum male flowers per vine (156.75), longest female flower (5.33 cm), longest pedicel and corolla and largest ovary (6.11 mm diameter). Genotype HUB-4 produced maximum female flowers per vine (39.50) with lower male to female sex ratio (2.65:1) and recorded longest male flower length (4.43 cm). Genotype, HUB-2 recorded lowest flower length (2.40 cm, 2.85 cm) and diameter, smallest corolla length (1.25 cm, 1.13 cm) and pedicel length (1.05 cm and 0.50 cm) for male and female flowers respectively. The sepals and petals were green and yellow in colour respectively with varied intensity. The genotype, HUB-9 recorded maximum ovary length (1.83 cm), fruit weight (86.03 g), fruit yield per vine (1.98 kg) and fruit yield per hectare (9.48 t/ha).