Stamens Research Articles

Development differs between independently evolved staminode whorls in the same flower.

Staminodes are commonly studied in hermaphroditic flowers, in which a fraction of the androecium evolves into infertile structures, but few studies have addressed the evolution of staminodes as they occur through the loss of stamen function in carpellate flowers. Plants of Paronychia (Caryophyllaceae) are monoecious with hermaphroditic flowers with one staminodial whorl, except for the dioecious P. chartacea and P. minima. Dioecious species have carpellate flowers that evolved an additional whorl of staminodes, providing an exceptional opportunity to study a second origin of staminodes in the same flower. Using scanning electron microscopy, we observed the development of carpellate and staminate flowers to determine whether the developmental pathway of the staminodes in hermaphroditic flowers was co-opted during the evolutionary transition to unisexual flowers. In carpellate flowers, antesepalous staminodes initiate as sterile anthers that develop similar to functioning stamens, but arrest before full development, leaving a rudimentary anther with lateral lobes that correspond to thecae. After antesepalous staminodes arrest, alternisepalous staminodes initiate as structures that correspond with filaments, as they do in staminate and hermaphroditic flowers. The second origin of staminodes in carpellate flowers evolved using a different developmental pathway than what had previously evolved in the alternisepalous whorl. The two androecial whorls in the same flowers are serialogous as members of the androecium, but are paralogous as staminodes on the basis of structural and developmental differences.

Reproductive challenges related to a complex sexual system in Euphorbia rosescens, a rare endemic herb

AbstractWhen the sexual system of a rare plant species is complex, characterizing floral development, plant morphology, and subpopulation structure is essential for assessing reproductive potential. Availability of pollinator rewards and positioning of sexual morphs within inflorescences relates to outcrossing potential. We studied the complex sexual system of the recently discovered Euphorbia rosescens E.L. Bridges & Orzell, a rare species occurring in a single Florida county. Euphorbia rosescens has both monomorphic subpopulations of female plants and mixed subpopulations with male and andromonoecious plants. Most data on cyathia sex, inflorescence architecture, floral visitors, and fruit set came from one female subpopulation and one mixed subpopulation. Cyathia longevity, flowering phase, nectar secretion, pollen production, and viability were measured in female, male, and hermaphrodite cyathia. Female plants had fewer inflorescence levels and cyathia and significantly smaller cyathia than male and andromonoecious plants. Andromonoecious plants were larger and produced more cyathia relative to male plants. Within mixed populations, sex switching occurred in both directions between male and andromonoecious plants. Female plants did not switch sexes. Proximal to distal inflorescence levels transitioned from hermaphrodite to male cyathia on andromonoecious plants. Nectar secretion corresponded to initiation of staminate flowering, but in female cyathia stigmas were receptive approximately a day before nectar secretion. Pollen production and viability were similar in male and hermaphrodite cyathia. Fruit maturation was minimal, primarily observed on andromonoecious plants. Nectar availability, pollen rewards, trimorphic inequalities in inflorescence display, and low fruit set suggest high geitonogamy, thus limiting outcrossing potential for this species.

A new species of Struthanthus Mart. (Loranthaceae) from Oaxaca, Mexico.

Struthanthusibe-dzisp. nov. is a new species described and illustrated from the cloud and pine-oak forests of the Sierra Madre del Sur in Oaxaca, Mexico. This species shares similarities of leaf shape and inflorescence type with S.deppeanus, S.quercicola, and S.ramiro-cruzii. However, S.ibe-dzi can be recognized by its glaucous branches, leaves and inflorescences; compressed nodes; convoluted distal half of styles in pistillate flowers; and staminate flowers with asymmetrical thecae and an extended connective forming an apiculate horn in both anther series. A distribution map and an identification key are provided to separate S.ibe-dzi from morphologically similar congeners present in the region.

TYPHA DOMINGENSIS POLENLERİNDEN BİYOAKTİF BİLEŞİKLERİN EKSTRAKSİYONUNDA GELENEKSEL VE ULTRASONİK YÖNTEMLERİN ARDIŞIK KULLANIMI

Typha domingensis pollen is obtained from staminate flowers of plant that is edible. In this study, bioactive compounds from pollen were extracted using ethanol and methanol with conventional method. Further ultrasonication was applied to the samples to improve extraction efficiency. The extraction yield was higher with ethanol (26.3±0.14%) than with methanol (25.4±0.3%) and applying ultrasonication increased the yields significantly (P <0.05). Total phenolic compounds in ethanol and methanol extracts were determined as 9.83±0.48 and 9.71±0.55 mg GAE/g dry matter with the conventional method, and 11.76±0.64 and 12.74±0.37 mg GAE/g dry matter after ultrasonication, respectively. The flavonoid content with ethanol extraction was significantly higher than with methanol in both conventional and ultrasonication methods (P <0.05). Antioxidant activities using DPPH, ABTS, CUPRAC, and FRAP tests, were determined, and enhanced antioxidant capacities were observed after ultrasonication. The bioactive compounds were qualitatively analyzed using UV-VIS spectroscopy and FTIR which confirmed the presence of polyphenols.

Flower development and sexual dimorphism in Vernicia montana

The mu oil tree (Vernicia montana Lour.) is a dioecious species, but the genetic mechanisms underlying its phenotypic sexual dimorphism are unclear. In this study, we determined two pivotal phases of sex differentiation of mu oil tree via morphological and histological analyses of unisexual flowers: (I) differentiation of male or female primordia to produce staminate flowers (SFs) or transient hermaphrodite flowers (HFs), and (II) complete abortion of stamens in transient HFs to generate pistillate flowers (PFs). A total of 1621 sex-biased genes were identified by comparative transcriptome analysis which exhibited elevated rates of protein evolution than unbiased genes. The female-biased genes were enriched in the production of defense compounds while male-biased genes were focused on the production of viable pollens. Transcriptome-based analysis revealed that the differentially expressed genes (DEGs) between PFs and SFs in phase I involved in abscisic acid (ABA), auxin (AUX), cytokinin (CK), ethylene (ET), and gibberellin (GA) biosynthesis and signaling showed higher expression levels in males than in females in general, whereas the DEGs involved in jasmonic acid (JA) and salicylic acid (SA) pathways displayed opposite expression patterns. Moreover, differentially expressed endogenous ABA, AUX, GAs, JA, and SA exhibited consistent biased expression patterns with the DEGs by UPLC-MS-based analysis. Exogenous application of an anti-ethylene plant growth regulator could promote the development of stamens in PFs and generated HFs. Comparative transcriptomic and hormonal analyses of PFs and SFs in phase II indicated an increase in ET concentration when abortion of stamens in PFs occurred. This study suggested that phytohormones play key roles in sex dimorphism and ET may determine the development of stamens in PFs of mu oil tree, which provides an insight into plant sex differentiation mechanisms.

Flower structure, anatomy, and sexuality of Chrysophyllum gonocarpum (Sapotaceae).

The Sapotaceae are a significant component of the humid forests of the Neotropics and have many species of economic interest. Chrysophyllum gonocarpum is one of them and its edible fruits have currently acquired a high commercial value. Since there are no studies that cover its floral anatomy and elucidate its sexual system, the objective of the present study is to describe these aspects based on field observations and a detailed anatomical analysis of their flowers. Conventional techniques of plant anatomy are implemented. The results indicate that the species presents cryptic dioecy, showing specimens with morphologically and functionally pistillate flowers (with reduced staminodes), and trees with morphologically hermaphrodite and functionally staminate flowers. In addition, data on floral nectaries and laticiferous are provided.

Comparative transcriptome analyses reveal insights into catkin bloom patterns in pecan protogynous and protandrous cultivars.

In perennial plants such as pecan, once reproductive maturity is attained, there are genetic switches that are regulated and required for flower development year after year. Pecan trees are heterodichogamous with both pistillate and staminate flowers produced on the same tree. Therefore, defining genes exclusively responsible for pistillate inflorescence and staminate inflorescence (catkin) initiation is challenging at best. To understand these genetic switches and their timing, this study analyzed catkin bloom and gene expression of lateral buds collected from a protogynous (Wichita) and a protandrous (Western) pecan cultivar in summer, autumn and spring. Our data showed that pistillate flowers in the current season on the same shoot negatively impacted catkin production on the protogynous 'Wichita' cultivar. Whereas fruit production the previous year on 'Wichita' had a positive effect on catkin production on the same shoot the following year. However, fruiting the previous year nor current year pistillate flower production had no significant effect on catkin production on 'Western' (protandrous cultivar) cultivar. The RNA-Seq results present more significant differences between the fruiting and non-fruiting shoots of the 'Wichita' cultivar compared to the 'Western' cultivar, revealing the genetic signals likely responsible for catkin production. Our data presented here, indicates the genes showing expression for the initiation of both types of flowers the season before bloom.

Pollination ecology of the early-spring-blooming dioecious shrub Eurya japonica (Pentaphylacaceae)

While the majority of angiosperm plants have hermaphrodite flowers, where a single pollinator visit can achieve both pollen removal and deposition, 5%–6% of angiosperms, including zoophilous species, are dioecious, necessitating pollen transport from male plants to females. As such, dioecy is considered less adaptive under low-temperature conditions that tend to restrict or lower potential pollinator activity. Interestingly, however, a number of dioecious, zoophilous plants such as Eurya japonica Thunb. (Pentaphylacaceae) bloom in low-temperature seasons. This study made a quantitative assessment of flower visitors/pollinators of E. japonica blooming in early spring in central Japan. A total of 15 families in 4 orders of insects were recorded on both pistillate and staminate flowers of E. japonica, of which Diptera (Empididae and Chironomidae, in particular) and Hymenoptera were predominant regardless of site/year. Hymenopteran visitors were more active at higher temperatures, while dipterans were observed even at low temperatures. The fruiting rate and the number of seeds were greater at the site where dipteran visitors were more abundant. The present study suggests that the system of multi-taxa, Diptera-dominated pollination may play an important role in the reproductive ecology of dioecious plant species, in particular those flowering at low temperatures.

The staminal column in Solanum pollination: important in attraction, essential as a landing platform

The staminal column-corolla association in solanums constitutes a floral pattern that is distinctive, and generalized across a number of genera and families – characterized as ‘solanum-type’ flowers. We conducted experiments in natural populations of Solanum xanti in California, USA, to test the structure-function of the solanum staminal column and corolla. We excised the corolla of some flowers, the stamens of others, and painted stamens of others to assay pollinator response to changes in visible and UV patterns. Acrylic-painted staminal columns were yellow like the original anther color or concolorous with the corollas, and reflected light in the UV range instead of absorbing it. The flowers with stamens excised or with paint-altered UV patterns showed significantly lower fruit set, including those painted yellow. Experimental flowers with staminal columns only, i.e. with excised corollas, set fruit at the same rate as control flowers. Thus, the bee pollinators visit experimentally-altered flowers; they do not simply avoid aberrant flowers. While the combination of stamens and corolla are undoubtedly important visual attractants, our experiments support the underappreciated, and essential, role of the staminal column as a scaffold for the common, but distinctive, ‘buzz’ pollinators of solanums.

Floral development of one of the oldest dioecious lineages of Arecaceae reveals different stages of dicliny in pistillate and staminate flowers

AbstractArecaceae subtribe Mauritiinae are a lineage of Neotropical dioecious species in subfamily Calamoideae, the earliest diverging and most diverse group of palms regarding sexual systems. Ontogenetic and anatomical studies of reproductive structures contribute to the understanding of evolutionary relationships, but there is a lack of detailed information. We describe the anatomical floral development of Lepidocaryum tenue, Mauritia flexuosa and Mauritiella armata (subtribe Mauritiinae) using standard light microscopy techniques. Three central moments in the development of pistillate and staminate flowers were identified: the initial phase of development of the floral meristem; the phase of determination of the whorls that will compose the pistillate and staminate flowers; and the phase of differentiation (pre-anthesis) of these whorls. Although the pre-anthetic flowers are diclinous, they are initially monoclinous, suggesting a hermaphrodite ancestor for Mauritiinae. The development is asynchronous since, in pre-anthesis, the pistillate flowers have staminodes that produce non-viable pollen grains, whereas the staminate flowers do not even have a pistillode. Staminodes may have a secondary function in attracting floral visitors.

Flowering and fruiting of Tape Seagrass Enhalus acoroides (L.f.) Royle from the Andaman Islands: observations from inflorescence buds to dehiscent fruits

Seagrass phenophases are crucial in understanding their reproductive biology but are seldom documented. We studied flowering and fruiting phenophases of Enhalus acoroides from a mixed-species intertidal seagrass meadow in Ritchie’s archipelago, Andaman Islands, India. The estimated mean densities of pistillate and staminate flowers were 16.0 ± 12.0/ m2 and 12.7 ± 7.3/ m2, respectively. We observed the bloom of free-floating male flowers (961.7 ± 360.4/ m2) during the spring low tides (at mean sea surface temperature ~30°C). Seagrass cover, shoot density, and canopy height of E. acoroides, along with flowering densities, showed a zonal variation within the sampled meadow. We report the first-time observations of several phenophases of E. acoroides, such as female inflorescence buds, male inflorescence, a bloom of released male flowers, pollination, and fertilized flowers from the Indian waters. We also report the prevailing threats to seagrass meadows, such as meadow scarring done by boat anchorage in the Andaman Islands.

Phenology of flowering and seed development of jernang rattan (Daemonorops spp.)

Abstract. Fridayanti N, Widajati E, Ilyas S, Budi SW, Palupi ER. 2023. Phenology of flowering and seed development of jernang rattan (Daemonorops spp.). Biodiversitas 24: 349-358. Jernang rattan has a high economic value due to its resin content in the exocarp, as the raw material of dyes, medicines, and cosmetics. The resin is highest in the immature fruit skin (exocarp); therefore, fruits are harvested before the seed is germinable. As a consequence, regeneration is very scarce, and the species is categorized as a rare plant. This research was aimed at investigating the flowering phenology and seed development of jernang rattan until they reach physiological maturity, when the viability and vigor are at their highest. The flowering phenology was observed based on Biologische Bundesanstalt Bundessortenamt and Chemische Industrie (BBCH), at the inflorescence stage, flowering stage, fruit development stage, and fruit ripening stage. The inflorescence development from flower bud until ready to bloom took 136.4 ±10.9 days for male plants and 141.6 ±16.4 days for female plants. The inflorescence of staminate flowers bloomed longer (29.4 ±2.7 days) than pistillate flowers (15.4 ± 4.0 days). Fruit abortion mostly occurs during the first six months of fruit development, coincides with the nuclear stage of endosperm, and the final seed set is 56%. It takes around 27 months of one reproduction cycle from the appearance of the inflorescence to seed maturity. The fruit reaches physiological maturity approximately at 22 MAA when the seed is of high viability and vigor, and harvesting at 22 MAA is best for seed production. It is recommended to set up a seed production area separated from the resin production area.

A Study on the Characteristics of Buds and Flowers in Pomegranate: Differences among Cultivars

The growing cultivation of pomegranate and the interest of consumers in the nutraceutical properties of the fruit have not yet spurred similar increases in the knowledge base of some important botanical and physiological aspects of this species, such as bud differentiation. The aim of this research was to study the bud morphology of four pomegranate cultivars (‘Comune S. Giorgio’, ‘Wonderful’, ‘Ki-Zakuro’, and ‘Haku Botan’) to better clarify the bud differentiation process. In all four cultivars, the number and the position of the buds were variable, from a typical two buds per node to a single bud or more (3). Two types of buds were observed: small and thin on the twigs (short, medium, and long) and large and round on the spurs; large buds were also observed on twigs but in a reduced number. Flowers showed differences among the cultivars, with a larger number of petals in ‘ornamental’ cultivars because of the petaloidy. Hermaphrodite flowers were larger and longer than the staminate flowers and also more abundant. Moreover, flowers developing from a flower bud were longer than flowers developing from mixed buds. The presence of an undifferentiated meristem, starch grains in the protective scales, and two small transition leaves were observed in all the types of buds from summer to the end of endodormancy in all cultivars. However, a dome-shaped meristem was observed in a few flower buds. Our observations indicate pomegranate behaves as a species for warm, sub-tropical, and tropical areas more than for temperate ones.

Emended description of the South American genus Elephantomene (Menispermaceae)

Elephantomene is a monospecific genus, distributed in South America. To our knowledge, there are no studies about the pistillate flower in Elephantomene eburnea. This is the first complete taxonomic description involving all floral whorls of staminate and pistillate flowers. Between January 2018 and October 2021, including types housed at 32 national and foreign herbaria. In the Neotropics, the Amazonian is the main center of concentration for the genus. The tripartite gynophores, the internal sepals fused forming a solid column and the stamens inserted in this column were the main characters used to identify the species. Descriptions and illustrations of the species are presented, as well as data concerning geographical distribution and additional comments of the species.

Petal-assisted artificial pollination method enhanced the fruit setting ratios in tea plant (<i>Camellia sinensis</i>)

<bold/> The pollinated method plays an important role in developing F1 population. Our study presents an improved method of petal-assisted artificial pollination in tea plants. The field operation using this method exhibited high efficiency in which more than 500 pistillate flowers per day can be pollinated per capita, and the pollen amount from only one staminate flower was sufficient to pollinate more than 5 pistillate flowers. Additionally, we surveyed the fruit-setting ratio in three F1 groups, which were established using this method and the influence of rainfall on the fruit-setting ratio. The results indicate that the fruit-setting ratio was superior among the tested F1 population with an average value of 12.90%, and a significant negative correlation was observed between rainfall and fruit-setting ratio. By analyzing the growth states of each F1 population, both a high germination rate and survival rate were observed. Furthermore, the purity for 184 individuals in the F1 population of ‘Jiaming 1’ × ‘Longjing 43’ (J×L) were analyzed with 32 selected simple sequence repeats (SSRs). The purposes of this paper are (1) to demonstrate that this method is beneficial to establish high purity F1 population and (2) to identify the number of SSR markers that are suitable for identification. The parentage analysis detected nine false-hybrid individuals, and the rate of false-hybrid was only 4.89% at 95% confidence, demonstrating that a low false-hybrid rate can be achieved by the method. Furthermore, one to two SSR markers randomly selected from each linkage group or chromosome were recommended as a sufficient quantity for SSR identification.

Aphananthe Planch. (Cannabaceae) flower preserved in the Mexican amber

Cannabaceae (Urticalean Rosids clade) is a small family with ten genera and a wide distribution in tropical and temperate regions worldwide. A complete understanding of the history of the lineage is fundamental to the integration of its fossil record, which needs to be better documented in low latitudes of North America. This work recognizes a new species, Aphananthe manchesteri Hernández-Damián, Rubalcava-Knoth et Cevallos- Ferriz sp. nov. (Cannabaceae), from the Miocene amber deposits of Simojovel de Allende, Chiapas, Mexico, based on a flower analyzed with reflected light and CT-scanning. Flowers of Cannabaceae are generally staminate or pistillate and small; staminate flowers have five sepals and opposite five stamens, and a pubescent pistillode, such as the fossil. However, the presence of three unguiculate and two ovate sepals with a puberulent surface are characteristics that allow its recognition as Aphananthe, the fossil is morphologically similar to Aphananthe monoica, an extant species that grows along the Pacific coast of Mexico. The presence of Aphananthe manchesteri sp. nov. in southern Mexico during the middle-early Miocene, ~23–15 Ma ago, supports the history of the lineage in lowlatitude North America, representing an expansion of the Boreotropical Flora. It adds to the taxonomical diversity of angiosperms preserved in Mexican amber, comparable with amber deposits from the Dominican Republic, where another anemophilous extinct species member of the Urticalean Rosids clade has been reported. This coincidence further supports the development of similar plant communities between these fossiliferous localities.

Floral Characterization of Pomegranate Genotypes to Improve Hybridization Efficiency.

Pomegranate (Punica granatum) has staminate (male), androgynous (hermaphrodite), and intermediate flower types. Floral characterization is difficult for breeding efficiency across many pomegranate genotypes in Pakistan, which is essential for pomegranate cultivar enhancements. The present research focused on the floral characterization and breeding efficiency of fifteen pomegranate genotypes. Flower sex ratio, floral morphological parameters, i.e., flower length, ovary width, flower notch, flower tip and stigma with style length, and fruit set percentage were examined during the experiment. In terms of sex ratio, male flowers were found to be higher among all genotypes. Due to clear differences in flower length, width, and heterostyly facilitating visual identification of the hermaphrodite flowers, genotype Ternab-2, Kandhari White, and Kandhari Red had higher fruit set (≥70%) among all cross combinations attempted. Genotype Sava had higher flower length and heterostyly of hermaphrodite flower type, but ovary width was not very distinct, leading to average crossing success (85-34%). In conclusion, single or combination of morphological characters can be used for accurate identification of hermaphrodite flowers, which can improve hybrid efficiency and fruit set after artificial cross-pollination.

Three new species of Elatostema (Urticaceae) from Thailand.

Three new species of Elatostema (Urticaceae) from Thailand, E.kaweesakii Triyutth. & L.F.Fu, sp. nov., E.rubricaule Triyutth. & L.F.Fu, sp. nov. and E.saxatile Triyutth. & L.F.Fu, sp. nov., are newly described and illustrated. These new species can be distinguished by the presence of rhizome. Elatostemakaweesakii is similar to E.atroviride. Elatostemakaweesakii is a lithophyte growing in limestone crevices. It differs from E.atroviride by its large swollen rhizome, glabrous stem, glabrous receptacle, number of tepal in staminate flower, absence of tepal in pistillate flower, presence of staminodes in pistillate flower and smooth achene. Elatostemarubricaule and E.saxatile are found on sandstone habitats. They have distinct flattened and disk-like rhizome. Elatostemarubricaule is distinguished by its distinct sulcate and reddish stem with flattened and disc-like rhizome and chartaceous leaves with entire margin. Elatostemasaxatile resembles E.bulbiferum but differs by its flattened and disc-like rhizome, acute leaf apex, glabrous receptacle in pistillate inflorescences, presence of staminodes in pistillate flower, and its sandstone habitat. Descriptions, distribution, ecological and phenological data are provided.

Understanding floral variation in Leiothrix (Poales: Eriocaulaceae): anatomy, development and insights into pollination

Abstract Leiothrix differs from other genera of Eriocaulaceae by having pistillate flowers with nectariferous and stigmatic branches that diverge at different heights on the style and staminate flowers with free or fused petals. To understand the ontogenetic processes that result in these morphological variations, we studied the development and floral vasculature in six species of the genus. In pistillate flowers, the nectariferous branches, which are in a carinal position, correspond to the apex of the carpels, whereas the stigmatic branches, in a commissural position, are formed by the marginal tissues of the carpels and initiate later than the nectariferous branches. The upper margins of the carpels elongate, forming a tubular structure that raises the stigmatic branches; the greater its development, the greater the distance between the stigmatic and nectariferous branches. In staminate flowers, the fusion of the petals appears to be post-genital in the median and apical portions and congenital in the more basal portion. Despite the differences in floral development, Leiothrix shares the same pattern of floral vasculature with other genera of Eriocaulaceae, exhibiting a central vascular plexus in the receptacle from which a single trace diverges for each sepal, petal and stamen. The staminodes are not vascularized. The dorsal carpellary bundles supply the nectariferous branches, but the ventral carpel bundles are reduced and are not involved in the supply of the ovules and stigmas. The differences in the height of insertion of the nectariferous branches are probably the result of selective pressure exerted by different groups of pollinating insects. Our hypothesis is that species in which the nectariferous branches are inserted below the stigmatic branches, and are therefore less accessible, exhibit a more specialized pollination system. The absence of nectariferous branches in L. angustifolia indicates secondary loss probably associated with spontaneous geitonogamy.

Effect of Inter-cultivation and Physical Barriers on Growth, Yield and Disease occurrence in Zucchini (Cucurbita pepo L.)

The present investigation was performed to study the effect of inter-cultivation and physical barriers on growth, yield and disease occurrence in zucchini during January-March, 2022. The field trial was laid out in Randomized Block Design (RBD) with three replications keeping the plot size 1.5 m x 1.5 m. During the experiment, observations for plant height, number of leaves, number of nodes, days to flower initiation (staminate and pistillate), total number of staminate and pistillate flowers, number of fruits per plant, weight of fruits, yield per hectare etc were recorded. The results revealed that the treatment T4 Zucchini + Aluminium foil (On the ridge) recorded maximum plant height (38.33 cm at 30 DAS, 49.75 cm at 45 DAS, 62.75 cm at 60 DAS), number of nodes (21.08), number of leaves per plant (19.58), minimum number of days to flower initiation (39.00 in case of staminate flowers and 44.83 in case of pistillate flowers), maximum number of staminate flowers (8.58) and pistillate flowers (13.00), maximum number of fruits per plant(5.33), maximum weight of fruits per plant (0.749 kg), maximum weight of fruits per plot (1.99 kg) and yield per hectare (7.49 t/ha-1 ).