Floral Senescence Research Articles

Shedding light on pollination deficits: Cueing into plant spectral reflectance signatures to monitor pollination delivery across landscapes

AbstractPollination underlies plant yield, health and reproductive success in agricultural and natural systems worldwide. It is therefore concerning that declining animal pollinator populations compounded by growing demands for food are leading to rising pollination deficits, with globally significant economic and environmental implications.Despite this urgent issue, accurate and scalable tools to quantify and track pollination across useful spatiotemporal scales are lacking. Here, we propose to shed new light on pollination deficits, looking to remote sensing platforms as a transformative mapping and monitoring tool and a solution for pollinator conservation and crop management.Providing a synthesis of our current understanding of pollination‐triggered floral senescence and underlying ultrastructural and metabolic changes, we propose how spectral reflectance technologies could be applied to accurately detect pollination events in real‐time and at the landscape scale.Synthesis and applications: We highlight where research efforts can be targeted to produce scalable methods for identifying field‐relevant bioindicators of pollination. We provide guidance on how spectral imaging accompanied by machine learning and coupled with autonomous operation technologies will enable applications to detect pollination delivery across complex landscapes. Ultimately, such an ecological application will transform our quantitative understanding of pollination services and, by directly linking plant yields and health, will reveal pollination deficits at high resolution to help mitigate risks to food security and ecosystem functioning.

Within-flower anther polymorphism and the floral biology of Jaltomata antillana (solanaceae) of the Greater Antilles

The small, unspecialized flowers of Jaltomata antillana (Solanaceae), typical of island species, are likely allochthonous in origin given similar congeneric close relatives in the Andes. Floral nectar, produced continuously during the life of the flower, is yellowish in color and is UV absorptive, in contrast with the white UV reflecting corolla. The day the flower opens flowers are pistillate (anthers not yet presenting pollen) for only a few hours and then become functionally hermaphroditic (anthers dehisce). Within each flower there is length variation among the stamens, size variation among anthers, and staggered anther dehiscence, collectively an apparent pollen-dispensing mechanism. Flowers close each night both when the flower will be functional the next day and at floral senescence. In a pollinator-free greenhouse, 100% of the flowers that were manually self-pollinated set fruits; however, 29% of the tagged unmanipulated flowers set fruit. Autonomous self-pollination takes place at the end of the corolla’s life and allows fruit and seed production in the absence of pollinators but results in fruits that are lighter and contain fewer seeds than fruits resulting from manual self-pollinations.

Evolutionary and Integrative Analysis of the Gibberellin 20-oxidase, 3-oxidase, and 2-oxidase Gene Family in Paeonia ostii: Insight into Their Roles in Flower Senescence

The brief longevity of tree peony blossoms constrains its ornamental value and economic worth. Gibberellins (GAs) are crucial in the modulation of flower senescence, and GA 20-oxidase (GA20ox), GA 3-oxidase (GA3ox), and GA 2-oxidase (GA2ox) catalyze the synthesis and deactivation of bioactive GAs. In Paeonia ostii, a total of three PoGA20ox, ten PoGA3ox, and twelve PoGA2ox proteins were identified and comprehensively analyzed. The analysis of the gene structures, conserved domains, and motifs revealed structural similarities and variances among the GA20ox, GA3ox, GA2ox-A, and GA2ox-B subfamilies. The synteny analysis indicated a scarcity of collinear blocks within the P. ostii genome, with no tandem or whole-genome duplication/segmental duplications found in PoGAoxs. The investigation into the binding of transcription factors to PoGAox promoters and the assessments of the expression levels suggest that PoGA2ox1 and PoGA2ox8.1 are promising candidate genes implicated in the regulation of floral senescence. Further, Pos.gene61099 (BPC6) and Pos.gene61094 (CIL2) appear to modulate PoGA2ox1 transcription in a positive and negative manner, respectively, while Pos.gene38359 (DDF1) and Pos.gene17639 (DREB1C) likely enhance PoGA2ox8.1’s expression. This study lays a foundation for an in-depth understanding of PoGAox functions and the development of strategies to delay flower senescence in tree peony.

The retardation of floral senescence by simultaneous action of nano silver and AVG in cut flowers, which have distinct sensitivities to ethylene and water stress

The retardation of floral senescence by simultaneous action of nano silver and AVG in cut flowers, which have distinct sensitivities to ethylene and water stress

How far can omics go in unveiling the mechanisms of floral senescence?

Floral senescence is of fundamental interest in understanding plant developmental regulation, it is of ecological and agricultural interest in relation to seed production, and is of key importance to the production of cut flowers. The biochemical changes occurring are well-studied and involve macromolecular breakdown and remobilisation of nutrients to developing seeds or other young organs in the plant. However, the initiation and regulation of the process and inter-organ communication remain to be fully elucidated. Although ethylene emission, which becomes autocatalytic, is a key regulator in some species, in other species it appears not to be as important. Other plant growth regulators such as cytokinins, however, seem to be important in floral senescence across both ethylene sensitive and insensitive species. Other plant growth regulators are also likely involved. Omics approaches have provided a wealth of data especially in ornamental species where genome data is lacking. Two families of transcription factors: NAC and WRKY emerge as major regulators, and omics information has been critical in understanding their functions. Future progress would greatly benefit from a single model species for understanding floral senescence; however, this is challenging due to the diversity of regulatory mechanisms. Combining omics data sets can be powerful in understanding different layers of regulation, but in vitro biochemical and or genetic analysis through transgenics or mutants is still needed to fully verify mechanisms and interactions between regulators.

Senescence in dahlia flowers is regulated by a complex interplay between flower age and floret position.

Mechanisms regulating flower senescence are not fully understood in any species and are particularly complex in composite flowers. Dahlia (Dahlia pinnata Cav.) florets develop sequentially, hence each composite flower head includes florets of different developmental stages as the whole flower head ages. Moreover, the wide range of available cultivars enables assessment of intraspecific variation. Transcriptomes were compared amongst inner (younger) and outer (older) florets of two flower head ages to assess the effect of floret vs. flower head ageing. More gene expression, including ethylene and cytokinin pathway expression changed between inner and outer florets of older flower heads than between inner florets of younger and older flower heads. Additionally, based on Arabidopsis network analysis, different patterns of co-expressed ethylene response genes were elicited. This suggests that changes occur in young inner florets as the whole flower head ages that are different to ageing florets within a flower head. In some species floral senescence is orchestrated by the plant growth regulator ethylene. However, there is both inter and intra-species variation in its importance. There is a lack of conclusive data regarding ethylene sensitivity in dahlia. Speed of senescence progression, effects of ethylene signalling perturbation, and patterns of ethylene biosynthesis gene expression differed across three dahlia cultivars ('Sylvia', 'Karma Prospero' and 'Onesta') suggesting differences in the role of ethylene in their floral senescence, while effects of exogenous cytokinin were less cultivar-specific.

Effect of Postharvest Temperature Management on Scent Emission from Cut Flowers of Tulip Cultivars

Tulip (Tulipa gesneriana L.) cultivars exhibit diverse floral scents, the emissions of which are generally influenced by temperature. To fully benefit from these scents and add value to cut tulips, it is necessary to evaluate the scent emission response to temperature. This study investigated the daily emission changes of 82 volatiles, including the main scent compounds, at different temperatures (13, 18, and 23°C), in the cut tulips from eight tulip cultivars with different scents. At 23 and 18°C, the total scent emissions of each cultivar increased with flower opening and subsequently decreased with visible senescence. Floral senescence progressed more rapidly at 23°C, and the decrease in total scent emission occurred most rapidly at 23°C. Scent emissions at 18°C tended to be lower than at 23°C. The vase life of the cut tulips was most prolonged at 13°C owing to the slow senescence; however, scent emissions remained low after the flower opening. These results indicate that improving both tulip scent emission and vase life under constant temperature conditions is difficult. It was observed that scent composition changed before and after flower opening, and with floral senescence. In contrast, temperature had little effect on scent composition. Cut tulips stored at a low temperature (10 or 15°C) over four and a half days and then transferred to room temperature (20°C) had a longer vase life than tulips maintained at room temperature, due to delayed senescence. In addition, scent emissions were low at low temperatures, but increased rapidly upon transfer to room temperature. Therefore, storage of cut tulips at low temperatures may lead to increased scent emissions upon transfer to room temperature. These findings imply that low-temperature storage of cut tulips before sale contributes to both vase life and a rich scent after sale. The results reported here demonstrate the improvement of cut tulip scent emissions by appropriate temperature management.

Regulation of floral senescence in Arabidopsis by coordinated action of CONSTANS and jasmonate signaling

Regulation of floral senescence in Arabidopsis by coordinated action of CONSTANS and jasmonate signaling

Regulation of floral senescence in Arabidopsis by coordinated action of CONSTANS and jasmonate signaling

In Arabidopsis, photoperiodic flowering is controlled by the regulatory hub gene CONSTANS (CO), whereas floral organ senescence is regulated by the jasmonates (JAs). Because these processes are chronologically ordered, it remains unknown whether there are common regulators of both processes. In this study, we discovered that CO protein accumulates in Arabidopsis flowers after floral induction, and it displays a diurnal pattern in floral organs different from that in the leaves. We observed that altered CO expression could affect flower senescence and abscission by interfering with JA response, as shown by petal-specific transcriptomic analysis as well as CO overexpression in JA synthesis and signaling mutants. We found that CO has a ZIM (ZINC-FINGER INFLORESCENCE MERISTEM) like domain that mediates its interaction with the JA response repressor JAZ3 (jasmonate ZIM-domain 3). Their interaction inhibits the repressor activity of JAZ3, resulting in activation of downstream transcription factors involved in promoting flower senescence. Furthermore, we showed that CO, JAZ3, and the E3 ubiquitin ligase COI1 (Coronatine Insensitive 1) could form a protein complex in planta, which promotes the degradation of both CO and JAZ3 in the presence of JAs. Taken together, our results indicate that CO, a key regulator of photoperiodic flowering, is also involved in promoting flower senescence and abscission by augmenting JA signaling and response. We propose that coordinated recruitment of photoperiodic and JA signaling pathways could be an efficient way for plants to chronologically order floral processes and ensure the success of offspring production.

Large flowers can be short‐lived: Insights from a high Andean cactus

AbstractLong‐lived and large flowers signify high floral maintenance costs. Species of arid/semiarid climates with large flowers are expected to have short flower life spans and pollination‐induced flower longevity in order to curb high floral water and other maintenance costs. We explored the context‐dependent large flower/short flower longevity hypothesis in Eriosyce curvispina (Cactaceae), a large‐flowered species of the semiarid central Chilean Andes. We determined breeding system, flower visitation rates, and open‐pollination fruit set and quantified floral water content. In a temperature‐controlled field manipulative experiment, we measured potential flower longevity and tested for the presence of pollination‐induced floral senescence. We measured the time span of the complete flower cycle defined as from when the flowers began to open to when they were totally closed, and the time span of fully open flowers defined as from when they were totally open until they began to close. The potential flower life span averaged 2.8 days (complete flower cycle) to 2.3 days (fully open flower). The complete flower cycle lasted 21.5 h, but flowers were fully open for only 10.1 h across days. Flower longevity in days was far shorter than reported for a large sample of species in the area. No evidence was found for pollination‐induced flower senescence as a complementary means for reducing floral maintenance costs. Eriosyce curvispina is self‐incompatible and abundantly pollinated by two megachilid bees. The level of pollen limitation (L = 0.36) was lower than the average reported for self‐incompatible angiosperms. Thus, the short flower life span in E. curvispina is not an impediment for high fruit set. Flowers contain >5 g of water of which >2 reside in >40 petaloid tepals. The amount of water is far higher than in another large‐flowered, non‐cactus species in the area, but only about 15% of that reported in the giant saguaro cactus which has larger flowers than E. curvispina.

Changes in female function and autonomous selfing across floral lifespan interact to drive variation in the cost of selfing.

PremiseMorphological and developmental changes as flowers age can impact patterns of mating. At the same time, direct or indirect costs of floral longevity can alter their fitness outcomes. This influence has been less appreciated, particularly with respect to the timing of selfing. We investigated changes in stigma events, autonomous selfing, outcross seed set capacity, and autofertility—a measure representing the potential for reproductive assurance—across floral lifespan in the mixed‐mating biennial Sabatia angularis.MethodsWe examined stigma morphology and receptivity, autonomous self‐pollen deposition, and seed number and size under autonomous self‐pollination and hand outcross‐pollination for flowers of different ages, from 1 d of female phase until 14 d. We compared autonomous seed production to maximal outcross seed production at each flower age to calculate an index of autofertility.ResultsThe stigmatic lobes begin to untwist 1 d post anthesis. They progressively open, sextend, coil, and increase in receptivity, peaking or saturating at 8–11 d, depending on the measure. Autonomous seed production can occur early, but on average remains low until 6 d, when it doubles. In contrast, outcross seed number and size start out high, then decline precipitously. Consequently, autofertility increases steeply across floral lifespan.ConclusionsChanges in stigma morphology and receptivity, timing of autonomous self‐pollen deposition, and floral senescence can interact to influence the relative benefit of autonomous selfing across floral lifespan. Our work highlights the interplay between evolution of floral longevity and the mating system, with implications for the maintenance of mixed mating in S. angularis.

RhWRKY33 Positively Regulates Onset of Floral Senescence by Responding to Wounding- and Ethylene-Signaling in Rose Plants.

Rose plants are one of the most important horticultural crops, whose commercial value mainly depends on long-distance transportation, and wounding and ethylene are the main factors leading to their quality decline and accelerated senescence in the process. However, underlying molecular mechanisms of crosstalk between wounding and ethylene in the regulation of flower senescence remain poorly understood. In relation to this, transcriptome analysis was performed on rose flowers subjected to various treatments, including control, wounding, ethylene, and wounding- and ethylene- (EW) dual treatment. A large number of differentially expressed genes (DEGs) were identified, ranging from 2,442 between the ethylene- and control-treated groups to 4,055 between the EW- and control-treated groups. Using weighted gene co-expression network analysis (WGCNA), we identified a hub gene RhWRKY33 (rchiobhmchr5g0071811), accumulated in the nucleus, where it may function as a transcription factor. Moreover, quantitative reverse transcription PCR (RT-qPCR) results showed that the expression of RhWRKY33 was higher in the wounding-, ethylene, and EW-treated petals than in the control-treated petals. We also functionally characterized the RhWRKY33 gene through virus-induced gene silencing (VIGS). The silencing of RhWRKY33 significantly delayed the senescence process in the different treatments (control, wounding, ethylene, and EW). Meanwhile, we found that the effect of RhWRKY33-silenced petals under ethylene and EW dual-treatment were stronger than those under wounding treatment in delaying the petal senescence process, implying that RhWRKY33 is closely involved with ethylene and wounding mediated petal senescence. Overall, the results indicate that RhWRKY33 positively regulates the onset of floral senescence mediated by both ethylene and wounding signaling, but relies heavily on ethylene signaling.

Flower stages, germination and viability of pollen grains of Annona squamosa L. in tropical conditions

The success in the application of artificial pollination techniques, aspects of floral biology should receive special attention, especially regarding the viability studies of pollen grains. In this sense, two experiments were carried out, aiming to determine the floral stages: floral opening (anthesis), female, male and senescence stages of A. squamosa L flowers under tropical climate conditions, and to evaluate the germination and viability of pollen grains submitted to different storage conditions. In the first experiment, observations and data collection began when flowers were still closed. Readings were taken every two hours for 46 hours until all the flowers reached the senescence stage. For the second, the experimental design was completely randomized, in a 2 x 7 factorial scheme, with 2 storage conditions (environment at 27 ± 2°C and refrigerated at 5 ± 2°C) and 7 pollen grain conditioning times (0, 4, 8, 12, 16, 20 and 24 hours), with 4 repetitions for the analysis of pollen grain germination and 3 repetitions for the analysis of pollen grain viability, and each repetition consisted of one blade. The variables evaluated were percentage of viable and non-viable pollen grains and percentage of germinated and non-germinated pollen grains. For tropical climatic conditions, the flower anthesis (female stage) of the sugar-apple begins at 00:00 h, extending until 12:00h on the same day. The flowers of the tree reach a functionally staminate stage (male stage) from 6 a.m. the next day. Pollen grains stored at room conditions (27 ± 2°C) remain viable for up to 24 hours after collection, showing that storage in a cold environment at low temperatures (5 ± 2°C) is not necessary. Seed pollen grains have a germination percentage of 51.25% when stored under ambient conditions (27 ± 2°C) for up to 4 hours after collection.

Pollination ecology and breeding systems of Cypripedium kentuckiense (Orchidaceae) in Tennessee1

The orchid Cypripedium kentuckiense is listed as imperiled in Tennessee and Oklahoma and critically imperiled in seven other states. We followed individuals' vegetative and floral traits over two seasons. Patterns of floral senescence were found to vary over two seasons and might be related to April temperatures when buds develop. Mechanical self-pollination was uncommon but perhaps “leaky.” Frequencies of insect-mediated pollination were surprisingly high (62%) for a Cypripedium species with large flowers but conversion of flowers into fruit was low (7% and 14%), suggesting that cryptic factors lower reproductive success, not inadequate pollinator visits. Hand-pollinations suggest flowers are self-compatible. As in other Cypripedium species, floral architecture relates to pollinator dimensions but at this site, only two bee species, Anthophora abrupta and A. bomboides, were primary pollinators. Male A. abrupta were common visitors although male bees are uncommon pollen vectors of Cypripedium species. For the first time, exit patterns of bees inside Cypripedium flowers were recorded based on bee species and gender. This behavior varied and was somewhat atypical of previous studies on other bee-pollinated species in the clade and genus. Specifically, Anthophora species within labella chewed on the epidermis lingering within the interior and exit canals. Consequently, C. kentuckiense might not be a trap.

Ethylene Biosynthesis, Signaling, and Regulation in Roses

Ethylene-mediated premature floral senescence influences the postharvest quality and longevity of rose flowers. In recent years, studies have unveiled the action of ethylene during the development and senescence of rose flowers. However, despite the evidence that ethylene is highly produced in ethylene-sensitive roses, there is not always a direct interrelationship between ethylene sensitivity and rose flower longevity. In addition, ethylene sensitivity and ethylene-related gene expressions in roses are still not clearly understood. In this review, we summarized and discussed ethylene synthesis and sensitivity, role of ethylene-related genes, and impacts of ethylene on the postharvest quality of cut roses. By combining the mechanism of ethylene biosynthesis and signaling with ethylene sensitivity, we also highlighted the potential use of ethylene inhibitors for ethylene control and to improve the postharvest quality of cut rose flowers. We believe that this review will provide sufficient information about ethylene biology in rose flowers and contribute in developing effective methods to extend the postharvest life of roses by preventing ethylene damage.

Silencing of FOREVER YOUNG FLOWER-Like Genes from Phalaenopsis Orchids Promotes Flower Senescence and Abscission.

Ectopic expression of FOREVER YOUNG FLOWER (FYF) delays floral senescence and abscission in transgenic Arabidopsis. To analyze the FYF function in Phalaenopsis orchids, two FYF-like genes (PaFYF1/2) were identified. PaFYF1/2 were highly expressed in young Phalaenopsis flowers, and their expression decreased significantly afterward until flower senescence. This pattern was strongly correlated with the process of flower senescence and revealed that PaFYF1/2 function to suppress senescence/abscission during early flower development. Interestingly, in flowers, PaFYF1 was consistently expressed less in petals than in lips/sepals, whereas PaFYF2 was expressed relatively evenly in all flower organs. This difference suggests a regulatory modification of the functions of PaFYF1 and PaFYF2 during Phalaenopsis flower evolution. Delayed flower senescence and abscission, which were unaffected by ethylene treatment, were observed in 35S::PaFYF1/2 and 35S::PaFYF1/2 + SRDX transgenic Arabidopsis plants due to the downregulation of the ethylene signaling and abscission-associated genes EDF1-4, IDA and BOP1/2. These results suggest a possible repressor role for Phalaenopsis PaFYF1/2 in controlling floral senescence/abscission by suppressing ethylene signaling and abscission-associated genes. To further validate the function of PaFYF1/2, PaFYF1/2-VIGS (virus-induced gene silencing) Phalaenopsis were generated and analyzed. Promotion of senescence and abscission was observed in PaFYF1/2-VIGS Phalaenopsis flowers by the upregulation of PeEDF1/2, PeSAG39 and PeBOP1/2 expression, the early occurrence of greening according to their increased chlorophyll content and the reduction in water content in flower organs. Our results support that PaFYF1/2 function as transcriptional repressors to prohibit flower senescence and abscission in Phalaenopsis.

Diversification of petal monoterpene profiles during floral development and senescence in wild roses: relationships among geraniol content, petal colour, and floral lifespan

Wild roses store and emit a large array of fragrant monoterpenes from their petals. Maximisation of fragrance coincides with floral maturation in many angiosperms, which enhances pollination efficiency, reduces floral predation, and improves plant fitness. We hypothesized that petal monoterpenes serve additional lifelong functions such as limiting metabolic damage from reactive oxygen species (ROS), and altering isoprenoid hormonal abundance to increase floral lifespan. Petal monoterpenes were quantified at three floral life-stages (unopened bud, open mature, and senescent) in 57 rose species and 16 subspecies originating from Asia, America, and Europe, and relationships among monoterpene richness, petal colour, ROS, hormones, and floral lifespan were analysed within a phylogenetic context. Three distinct types of petal monoterpene profiles, revealing significant developmental and functional differences, were identified: Type A, species where monoterpene abundance peaked in open mature flowers depleting thereafter; Type B, where monoterpenes peaked in senescing flowers increasing from bud stage, and a rare Type C (8 species) where monoterpenes depleted from bud stage to senescence. Cyclic monoterpenes peaked during early floral development, whereas acyclic monoterpenes (dominated by geraniol and its derivatives, often 100-fold more abundant than other monoterpenes) peaked during floral maturation in Type A and B roses. Early-diverging roses were geraniol-poor (often Type C) and white-petalled. Lifetime changes in hydrogen peroxide (H2O2) revealed a significant negative regression with the levels of petal geraniol at all floral life-stages. Geraniol-poor Type C roses also showed higher cytokinins (in buds) and abscisic acid (in mature petals), and significantly shorter floral lifespan compared with geraniol-rich Type A and B roses. We conclude that geraniol enrichment, intensification of petal colour, and lower potential for H2O2-related oxidative damage characterise and likely contribute to longer floral lifespan in monoterpene-rich wild roses.

Fitness costs of delayed pollination in a mixed-mating plant.

To predict the evolutionary consequences of pollinator declines, we need to understand the evolution of delayed autonomous self-pollination, which is expected to evolve as a mechanism of reproductive assurance when cross-pollination becomes unreliable. This involves estimating the costs of increased levels of selfing as well as those associated with floral senescence. We studied the mechanisms and costs of delayed self-pollination in the mixed-mating vine Dalechampia scandens (Euphorbiaceae) by first assessing among-population variation in herkogamy and dichogamy, which together determine the rate and timing of autonomous self-pollination. We then tested whether floral longevity responds plastically to delayed pollination. Finally, we assessed the costs of delayed self-pollination in terms of seed number and size, explicitly separating inbreeding depression from effects of floral senescence. Herkogamy varied extensively, while variation in dichogamy was more limited. Unpollinated blossoms increased their longevity, but seed quantity and quality decreased with increasing delays in pollination, independently of inbreeding depression. In D. scandens, earlier autonomous selfing is facilitated by reduced herkogamy rather than reduced protogyny, providing reproductive assurance while maintaining the possibility for outcrossing events. Effective early autonomous self-pollination may evolve under reduced cross-pollination reliability in response to costs associated with floral senescence.

The NOP-1 peptide derived from the central regulator of ethylene signaling EIN2 delays floral senescence in cut flowers

The plant hormone ethylene was identified as important triggering factor and primary regulator of flower senescence in many species. Consequently, application of chemical inhibitors of ethylene biosynthesis and action is used to extend the longevity of ethylene-sensitive flowers. Here, we show that the peptide NOP-1, a biological derived from the nuclear localization signal of ethylene regulator EIN2 tightly binds to the ethylene receptor of carnation plants - a model to study flower senescence. When applied on cut flowers the peptide biological delays petal senescence similar to previously identified and currently used chemical inhibitors, but offers significant advances to these chemicals in biodegradability, sustainability and ecotoxicity. Our bioinformatic analysis of a wide range of ethylene receptors indicates complete sequence conservation of the anticipated NOP-1 binding site in flower species supporting a widespread use of the peptide on flowering ornamentals to delay senescence and decay in cut flowers. We anticipate our innovative approach to extend flower longevity by a new class of biomolecules such as peptides, peptide analogues and peptide mimetics will significantly advance our technological capability to delay flower senescence and expand vase-life of cut flowers in a sustainable and environmentally friendly manner.

Effects of bisphenol-A and folic acid on growth, reproductive development, and DNA methylation in snapdragons (Antirrhinum majus)

Bisphenol-A (BPA), used in the production of polycarbonate plastics, exerts complex effects on the development of organisms and on their epigenomes as a methylation disruptor. BPA is of concern due to its ubiquity in the environment. In contrast, folic acid can promote plant growth and has been shown to correct the methyl-disrupting effects of BPA in mice. We investigated the effects of prolonged exposure to BPA and folic acid on plant height, dry mass, and DNA methylation of floral tissues of Antirrhinum majus L. (snapdragons) from seedling to floral senescence. At low and medium concentrations (5 and 25 mg/L), BPA had a growth-promoting effect early in development and appeared to accelerate floral development compared with the controls. At senescence, plants treated with the low and medium concentrations of BPA had decreased dry mass compared with the controls. Folic acid promoted growth early through mid-vegetative development and also promoted early flowering. In general, the acceleration of floral development associated with the low concentration of BPA and folic acid correlated with higher DNA methylation percentages. These data suggest that prolonged exposure to BPA influences plant growth and floral development, and causes epigenetic modifications that may potentially be alleviated through the application of folic acid, thus suggesting the significance of folic acid for environmental protection.