Flower Opening Research Articles

Effective Behavior of Insects Pollinators of Flowers in Gadung Mango Clone 21 Variety

Pollinating insects are referred as support services, namely services by the processes in the ecosystems that support human well-being by maintaining or enhancing ecosystem services. The availability of flowers, diversity, and behavior of visiting pollinator insects affect the effectiveness of pollination to increase the formation of fruit sets of mango plants. The purpose of this study is to observe the behavior of pollinator insects visiting the mango gadung clone 21 varieties and their effectiveness in increasing the formation of fruit sets. Research has been carried out on two flower seasons: March-May (Off season) and July-September (On season) 2020. Visiting behaviors observed were the number of visits per minute (foraging rate) and the length of visit per flower (flower handling time). Pollination effectiveness was measured from the number of fruit sets formed from the open flower panicles and confined with a tangerine gauze. The results of the study obtained seven species including Apis sp., Trigona sp., Xylocopa sp., Polistes sp. 1, Polistes sp. 2, Chrysomya sp., and Eristalis sp. Visits of pollinating insects on the highest number of mango panicle flowers were (31.69 ± 7.69) flowers / 60 seconds by Trigona sp insects, and the lowest numbers were (2.70 ± 0.67) flowers / 60 seconds by Eristalis sp. insects. The longest visits of pollinator insects on mango flowers were obtained by Eristalis sp for (25.3 ± 8.50) sec/individual/flower and the shortest visits were by Trigona sp for (1.8 ± 0.63) seconds/individual/flower. Insect pollination increases fruit formation by 267.5%. Keywords: insect visits, pollinating insects, fruit formation, gadung 21 varieties mango

Predicting F v /F m and evaluating cotton drought tolerance using hyperspectral and 1D-CNN.

The chlorophyll fluorescence parameter Fv/Fm is significant in abiotic plant stress. Current acquisition methods must deal with the dark adaptation of plants, which cannot achieve rapid, real-time, and high-throughput measurements. However, increased inputs on different genotypes based on hyperspectral model recognition verified its capabilities of handling large and variable samples. Fv/Fm is a drought tolerance index reflecting the best drought tolerant cotton genotype. Therefore, Fv/Fm hyperspectral prediction of different cotton varieties, and drought tolerance evaluation, are worth exploring. In this study, 80 cotton varieties were studied. The hyperspectral cotton data were obtained during the flowering, boll setting, and boll opening stages under normal and drought stress conditions. Next, One-dimensional convolutional neural networks (1D-CNN), Categorical Boosting (CatBoost), Light Gradient Boosting Machines (LightBGM), eXtreme Gradient Boosting (XGBoost), Decision Trees (DT), Random Forests (RF), Gradient elevation decision trees (GBDT), Adaptive Boosting (AdaBoost), Extra Trees (ET), and K-Nearest Neighbors (KNN) were modeled with F v /F m. The Savitzky-Golay + 1D-CNN model had the best robustness and accuracy (RMSE = 0.016, MAE = 0.009, MAPE = 0.011). In addition, the F v /F m prediction drought tolerance coefficient and the manually measured drought tolerance coefficient were similar. Therefore, cotton varieties with different drought tolerance degrees can be monitored using hyperspectral full band technology to establish a 1D-CNN model. This technique is non-destructive, fast and accurate in assessing the drought status of cotton, which promotes smart-scale agriculture.

Optimization and Validation of Hyperspectral Estimation Capability of Cotton Leaf Nitrogen Based on SPA and RF

By studying the spectral information of cotton leaf nitrogen content, sensitive feature bands and spectral indices for leaf nitrogen content were screened, and different methods were used to model the screened feature bands and indices to find a method with higher accuracy and stability of the inversion model, which provides a theoretical basis and technical support for remote sensing estimation of cotton nitrogen content in Xinjiang. The experiment was conducted in 2019–2020 at the Second Company of Shihezi University Teaching Experimental Farm in Xinjiang, China, with six fertilization treatments (0, 120, 240, 360, 480 kg/hm pure N), sampled at five key fertility stages of cotton (squaring stage, full budding stage, flowering, boll stage, and boll opening stage), and the obtained data were used in two modeling approaches (eigenbands and spectral indices) to establish a cotton nitrogen estimation model and estimate the cotton leaf N content. The results showed that the nonlinear model using SVR was validated with an R2 of 0.71 and an RMSE of 3.91. The linear models of MLR and PLS were developed for the feature bands screened by SPA and RF, respectively, and the best modeling result was achieved by SPA-PLS with a validated R2 of 0.722 and an RMSE of 3.83. The existing spectral indices were optimized by screening the central wavelength and the simple linear regression model was constructed. The inversion effect of the SVR model with the characteristic spectral modeling was better than the index results. However, compared with the direct use of the characteristic wavelengths and the SVR way of modeling, the accuracy of leaf N content estimation by the model built by optimizing the spectral indices was reduced but the stability was greatly improved, and it can be used as a hyperspectral model for leaf N content at full fertility. The hyperspectral estimation of leaf N content in cotton can be used as a hyperspectral estimation method for the whole fertility period.

Effects of Different Media on Growth and Flowering Traits of Calendula Officinalis L.

Effects of eight different potting media compositions on growth and flowering traits of Calendula was studied. Among different media compositions, T5 have positive effect on root length (18.33 cm), number of leaves (62.77) and number of branches (9.12) per plant while T3 was found to be best for root spread (14.10 cm) and plant spread (22.67 cm). Calendula plants raised in T5 exhibited maximum (6.10 cm) flower diameter and flower bud diameter (1.40 cm), took minimum days (66.39) for flower bud initiation and also for flower bud opening (74 days). Maximum number of flower buds and flowers per plant were recorded in T2. The growth and flowering of Calendula was found superior in media composition of vermicompost and cocopeat. Bangladesh J. Bot. 51(3): 417-424, 2022 (September)

No‐mow amenity grassland case study: Phenology of floral abundance and nectar resource

Abstract Popular campaigns such as No Mow May seek to encourage early‐season forage resource for pollinators in urban green spaces. Land managers need to balance ecological benefits with extent of accessible amenity grassland. To pilot the identification of a ‘tipping point’ when the nectar resource of unmown grassland exceeds that mown, we surveyed floral abundance in 30 plots on an amenity grassland site at 11 time points between late April and July. Each species’ floral abundance per 1 m2 was multiplied by published nectar sugar values to obtain an overall nectar sugar value per plot. The nectar sugar value of no‐mow plots was overall significantly higher than for mown plots. However, week‐by‐week analysis revealed that the first significant difference did not occur until mid‐late May when no‐mow plots yielded three times the nectar sugar value of the mown plots. In early‐mid June, there was a significant eightfold divergence followed by a late June to early July decline. Common Ragwort (Senecio jacobaea) provided the greatest nectar sugar value, driving significant differences again in mid‐July. No‐mow plots contained twice as many (22 vs. 11) open flower broadleaf species compared to the mown plots. Land managers could consider extending No Mow May management into June and beyond to maximize nectar sugar resource for pollinators. To comply with S. jacobaea legislation, a management plan and financial resource should be allocated to no‐mow projects.

Deflowering as a Tool to Accelerate Growth of Young Trees in Both Intensive and Super-High-Density Olive Orchards

In 2019–2020, trials were carried out in both intensive (cultivar Moraiolo) and super-high-density (cultivar Sikitita) young olive orchards to drastically reduce early production and, consequently, accelerate tree growth. Different concentrations of naphthaleneacetic acid (NAA) (0 ppm–control, 20 ppm, 40 ppm, 80 ppm, 160 ppm and 250 ppm) were applied at full bloom (open flowers > 80%), using a shoulder sprayer, and their effects on vegetative growth and reproductive behavior were evaluated, also compared to manually deflowered trees. The treatments with NAA reduced fruit set (down to values close to zero) compared to the control, and the reduction was correlated with the NAA concentration. In particular, 160 ppm virtually eliminated fruit set and thus production in both Moraiolo and Sikitita cultivars. In Moraiolo, 160 ppm NAA and manual deflowering determined similar shoot and trunk growths, which were greater than in control trees. Application of 160 ppm NAA for two consecutive years gave a progressively higher increase in trunk growth compared to the control. In conclusion, in young olive trees, the treatment with 160 ppm NAA at full bloom practically eliminated fruit set and production, with a parallel great increase in vegetative growth. This can be exploited as a powerful technique to accelerate the growth of young olive trees in both intensive and super-high-density orchards, as well as in nurseries. A more rapid transition to the adult stage/size of the trees and to full production of the orchard allows us to anticipate the use of mechanical harvesting and the recovery of the planting investment.

Metabolic and transcriptional regulatory mechanisms of differential carbohydrates formation from flower buds to flowers of Hemerocallis citrina

The flower buds of Hemerocallis citrina that are about to open are an edible vegetable with health care functions of "forgetting worries". However, the flower buds that open into flowers will be discarded due to changes in nutritional composition such as carbohydrates which is still unclear on their difference and formation mechanism from flower buds. In this study, the combined analysis of transcriptome, metabolome and degradome was used to investigate the above problems. The results found that there were 32 differential carbohydrates, 370 differential genes, 23 differential miRNAs and their 49 target genes in flowers compared to flower buds, among which at least nine conserved miRNA families such as miR393, miR394, miR395 and miR156 targeted to act on eleven key enzyme genes, such as INV (beta-fructofuranosidase), BAM (beta-amylase), malZ (alpha-glucosidase) and pgm (phosphoglucomutase), and then involved together in the regulation of differential carbohydrates metabolism including starch and sucrose, amino sugar and nucleotide sugar, fructose and mannose, and galactose metabolism in flower opening development of H. citrina.

Retention of colour-changed flowers increases pollinator attraction to Lantana undulata inflorescences

Many flowers change colour as they age or after pollination, which can have direct effects on pollinator behaviour affecting both pollination (on the plant side) and foraging efficiency (on the insect side). The retention of colour-changed flowers might increase plant attractiveness to pollinators over long distances, while directing pollinators at short range towards flowers that still present rewards and are sexually receptive. In this study, we used Lantana undulata Schrank (Verbenaceae), which presents yellow-centered and white flowers within an inflorescence, as a model plant species to study the influence of floral colour change on pollinator visitation. We first show that colour change from yellow to white occurs over a 24 h period regardless of pollination, and is associated with reduced stigma receptivity and nectar reward availability. We then used pollinator visitor observations and experimental manipulations of inflorescence display patterns to investigate the effects of floral colour change on pollinator attraction, behavior and choices. Pollinators exhibited strong preference for visiting yellow-centered flowers, suggesting the colour change to white in older flowers is an honest signal directing pollinators to rewarding and receptive flowers within the inflorescence. In addition, the absence of white flowers on manipulated inflorescences significantly reduced their attractiveness to pollinators. Our results suggest that the retention of colour-changed white flowers is important to attract pollinators at long distances, while the yellow colour of young flowers guides pollinators to the sexually viable, rewarding flowers on inflorescences at short distances, maximizing both pollination and foraging efficiency.

Temporal changes in the Swiss flora: implications for flower-visiting insects

BackgroundLocal floristic diversity has massively decreased during the twentieth century in Central Europe even though in the 1990s diversity began increasing again in several regions. However, little is known whether this increase is equally distributed among plant groups with different reproductive traits.MethodsOur study is based on data of the Swiss Biodiversity Monitoring Program. In this program, plant species occurrence is recorded since 2001 in 450 regularly distributed 1 km2 study sites. For all 1774 plant species registered in the study, we researched data on flower/pseudanthium type and colour, reproductive system, and groups of flower visitors. We then tested whether temporal changes in species frequency were equally distributed among species with different trait states.ResultsSpecies richness and functional richness significantly increased in the study sites while functional evenness decreased. The frequency of wind-pollinated species increased more strongly than that of insect-pollinated species. Further, the frequency of species with simple, open insect-pollinated flowers and pseudanthia visited by generalist groups of insects increased slightly more strongly than the frequency of species with complex flowers visited by more specialized groups of flower visitors. Additionally, the frequency of self-compatible species increased significantly more than that of self-incompatible species. Thus, the overall increase in local plant species richness in Switzerland is mostly driven by wind- and generalist insect-pollinated, self-compatible species. In contrast, species with complex flowers, which are essential for specialized groups of flower visitors and species with self-incompatible reproductive systems profited less.ConclusionsOur study thus emphasizes the need to consider functional traits in the planning and monitoring of conservation activities, and calls for a special focus on plant species with specialized reproductive traits.

The FloRes Database: A floral resources trait database for pollinator habitat-assessment generated by a multistep workflow.

The decline of pollinating insects in agricultural landscapes proceeds due to intensive land use and the associated loss of habitat and food sources. The feeding of those insects depends on the spatial and temporal distribution of nectar and pollen as food resource. Hence, to protect insect biodiversity, a spatio-temporal assessment of food quantity of their habitats is necessary. Therefore, sufficient data on traits of floral resources are required. As floral resources' traits of plants are important to quantify food availability, we present two databases, the FloRes Database (Floral Resources Database) and the raw database, from where FloRes was derived. Both databases contain the plant traits: (1) flowering period, (2) floral-unit density per day, (3) nectar volume per floral unit per day, (4) sugar content per floral unit, (5) sugar concentration in nectar, (6) pollen mass or volume per floral unit and per day, (7) protein content of pollen and (8) corolla depth. All traits were sampled from literature and online databases. The raw database consists of 702 specified plant species, 138 unspecified species 37 species (spec., sp), 22 species pluralis (spp) and, for 79, only the genus was identified) and two species complexes (agg.). Those 842 taxa belong to 488 genera and 102 families. Finally, only 27 taxa have a complete set of traits, too few for a sufficient assessment of spatio-temporal availability of floral food-resources.As information on floral resources is scattered throughout many publications with different units, we also present our multistep workflow implemented in five consecutive R-scripts. The multistep workflow standardises the trait units of the raw database to comparable entities with identical units and aggregates them on a reasonable taxonomic level into the second application database, the FloRes Database. Finally, the FloRes Database contains aggregated information of traits for 42 taxa and, when corolla depth is excluded, for 72 taxa.This is the first attempt to gather these eight traits from different literature sources into one database with a multistep workflow. The publication of the multistep workflow enables the users to extend the FloRes Database on their own demands with other literature data or newly-gathered data to improve quantification of food resources. Especially, the combination of pollen, nectar and the open flowers per square metre is, as far as we know, a novelty.The FloRes Database can be used to evaluate the quantity of food-resource habitats available for pollinators, for example, to compare seed mixtures of agri-environmental measures, such as flower strips, considering flower phenology on a daily basis.

Daily light integral and/or photoperiod during the young plant and finishing stages influence floral initiation and quality of witchgrass and marigold cut flowers.

To produce consistent and high-quality specialty cut flowers throughout the year, growers in temperate climates must utilize controlled environment greenhouses. Research-based information on photoperiod management and supplemental lighting for specialty cut flowers is limiting. Therefore, our objectives were (1) to determine the effect of photoperiod during the young-plant and finishing stages on floral initiation and morphology of witchgrass ‘Frosted Explosion’ (Panicum capillare) and marigold ‘Xochi’ (Tagetes erecta) and (2) to quantify the effect of daily light integral (DLI) on floral initiation and morphology of witchgrass during the finishing stage. Seeds of marigold and multi-seed pellets of witchgrass were sown and placed under 9-, 11- (marigold only), 12-, 13-, 14-, 15-, 16-, 18-, or 24-h photoperiods or a 9-h short day with a 4-h night interruption (NI) from 2200 to 0200 h. Plugs were distributed among 10-, 11-, 12-, 13-, 14-, 15-, or 16-h photoperiods or a 4-h NI, for finishing. Witchgrass was finished under a very low or moderate DLI of ≈3 or 10 mol⋅m–2⋅d–1, respectively, while marigold was finished under a DLI of ≈10 mol⋅m–2⋅d–1. Marigold grown under a photoperiod ≥ 11 h or a 4-h NI during the young-plant stage and finished under an 11- or 12-h photoperiod had thick stems and consistently met the marketable stem length of ≥ 65 cm. Up to 29% and 107% more stems were harvestable under 11- and 12-h finishing photoperiods, respectively, compared to a 10-h finishing photoperiod. Marigold visible buds were delayed, and stems were not harvestable under photoperiods ≥ 13 h or a 4-h NI after 8 weeks. Young witchgrass plants grown under a photoperiod between 14- and 24-h or a 4-h NI and finished under photoperiods ≥ 14 h or a 4-h NI, and at least a moderate DLI, were reliably harvestable (≥ 50 cm long with a fully developed panicle). Witchgrass finished under day lengths < 13 h (rep. 1) or < 14 h (rep. 2) flowered prematurely and were roughly one-sixth the length of harvestable stems at an open flower. All witchgrass stems grown under a very low DLI were shorter and thinner than those grown under a moderate DLI, and none were harvestable. Therefore, we recommend growing marigold ‘Xochi’ young plants under a photoperiod ≥ 11 h or a 4-h NI and finishing under a 12-h photoperiod. Additionally, witchgrass ‘Frosted Explosion’ young plants should be grown under a photoperiod ≥ 14 h or a 4-h NI and finished under photoperiods ≥ 14 h or a 4-h NI to prevent premature flowering. Witchgrass and marigold cut flowers should be finished under a DLI of ≥ 10 mol⋅m–2⋅d–1 for consistent production of high-quality stems.

Base Temperature Comparisons for Leafing Date, Pistillate Flower Receptivity, and Pollen Shedding in Persian Walnut

Leafing dates and the male and female bloom periods in Persian walnut (Juglans regia L.) vary with cultivars and years. Changes in phenological phases and the process of passing through the phenological stages could be explained by the growing degree days (GDD) if the minimum base temperature (Tb) were determined. In this study, the long-term phenological data of some walnut cultivars derived and/or grown in Hungary and Iran were used to determine the Tb values for leafing date (LD), pistillate flower receptivity start (PRS), pistillate flower receptivity end (PRE), and start and end of the pollen shedding period (PSS and PSE, respectively). The GDD were calculated (with 0.1 °C precision) for the LD and PSS with respect to the earliest cultivar as well as for PRS compared to LD and PRE. Furthermore, the GDD were reckoned for PSE based on PRS and PSS of the same cultivar in each year. The analysis of the data revealed that for the LD, PRS, and PRE, the Tb5.5 with the highest correlation was shown to be the most appropriate. For the PSS and PSE, the best correlation was observed at Tb0 in both countries. The strongest coefficients were observed (0.72 for Iranian and 0.8 for Hungarian conditions) between GDD with Tb of 5.5 °C for PRS and LD. The less correlation was observed between LD and PSS (0.5 for Iranian and 0.57 for Hungarian conditions). The correlation coefficients between GDD and leafing date were the same (0.52) in both countries. Cultivars involved in the trial required more GDD in Iran than in Hungary.

An integrated metabolome and transcriptome analysis of the Hibiscus syriacus L. petals reveal the molecular mechanisms of anthocyanin accumulation.

Hibiscus syriacus L. var. Shigyoku is a new double-flowered bluish-purple variety in China that changes color during flower development from bluish-purple to light purple. There is limited information on the anthocyanin accumulation patterns and associated transcriptome signatures in Shigyoku from D1 (bud) to open flower (D3). Here, we employed a combined transcriptome and metabolome approach to understanding the mechanism of this color change. Our results demonstrate that cyanidins, pelargonidins, delphinidins, petunidins, peonidins, and malvidins were differentially accumulated in Shigyoku petals. The anthocyanin biosynthesis started in D1, was significantly upregulated in D2 (semi-open flower), and reduced in D3. However, malvidins, pelargonidins, and peonidins could be associated with the bluish-purple coloration on D2. Their reduced accumulation in D3 imparted the light purple coloration to Shigyoku petals on D3. Significant contributions in the color change could be associated with the expression changes in anthocyanin biosynthesis genes i.e., LARs, ANSs, DFRs, UGT79B1, C3’Hs, 3ATs, and BZ1s. The UFGTs were associated with the higher accumulation of glycosylated anthocyanins in D2 and D3. Furthermore, the changes in the expressions of the MYB and bHLH transcription factors were consistent with the anthocyanin accumulation. Finally, we discussed the possible roles of Jasmonic acid, auxin, and gibberellic acid signaling in regulating the MBW complex. Taken together, we conclude that H. syriacus petal coloration is associated with anthocyanin biosynthesis genes, the MBW complex, and phytohormone signaling.

Multi-class detection of kiwifruit flower and its distribution identification in orchard based on YOLOv5l and Euclidean distance

Asynchrony of kiwifruit flowering time results in different flower phenological stages in canopy at the same time. Pollination quality of flowers is influenced by their phenological stages, while their distributions determine fruit distributions and influence kiwifruit quality and yield. Thus, it’s necessary to find suitable flowers to be pollinated based on flower phenology and its distribution. However, influences of flower phenology and flower distribution were not considered in most previous studies about robotic pollination of kiwifruit, where pollination of all open flowers was indiscriminate. Therefore, a method was proposed for multi-class detection of kiwifruit flower and its distribution identification in orchard, which was based on You Only Look Once version 5 large (YOLOv5l) and Euclidean distance. According to kiwifruit flower phenology, kiwifruit flowers were classified into 10 classes to find suitable flowers for pollination, while flower cluster and branch junction were divided into 4 classes for obtaining flower distributions. All classes were manually labeled by rectangular bounding boxes for training and testing. Considering high detection accuracy requirements with small model size, YOLOv5l was applied to do transfer learning for multi-class detection of kiwifruit flower. Then, pixels coordinate of multi-class objects and their corresponding Euclidean distances could be gained. Finally, flower distributions in canopy were obtained by matching method. Total mean Average Precision (mAP) was 91.60 % in YOLOv5l, while the mAP of multi-class flower (10 classes) was 93.23 %, which was 5.70 % higher than that of the other 4 classes. Matching accuracy (MA) of flowers matching flower clusters was up to 97.60 %. Moreover, MA of flower cluster matching branch junction (96.20 %) and total MA (93.30 %) increased by 1.20 % and 1.00 % based on improved matching method, respectively. Total processing speed of multi-class flower detection and its distribution identification was 112.46 ms per image including 15.50 ms for image detection by YOLOv5l. Results showed that multi-class kiwifruit flowers and relative flower distributions could be fast and accurately obtained for further selecting suitable flowers for robotic pollination.

Fenologia de Solidago canadensis L. e Delphinium elatum cultivados em casa de vegetação e associação com variáveis microclimáticas

Abstract Solidago canadensis L. cv. Tara and Delphinium elatum, the hybrid White River are summer flowers with great agronomic potential. The goal of this study was to establish the phenology of these species grown under greenhouse conditions, as well as to determine the correlation between climatic elements (relative humidity - RH, growing degree-days for development - GDD and soil moisture - SM) with growth variables (stem length and diameter, fresh weight FW - and dry weight - DW) in S. canadensis and D. elatum. The life cycle for S. canadensis and D. elatum ended when reaching 30% of the flower opening, the stem length reached 118.05 and 123.74 cm, at 94 and 77 days, respectively. The growth of both species showed a logistic curve pattern throughout the crop cycle; S. canadensis showed maximum values for absolute growth rate (AGR) and relative growth rate (RGR) at 77 and 42 days after transplanting (DAT), respectively; in contrast to D. elatum which occurred at 77 and 28 DAT. On the other hand, for the correlation between climatic elements and growth variables in S. canadensis, the GDD and RH were directly correlated with both FW and DW, stem diameter and length, while an inverse correlation occurred for SM. D. elatum showed a direct correlation between climatic conditions and growth variables.

Effect of processing methods on the content of phenolic compounds in Vicia faba L. tissues grown in field and greenhouse

Environmental conditions during the growth of Vicia faba plants and post-harvest processing methods influence its contents of secondary metabolites. In this study, total phenolic compounds (TP) and total flavonoids (TF) were quantified in broad bean plants at 10, 15 and 20 days after emergence (DAE), in floral buds and open flowers developed in the field or in a greenhouse with soil (GH-S) or tezontle (GH-T) as substrate. The effects of post-harvest processing, namely oven-drying and freeze-drying, were also evaluated. The analysis of variance showed, in all growth conditions, that the content of TP and TF varied significantly (P≤0.05 or P≤0.01) according to the age of the plant or the flowering stage, the processing methods and the interaction between those factors. Field-grown plants at 10, 15 and 20 DAE exhibited a higher mean value of TP (113.55 mg·g·-1 of gallic acid equivalent) and TF (126.60 mg·g·-1 of quercetin equivalent) with oven-dried samples, compared with those plants harvested in GH-S and GH-T conditions. Drying in the oven was most efficient in conserving phenolic compounds in field plants while freeze-drying preserved the levels of metabolites in greenhouse plants more effectively. In order to obtain the maximum content of phenolic compounds in minimal time, it is suggested to grow broad beans in the field, harvest plants at 10 DAE, and process them by oven-drying.

Ceratopogonidae: su rol en la polinización y fecundación en varios niveles tecnológicos de producción de Theobroma cacao L.

The goal of this study was to evaluate the role of pollinators on the pollination, fertilization and fruit set process in three technological production levels and three reproduction substrates, determinants in cocoa yield. Two pollination techniques (natural and assisted) were compared and as a control, flowers were isolated with antiaphid. Twenty-seven observation units were formed, with three biological replicates. A known number of flowers were evaluated 6, 14, 21 and 36 days after the opening of each flower on marked branches. The number of active flowers, pollinated, fertilized and fruits formed was recorded. Pollinators present in experimental units were collected using yellow sticky cards, then taken to the lab and identified. Pollination occurred up to three days after opening, the flower that remained with the ovary swollen and attached to the branch/stem was considered pollinated. Fertilization was recorded fourteen days after flower opening, fruit set begins after fertilization, an event that was quantified twenty-one days after flower opening. The systems studied did not influence the percentage of pollination, fertilization and fruit formation. However, the substrates did influence pollination, fertilization and fruit set. The assisted pollination technique is significantly superior to natural pollination. The same species of Ceratopogonidae were reported at all three levels and substrates, with genera Forcipomyia and Dasyhelea being the most abundant.

The Comparison of Temporal Transcriptome Changes Between Morning-Opening and Afternoon-Opening Iris Flowers Reveals the Candidate Genes Regulating Flower Opening and Closing

The Comparison of Temporal Transcriptome Changes Between Morning-Opening and Afternoon-Opening Iris Flowers Reveals the Candidate Genes Regulating Flower Opening and Closing

Divergent strategies of nectar secretion in two bat-pollinated Passiflora species

The secretion dynamics and chemical compositions of flower nectar can vary according to the plant physiology and the pollinator type. Bat-pollinated flowers are commonly associated with nocturnal nectar secretion as well as large amounts of nectar per flower, which is generally diluted and composed mostly of hexose sugars. The nectar traits in bat-pollinated Passiflora species are poorly understood and in this work, we describe these for two such species. We conducted field experiments to assess the nectar secretion dynamics of two species with nocturnal anthesis and similar colours and structures, performed chemical analyses of the sugar components of nectar from these two species, and combined these data with systematic observations of floral visitors. The nectar dynamics of both Passiflora species are similar to those of other bat-pollinated species. In Passiflora mucronata, nectar secretion starts before the flower opens, which occurs around 04h00, with secretion ending after 10h00. Passiflora setacea starts secreting nectar at the time of flower opening, around 22h00, finishing secretion between 04h00 and 06h00. In P. setacea, the final period of anthesis is characterised by active nectar resorption. The different blooming times of these two bat-pollinated passionflowers and the significant differences in their nectar secretion schedules suggest a divergent nectar secretion dynamics: the nectar of P. mucronata is made available only by the end of the bats’ foraging activity period, continuing throughout the morning, while P. setacea secretes nectar earlier, with very little overlap in the secretion period between the species. We hypothesise that this segregation in time helps avoid the negative effects from competition for pollinators or pollen interference between flowers with a similar structure, while the outstanding nectar traits and the constant production of flowers throughout the year make these closely related vines important nectar sources for their bat pollinators where they co-occur.

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 &gt;5 g of water of which &gt;2 reside in &gt;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.