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Aim: Flower traits are critical to the mutualistic networks that underpin ecosystem function. However, the broad‐scale drivers of flower traits are unclear. Using the megadiverse islands of Malesia, we test three hypotheses: (1) Flower size, openness and colourfulness (i.e. the trend from white to colourful flowers) will decrease with increasing temperature, but not with increasing precipitation seasonality. (2) Flower size, openness and colourfulness will increase with island area, and decrease with isolation. (3) Models parameterised by climate, rather than non‐climatic island characteristics will have the greatest predictive capacity as climate affects both pollinator communities and energetic/physiological constraints upon flower traits. Location: Fourteen Malesian islands. Taxon: Angiosperms. Methods: We applied Bayesian phylogenetic models of occurrence for >2500 species in 400 m elevation bands, across islands, as a function of flower trait interactions with either climatic variables or islands characteristics. We compare predictive capacity of models based on climate versus island characteristics using Leave One Out‐Cross Validation. Results: All six flower traits examined varied with at least temperature, precipitation seasonality, island area and isolation. Flowers are larger in cold environments. The lowland tropics are mostly inhabited by white flowered species. At cold high elevations, red and pink flowered species are more frequent whereas green and purple flowered species increase in the drought‐prone seasonally dry tropics. Flower openness declined with precipitation seasonality and increased with isolation. Models parameterised by climate performed best for perianth length, red and white flowers, whereas pink flowers and flower openness were better predicted using island characteristics. Main Conclusions: There are relationships between flower traits and climatic gradients within Malesia. However, island characteristics have also left a legacy upon current flower trait distributions. These island biogeographical impacts are likely key for the eco‐evolutionary drivers of flower traits. [ABSTRACT FROM AUTHOR]

Simple Summary: Many plants depend on pollination by bees, whereas bees depend on flowers as food sources. Bees use a variety of floral cues such as the color, scent, or shape of the flower to find host plants. The preferred cues of honeybees and bumblebees are well studied, but the preferences of other bee species are almost unknown. Thus, we have performed behavioral experiments with artificial flowers to test whether three common bee species of the genera Lasioglossum, Bombus, and Osmia are attracted by the same or different floral cues. Our experiments showed consistent behaviors across species in experiments testing flower sizes and scent mixtures that differed in compound richness and identities. The color hue experiments, however, revealed different preferences that were probably influenced by previous foraging experience. Within colors, bee species preferred mostly intense colors that formed a high contrast to background colors. A high attractiveness of floral cues enables bees to effectively find foraging plants. With this study, we learned more about flower choice in bee species that are not used as model organisms but are important for pollination. The interaction between bees and flowering plants is mediated by floral cues that enable bees to find foraging plants. We tested floral cue preferences among three common wild bee species: Lasioglossum villosulum, Osmia bicornis, and Bombus terrestris. Preferences are well studied in eusocial bees but almost unknown in solitary or non-eusocial generalist bee species. Using standardized artificial flowers altered in single cues, we tested preferences for color hue, achromatic contrast, scent complexity, corolla size, and flower depth. We found common attractive cues among all tested bees. Intensively colored flowers and large floral displays were highly attractive. No preferences were observed in scent complexity experiments, and the number of volatiles did not influence the behavior of bees. Differing preferences were found for color hue. The specific behaviors were probably influenced by foraging experience and depended on the flower choice preferences of the tested bee species. In experiments testing different flower depths of reward presentation, the bees chose flat flowers that afforded low energy costs. The results reveal that generalist wild bee species other than well-studied honeybees and bumblebees show strong preferences for distinct floral cues to find potential host plants. The diverse preferences of wild bees ensure the pollination of various flowering plants. [ABSTRACT FROM AUTHOR]

In high mountain environments, the availability of pollinators may decrease as elevation increases, affecting plant reproductive success. Floral volatile organic compounds (VOCs) are relevant to pollinator attraction; however, few studies have explored the variation of floral VOCs at different elevational sites. We analyzed the floral VOCs, flower size and nectar volume in Bidens triplinervia (a species with a generalized pollination system) and Penstemon roseus (with bee and bird pollination system) at three elevations (2800, 3300, and 3700 m) in the Nevado de Colima Volcano in Mexico. We recorded visitation rate and the identity of pollinators and explored the relationships between floral traits and pollinator visitation. The floral scent profile (composition and relative amounts of VOCs) of B. triplinervia and P. roseus differed between the three elevations. The highest number of VOCs and the largest flowers were found at high elevation, which had the lower visitation rate. Nectar volume was higher at low elevation and nectar concentration was lower at middle elevation. In B. triplinervia, Bombus ephippiatus was the main pollinator at low and middle elevation, while Musca domestica predominated at the highest elevation. Penstemon roseus was visited by hummingbirds and bumblebees, which were the most frequent pollinators at all three elevations. The floral traits (i.e., flower size, floral VOCs and nectar) were significantly associated with pollinator visitation. This study provides evidence of floral VOCs variation at different elevations, which was correlated with the visitation rate of local pollinators. The larger flowers at higher elevations may increase the attraction of pollinators where the environment is more extreme and erratic. [ABSTRACT FROM AUTHOR]

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Abstract Background The orchid industry has seen a recent surge in export values due to the floral morphology and versatile applications of orchids in various markets for medicinal, food additive, and cosmetic usages. However, plant-related diseases, including the yellow leaf disease caused by Fusarium solani, have caused significant losses in the production value of Phalaenopsis (up to 30%). Results In this study, 203 Phalaenopsis cultivars were collected from 10 local orchid nurseries, and their disease severity index and correlation with flower size were evaluated. Larger flowers had weaker resistance to yellow leaf disease, and smaller flowers had stronger resistance. For the genetic relationship of disease resistance to flower size, the genetic background of all cultivars was assessed using OrchidWiz Orchid Database Software and principal component analysis. In addition, we identified the orthologous genes of BraTCP4, namely PeIN6, PeCIN7, and PeCIN8, which are involved in resistance to pathogens, and analyzed their gene expression. The expression of PeCIN8 was significantly higher in the most resistant cultivars (A7403, A11294, and A2945) relative to the most susceptible cultivars (A10670, A6390, and A10746). Conclusions We identified a correlation between flower size and resistance to yellow leaf disease in Phalaenopsis orchids. The expression of PeCIN8 may regulate the two traits in the disease-resistant cultivars. These findings can be applied to Phalaenopsis breeding programs to develop resistant cultivars against yellow leaf disease.

Premise of research. Floral longevity, the amount of time from anthesis to floral senescence, is a key floral trait that determines the opportunity for pollinator visitation. However, the causes and consequences of variation in longevity have primarily been studied among species, which may not reflect patterns of variation within populations. Methodology. To determine the causes and consequences of within-population variation in floral longevity, we exposed Mimulus guttatus to either an ambient- or reduced-pollination treatment. We measured floral longevity to test whether reduced pollinator access (which simulates pollinator decline) causes a plastic extension in floral longevity. We also measured two traits—flower size and anther-stigma distance—that could cause floral longevity to vary and two traits—daily display size and flowering duration—that could vary in response to longevity. Pivotal results. Floral longevity was not affected by experimentally reducing pollinator access or by anther-stigma distance. However, longevity was reduced in M. guttatus plants with larger flowers. Variation in floral longevity did not affect the flowering duration of M. guttatus plants and (depending on the pollination treatment) had either a negative effect or no effect on daily display size. Conclusions. We found evidence that within-population variation in floral longevity in M. guttatus can be caused by correlations with flower size and can have consequences for daily display size that vary depending on the pollination environment. These results contrast with among-species studies of variation in floral longevity, which have not included display size but have found that longevity either is extended in species with larger flowers or is not related to flower size. Consequently, predictions about the causes of within-population variation in floral longevity based on among-species studies may be misleading. [ABSTRACT FROM AUTHOR]

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

Weed species are ecological models that recently received considerable attention due to their particular strategies linked to their ruderal‐competitive traits. They are known to have the potential to provide additional floral resources for insects in flower‐poor agroecosystems. However, their floral traits are much more scarcely studied than those of plants found in other habitats, such as grasslands. The aim of this study was to describe the floral phenotype of weeds and to determine to what extent their floral traits match their ecological strategies as described based on leaf traits. We cultivated 19 forb weeds from perennial agroecosystems, previously identified in Mediterranean fields, in a greenhouse for seven months and collected data on 12 floral and five leaf traits. We tested whether these traits covaried and exhibited an ecological strategy at the phenotype scale. We found that in matters of flower production, weed species face a tradeoff: either numerous small, low‐stature flowers with small quantities of pollen and nectar, or few, large, higher‐held flowers with more pollen and nectar. The floral traits were found to reflect Grime's CSR strategies: the weed species producing fewer but costlier flowers belonged to C‐strategy species, whereas those producing more but less costly flowers belonged to species dominated by an R strategy. These findings indicate that the potential of weeds as floral resources for insects is related to their ecological strategies, which are known to be affected by agricultural practices that filter species composition. This implies that, as for the provision of other ecosystem services, weed communities can be managed to select species with floral traits matching the requirements of flower‐visiting insects like pollinators or parasitoid wasps. [ABSTRACT FROM AUTHOR]

To explain the co-existence and maintenance of females along with hermaphrodite plants, the female advantage hypothesis has been proposed where females should show greater fecundity compared to their conspecific hermaphrodites. On the other hand, greater attraction would be selected in the hermaphrodites to increase their male function, potentially leading to larger showier flowers, with more rewards. Here, I tested the sexual dimorphism trade-off hypothesis with the gynomonoecious-gynodioecious Dianthus plumarius (Caryophyllaceae), in the gardens of Bariloche (Patagonia, Argentina). I measured in female and hermaphrodite plants: flower size, nectar volume and concentration, flower lifespan, ovule production, seed number, seed set and seed weight. Additionally, bagging and pollen supplementation experiments were carried out to evaluate pollen limitation, probability of apomixis, if spontaneous autogamy is possible, and to examine the importance of pollen origin. I found that hermaphrodite flowers are more attractive, with larger-sized flowers and higher nectar volume, whereas female flowers compensate with longer lifespan of stigmatic receptivity and more concentrated nectar. Despite ovule number was lower in female flowers, these showed higher seed set and produced more and heavier seeds than hermaphrodites under open pollination. No evidence of apomixis was found in females, but spontaneous autogamy may occur in hermaphrodites. Hand-pollination experiments showed first that both flower types suffered pollen limitation, but it was higher on hermaphrodite flowers. Finally, despite self-compatibility, pollen origin is important because hand self-pollination decreases seed weight. These findings provide strong evidence in support of the mechanisms and underlying conditions that would allow the co-existence and maintenance of female and hermaphrodite individuals within populations. [ABSTRACT FROM AUTHOR]

Adaptations that attract pollinators to flowers are central to the reproductive success of insect‐pollinated plants, including crops. Understanding the influence of these non‐rewarding traits on pollinator preference is important for our future food security by maintaining sufficient crop pollination. We have identified substantial variation in flower shape, petal size, corolla‐tube length, petal spot size and floral volatile compounds among a panel of 30 genetically distinct lines of Vicia faba. Using this variation, we found that Bombus terrestris was able to distinguish between natural variation in petal spot size, floral volatile emissions and corolla‐tube length. Foragers showed some innate preference for spotted flowers over non‐spotted flowers and preferred shorter corolla‐tube lengths over longer tubes. Our results suggest that some floral traits may have significant potential to enhance pollinator attraction to V. faba crops, particularly if paired with optimised rewards. [ABSTRACT FROM AUTHOR]

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

The interaction between bees and flowering plants is mediated by floral cues that enable bees to find foraging plants. We tested floral cue preferences among three common wild bee species: Lasioglossum villosulum, Osmia bicornis, and Bombus terrestris. Preferences are well studied in eusocial bees but almost unknown in solitary or non-eusocial generalist bee species. Using standardized artificial flowers altered in single cues, we tested preferences for color hue, achromatic contrast, scent complexity, corolla size, and flower depth. We found common attractive cues among all tested bees. Intensively colored flowers and large floral displays were highly attractive. No preferences were observed in scent complexity experiments, and the number of volatiles did not influence the behavior of bees. Differing preferences were found for color hue. The specific behaviors were probably influenced by foraging experience and depended on the flower choice preferences of the tested bee species. In experiments testing different flower depths of reward presentation, the bees chose flat flowers that afforded low energy costs. The results reveal that generalist wild bee species other than well-studied honeybees and bumblebees show strong preferences for distinct floral cues to find potential host plants. The diverse preferences of wild bees ensure the pollination of various flowering plants.

Abstract Adaptations that attract pollinators to flowers are central to the reproductive success of insect‐pollinated plants, including crops. Understanding the influence of these non‐rewarding traits on pollinator preference is important for our future food security by maintaining sufficient crop pollination. We have identified substantial variation in flower shape, petal size, corolla‐tube length, petal spot size and floral volatile compounds among a panel of 30 genetically distinct lines of Vicia faba. Using this variation, we found that Bombus terrestris was able to distinguish between natural variation in petal spot size, floral volatile emissions and corolla‐tube length. Foragers showed some innate preference for spotted flowers over non‐spotted flowers and preferred shorter corolla‐tube lengths over longer tubes. Our results suggest that some floral traits may have significant potential to enhance pollinator attraction to V. faba crops, particularly if paired with optimised rewards.

Body size is a trait that can affect plant–pollinator interaction efficiency and plant reproductive success. We explored the impact of intraspecific size shifts on the interactions between pollinators and flowering plants under controlled conditions. We considered two development conditions leading to the production of large and small individual flowers of Borago officinalis and Echium plantagineum. We also used the natural variability of worker size within bumblebee colonies to isolate small and large workers. We performed a fully crossed experiment with the two flower sizes of each plant species and the two sizes of bumblebee workers. Our results show that the size of both partners did not affect bee foraging behavior in most of the evaluated parameters and both bee sizes were equally efficient in depositing pollen. Significant differences were found only in pollen deposition across the life of a flower in small flowers of B. officinalis, with the greatest quantity of pollen deposited by small bees. We did not find a relationship between pollinator size and plant fitness. Our results suggest that generalist plant–pollinator interactions may be resilient to future potential mismatches in the size of the partners but remain to be tested if they are still resilient under the new environmental conditions resulting from global changes. [ABSTRACT FROM AUTHOR]

Rose (Rosa spp.) is one of the most economically important ornamental species worldwide. Flower diameter, flower weight, and the number of petals and petaloids are key flower-size parameters and attractive targets for DNA-informed breeding. Pedigree-based analysis (PBA) using FlexQTL software was conducted using two sets of multi-parental diploid rose populations. Phenotypic data for flower diameter (Diam), flower weight (fresh (FWT)/dry (DWT)), number of petals (NP), and number of petaloids (PD) were collected over six environments (seasons) at two locations in Texas. The objectives of this study were to 1) identify new and/or validate previously reported QTL(s); 2) identify SNP haplotypes associated with QTL alleles (Q-/q-) of a trait and their sources; and 3) determine QTL genotypes for important rose breeding parents. Several new and previously reported QTLs for NP and Diam traits were identified. In addition, QTLs associated with flower weight and PD were identified for the first time. Two major QTLs with large effects were mapped for all traits. The first QTL was at the distal end of LG1 (60.44-60.95 Mbp) and was associated with Diam and DWT in the TX2WOB populations. The second QTL was consistently mapped in the middle region on LG3 (30.15-39.34 Mbp) and associated with NP, PD, and flower weight across two multi-parent populations (TX2WOB and TX2WSE). Haplotype results revealed a series of QTL alleles with differing effects at important loci for most traits. This work is distinct from previous studies by conducting co-factor analysis to account for the DOUBLE FLOWER locus while mapping QTL for NP. Sources of high-value (Q) alleles were identified, namely, 'Old Blush' and Rosa wichuraiana from J14-3 for Diam, while 'Violette' and PP-J14-3 were sources for other traits. In addition, the source of the low-value (q) alleles for Diam was 'Little Chief', and Rosa wichuraiana through J14-3 was the source for the remaining traits. Hence, our results can potentially inform parental/seedling selections as means to improve ornamental quality in roses and a step towards implementing DNA-informed techniques for use in rose breeding programs. [ABSTRACT FROM AUTHOR]

Flower traits, such as flower size or color changes, can act as honest signals indicating greater rewards such as nectar; however, nothing is known about shelter-rewarding systems. Large flowers of Royal irises offer overnight shelter as a reward to Eucera bees. A black patch might signal the entrance to the tunnel (shelter) and, together with the flower size, these might act as honest signals. We hypothesize that larger flowers and black patches indicate larger tunnels, and larger tunnels will increase pollinator visits, enhancing the plants' reproductive success. We measured seven species in a controlled environment and two species from three natural populations varying in flower size. Fruit and seed sets were assessed in these natural populations. We found a positive correlation between the flower, patch size, and tunnel volume, suggesting that the flowers and patch size act as honest signals, both under controlled conditions and in the wild. However, in natural populations, this positive relationship and its effect on fitness was population-specific. Flower size increased the fitness in YER I. petrana, and interactions between flower/patch size and tunnel size increased the fitness in YER and I. atropurpurea NET populations. This suggests that the honesty of the signal is positively selected in these two populations. This study supports the hypothesis that pollinator-mediated selection leads to the honest signaling of flower advertisement. [ABSTRACT FROM AUTHOR]

Abstract Body size is a trait that can affect plant–pollinator interaction efficiency and plant reproductive success. We explored the impact of intraspecific size shifts on the interactions between pollinators and flowering plants under controlled conditions. We considered two development conditions leading to the production of large and small individual flowers of Borago officinalis and Echium plantagineum. We also used the natural variability of worker size within bumblebee colonies to isolate small and large workers. We performed a fully crossed experiment with the two flower sizes of each plant species and the two sizes of bumblebee workers. Our results show that the size of both partners did not affect bee foraging behavior in most of the evaluated parameters and both bee sizes were equally efficient in depositing pollen. Significant differences were found only in pollen deposition across the life of a flower in small flowers of B. officinalis, with the greatest quantity of pollen deposited by small bees. We did not find a relationship between pollinator size and plant fitness. Our results suggest that generalist plant–pollinator interactions may be resilient to future potential mismatches in the size of the partners but remain to be tested if they are still resilient under the new environmental conditions resulting from global changes.

Rose (Rosa spp.) is one of the most economically important ornamental species worldwide. Flower diameter, flower weight, and the number of petals and petaloids are key flower-size parameters and attractive targets for DNA-informed breeding. Pedigree-based analysis (PBA) using FlexQTL software was conducted using two sets of multi-parental diploid rose populations. Phenotypic data for flower diameter (Diam), flower weight (fresh (FWT)/dry (DWT)), number of petals (NP), and number of petaloids (PD) were collected over six environments (seasons) at two locations in Texas. The objectives of this study were to 1) identify new and/or validate previously reported QTL(s); 2) identify SNP haplotypes associated with QTL alleles (Q-/q-) of a trait and their sources; and 3) determine QTL genotypes for important rose breeding parents. Several new and previously reported QTLs for NP and Diam traits were identified. In addition, QTLs associated with flower weight and PD were identified for the first time. Two major QTLs with large effects were mapped for all traits. The first QTL was at the distal end of LG1 (60.44–60.95 Mbp) and was associated with Diam and DWT in the TX2WOB populations. The second QTL was consistently mapped in the middle region on LG3 (30.15–39.34 Mbp) and associated with NP, PD, and flower weight across two multi-parent populations (TX2WOB and TX2WSE). Haplotype results revealed a series of QTL alleles with differing effects at important loci for most traits. This work is distinct from previous studies by conducting co-factor analysis to account for the DOUBLE FLOWER locus while mapping QTL for NP. Sources of high-value (Q) alleles were identified, namely, ‘Old Blush’ and Rosa wichuraiana from J14-3 for Diam, while ‘Violette’ and PP-J14-3 were sources for other traits. In addition, the source of the low-value (q) alleles for Diam was ‘Little Chief’, and Rosa wichuraiana through J14-3 was the source for the remaining traits. Hence, our results can potentially inform parental/seedling selections as means to improve ornamental quality in roses and a step towards implementing DNA-informed techniques for use in rose breeding programs.

Sexual dimorphism is expressed as different morphologies between the sexes of a species. Dimorphism is pronounced in gynodioecious populations which consist of female and hermaphrodite individuals. The small size of female flowers in gynodioecious species is often explained by resource re‐allocation to seed production instead of large flowers. However, pollinator attraction is critical to female fitness, and factors other than resource savings are needed to explain the small size of female flowers. We hypothesized that the floral size dimorphism in the perennial gynodioecious Geranium sylvaticum (L.) is adaptive in terms of pollination. To test this "pollination hypothesis," we video recorded the small female and large hermaphrodite G. sylvaticum flowers. We parameterized floral visitor behavior when visiting a flower and calculated pollination probabilities by a floral visitor as the probability of touching anther and stigma with the same body part. Pollination probability differed in terms of flower sex and pollinator species. Bumblebees had the highest pollination probability. The small female flowers were more likely to receive pollen via several pollinator groups than the large hermaphrodite flowers. The pollen display of hermaphrodites matched poorly with the stigma display of hermaphrodites, but well with that of females. Although the small size of female flowers is commonly explained by resource re‐allocation, we show that sexual dimorphism in flower size may increase the main reproductive functions of the females and hermaphrodites. Dimorphism increases pollination probability in females and fathering probability of the hermaphrodites likely driving G. sylvaticum populations towards dioecy. [ABSTRACT FROM AUTHOR]

Flower traits, such as flower size or color changes, can act as honest signals indicating greater rewards such as nectar; however, nothing is known about shelter-rewarding systems. Large flowers of Royal irises offer overnight shelter as a reward to Eucera bees. A black patch might signal the entrance to the tunnel (shelter) and, together with the flower size, these might act as honest signals. We hypothesize that larger flowers and black patches indicate larger tunnels, and larger tunnels will increase pollinator visits, enhancing the plants’ reproductive success. We measured seven species in a controlled environment and two species from three natural populations varying in flower size. Fruit and seed sets were assessed in these natural populations. We found a positive correlation between the flower, patch size, and tunnel volume, suggesting that the flowers and patch size act as honest signals, both under controlled conditions and in the wild. However, in natural populations, this positive relationship and its effect on fitness was population-specific. Flower size increased the fitness in YER I. petrana, and interactions between flower/patch size and tunnel size increased the fitness in YER and I. atropurpurea NET populations. This suggests that the honesty of the signal is positively selected in these two populations. This study supports the hypothesis that pollinator-mediated selection leads to the honest signaling of flower advertisement.

Premise: Ex situ cultivation is important for plant conservation, but cultivation in small populations may result in genetic changes by drift, inbreeding, or unconscious selection. Repeated inbreeding potentially influences not only plant fitness, but also floral traits and interactions with pollinators, which has not yet been studied in an ex situ context. Methods: We studied the molecular genetic variation of Digitalis lutea from a botanic garden population cultivated for 30 years, a frozen seed bank conserving the original genetic structure, and two current wild populations including the source population. In a common garden, we studied the effects of experimental inbreeding and between‐population crosses on performance, reproductive traits, and flower visitation of plants from the garden and a wild population. Results: Significant genetic differentiation was found between the garden population and the wild population from which the seeds had originally been gathered. After experimental selfing, inbreeding depression was only found for germination and leaf size of plants from the wild population, indicating a history of inbreeding in the smaller garden population. Moreover, garden plants flowered earlier and had floral traits related to selfing, whereas wild plants had traits related to attracting pollinators. Bumblebees visited more flowers of outbred than inbred plants and of wild than garden plants. Conclusions: Our case study suggests that high levels of inbreeding during ex situ cultivation can influence reproductive traits and thus interactions with pollinators. Together with the effects of genetic erosion and unconscious selection, these changes may affect the success of reintroductions into natural habitats. [ABSTRACT FROM AUTHOR]

The orchid market is a dynamic horticultural business in which novelty and beauty command high prices. The two main interests are the development of flowers, from the miniature to the large and showy, and their fragrance. Overall organ size might be modified by doubling the chromosome number, which can be accomplished by careful study of meiotic chromosome disjunction in hybrids or species. Meiosis is the process in which diploid (2n) pollen mother cells recombine their DNA sequences and then undergo two rounds of division to give rise to four haploid (n) cells. Thus, by interfering in chromosome segregation, one can induce the development of diploid recombinant cells, called unreduced gametes. These unreduced gametes may be used for breeding polyploid progenies with enhanced fertility and large flower size. This review provides an overview of developments in orchid polyploidy breeding placed in the large context of meiotic chromosome segregation in the model plants Arabidopsis thaliana and Brassica napus to facilitate molecular translational research and horticultural innovation. [ABSTRACT FROM AUTHOR]

Plant pathogens evade basal defense systems and attack different organs and tissues of plants. Genetic engineering of plants with genes that confer resistance against pathogens is very effective in pathogen control. Conventional breeding for disease resistance in ornamental crops is difficult and lagging relative to that in non-ornamental crops due to an inadequate number of disease-resistant genes. Therefore, genetic engineering of these plants with defense-conferring genes is a practical approach. We used rice BSR2 encoding CYP78A15 for developing transgenic Torenia fournieri Lind. lines. The overexpression of BSR2 conferred resistance against two devastating fungal pathogens, Rhizoctonia solani and Botrytis cinerea. In addition, BSR2 overexpression resulted in enlarged flowers with enlarged floral organs. Histological observation of the petal cells suggested that the enlargement in the floral organs could be due to the elongation and expansion of the cells. Therefore, the overexpression of BSR2 confers broad-spectrum disease resistance and induces the production of enlarged flowers simultaneously. Therefore, this could be an effective strategy for developing ornamental crops that are disease-resistant and economically more valuable. [ABSTRACT FROM AUTHOR]

Purpose: The purposes of this research were to assess important traits and heterosis and to introduce superior hybrids of Iris germanica.Research method: 28 hybrids and seven parents of Iris rhizomatous were evaluated. The experiment was carried out in a randomized complete block design (RCBD) with three replications at the Ornamental Plants Research Center (OPRC) from 2014 to 2018. Findings: Hybrid of oprc37 (cross of V5×V4) had a higher positive of heterosis in flower size, leaf width, and hybrid of oprc25 (V8×V6) in the inner tepal length and outer tepal width in superior parents compared to their parents. The highest heterosis was observed for the traits of peduncle length, peduncle diameter and crown diameter, respectively, in some hybrids of oprc20 (V2×V4) and oprc16 (V2×V5). Hybrids of oprc42 and oprc43 of the cross between I. spuria and I. germanica (V7×V2) in the most traits in superior parents and self-parents had higher positive of heterosis. It can be expected that these selected F1 (oprc37, oprc25, oprc20 and oprc16) to able introduced as a variety of commercial, developed on the market ornamental plants.Limitations: No limitations were found. Originality/Value: Inter-varietal hybridization is an effective way to contribute to the phenotypic variation of Iris flowers, to produce new plant materials for breeding purposes and to release new cultivars.

Altered precipitation patterns associated with anthropogenic climate change are expected to have many effects on plants and insect pollinators, but it is unknown if effects on pollination are mediated by changes in water availability. We tested the hypothesis that impacts of climate on plant-pollinator interactions operate through changes in water availability, and specifically that such effects occur through alteration of floral attractants. We manipulated water availability in two naturally occurring Mertensia ciliata (Boraginaceae) populations using water addition, water reduction and control plots and measured effects on vegetative and floral traits, pollinator visitation and seed set. While most floral trait values, including corolla size and nectar, increased linearly with increasing water availability, in this bumblebee-pollinated species, pollinator visitation peaked at intermediate water levels. Visitation also peaked at an intermediate corolla length, while its relationship to corolla width varied across sites. Seed set, however, increased linearly with water. These results demonstrate the potential for changes in water availability to impact plant-pollinator interactions through pollinator responses to differences in floral attractants, and that the effects of water on pollinator visitation can be nonlinear. Plant responses to changes in resource availability may be an important mechanism by which climate change will affect species interactions.

Abstract Background Geographic differences in floral size sometimes reflect geographic differences in pollinator size. However, we know little about whether this floral size specialization to the regional pollinator size occurred independently at many places or occurred once and then spread across the distribution range of the plant species. Results We investigated the relationship between the local floral size of flowers and local pollinator size in 12 populations of Lamium album var. barbatum on two different mountains in the Japan Alps. Then, using 10 microsatellite markers, we analyzed genetic differentiation among the 12 populations. The results showed that local floral size was correlated with the average size of relevant morphological traits of the local pollinators: floral size was greater in populations visited frequently by the largest flower visitors, Bombus consobrinus queens, than it was in other populations. We also found that the degree of genetic similarity between populations more closely reflected interpopulation geographic proximity than interpopulation similarity in floral size. Conclusions Although genetic similarity of populations was highly associated with geographic proximity, floral size varied independently of geographic proximity and was associated with local pollinator size. These results suggest that in L. album var. barbatum, large floral size evolved independently in populations on different mountains as a convergent adaptation to locally abundant large bumblebee species.

We exploited ecotypic variation in Impatiens capensis (Balsaminaceae) to test the hypothesis that mutation accumulation accompanying relaxed selection on the chasmogamous (CH) flower leads to more variable flower shapes and smaller flowers. Sun ecotype populations of this species occur along sunny riverbanks and marshes and produce both CH and cleistogamous (CL) flowers, while shade ecotype populations occur in shady forest floors and produce only CL flowers. In the shade ecotype, it is assumed that selection on the CH flower has been relaxed. Seedlings from population samples of the two ecotypes exhibited different first internode growth responses to low ratios of red:far-red light as seen in earlier studies of ecotypic differentiation to sunny versus shady conditions, helping to verify historical illumination conditions in the populations. We examined the CH floral mutation accumulation hypothesis by comparing the shape and size of the modified CH flower sepal under greenhouse conditions that triggered CH flowering in plants of both ecotypes. Contrary to our predictions, geometric morphometric analysis of sepal shape variation indicated little difference between the shade and sun ecotypes. We suggest that mutations that influence CH flower shape may have pleiotropic effects on structures or processes that remain under selection even when the CH flowers are not produced. On the other hand, sepal size was significantly smaller in the shade ecotype populations. In the case of CH sepal size, the mutational effects appear to be directional, towards producing smaller sepals, and would likely be deleterious if shade ecotype plants encounter sunnier conditions where the plants can produce CH flowers. [ABSTRACT FROM AUTHOR]

Geographic differences in floral traits may reflect geographic differences in effective pollinator assemblages. Independent local adaptation to pollinator assemblages in multiple regions would be expected to cause parallel floral trait evolution, although sufficient evidence for this is still lacking. Knowing the intraspecific evolutionary history of floral traits will reveal events that occur in the early stages of trait diversification. In this study, we investigated the relationship between flower spur length and pollinator size in 16 populations of Aquilegia buergeriana var. buergeriana distributed in four mountain regions in the Japanese Alps. We also examined the genetic relationship between yellow‐ and red‐flowered individuals, to see if color differences caused genetic differentiation by pollinator isolation. Genetic relationships among 16 populations were analyzed based on genome‐wide single‐nucleotide polymorphisms. Even among populations within the same mountain region, pollinator size varied widely, and the average spur length of A. buergeriana var. buergeriana in each population was strongly related to the average visitor size of that population. Genetic relatedness between populations was not related to the similarity of spur length between populations; rather, it was related to the geographic proximity of populations in each mountain region. Our results indicate that spur length in each population evolved independently of the population genetic structure but in parallel in response to local flower visitor size in different mountain regions. Further, yellow‐ and red‐flowered individuals of A. buergeriana var. buergeriana were not genetically differentiated. Unlike other Aquilegia species in Europe and America visited by hummingbirds and hawkmoths, the Japanese Aquilegia species is consistently visited by bumblebees. As a result, genetic isolation by flower color may not have occurred. [ABSTRACT FROM AUTHOR]

The present study evaluated the size of crocus flowers as an element of ornamental quality, depending on the biometric parameters of the plants, against the background of different growing substrates. Two types of crocus were studied: "Queen of the Blues" crocus and "Yellow" crocus. The plants were evaluated in terms of height (Ph, cm) at the beginning of flowering (Ph B-Flo) and at the end of flowering (Ph E-Flo). The size of the flowers (Fs) was evaluated based on the diameter (Fs, cm). Three different substrates were used: sand (V1), mixture of sand and compost (V2) and soil (V3). The bulbs were planted at t1 - mid-October (a), t2 - early November (b), and t3 - mid-November (c). There were 9 experimental variants: V1a - sand at t1; V2a - sand and compost at t1; V3a - soil at t1; V1b-sand at t2; V2b - sand and compost at t2; V3b - soil at t2; V1c - sand at t3; V2c - sand and compost at t3; V3c - soil at t3. The size of the flowers (Fs) varied between 3.97 cm (V1c) and 5.07 cm (V2a) in "Queen of the Blue", respectively between 3.83 cm (V1c) and 4.07 cm (V2b) in "Yellow" crocus. 3D models and in the form of isoquants graphically represented the variation of Fs depending on the physiological parameters (Ph B-Flo and Ph E-Flo). The fs estimation safety was quantified by evaluating the degree of fit between the true values (RFs) and the predicted values (PFs). PC1 explained 79.234% of variance, and PC2 explained 19.046% of variance in the case of the "Queen of the Blues" crocus, and in the case of Yellow crocus, PC1 explained 88.851% of variance, and PC2 explained 8.8951% of variance. [ABSTRACT FROM AUTHOR]

Main conclusion: Elevated temperatures suppress cell division in developing petunia buds leading to smaller flowers, mediated by ABA. Flower size is one of the most important showy traits in determining pollinator attraction, and a central factor determining the quality of floricultural products. Whereas the adverse effects of elevated temperatures on showy traits have been described in detail, its underlining mechanisms is poorly understood. Here, we investigated the physiological mechanism responsible for the reduction of flower size in petunia under elevated temperatures. We found that the early stages of flower-bud development were most sensitive to elevated temperatures, resulting in a drastic reduction of flower diameter that was almost independent of flower load. We demonstrated that the temperature-mediated flower size reduction occurred due to a shorter growth period, and a lower rate of corolla cell division. Consistently, local application of cytokinin, a phytohormone that promotes cell division, resulted in recovery of flower dimensions when grown under elevated temperatures. Hormone analysis of temperature-inhibited flower buds revealed no significant changes in levels of cytokinin, and a specific increase of abscisic acid (ABA) levels, known to inhibit cell division. Moreover, local application of ABA on flower buds caused a reduction of flower dimensions as a result of lower levels of cell division, suggesting that ABA mediates the reduction of flower size at elevated temperatures. Taken together, our results shed light on the mechanism by which elevated temperatures decrease petunia flower size, and show that temperature-mediated reduction of flower size can be alleviated by increasing the cytokinin/ABA ratio. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

In many communication systems, signal receivers profit from honest signals that indicate the signaller's quality, whereas low‐quality signallers should profit from cheating. Under such a conflict of interests between signallers and signal receivers, the maintenance of honest signals presents a puzzle. In theory, honesty can represent an evolutionarily stable strategy, but the actual mechanisms have been studied in few systems only.Here, we investigate honest signalling in a plant species, Brassica rapa, that advertises nectar volumes to pollinators by two honest floral signals; corolla size and the floral volatile phenylacetaldehyde. In a series of experiments we tested for physiological constraints and pollinator behaviours related to honest floral signals and nectar volume, incorporated the result into a mathematical model, and verified its predictions experimentally.While honest floral signals attracted pollinators, the bees' flower visitation time depended on nectar volume and was associated with the number of seeds that flowers developed. Furthermore, honest floral signals and seed set without pollen limitation both increased after soil fertilisation, indicating nutrient limitation in these traits.The mathematical model which incorporates these findings showed that honest signalling in B. rapa can be maintained by a combination of pollinator behaviour and resource limitation causing differential benefits of nectar production. The study demonstrates how honest floral signalling can evolve as a stable strategy in a plant species. A free Plain Language Summary can be found within the Supporting Information of this article. [ABSTRACT FROM AUTHOR]

Abstract Severe droughts are forecast to increase with global change. Approaches that enable the study of contemporary evolution, such as resurrection studies, are valuable for providing insights into the responses of populations to global change. In this study, we used a resurrection approach to study the evolution of the California native Leptosiphon bicolor (true babystars, Polemoniaceae) across populations differing in precipitation in response to the state's recent prolonged drought (2011–2017). In the Mediterranean climate region in which L. bicolor grows, this historic drought effectively shortened its growing season. We used seeds collected both before and after this drought from three populations found along a moisture availability gradient to assess contemporary evolution in a common garden greenhouse study. We coupled this with a drought experiment to examine plasticity. We found evolution toward earlier flowering after the historic drought in the wettest of the three populations, while plasticity to experimental drought was observed across all three. We also observed trade‐offs associated with earlier flowering. In the driest population, plants that flowered earlier had lower intrinsic water‐use efficiency than those flowering later, which was an expected pattern. Unexpectedly, earlier flowering plants had larger flowers. Two populations exhibited evolution and plasticity toward smaller flowers with drought. The third exhibited evolution toward larger flowers, but displayed no plasticity. Our results provide valuable insights into differences among native plant populations in response to drought.

Florivory and floral larceny are very common antagonistic interactions in nature. Florivory can be especially harmful to species with polymorphisms because it may hinder the transfer of pollen in one of the floral morphs. Flower size is one of the floral signals that can influence the attraction of these antagonists. In addition, little is known about the effects of florivory on other antagonistic interactions. Thus, the objective of this study was to investigate the natural patterns of florivory and the relationship between florivory and robbery in the attraction of larcenists in the species Senna rugosa. All flowers damaged by florivores were collected for measurement of natural patterns of florivory with aid of the ImageJ software. Florivory were simulated by holes in the base of the petals and photographs and focal observations were made to assess the effect of flower area and florivory on the attraction of floral larcenists. Smaller flowers had higher florivory rates. In larger flowers, the inner part of the corolla and the anthers had a greater probability of suffering florivory. Although the damage caused by florivory occurred discontinuously regardless of flower size, larger flowers presented continuous marks of florivory more frequently than smaller ones. Larcenists visited flowers regardless of flower size or damaged parts. Thus, flower size and florivory are not determinant factors for the attraction of floral larcenists in enantiostylous S. rugosa. [ABSTRACT FROM AUTHOR]

The study evaluated the vegetation and quality parameters associated with chrysanthemum flowers. Four cultivars of chrysanthemums were studied, cultivated in protected conditions: 'Yellow Snowdon', 'Tom Pearce', 'Palisade' si 'Avignon'. Shoots height (SH) and shoots number (SN) were evaluated as vegetative parameters that express the vegetation state of the plants; the determinations were made at the beginning of August - T1 and at the beginning of September - T2. Flowers diameter (FD) and flowering time (FT) were also evaluated as floral quality indices. The 'Yellow Snowdon' and 'Palisade' cultivars had high shoot height, with significant differences (LSD5%, LSD1%). Regarding the number of shoots, significant differences were registered for the cultivars 'Tom Pearce', 'Palisade', 'Avignon' (LSD5%, LSD1%). Flowers dimension (FD), as a quality parameter, showed significant differences for the cultivars 'Palisade' (LSD0.1%), 'Yellow Snowdon' and 'Tom Pearce' (LSD1%, LSD5%). Longer flowering time was recorded for the 'Avignon' cultivar (58 days) and shorter for the 'Yellow Snowdon' cultivar (52 days). The regression analysis facilitated the obtaining of some equations, as models that described the variation of FD and FT in relation to vegetative parameters (SH and SN), in statistical safety conditions (p <0.001). It was found that a number of 2.223 shoots (SN-T1), respectively 2.765 shoots (SN-T2), provided large flowers. The height of the shoots of 27.191 cm (SH-T1) and 91.816 cm (SH-T2) showed optimal values in relation to the flowering time (FT). [ABSTRACT FROM AUTHOR]

This experiment was performed in Ornamental Nursery at the Department of Horticulture, The University of Agriculture Peshawar during 2016. The experiment was laid out on Randomized Complete Block Design (RCBD) with split plot arrangement and replicated three times. Seedlings of Zinnia cultivars (Dahlia, Candy Cane, and Dream land) were tested against five different levels of humic acid (0, 2.5, 5, 7.5, and 10 kg ha-1). Experimental data was collected on days to flowering, plant height (cm), number of leaves plant-1, leaf area (cm2), number of branches plant-1, number of flower plant-1, diameter of flower (cm), fresh flower weigh (g), flower stalk length (cm) and flower vase life. The above mentioned parameters are highly influenced by most of humic acid levels. The increment value were shown on humic acid at the rate of 10 kg ha -1 for days to flowering (21.2 days), plant height (85.0 cm), number of leaves plant-1 (183.7), leaf area (56.7 cm2), number of branches plant-1 (15.9), number of flower plant-1 (18.4), flower diameter (9.8 cm), fresh flower weight (12.9 g), flower stalk length (16.9 cm) and flower vase life (7.0 days), while among different cultivars, "Dahlia" showed minimum days to flowering (23.9), maximum plant height (96.3 cm), flower weight (14.7 g), flower diameter (9.6 cm) and leaf area (62.1 cm2). Cultivar Candy Cane showed maximum number of leaves plant-1 (190), number of branches plant-1 (14.6), flower stalk length (17.1 cm), and flower vase life (6.1 days), whereas number of flower plant-1 (16) was found maximum in cultivar "Dream land". The cultivar and humic acid interaction was not significant in all parameters. Zinnia Cv. Dahlia and Candy Cane both adapted to the agro-climatic conditions of Peshawar. Humic acid level at the rate of 10 kg ha-1 showed better results upon application to Zinnia and hence it is suggested for best production. [ABSTRACT FROM AUTHOR]

The orchid market is a dynamic horticultural business in which novelty and beauty command high prices. The two main interests are the development of flowers, from the miniature to the large and showy, and their fragrance. Overall organ size might be modified by doubling the chromosome number, which can be accomplished by careful study of meiotic chromosome disjunction in hybrids or species. Meiosis is the process in which diploid (2n) pollen mother cells recombine their DNA sequences and then undergo two rounds of division to give rise to four haploid (n) cells. Thus, by interfering in chromosome segregation, one can induce the development of diploid recombinant cells, called unreduced gametes. These unreduced gametes may be used for breeding polyploid progenies with enhanced fertility and large flower size. This review provides an overview of developments in orchid polyploidy breeding placed in the large context of meiotic chromosome segregation in the model plants Arabidopsis thaliana and Brassica napus to facilitate molecular translational research and horticultural innovation.

The high variability observed in floral traits has been interpreted as resulting from the adaptation of plants to pollinators, as the latter present innate preferences for specific floral traits and impose selection over them. However, some pollinators such as bees can learn to associate floral signals with rewards, thus increasing floral constancy on more rewarding flowers. The integration of all these rewards and cues is markedly important at community level, where co‐flowering species compete for pollinators.In order to verify the honesty of the above‐mentioned signals, we examined the association between floral visual signals (size, colour, symmetry and floral display) and rewards (pollen and nectar) for 98 species in a Mediterranean community. The associations between floral traits were analysed considering the phylogenetic relationship between the different species.Flower colour, size, pollen volume or amount of sucrose exhibited no phylogenetic signal, which suggests an adaptive evolution in response to different conditions in the pollinator community. Flower size was seen to constitute the most honest signal for pollinators, as this was significantly associated with quantities of pollen and nectar. In contrast, nectar concentration was observed to be positively associated with chromatic contrast. We detected no relationship between flower shape and rewards, on the one hand, nor between flower display and rewards, on the other.Our study unequivocally demonstrates the correlation between rewards and the visual signals perceived by bees, the most effective pollinators in the Mediterranean Basin. In the community studied, bees employed flower size at longer distances and chromatic contrast at shorter distances to predict rewards. The limited number of studies existing in this sense indicates that this kind of association appears to be community specific. [ABSTRACT FROM AUTHOR]

Main conclusion: Morpho-physiological changes were observed in Arabidopsis plants acclimated to long-term combined cold and water deficit stresses. Limiting growth and differences in bolting, flowering, and silique development were evidenced. In nature, plants are exposed to multiple and simultaneous abiotic stresses that influence their growth, development, and reproduction. In the last years, the study of combined stresses has aroused the interest to know the physiological and molecular responses, because these new stress conditions are probed to be different from the sum of the individual stress. We are interested in the study of the acclimation of plants growing under the combination of cold and water deficit stresses prevalent in cold-arid or semi-arid climates worldwide. We hypothesized that the reproduction of the acclimated plants will be compromised and affected. Arabidopsis plants were submitted to long-term combined stress from the beginning to the reproductive stage, when floral bud was visible, until the silique development. Our results demonstrate severe morpho-anatomical changes after acclimation to combined stress. Inflorescence stem morphology was altered having a delayed bolting and a limited growth. Flowering and silique formation were delayed, and a higher size in the corolla and the petals was observed. Flower and silique number were severely diminished as a result of combined stress, unlike acclimated plants to individual cold stress. These traits were recovered after deacclimation to optimal conditions and plants achieved similar silique production as control plants. The long-term stress results suggest that there is not a single dominant stress, but there is an alternating dominance depending on the structure or the plant stage development evaluated. [ABSTRACT FROM AUTHOR]

Background and Aims: Pollinators provide critical ecosystem services, maintaining biodiversity and benefiting global food production. However, plants, pollinators, and their mutualistic interactions may be affected by drought, which has increased in severity and frequency under climate change. Using two annual, insect-pollinated wildflowers (Phacelia campanularia and Nemophila menziesii), we asked how drought impacts floral traits and foraging preferences of a solitary bee (Osmia lignaria) and explore potential implications for plant reproduction., Methods: In greenhouses, we experimentally subjected plants to drought to induce water stress, as verified by leaf water potential. To assess the impact of drought on floral traits, we measured flower size, floral display size, nectar volume, and nectar sugar concentration. To explore how drought-induced effects on floral traits affected bee foraging preferences, we performed choice trials. Individual female bees were placed into foraging arenas with two conspecific plants, one droughted and one non-droughted, and were allowed to forage freely., Key Results: We determined that P. campanularia is more drought-tolerant than N. menziesii based on measures of turgor loss point, and confirmed that droughted plants were more drought-stressed than non-droughted plants. For droughted plants of both species, floral display size was reduced, and flowers were smaller and produced less, more-concentrated nectar. We found that bees preferred non-droughted flowers of N. menziesii. However, bee preference for non-droughted P. campanularia flowers depended on the time of day and was detected only in the afternoon., Conclusions: Our findings indicate that bees prefer visiting non-droughted flowers, likely reducing pollination success for drought-stressed plants. Lack of preference for non-droughted P. campanularia flowers in the morning may reflect the higher drought tolerance of this species. This work highlights the potentially intersecting, short-term physiological and pollinator behavioral responses to drought and suggests that such responses may reshape plant-pollinator interactions, ultimately reducing reproductive output for less drought-tolerant wildflowers., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Premise: We tested 25 classic and novel hypotheses regarding trait–origin, trait–trait, and trait–environment relationships to account for flora‐wide variation in life history, habit, and especially reproductive traits using a plastid DNA phylogeny of most native (96.6%, or 1494/1547 species) and introduced (87.5%, or 690/789 species) angiosperms in Wisconsin, USA. Methods: We assembled data on life history, habit, flowering, dispersal, mating system, and occurrence across open/closed/mixed habitats across species in the state phylogeny. We used phylogenetically structured analyses to assess the strength and statistical significance of associations predicted by our models. Results: Introduced species are more likely to be annual herbs, occupy open habitats, have large, visually conspicuous, hermaphroditic flowers, and bear passively dispersed seeds. Among native species, hermaphroditism is associated with larger, more conspicuous flowers; monoecy is associated with small, inconspicuous flowers and passive seed dispersal; and dioecy is associated with small, inconspicuous flowers and fleshy fruits. Larger flowers with more conspicuous colors are more common in open habitats, and in understory species flowering under open (spring) canopies; fleshy fruits are more common in closed habitats. Wind pollination may help favor dioecy in open habitats. Conclusions: These findings support predictions regarding how breeding systems depend on flower size, flower color, and fruit type, and how those traits depend on habitat. This study is the first to combine flora‐wide phylogenies with complete trait databases and phylogenetically structured analyses to provide powerful tests of evolutionary hypotheses about reproductive traits and their variation with geographic source, each other, and environmental conditions. [ABSTRACT FROM AUTHOR]

The flower is the main organ that produces essential oils in many plants. The yield of raw flowers and the number of secretory epidermal cells are the main factors for essential oil production. The cultivated rose species “Pingyin 1” in China was used to study the effect of RrANT1 on floral organ development. Eighteen AP2 transcription factors with dual AP2 domains were identified from Rosa rugosa genome. RrANT1 belonged to euANT. The subcellular localization results showed that RrANT1 protein is localized in the nucleus. The relative expression level of RrANT1 in the receptacle is higher than that in petals in the developmental stages, and both decreased from the initial phase to senescence. Compared with the RrANT1 expression level in petals in the blooming stage, RrANT1 expression level was significant in petals (~48.8) and highest in the receptacle (~102.5) in the large bud stage. It was only highly expressed in the receptacle (~39.4) in the blooming period. RrANT1 overexpression significantly increased petunia flower and leaf sizes (~1.2), as well as flower fresh weight (~30%). The total number of epidermis cells in the petals of overexpressing plants significantly increased (>40%). This study concluded that RrANT1 overexpression can increase the size and weight of flowers by promoting cell proliferation, providing a basis for creating new rose germplasm to increase rose and essential oil yield.

Background and Aims Sexual dimorphism for floral traits is common in dioecious plant species. Beyond its significance for understanding how selection acts on plant traits through male vs. female reproductive function, sexual dimorphism has also been proposed as a possible risky characteristic for insect-pollinated plants, as it could drive pollinators to forage mostly on male plants. However, even though most flowering plant species spread their flowering across several weeks or months, the temporal variation of floral phenotypes and sexual dimorphism have rarely been investigated. Methods We performed a survey of male and female plants from the dioecious generalist-pollinated Silene dioica (Caryophyllaceae) in a common garden experiment, over two consecutive flowering seasons. Flower number and floral size were measured each week, as well as pollen quantity and viability in male plants. Key Results Sexual dimorphism was found for all investigated floral traits, with males showing an overall higher investment in flower production and flower size. Males and females showed a similar temporal decline in flower size. The temporal dynamics of daily flower number differed between sexes, with males showing a peak in the middle of their flowering season, whereas flower production by females was quite stable over time. At the scale of the experimental population, both individual and floral sex ratios appeared to vary across the flowering season. Moreover, because the onset of flowering varied among plants, the magnitude of sexual dimorphism in floral size also fluctuated strongly through time. Conclusions Capturing male/female differences with only one temporal measurement per population may not be informative. This opens stimulating questions about how pollinator behaviour and resulting pollination efficiency may vary across the flowering season. [ABSTRACT FROM AUTHOR]

In the protologue, Epimedium tianmenshanense (Berberidaceae), a species endemic to western Hunan, China, was described as 'flower small, 0.2–0.4 cm diam., inner sepals white, petals as long as inner sepals or a little shorter than the latter, spur very short, ca 5.0 mm'. However, both morphological characteristics and molecular evidence suggest that E. tianmenshanense is closely related to E. baojingense, a taxon with a long spur, thus suggesting that the size of the floral parts is not as reliable as previously believed. When investigating the variability of E. tianmenshanense in more detail, in the field as well as in cultivation, we found that the petals were are highly variable in morphology (both shape and size), being cucullate, subulate, short to long spurred, and with various transitions. The flowers size varied from small to large accordingly. The flowers with cucullate and subulate petals, which were a little shorter than the inner sepals or almost as long as the latter, were small (about 0.8 cm in diameter). The flowers with long spurs, which were much longer than the inner sepals, were also large (about 2.5–3.5 cm in diameter). Finally, the flowers with short spurs, which were a little longer than the inner sepals, were medium‐sized (about 1.0–1.2 cm in diameter). In addition, the color of inner sepals was revised from 'white, occasionally light mulberry‐purple' to yellowish green or yellowish white. Epimedium tianmenshanense is a perfect example of natural petal evolution, which could be used for further taxonomic and evolutionary studies. The reason for the variation and the taxonomic treatment of the species still need further study. [ABSTRACT FROM AUTHOR]

Theoretical models indicate that the structure of plant–pollinator networks has important implications for the reproduction and survival of species. However, despite the growing information on the mechanisms underlying such a structure, it is still difficult to predict the functional consequences of species' structural positions in these networks. From the plant perspective, species position and roles in pollination networks might be related to traits describing flower attractiveness, availability and dependence on pollinators. In turn, both network metrics and plant traits might influence plant species fitness.During two field seasons, we collected data from the 23 most abundant plant species in a rich coastal community, to evaluate the association between population and floral traits (floral abundance at population level and flowers per individual, flower shape and size, flowering length, nectar volume, pollinator dependence), species‐level network metrics (linkage level, specialization –d′–, weighted closeness centrality, network roles related to modularity) and plant fitness (seeds/flower, seed weight).Flowering length, flower size, flower abundance and pollinator dependence were positively related to greater generalization, as measured by various indices. More abundant species and those with larger flowers showed higher linkage levels (i.e. higher number of pollinator species), whereas longer flowering periods were negatively related to d′ and positively related to closeness centrality and important roles in the network. Likewise, plants species more dependent on pollinators occupied more central positions in the network. Furthermore, centrality in the networks was significantly associated with plant fitness. Specifically, central species in the network produced more and heavier seeds than the others. However, other plant traits, such as flower size and pollinator dependence had additional direct effects on seed production.Synthesis. Our study highlights how population and floral traits define the positions and roles of species structuring the pollination communities. Moreover, the relationships between network metrics and plant reproduction indicate, for the first time, the functional implications of these structural positions at the interspecific level of community assembly. [ABSTRACT FROM AUTHOR]

Sexual dimorphism is a pervasive form of variation within species. Understanding how and why sexual dimorphism evolves would contribute to elucidating the mechanisms underlying the diversification of traits. In flowering plants, pollinators are considered a driver of sexual dimorphism when they affect female and male plant fitness in distinct ways. Here, we found that flowers appear to manipulate the behavior of pollinators using sexually dimorphic traits in the dioecious tree Eurya japonica. In this plant, female flowers present a higher-quality reward for pollinators, whereas male flowers have a more conspicuous appearance. Plants benefit by inducing pollinators to carry pollen from male to female flowers, and their sexual dimorphism might thus facilitate pollen movement through pollinator behavior. In two-choice experiments, pollinators frequently moved from male to female flowers, whereas computer simulation suggested that sexually dimorphic traits would evolve if pollinators changed behavior depending on the traits of the flowers they had just visited. These results suggest that the floral traits affecting the visiting order of pollinators have evolved in plants. Using E. japonica, we theoretically show that the induction of sequential behavior in pollinators might be crucial to the evolution of sexual dimorphism in flowers, and our experiments support these findings. [ABSTRACT FROM AUTHOR]