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Summary Plant phenology, the timing of recurrent biological events, shows key and complex response to climate warming, with consequences for ecosystem functions and services. A key challenge for predicting plant phenology under future climates is to determine whether the phenological changes will persist with more intensive and long‐term warming. Here, we conducted a meta‐analysis of 103 experimental warming studies around the globe to investigate the responses of four phenophases – leaf‐out, first flowering, last flowering, and leaf coloring. We showed that warming advanced leaf‐out and flowering but delayed leaf coloring across herbaceous and woody plants. As the magnitude of warming increased, the response of most plant phenophases gradually leveled off for herbaceous plants, while phenology responded in proportion to warming in woody plants. We also found that the experimental effects of warming on plant phenology diminished over time across all phenophases. Specifically, the rate of changes in first flowering for herbaceous species, as well as leaf‐out and leaf coloring for woody species, decreased as the experimental duration extended. Together, these results suggest that the real‐world impact of global warming on plant phenology will diminish over time as temperatures continue to increase. [ABSTRACT FROM AUTHOR]

As red-fleshed pitaya (Hylocereus polyrhizus) is not native to the tropical environment of the Malaysian state of Sabah, Borneo, little is known about its flowering phenology, pollination requirements, and potential pollinators, which has discouraged many farmers from growing this crop. Therefore, this study aimed to examine better pollination techniques to achieve acceptable fruit quality for red-fleshed pitaya production under local climatic conditions. For this purpose, stingless bees (Tetragonula laeviceps), self-pollination, natural pollination, and hand pollination were used. Pitayas were planted in the field from January 2018 to February 2022, and 40 flowers were observed to obtain data on flowering phenology and fruit quality. This study observed that anthesis of red-fleshed pitaya took about 24 hours in all treatments, depending on the local climate, starting at 6.30 p.m. and ending at 6.30 p.m. the next day. Besides self-pollination, the pitaya flowers were also successfully pollinated by natural, hand, and stingless bees. However, the fruits pollinated by stingless bees were the heaviest, longest, and thickest, indicating that the integration of pitaya cultivation and stingless bees is likely to improve the yield and quality of the fruits on the farm. [ABSTRACT FROM AUTHOR]

Plant reproduction may experience distinct evolutionary and ecological dynamics depending on their flowering phenology. Consequently, floral traits might undergo divergence selection to adapt to the difference in the abiotic and the biotic environment, especially if these traits affect intensity of competition plants experience due to pollinators. The present study analyzed the plant floral display, floral rewards, and the pollination and breeding systems of two related species of Leucojum, the autumn-blooming L. autumnale and the spring-blooming L. trichophyllum. The aim of the current study is to compare reproductive aspects of L. autumnale and L. trichophyllum due to differing environmental conditions. Both species needed pollinators to reproduce sexually, with zero (L. trichophyllum) or low values (c. 7.7%; L. autumnale) for fructification after self-pollination vs. over 90% after natural pollination (both species). Their flowers opened in the morning and closed at night, and neither produced nectar, only pollen as reward to pollinators. Plants of the L. autumnale studied population produced 1–4 inflorescences per plant vs. only 1 in L. trichophyllum, and the former presented a greater density of flowers per surface unit. Leucojum autumnale flowers were visited by Hymenoptera and those of L. trichophyllum only by two Coleoptera, which were most abundant at sunrise and sunset, whereas in the middle of the day, they visited Cistaceae flowers. This latter occurrence may represent a temporal niche partitioning rather than competition in relation to visiting hours, as the L. trichophyllum flowers offer a place for insects to spend the night, a period in which the flowers of the Cistaceae species have lost their petals. [ABSTRACT FROM AUTHOR]

Management of food resources is considered fundamental for supporting insect pollinators, whose abundance shows a downward trend on the global scale. Here, the nectar and pollen production (per flower, per 1 m2 of tree crown), the composition of nectar carbohydrates and the levels of pollen proteins was evaluated in eight Tilia species (Malvaceae) growing in SE Poland. In the warm-summer continental climate, Tilia species can improve nectar and pollen resources mainly in June/July. Although the flowering period of each species is short (8.0–14.7 days), appropriate selection of species can extend the availability of food for more than a month. However, the considerable variations in the flowering onset (11.2–20.1 days) may cause significant inter-seasonal shifts in food accessibility. The nectar with its highly changeable sugar concentration (29.5–77.4%) was composed of sucrose, glucose, and fructose; protein content in pollen was 7.2–16.8%. The mean sugar yield was in the range of 0.95–19.1 g per 1 m2 (T. amuriensis – T. platyphyllos, respectively), whereas the mean pollen yield was 1.37–4.1 g per 1 m2 of tree crown (T. amuriensis – T. × euchlora, respectively). Significant year-to-year fluctuations of sugar and pollen yield in linden trees have to be taken into account in conservation schemes, and the introduction of other flowering plants with more stable sugar and pollen production should be considered in an area with a high density of linden trees. Linden flowers mainly support honey bees; nevertheless, wild pollinators (bumble bees, solitary bees, and dipterans) can also benefit from linden floral resources. [ABSTRACT FROM AUTHOR]

Natural selection on traits expressed repeatedly by individuals is usually investigated with a focus on mean values, although within‐individual trait distributions often differ also in other aspects, such as their spread and shape. In plants producing multiple flowers during a season, there might not be a single optimal flowering time, but rather an optimal distribution of flower opening dates. This optimal distribution might depend on both resource allocation patterns and interactions with the abiotic and biotic environment. In this study, we quantified mean, variance, skewness and kurtosis of 495 individual flowering schedules (5287 flowers) over 3 years, and assessed phenotypic selection on these aspects of the within‐individual distribution of opening dates in the perennial herb Lathyrus vernus. We also explored how selection on within‐individual variation in flowering schedules was related to effects on two fitness components: fruit set and the proportion of seeds escaping pre‐dispersal predation. Within‐individual variation in phenology was larger than, or at least similar to, among‐individual variation in all years. We found phenotypic selection on several aspects of individual flowering schedules. In 1 year, selection favoured plants with higher variance in opening dates, and this coincided with a higher fruit set in plants with an increased spread of the flowering schedule. In two of the study years, selection favoured a higher asymmetry of the flowering schedule, and plants with more right‐skewed distributions had higher fruit set and higher proportions of seeds escaping predation. Both fruit set and seed predation increased with an earlier mean flowering, resulting in no net selection on mean flowering date. Synthesis: Our results suggest that phenotypic selection on the spread and shape of flower opening date distributions might be at least as important as selection on the mean flowering date. In a broad sense, this implies that we should consider the entire trait distribution if we aim to understand the evolution of traits that are expressed multiple times within individuals. [ABSTRACT FROM AUTHOR]

The extent to which weeds in arable land are useful to pollinators depends in part on the temporal pattern of flowering and insect flight activity. We compiled citizen science data on 54 bees and hoverflies typical of agricultural areas in southern Sweden, as well as 24 flowering weed species classified as pollinator‐friendly in the sense that they provide nectar and/or pollen to pollinators. The flight periods of the bees and hoverflies varied greatly, but there were also some consistent differences between the four groups studied. The first group to fly were the early flying solitary bees (7 species), followed by the social bees (18 species). In contrast, other solitary bees (11 species) and hoverflies (22 species) flew later in the summer. Solitary bees had the shortest flight periods, while social bees and hoverflies had longer flight periods. Flowering of weed species also varied greatly between species, with weeds classified as winter annuals (e.g., germinating in autumn) starting early together with germination generalists (species that can germinate in both autumn and spring). Summer annuals (spring germinators) and perennials started flowering about a month later. Germination generalists had a much longer flowering period than the others. Weekly pollinator records were in most cases significantly explained by weed records. Apart from early flying solitary bees, all models showed strong positive relationships. The overall best explanatory variable was the total number of weeds, with a weight assigned to each species based on its potential as a nectar/pollen source. This suggests that agricultural weeds in Sweden provide a continuous potential supply of nectar and pollen throughout the flight season of most pollinators. [ABSTRACT FROM AUTHOR]

Background and Aims The timing of flowering onset is often correlated with latitude, indicative of climatic gradients. Flowering onset in temperate species commonly requires exposure to cold temperatures, known as vernalization. Hence, population differentiation of flowering onset with latitude might reflect adaptation to the local climatic conditions experienced by populations. Methods Within its western range, seeds from Linum bienne populations (the wild relative of cultivated Linum usitatissimum) were used to describe the latitudinal differentiation of flowering onset to determine its association with the local climate of the population. A vernalization experiment including different crop cultivars was used to determine how vernalization accelerates flowering onset, in addition to the vernalization sensitivity response among populations and cultivars. Additionally, genetic differentiation of L. bienne populations along the latitudinal range was scrutinized using microsatellite markers. Key Results Flowering onset varied with latitude of origin, with southern populations flowering earlier than their northern counterparts. Vernalization reduced the number of days to flowering onset, but vernalization sensitivity was greater in northern populations compared with southern ones. Conversely, vernalization delayed flowering onset in the crop, exhibiting less variation in sensitivity. In L. bienne , both flowering onset and vernalization sensitivity were better predicted by the local climate of the population than by latitude itself. Microsatellite data unveiled genetic differentiation of populations, forming two groups geographically partitioned along latitude. Conclusions The consistent finding of latitudinal variation across experiments suggests that both flowering onset and vernalization sensitivity in L. bienne populations are under genetic regulation and might depend on climatic cues at the place of origin. The association with climatic gradients along latitude suggests that the climate experienced locally drives population differentiation of the flowering onset and vernalization sensitivity patterns. The genetic population structure suggests that past population history could have influenced the flowering initiation patterns detected, which deserves further work. [ABSTRACT FROM AUTHOR]

Summary: Plant pollen is rich in protein, sterols and lipids, providing crucial nutrition for many pollinators. However, we know very little about the quantity, quality and timing of pollen availability in real landscapes, limiting our ability to improve food supply for pollinators.We quantify the floral longevity and pollen production of a whole plant community for the first time, enabling us to calculate daily pollen availability. We combine these data with floral abundance and nectar measures from UK farmland to quantify pollen and nectar production at the landscape scale throughout the year.Pollen and nectar production were significantly correlated at the floral unit, and landscape level. The species providing the highest quantity of pollen on farmland were Salix spp. (38%), Filipendula ulmaria (14%), Rubus fruticosus (10%) and Taraxacum officinale (9%). Hedgerows were the most pollen‐rich habitats, but permanent pasture provided the majority of pollen at the landscape scale, because of its large area. Pollen and nectar were closely associated in their phenology, with both peaking in late April, before declining steeply in June and remaining low throughout the year.Our data provide a starting point for including pollen in floral resource assessments and ensuring the nutritional requirements of pollinators are met in farmland landscapes. [ABSTRACT FROM AUTHOR]

Context: There have been few long-term studies of the flora, phenology, and ecology of specific reserves in the species-rich flora of the Southwest Australian Floristic Region. Aims: This project, extending over five decades, aimed to develop an authoritative flora list and acquire data on phenology, threatened species, endemism, old and young landscapes, phytogeography, old lineages, and fire responses at Two Peoples Bay Nature Reserve. Methods: The study used botanical collection on repeat surveys, herbarium studies, granite outcrop surveys and comparative phytogeographic analyses from maps on the Western Australian Herbarium's Florabase. Key results: Floristic survey recovered 853 taxa, 26% of those known in the Albany local government area. Possibly as many as 950–1000 taxa will be found in the future. The herbarium collections are the second largest of any conservation reserve in the Albany area. Flowering was most evident in spring and least in autumn. Three declared rare species and 20 conservation priority species were identified, as were short-range endemics, old clades, and natural hybrids. Conclusions: The flora is dominated by species predominantly from wetter forest regions. Consequently, Two Peoples Bay Nature Reserve is correctly placed within the Bibbulmun Botanical Province. Several hypotheses of OCBIL theory (which addresses old, climatically-buffered, infertile landscapes) were supported, with increased local endemism, ancient clades, and reduced rates of natural hybridisation identified for the granite inselberg OCBIL Maardjitup Gurlin/Mt Gardner. Implications: Long term studies are invaluable for plant inventory. Continuing the minimal use of prescribed burning is advocated from plant data, in support of approaches to help conserve threatened animals. This project, extending over five decades, aimed to develop an authoritative flora list and acquire data on phenology, threatened species, endemism, old and young landscapes, phytogeography, old lineages, and fire responses at Two Peoples Bay Nature Reserve. Intensive field work by many collectors was involved. Floristic survey recovered 853 taxa, 3 declared rare species, 20 conservation priority species and various short-range endemics, old clades, and natural hybrids. Continued avoidance of prescribed burning is advocated. This article belongs to the Collection The Natural History of Two Peoples Bay Nature Reserve, Western Australia. [ABSTRACT FROM AUTHOR]

Iris ruthenica Ker-Gawl. (Russian iris) is a perennial, clonal, herbaceous plant that is spread across the degradedmountain grasslands in northern Xinjiang. In this study, to explore the breeding system and the impact of slope orientation on the flowering phenology, pollination characteristics, and other aspects of I. ruthenica, we used a combination of field observations and controlled experiments to compare the population density, flowering phenology, floral characteristics, breeding system, and pollinator type and behavior of plants on different slope orientations. Vegetation coverage on the north (N), southwest (SW), and southeast (SE) slopes was 90%, 67%, and 53%, respectively. Differences in plant height and diameter were observed between the SE slope and the N and SW slopes, whereas the N and SW slopes were similar in these respects. The SE slope exhibited the earliest initial flowering time, followed by the SW and N slopes. The diameter of the corolla, distance between the stigma and anther, length of the anther and ovary, number of pollen grains, and number of ovules on the N slope were smaller than those on the SE and SWslopes, whereas those of the SE and SW slopes were similar. Artificial pollination experiments showed that neither bagging nor unbagging resulted in seed formation after emasculation for all slope orientations. The pollinating insects of I. ruthenica included Bombus sp., Amegilla leptocoma, Andrena sp., and Halictus sp.; the types and numbers of pollinating insects differed among slopes. In summary, on SE and SW slopes with high temperatures and sufficient sunlight, this species attracted pollinators and provided them with more opportunities to visit and pollinate by flowering early, with large numbers of blooms, and a longer flowering period and lifespan, ensuring successful reproduction. Under unfavorable conditions, such as insufficient pollinators and limited activity caused by the more stressful environmental conditions of the N slope (including low temperature and insufficient light), this species ensures a certain seed yield by increasing its self-compatibility. [ABSTRACT FROM AUTHOR]

Phenological shifts due to changing climate are often highly species and context specific. Land‐use practices such as mowing or grazing directly affect the phenology of grassland species, but it is unclear if plants are similarly affected by climate change in differently managed grassland systems such as meadows and pastures. Functional traits have a high potential to explain phenological shifts and might help to understand species‐specific and land‐use‐specific phenological responses to changes in climate. In the large‐scale field experiment Global Change Experimental Facility (GCEF), we monitored the first flowering day, last flowering day, flowering duration, and day of peak flowering, of 17 herbaceous grassland species under ambient and future climate conditions, comparing meadows and pastures. Both climate and land use impacted the flowering phenology of plant species in species‐specific ways. We did not find evidence for interacting effects of climate and land‐use type on plant phenology. However, the data indicate that microclimatic and microsite conditions on meadows and pastures were differently affected by future climate, making differential effects on meadows and pastures likely. Functional traits, including the phenological niche and grassland utilization indicator values, explained species‐specific phenological climate responses. Late flowering species and species with a low mowing tolerance advanced their flowering more strongly under future climate. Long flowering species and species following an acquisitive strategy (high specific leaf area, high mowing tolerance, and high forage value) advanced their flowering end more strongly and thus more strongly shortened their flowering under future climate. We associated these trait–response relationships primarily with a phenological drought escape during summer. Our results provide novel insights on how climate and land use impact the flowering phenology of grassland species and we highlight the role of functional traits in mediating phenological responses to climate. [ABSTRACT FROM AUTHOR]

Copyright of Glasnik Zastite Bilja is the property of Zadruzna Stampa D.D. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Restoration of terrestrial ecosystems often requires re‐introduction of plants. In restored sites, the plants often face environments that differ from those of natural populations. This can affect plant traits, reduce performance and impose novel selection pressures. As a response, restored populations might rapidly evolve and adapt to the novel conditions. This may enhance population survival and contribute to restoration success, but has been rarely tested so far.Here, we focused on populations of three grassland species restored 20 years ago (Galium wirtgenii, Inula salicina and Centaurea jacea) by the transfer of green hay, and compared them with donor populations that were the source of the hay. We measured plants both in situ, and in a common garden under control and three stress conditions.In situ, plants in restored sites flowered earlier than plants in donor sites in two out of the three species. In the common garden, plants from the restored populations flowered earlier (in Galium) or showed increased plasticity of clonal propagation in response to clipping (in Inula). Both these traits suggest rapid adaptation to the contrasting mowing regimes in restored in comparison with the donor sites. In Centaurea, we detected no differentiation, neither in situ, nor in the common garden.Synthesis and applications. Grassland plants introduced into degraded habitats within the framework of ecological restoration may quite commonly evolve in response to novel selection pressures at restored sites. This rapid evolution likely increases the plant's adaptation to the new conditions of the restored grassland and thus enhances the likelihood of survival of the population and ultimately restoration success. While most practitioners do not consider evolution to be part of restoration, our finding highlights that restored populations of grassland species can be systems with considerable eco‐evolutionary dynamics. [ABSTRACT FROM AUTHOR]

Spathiphyllum is a mostly Neotropical genus of the Araceae plant family. Many species have a long flowering period and emit a strong, pleasant, and species‐specific floral scent. In Mexico, Spathiphyllum is represented by 14 species, 9 of which are endemic. Here, we describe the morphology, floral scent composition, and flowering phenology of a hitherto unknown species, S. hentrichianum sp. nov. This species is characterized by having a petiole not sheathed to the geniculum, leaf blades with less than 25 primary lateral veins per side, 1–2 ovules per locule, and 3–5 ovules per ovary. The strong scent consists of various terpenes and aromatic compounds, mainly (E,E)‐α‐Farnesene, (E)‐Cinnamyl acetate and (E)‐Cinnamyl alcohol. The new species is morphologically similar to S. cochlearispathum, but the latter differs in having a petiole sheathed to the geniculum, leaf blades with up to 31 primary lateral veins per side, 2–6 ovules per locule and 6–16 ovules per ovary, and the floral scent is also different between both species. In S. cochlearispathum, the scent is dominated by aromatic compounds, one terpene and one nitrogen‐containing compound, such as Methyl salicylate, Methyl p‐anisate, Methyl (E)‐cinnamate, (R)‐Linalool and 2‐Phenylacetonitrile. The flowering cycle of an inflorescence in S. hentrichianum lasted between 25 and 29 days. We suggest that detailed volatile organic compounds in the floral scent could be useful when defining a new taxon, especially among cryptic and sympatric aroid species. [ABSTRACT FROM AUTHOR]

ABSTRACT: From a pollination biology standpoint, this study compared modifications in the flowering phenology, soluble sugar and protein content of pollen, antioxidant enzyme system, and storage traits of five cultivated populations of Paeonia ostii ‘Feng dan’ at various altitudes in Luoyang. The findings indicated that the first blooming phase was delayed at greater altitudes. There was a significant difference in the soluble sugar content of pollen between sites; and there was no discernible relationship between soluble sugar content and altitude. With increasing altitude, there is a tendency for soluble protein content to decrease. The activities of antioxidant enzymes in pollen from cultivated populations at varying altitudes showed SOD and POD enzyme activities generally increasing with decreasing temperature, whereas CAT enzymes showed divergent patterns. Differences existed in the storage time of pollen across populations at different altitudes, and pollen from higher altitudes appeared to be better adapted to low-temperature storage environments. The rate of decrease in pollen viability under dry storage at -74.7 °C was significantly lower than under other storage conditions. The comprehensive analysis concludes that the variations in ‘Feng dan’ cultivation populations within the same region at different altitude zones can be leveraged for cross-pollination among proximate populations, utilizing low-temperature dry pollen storage technology, with the aim of achieving abundant oil peony production.

Abstract The extent to which weeds in arable land are useful to pollinators depends in part on the temporal pattern of flowering and insect flight activity. We compiled citizen science data on 54 bees and hoverflies typical of agricultural areas in southern Sweden, as well as 24 flowering weed species classified as pollinator‐friendly in the sense that they provide nectar and/or pollen to pollinators. The flight periods of the bees and hoverflies varied greatly, but there were also some consistent differences between the four groups studied. The first group to fly were the early flying solitary bees (7 species), followed by the social bees (18 species). In contrast, other solitary bees (11 species) and hoverflies (22 species) flew later in the summer. Solitary bees had the shortest flight periods, while social bees and hoverflies had longer flight periods. Flowering of weed species also varied greatly between species, with weeds classified as winter annuals (e.g., germinating in autumn) starting early together with germination generalists (species that can germinate in both autumn and spring). Summer annuals (spring germinators) and perennials started flowering about a month later. Germination generalists had a much longer flowering period than the others. Weekly pollinator records were in most cases significantly explained by weed records. Apart from early flying solitary bees, all models showed strong positive relationships. The overall best explanatory variable was the total number of weeds, with a weight assigned to each species based on its potential as a nectar/pollen source. This suggests that agricultural weeds in Sweden provide a continuous potential supply of nectar and pollen throughout the flight season of most pollinators.

Abstract Tropical plants exhibit virtually all known phenological responses, which can range from near-continuous to brief events, and from complete synchrony to complete asynchrony. This wide variety of phenological patterns is related to high tropical biodiversity and complex interactions with diverse abiotic and biotic factors, such as plant-pollinator interactions. Changes in these factors will therefore influence plant phenology, and differences in those phenological responses can impact reproductive success and plant fitness. We report here interspecific variations in the reproductive ecology (flowering phenology, floral biology, reproductive systems, and pollination) of 10 Myrtaceae species in a gallery forest in northeastern, Brazil. We evaluated flowering patterns and strategies, considering the frequency and duration of each phenophase from monthly observations, using the semi-quantitative Fournier scale. We also analyzed floral biology, recorded floral visitors, conducted pollination experiments (autonomous self-pollination, hand self-pollination, hand cross-pollination, and natural/open pollination), and calculated sefl-incompatibility (SII) and autogamy (AI) indices. Most species exhibited synchronous and annual flowering lasting between 1 and 5 months, with a “pulsed bang” strategy (i.e., mass flowering concentrated within just a few days, with intervals). These patterns were repeated among congeneric species, except in Myrcia, in which half of the species accompanied were classified as having a “pulsed bang” and the other half a “big bang” strategy. The flowering strategies appeared to be associated with distinct patterns of inflorescence development, bud production, flowering duration, and the timing of flowering in individual plants. Bee species were considered pollinators. Most species studied were self-incompatible and allogamous. In general, the species produced large quantities of flowers during short temporal intervals, favoring crosses between individuals having precise synchrony.

Understanding the relationship between solitary bee flight and flowering phenology is globally relevant for environmental management and habitat restoration. Using Swedish citizen science data over an 11-year period, the flight behaviours of two oligolectic solitary bees (Andrena hattorfiana and Andrena marginata) were compared to the flowering phenology of their hosts (Knautia arvensis and Succisa pratensis) in southern Sweden. There were 2,327 and 4,566 records of flight and flowering, respectively. While associative studies cannot resolve the degree of oligolecty, a strong temporal association of Andrena hattorfiana with Knautia arvensis and Andrena marginata with Succisa pratensis was indicated. Three conclusions emerged when comparing annual data: first, the flight period of both bee species studied overlapped with the flowering period of their corresponding host plants. Second, earlier flowering of Knautia arvensis corresponded with the earlier flight of Andrena hattorfiana. Third, the flight period duration was unaffected by the flowering period duration. For Andrena hattorfiana/Knautia arvensis, climate change may shift the start of flight and flowering periods to earlier dates in the year. A similar response would be expected for Andrena marginata/Knautia arvensis, but not for Andrena marginata/Succisa pratensis where there instead might be an increasing mismatch between the flight and flowering periods.

Abstract Although Chaenomeles is widely used in horticulture, traditional Chinese medicine and landscape greening, insufficient research has hindered its breeding and seed selection. This study investigated the floral phenology, floral organ characteristics, palynology, and breeding systems of Chaenomeles speciosa (Sweet) Nakai. The floral characteristics of C. speciosa were observed both visually and stereoscopically. The microstructures of the flower organs were observed using scanning electron microscopy. Pollen stainability was determined using triphenyl tetrazolium chloride staining. Stigma receptivity was determined using the benzidine-H2O2 method and the post-artificial pollination pollen germination method. The breeding system was assessed based on the outcrossing index and pollen–ovule ratio. The flowers of C. speciosa were bisexual with a flowering period from March to April. The flowering periods of single flowers ranged from 8 to 19 d, and those of single plants lasted 18–20 d. The anthers were cylindrical, with the base attached to the filament, and were split longitudinally to release pollen. The flower had five styles, with a connate base. The ovaries had five carpels and five compartments. The inverted ovules were arranged in two rows on the placental axis. The stigma of C. speciosa was dry and had many papillary protrusions. In the early flowering stage (1–2 d of flowering), the pollen exhibited high stainability (up to 84.24%), but all stainability was lost at 7 d of flowering. Storage at – 20 °C effectively delayed pollen inactivation. The stigma receptivity of C. speciosa lasted for approximately 7 days, and the breeding system was classified as outcrossing with partial self-compatibility.

Although Chaenomeles is widely used in horticulture, traditional Chinese medicine and landscape greening, insufficient research has hindered its breeding and seed selection. This study investigated the floral phenology, floral organ characteristics, palynology, and breeding systems of Chaenomeles speciosa (Sweet) Nakai. The floral characteristics of C. speciosa were observed both visually and stereoscopically. The microstructures of the flower organs were observed using scanning electron microscopy. Pollen stainability was determined using triphenyl tetrazolium chloride staining. Stigma receptivity was determined using the benzidine-H2O2 method and the post-artificial pollination pollen germination method. The breeding system was assessed based on the outcrossing index and pollen–ovule ratio. The flowers of C. speciosa were bisexual with a flowering period from March to April. The flowering periods of single flowers ranged from 8 to 19 d, and those of single plants lasted 18–20 d. The anthers were cylindrical, with the base attached to the filament, and were split longitudinally to release pollen. The flower had five styles, with a connate base. The ovaries had five carpels and five compartments. The inverted ovules were arranged in two rows on the placental axis. The stigma of C. speciosa was dry and had many papillary protrusions. In the early flowering stage (1–2 d of flowering), the pollen exhibited high stainability (up to 84.24%), but all stainability was lost at 7 d of flowering. Storage at – 20 °C effectively delayed pollen inactivation. The stigma receptivity of C. speciosa lasted for approximately 7 days, and the breeding system was classified as outcrossing with partial self-compatibility. [ABSTRACT FROM AUTHOR]

Understanding the relationship between solitary bee flight and flowering phenology is globally relevant for environmental management and habitat restoration. Using Swedish citizen science data over an 11-year period, the flight behaviours of two oligolectic solitary bees (Andrena hattorfiana and Andrena marginata) were compared to the flowering phenology of their hosts (Knautia arvensis and Succisa pratensis) in southern Sweden. There were 2,327 and 4,566 records of flight and flowering, respectively. While associative studies cannot resolve the degree of oligolecty, a strong temporal association of Andrena hattorfiana with Knautia arvensis and Andrena marginata with Succisa pratensis was indicated. Three conclusions emerged when comparing annual data: first, the flight period of both bee species studied overlapped with the flowering period of their corresponding host plants. Second, earlier flowering of Knautia arvensis corresponded with the earlier flight of Andrena hattorfiana. Third, the flight period duration was unaff ected by the flowering period duration. For Andrena hattorfiana/Knautia arvensis, climate change may shift the start of flight and flowering periods to earlier dates in the year. A similar response would be expected for Andrena marginata/Knautia arvensis, but not for Andrena marginata/Succisa pratensis where there instead might be an increasing mismatch between the flight and flowering periods. [ABSTRACT FROM AUTHOR]

In order to understand the unique characteristics of flowering phenology and reproduction of Pinellia ternata (Thunb.) Breit., in this study, flower morphological characteristics, individual flowering and pollination habits, population flowering phenology and seed setting characteristics of Pinellia ternata (Thunb.) Breit. flowers were studied. The results showed that the population flowering rule of Pinellia ternata (Thunb.) Breit. presented the single peak pattern, and the florenscence was about 58 d that was concentrated between late May and late June. The diurnal changes of flowering and pollination were both presented the inverted single peak pattern. The peak hours of flowering and pollination were 7:00-11:00 and 7:00-9:00 in a day. The duration of pollen dispersal was 47.22 h. The individual flowering, inflorescence opening, single inflorescence opening, and population flowering were respectively averaged 18 d, 13 d, 5.3 d, and 51.5 d. The highest frequency of inflorescence opening process and single inflorescence opening duration occurred at 14 d and 6 d respectively. Its flower was not anemophilous or entomophilous. Its pollination absolutely relied on pollens scattering naturally, which was prabably the main reason for its seed setting rate. The correlation analysis indicated that there was a significantly negative correlation between onset and flowering rate, and between onset and seed setting rate, while there was a extremely significantly positive correlation among duration, flowering rate and seed setting rate. The flowering rate and seed setting rate were closely related to its tuber diameter. In conclusion, artificial assistance in prolonging the flowering period and increasing the flowering rate of Pinellia ternata (Thunb.) Breit. facilitated to improve its seed setting rate, thereby improving its sexual reproduction efficiency. [ABSTRACT FROM AUTHOR]

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Summary: Species are altering their phenology to track warming temperatures. In forests, understorey plants experience tree canopy shading resulting in light and temperature conditions, which strongly deviate from open habitats. Yet, little is known about understorey phenology responses to forest microclimates.We recorded flowering onset, peak, end and duration of 10 temperate forest understorey plant species in two mesocosm experiments to understand how phenology is affected by sub‐canopy warming and how this response is modulated by illumination, which is related to canopy change. Furthermore, we investigated whether phenological sensitivities can be explained by species' characteristics, such as thermal niche.We found a mean advance of flowering onset of 7.1 d per 1°C warming, more than previously reported in studies not accounting for microclimatic buffering. Warm‐adapted species exhibited greater advances. Temperature sensitivity did not differ between early‐ and later‐flowering species. Experimental illumination did not significantly affect species' phenological temperature sensitivities, but slightly delayed flowering phenology independent from warming.Our study suggests that integrating sub‐canopy temperature and light availability will help us better understand future understorey phenology responses. Climate warming together with intensifying canopy disturbances will continue to drive phenological shifts and potentially disrupt understorey communities, thereby affecting forest biodiversity and functioning. [ABSTRACT FROM AUTHOR]

One important goal in prairie restorations is to have forb species that flower throughout the growing season (i.e. a range of flowering phenology). We conducted an experiment to test whether three early‐ and three late‐flowering forb species are seed or recruitment limited, if mowing can influence this limitation, and if forb additions will impact overall plant diversity in ongoing restorations.The experiment was conducted at two restorations in northern Iowa and one in southern Minnesota, USA, using a split‐plot design. Whole plots tested the effect of mowing, and subplots tested the effect of target forbs being added as seeds or small transplants at varied richness levels (0, 1, 3 or 6 species added). Control plots received no forb additions. To compare establishment success, we estimated target species biomass, survivorship and per cent cover of target species across 3 years (2019–2021). Plant diversity measures (richness, inverse Simpson's diversity) were estimated within subplots to determine whether forb additions impacted diversity.Biomass and relative abundance of early‐ and late‐flowering forbs was much higher when they were added as transplants than when added as seeds. Survivorship across life stages indicated that the transition from seed to adult had lower survivorship probabilities (0.6%) than the transition from transplant (juvenile) to adult (75%).Plant diversity of these ongoing restorations was higher when target forbs were added compared to controls. Diversity was higher when target forbs were transplanted (8.4 species/plot and inverse Simpson's diversity of 4.0) than when they were seeded (7.6 species/plot and inverse Simpson's diversity of 3.8). Early‐flowering treatments increased diversity more than late‐flowering treatments, and diversity increased linearly with the number of forb species added.Mowed and unmowed plots had similar levels of target species establishment and plant diversity.Synthesis and applications: Our results indicate that early‐ and late‐flowering species are more recruitment limited than seed limited and that diversity is lower when these species are missing in restorations. We recommend transplanting a rich mix of early‐ and late‐flowering forbs to increase their biomass and ensure that flowering occurs throughout the growing season. [ABSTRACT FROM AUTHOR]

Measuring the strength of different reproductive barriers across species pairs is key to reveal the mechanisms that have led to evolutionary radiations. Here we study a genus of miniature plants, Argyroderma , which comprises 11 species restricted to a single plain of the Southern African desert. We measure different reproductive barriers to understand how species boundaries are maintained in this genus. Our results show that reproductive isolation is almost complete between all species pairs and relies on three pre-mating barriers: geographic isolation operating at spatial scales of c. 10 km, phenological isolation in flowering time, and habitat isolation operating at spatial scales of just a few metres, which is thought to be due to contrasting edaphic preferences between species. In comparison, post-mating isolation arising before seed formation is weak and does not restrict gene flow much between species. Interestingly, the high levels of both geographic and habitat isolation that we have measured between Argyroderma species might be due to their miniature size, which leads to restricted gene flow across space and to adaptation to spatially restricted micro-habitats. [ABSTRACT FROM AUTHOR]

Bidens pilosa L. is native to tropical America and has widely naturized from tropical to warm temperate regions in Europe, Africa, Asia, Australia, and North and South America. The species has infested a wide range of habitats such as grasslands, forests, wetlands, streamlines, coastal areas, pasture, plantations, agricultural fields, roadsides, and railway sides and has become a noxious invasive weed species. B. pilosa forms thick monospecific stands, quickly expands, and threatens the indigenous plant species and crop production. It is also involved in pathogen transmission as a vector. The species was reported to have (1) a high growth ability, producing several generations in a year; (2) a high achene production rate; (3) different biotypes of cypselae, differently germinating given the time and condition; (4) a high adaptative ability to various environmental conditions; (5) an ability to alter the microbial community, including mutualism with arbuscular mycorrhizal fungi; and (6) defense functions against natural enemies and allelopathy. The species produces several potential allelochemicals such as palmitic acid, p-coumaric acid, caffeic acid, ferulic acid, p-hydroxybenzoic acid, vanillic acid, salycilic acid, quercetin, α-pinene, and limonene and compounds involved in the defense functions such as 1-phenylhepta-1,3,5-trine, 5-phenyl-2-(1-propynyl)-thiophene, 5-actoxy-2-phenylethinyl-thiophene, and icthyothereol acetate. These characteristics of B. pilosa may contribute to the naturalization and invasiveness of the species in the introduced ranges. This is the first review article focusing on the invasive mechanisms of the species. [ABSTRACT FROM AUTHOR]

In order to study the flowering phenology and reproductive characteristics of Northland blueberry, from April to July in 2022, the flowering phenology characteristics and the morphological characteristics of single flower of Northland blueberry at four levels were observed, counted and analyzed in the open field and in the greenhouse respectively. The results showed that the flowering period of blueberry in the open field was from late May to early June, and the flowering duration at four levels of population, individual, inflorescence and single flower was (251), (151), (12±1) and (10±1) d, respectively. At the individual level, the flowering amplitude curve was a unimodal curve, and the flowering synchronization index was 0.723, which belonged to the centralized flowering mode with high flowering intensity, and the skewness of its distribution frequency was 1.12. Under the greenhouse environment, the flowering period of Northland blueberry was from late April to early May, which was about a month earlier than that of the outdoor blueberry population. The flowering duration was (17±1), (12±1), (10±1) and (10±1) d at population, individual, inflorescence and single flower levels, respectively. The flowering amplitude curve was a unimodal curve, the flowering synchronization index was 0.745, and the skewness of its distribution frequency was 1.23. The single flower had a special flower structure, which was shaped like a jar and bell. It could be divided into four stages according to the size of the petal opening, that was before the flowering stage, the early flowering stage, the high flowering stage and the late flowering stage. The top of the petal did not open at the early flowering stage, the top of the petal opened 1-2 mm at the early flowering stage, the top of the petal opened 3-5 mmm at the high flowering stage, and the petals fall off at the late flowering stage. On the level of inflorescence, there was a significant positive correlation between the number of flowers and the number of fruits, the duration of flowering period, and the initial flowering period. The results of this study could provide theoretical basis and practical basis for the variety breeding of Northland blueberry in the Northeast Plain and the formulation of efficient cultivation measures. [ABSTRACT FROM AUTHOR]

Premise of research. The maintenance of mixed selfing and outcrossing is an enduring mystery in evolutionary biology. Cleistogamy, in which individuals produce both potentially outcrossing chasmogamous (CH) and obligately selfing cleistogamous (CL) flowers, provides an ideal framework in which to study the evolutionary forces maintaining mixed mating. Despite their promise for providing insight into mating system evolution, few studies of cleistogamous species have comprehensively investigated the relative costs and benefits of CL selfing. Methodology. We quantified the necessary components to calculate the relative energetic cost of reproduction of each flower type—CH and CL—in a greenhouse study using three populations of the perennial Ruellia humilis Nutt (Acanthaceae). These components included flower dry mass, fertility (i.e., fruit set), seed mass per fruit, and number of seeds per fruit. We also measured pollen-ovule ratios for both flower types as another measure of relative energetic investment. Last, we tracked phenology of the two flower types and used the proportion of CH flowers to estimate maximum potential outcrossing rates. Pivotal results. We found that the energetic cost of reproduction via CL flowers was four to 10 times lower than that of reproduction via CH flowers. This energetic economy derived both from the reduced mass and from the increased fertility of CL flowers. Pollen-ovule ratios in CL flowers were one-third to one-half those of CH flowers, providing additional support for their energetic economy. Maximum potential outcrossing rates in these populations based on CH flower production were between 43% and 61%, but CH flowers can autogamously self at rates between 33% and 75%. Conclusions. These results suggest that selection should favor only CL flowers due to their greater energetic economy. Additional work in this species demonstrates that neither inbreeding depression nor heterosis can provide an advantage strong enough to overcome the energetic benefits of CL reproduction. Further research on the developmental genetics of the two flower types and potential genetic constraints on the loss of CH flowers is needed. [ABSTRACT FROM AUTHOR]

Flowering phenology of alpine plant communities and seasonal dynamics of flower visitors have been scarcely studied in the tropical/subtropical alpine regions. We report flowering phenology, flower production, and flower‐visiting insects in an alpine site of central Taiwan. Throughout the research period (2017–2018), we recorded flowering phenology of 130 plant species, flower production of 81 species, and 15,127 insects visiting alpine flowers. Most of the alpine plants were visited by dipteran insects and/or hymenopteran insects. The seasonal patterns of flowering were more apparent in bee‐visited plants compared to fly‐visited plants in which the flowering of bee‐visited plants clearly increased as the season progressed. About 63% of flower visitors were dipteran insects (syrphid and non‐syrphid flies), and 30% were hymenopteran insects (mostly bumble‐bee workers). Although the seasonal trend in fly abundance was less clear between years, bumble‐bee abundance consistently increased in the middle to late seasons, reflecting colony development. There was a positive correlation between bee abundance and the number of flowering species of bee‐visited plants, but there was no correlation between fly abundance and the number of flowering species of fly‐visited plants throughout the season. These results suggest that the flowering phenology of subtropical alpine communities is influenced by the seasonal availability of pollinators. Bumble bees, syrphid flies, and non‐syrphid flies had wide ranges of foraging flowers, but their niche overlap was relatively small. Because cold‐adapted bumble bees are threatened by climate change in Taiwan, plant–pollinator interactions may be disturbed by global warming. [ABSTRACT FROM AUTHOR]

Premise: The timing and pattern of a plant's flowering can have important consequences for reproductive success. Variation in flowering phenology may influence the number of prospective mates, the risk of mating with lower quality individuals, and the likelihood of self‐pollination. Here we use a common garden experiment to explore within‐ and among‐population variation in phenology. Our work provides new insights into how flowering phenology shapes mating opportunity and flowering synchrony in a self‐compatible perennial. Methods: To quantify variation in flowering phenology we raised progeny from nine populations of Mimulus ringens in a common garden. For each individual, we measured phenological traits including age at flowering onset, daily floral display size, total flower number, and flowering synchrony with other members of the population, and related these traits to mating opportunity. We also tested how individual flowering schedules influence the magnitude of synchrony. Results: Flowering phenology and synchrony varied substantially within and among populations. From day to day, plants often oscillated between large and small daily floral displays. Additionally, flowering schedules of individual plants strongly influenced flowering synchrony and, along with the number of flowering days, markedly affected plants' mating opportunity. Conclusions: Phenological traits such as flowering synchrony can affect the quantity of mating opportunities and may be important targets of natural selection. Our results highlight the need for studies that quantify flowering patterns of individuals as well as populations. [ABSTRACT FROM AUTHOR]

This article is a Commentary on Duncan et al. (2024), 244: 307–317. [ABSTRACT FROM AUTHOR]

The apple orchards with large land extensions represent a challenge in monitoring crops. Remote sensing techniques can analyze and obtain information on the general state of crops using multispectral data and vegetation indexes. This study aimed to analyze the flowering phenological of three apple orchards using images from Sentinel-2 satellite and a Phantom 4 pro/pro+ drone in three apple-producing regions. The images were processed using ArcGIS software and the Normalized Difference Vegetation Index (NDVI). The results were statistically analyzed through discriminant to classify and identify significant differences between the flowering phenological stages. NDVI maps were obtained for the study areas, and the NDVI values ranged from 0.09 to 0.26 and from 0.22 to 0.35 for drone and satellite images, respectively. It was possible to differentiate between two groups of phenological stages in the apple orchards (pre-bloom and post-bloom). The information generated can be a complementary tool for monitoring the apple tree crop.

Abstract Phenological shifts due to changing climate are often highly species and context specific. Land‐use practices such as mowing or grazing directly affect the phenology of grassland species, but it is unclear if plants are similarly affected by climate change in differently managed grassland systems such as meadows and pastures. Functional traits have a high potential to explain phenological shifts and might help to understand species‐specific and land‐use‐specific phenological responses to changes in climate. In the large‐scale field experiment Global Change Experimental Facility (GCEF), we monitored the first flowering day, last flowering day, flowering duration, and day of peak flowering, of 17 herbaceous grassland species under ambient and future climate conditions, comparing meadows and pastures. Both climate and land use impacted the flowering phenology of plant species in species‐specific ways. We did not find evidence for interacting effects of climate and land‐use type on plant phenology. However, the data indicate that microclimatic and microsite conditions on meadows and pastures were differently affected by future climate, making differential effects on meadows and pastures likely. Functional traits, including the phenological niche and grassland utilization indicator values, explained species‐specific phenological climate responses. Late flowering species and species with a low mowing tolerance advanced their flowering more strongly under future climate. Long flowering species and species following an acquisitive strategy (high specific leaf area, high mowing tolerance, and high forage value) advanced their flowering end more strongly and thus more strongly shortened their flowering under future climate. We associated these trait–response relationships primarily with a phenological drought escape during summer. Our results provide novel insights on how climate and land use impact the flowering phenology of grassland species and we highlight the role of functional traits in mediating phenological responses to climate.

AbstractExploring the genetic basis of adaptive divergence at fine spatial scales can broaden our basic understanding of evolution and how organisms may adapt to changing environments in the future. Cave-associated microhabitats provide a unique opportunity to gain insight into microgeographic adaptation. We studied the genetic architecture of microhabitat-related divergence in flower phenology and leaf traits between two sister species of Primulina, P. depressa and P. danxiaensis, which live in sympatry but occupy contrasting microhabitats. We identified 40 significant quantitative trait loci (QTLs) associated with the interspecific differences in these microhabitat adaptation traits. Flowering time was controlled by one major-effect and six minor-effect QTLs, while leaf traits were influenced by 9–12 QTLs of small to moderate effect. The genetic architecture of the flowering time and the specific leaf area was genetically independent of other traits. Our results suggest that microhabitat adaptation in sympatric populations of Primulina differs according to different traits, with leaf traits diverging with the accumulation of many small changes and flowering phenology being driven by major effect variance.

Coffea arabica, C. canephora, and C. liberica's coexistence in one location or proximity areas could promote interspecific pollination. However, information related to floral phenology and flower structure of these three coffee species is insufficient. This research aimed to identify the divergence of flowering phenology and flower morphometrics among C. arabica, C. canephora, and C. liberica. Flowering phenology observations continued daily from July to October 2020, extending to two locations of parapatric populations of three coffee species. Flower morphometric measurements ensued at the peak period of flowering. The results showed some co-anthesis periods among the three coffee species, with C. liberica starting to flower early. Moreover, C. liberica var liberica had the broadest flower diameter and the highest petal number, whereas the tetraploid C. arabica had the lowest. Consequences of flowering phenology and flower structure on a pre-zygotic barrier of spontaneous, as well as, controlled interspecific hybridization among the three coffee species were the discussion focus. [ABSTRACT FROM AUTHOR]

Biological processes can be disrupted by global climate warming, causing phenological mismatching and mistiming. On Hokkaido Island (Japan), which has a cool temperate climate, warmer and shorter winters affect plant flowering phenology. Rapid changes in flowering phenology suggest that shorter winters will result in earlier flowering. Flowering phenology patterns were recorded for nine years (2013–2021), and nine species were selected for analysis. I analyzed climate variables that affect plant flowering phenology, including annual changes in aerial temperature, snow depth, and snowmelt timing. The results indicated that winters are getting shorter and that the accumulated degree hours of aerial temperature have not significantly changed over nine years for these plant species except one species. Plant responses to these changes differed between species, with the first flowering day occurring earlier (1.5–1.8 days per year) for two species, although that of the other seven not. If climate warming continues, it will have diverse, complex, and unpredictable effects on various individual organisms and biological relationships among species. Detailed studies are needed to link climate change predictions to the predicted degree of mismatch in species interactions and networks. [ABSTRACT FROM AUTHOR]

Flowering phenology is important in the adaptation of many plants to their local environment, but its adaptive value has not been extensively studied in herbaceous perennials. We used Arabis alpina as a model system to determine the importance of flowering phenology to fitness of a herbaceous perennial with a wide geographical range. Individual plants representative of local genetic diversity (accessions) were collected across Europe, including in Spain, the Alps and Scandinavia. The flowering behaviour of these accessions was documented in controlled conditions, in common-garden experiments at native sites and in situ in natural populations. Accessions from the Alps and Scandinavia varied in whether they required exposure to cold (vernalization) to induce flowering, and in the timing and duration of flowering. By contrast, all Spanish accessions obligately required vernalization and had a short duration of flowering. Using experimental gardens at native sites, we show that an obligate requirement for vernalization increases survival in Spain. Based on our analyses of genetic diversity and flowering behaviour across Europe, we propose that in the model herbaceous perennial A. alpina, an obligate requirement for vernalization, which is correlated with short duration of flowering, is favoured by selection in Spain where the plants experience a long growing season. [ABSTRACT FROM AUTHOR]

Flowering phenology is closely related to plant reproduction, and its response to climate change is obvious; therefore, revealing its influencing factors and interspecific changes has become an important issue in global change ecology and physical geography. Previous studies have reported that interspecific changes in flowering phenology are affected by climatic factors (such as temperature and precipitation) and related to plant functional traits. However, the magnitude of the correlation between functional traits and flowering phenology varies greatly among different regions and climatic zones, and the relationship between them remains unclear. In this study, to explore whether functional traits affect interspecific changes in the flowering phenology of subtropical evergreen broadleaf species, 67 woody species in the Ningbo Botanical Garden were chosen as the study objects. Four types of flowering phenological characteristics (initial flowering time, full bloom time, falling flower time, and duration of the flowering period) were observed. General statistical analyses (i.e., maximum, minimum, mean, coefficient of variation, and frequency) were used to test the distribution patterns of flowering phenology. Four statistical methods (independent samples t-test, one-way analysis of variance, linear fitting, and generalized linear mixed effect regression models) were used to analyze the differences in flowering phenology between different types (tree vs. shrubs, different types of flower color, and fruit type) and the contributions of different functional traits (i.e., potential maximum tree height, life form, flower color, and fruit type) to the changes in flowering phenology. The results showed that: (1) the initial flowering time, full bloom time, falling flower time, and duration of the flowering period of 67 woody plants were March 28 ± 21.64 d, March 30 ± 27.02 d, April 15 ± 30.78 d, and 23.82 ± 13.31 d, respectively. (2) The initial flowering time and full bloom time of trees were significantly earlier than those of shrubs (P < 0.05); however, no significant difference was observed between them in the falling flower time or duration of the flowering period (P > 0.05). The standard deviation of the flowering phenology of trees was lower than that of shrubs, indicating that the flowering phenology of trees was more stable than that of shrubs. (3) The results of generalized linear mixed-effect regression models showed that the effects of the four functional traits on flowering phenology differed. More specifically, flower color significantly affected falling-flower time (P < 0.01). The falling flower time of colored flowers was earlier than that of white flowers. Life form and potential maximum tree height significantly affected the duration of the flowering period (P < 0.01). Plants with higher potential maximum heights have longer flowering periods. In conclusion, our study indicates that the flowering phenology of 67 woody species in the Ningbo Botanical Garden is affected by functional traits. However, the magnitude of the influence is related to the type of functional trait. Flower color and potential maximum tree height contributed more to interspecific changes in flowering phenology than other functional traits. Our results help us understand the variation in flowering phenology among woody species in subtropical regions and provide a new perspective for the theoretical exploration of phenology.

Premise of research. Cosexual plants reproduce as females by maturing seeds from fertilized ovules and as males by fertilizing their own ovules or those of other plants. Condition-dependent sex allocation occurs when the environment elicits quantitative differences in the rate at which fitness increases as resources are invested in male versus female function. Here, we examine whether resource availability and the pollination environment generate plastic responses in floral sex allocation and correlated traits. Methodology. We exposed the cosexual mustard species Brassica rapa to variation in resource availability (altered pot size) and in the pollination environment (unpollinated or fully pollinated). We assessed investment in anther and ovary length, which are known to correlate with pollen and ovule number; in flower buds produced at the onset of reproduction; and in buds produced approximately 15 d later. We also measured plant size and flower size, which are often correlated with increased allocation to female and male function, respectively. Pivotal results. In contrast to our predictions, anther-to-ovary length ratios at the onset of reproduction did not vary across plants of different sizes and were unaffected by the pot size treatment, despite an increase in anther lengths in the small pot treatment. Similarly, neither the pot size nor the pollination treatments elicited plasticity in anther-to-ovary length ratios over the course of reproduction. However, independent of plant size and as predicted, plants produced larger flowers over the course of reproduction in the pollination-absent treatment. Conclusions. We discuss the contexts in which resource availability and the pollination environment can influence sex allocation and provide cautionary advice on effective methods for experimentally generating and measuring sex allocation plasticity. [ABSTRACT FROM AUTHOR]

The timing of flowering and fruiting plays a critical role in the reproduction, population size, and range of fruit-eating animals. The Hainan Tropical Rainforest National Park, China, hosts one of the world's most endangered primate species, the Hainan gibbon (Nomascus hainanus). Understanding the phenological patterns of the principal food sources of the Hainan gibbon is crucial for the effective management of their habitats and the conservation of this threatened population. To that end, we conducted a regression analysis to better understand how climate may impact the timing and availability of fruits known to support the Hainan gibbon. We observed significant seasonal and inter-annual variations in the reproductive phenology of these fruiting species, with most species flowering from March to June and fruiting from August to December. Importantly, we found that Hainan gibbons face severe food scarcity between January and April. We show that sunshine exerts a significant effect on the flowering time, while fruiting phenology is most sensitive to temperature. We suggest that the restoration of the Hainan gibbon habitat should include planting more tree species which that produce fruit in the time of low food availability between January-April, including the species Memecylon ligustrifolium, Wrightia pubescens, Sarcosperma laurinum, Eurya ciliata, and Pouteria annamensis. [ABSTRACT FROM AUTHOR]

Vitex cymosa Bert. ex Spreng. (Lamiaceae) is a native species of tropical and subtropical Central and South America. Its medicinal, antioxidant, antifungal and antibacterial properties are noteworthy and widely studied. This study aims to contribute towards the knowledge of the reproductive biology of V. cymosa, through: the determination of the reproductive system; the description of reproductive morphological attributes (flower, fruit, pollen and nectary), attractants and floral phases, as well as the record and function of floral visitors. Vitex cymosa presents melitophilic floral traits: diurnal anthesis, bluish coloration, bilabiate structural type, presence of visual guides in the corolla indicating the location of the reward (nectar), and a soft, sweet and pleasant aroma to humans. The pollen has pollenkit and is deposited nototribically on the pollinators. The nectary is of gynoecial origin, the nectar is released through nectarostomes located on the apex of the ovary, remaining available even after corolla abscition, as a post-floral nectary; such zone is distinguished by a purple coloration, different from that of the rest of this organ, which grows basipetally as the fruit develops. The reproductive system of V. cymosa is mixed, resulting in more than 75% of fructification, through both allogamy mediated by pollinators and spontaneous self-pollination, presenting a slight hercogamy that would contribute to cross-pollination. Eleven species of floral visitors were recorded, all belonging to the Class Insecta. Among these floral visitors, Apis mellifera was the most frequent species, and along with other species of native bees (of the genera Bombus, Centris, Plebeia, Tetragonisca, Trigona), wasps and butterflies, they would be pollinators when they visit legitimately (in the case of the hymenopterans, as some of them thieve pollen). Despite this visitor assembly, the most important pollinators are the bees, which coincides with the melitophilic characteristics of the flowers. The nectar exposed in flowers where the corolla has already fallen, more accessible to some bees and to the wasps, would contribute to greater attraction to pollinators, as well as predatory insects of herbivores of the developing fruits. [ABSTRACT FROM AUTHOR]

Nutrient availability significantly regulates plant growth and metabolic functions, but whether and how the long-term exposure of ancestral plants to contrasting nutrient environments influences offspring phenotypic performance (i.e., transgenerational plasticity) remain poorly addressed. Here we conducted experimental manipulations using Arabidopsis thaliana with the ancestral plants grown in different nitrogen (N) and phosphorus (P) availabilities over eleven consecutive generations, and then examined the offspring phenotypic performance under the interactive effects of current and ancestral nutrient environments. We found that current rather than ancestral nutrient environments dominantly explained the variations in offspring plant traits (i.e., flowering time, aboveground biomass and biomass allocation fractions), suggesting the relatively weak transgenerational effects of ancestral N and P availabilities on offspring phenotypes. In contrast, increasing N and P availabilities in the offspring generation remarkably shortened the flowering time, increased the aboveground biomass, and altered biomass allocation fractions differentially among organs. Despite the overall weak transgenerational phenotypic plasticity, under the low nutrient environment, the offspring of ancestral plants from the low nutrient environment had a significantly higher fruit mass fraction than those from the suitable nutrient environment. Taken together, our findings suggest that A. thaliana exhibits a much stronger within- than trans-generational trait plasticity under contrasting nutrient availabilities, and may provide important insights into the understanding of plant adaptation and evolutionary processes under changing nutrient environments. [ABSTRACT FROM AUTHOR]

In recent decades, the final frost dates of winter have advanced throughout North America, and many angiosperm taxa have simultaneously advanced their flowering times as the climate has warmed. Phenological advancement may reduce plant fitness, as flowering prior to the final frost date of the winter/spring transition may damage flower buds or open flowers, limiting fruit and seed production. The risk of floral exposure to frost in the recent past and in the future, however, also depends on whether the last day of winter frost is advancing more rapidly, or less rapidly, than the date of onset of flowering in response to climate warming. This study presents the first continental-scale assessment of recent changes in frost risk to floral tissues, using digital records of 475,694 herbarium specimens representing 1,653 angiosperm species collected across North America from 1920 to 2015. For most species, among sites from which they have been collected, dates of last frost have advanced much more rapidly than flowering dates. As a result, frost risk has declined in 66% of sampled species. Moreover, exotic species consistently exhibit lower frost risk than native species, primarily because the former occupy warmer habitats where the annual frost-free period begins earlier. While reducing the probability of exposure to frost has clear benefits for the survival of flower buds and flowers, such phenological advancement may disrupt other ecological processes across North America, including pollination, herbivory, and disease transmission.

Flower initiation is a phenological developmental process strictly regulated in all flowering plants. Studies in Arabidopsis thaliana, a model plant organism in plant biology and genetics, and major cereal crops have provided fundamental knowledge and understanding of the underlying molecular mechanisms and regulation in annuals. However, this flowering process and underly molecular mechanisms in perennials are much more complicated than those in annuals and remain poorly understood and documented. In recent years, the increasing availability of perennial plant genomes and advances in biotechnology have allowed the identification and characterization of flowering-associated gene orthologs in perennials. In this review, we compared and summarized the recent progress in regulation of flowering time in perennial trees, with an emphasis on the perennial-specific regulatory mechanisms. Pleiotropic effects on tree growth habits such as juvenility, seasonal activity–dormancy growth, and the applications of tree flowering phenology are discussed.

Bidens pilosa L. is native to tropical America and has widely naturized from tropical to warm temperate regions in Europe, Africa, Asia, Australia, and North and South America. The species has infested a wide range of habitats such as grasslands, forests, wetlands, streamlines, coastal areas, pasture, plantations, agricultural fields, roadsides, and railway sides and has become a noxious invasive weed species. B. pilosa forms thick monospecific stands, quickly expands, and threatens the indigenous plant species and crop production. It is also involved in pathogen transmission as a vector. The species was reported to have (1) a high growth ability, producing several generations in a year; (2) a high achene production rate; (3) different biotypes of cypselae, differently germinating given the time and condition; (4) a high adaptative ability to various environmental conditions; (5) an ability to alter the microbial community, including mutualism with arbuscular mycorrhizal fungi; and (6) defense functions against natural enemies and allelopathy. The species produces several potential allelochemicals such as palmitic acid, p-coumaric acid, caffeic acid, ferulic acid, p-hydroxybenzoic acid, vanillic acid, salycilic acid, quercetin, α-pinene, and limonene and compounds involved in the defense functions such as 1-phenylhepta-1,3,5-trine, 5-phenyl-2-(1-propynyl)-thiophene, 5-actoxy-2-phenylethinyl-thiophene, and icthyothereol acetate. These characteristics of B. pilosa may contribute to the naturalization and invasiveness of the species in the introduced ranges. This is the first review article focusing on the invasive mechanisms of the species.

Many plants express their female and male sex roles at different times (dichogamy), with important consequences for mating. Dichogamy can yield mate limitation via biased floral sex ratios, particularly at the beginning and end of the flowering season when many plants simultaneously function as the same sex. This form of mate limitation should be reduced if plants adjust their allocations to female versus male sex functions in a manner that tracks seasonal variability in mating opportunities. For example, under protogyny (i.e. dichogamy with female function expressed first) plants with male-biased sex expression should have enhanced mating opportunities early in the flowering season as other plants begin to flower (in female sex phase). We quantified seasonal changes in sex allocation, patterns of mate availability and realized siring success in a population of protogynous Sagittaria latifolia. Our results were consistent with previous findings that seasonal changes in sex allocation should compensate for lost mating opportunities under the temporally variable mating environments caused by dichogamy. However, patterns of siring success in the population were inconsistent with this interpretation. We suggest that realized siring success might depend more strongly on spatial than on temporal aspects of mate availability.