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Reproductive allocation and cost play a crucial role in the survival of organisms, but research on these traits in bryophytes has been limited and inconsistent. To address this, we conducted a literature review focusing on bryophyte studies. Our goal was to clarify inconsistencies and explore reproductive allocation and cost concepts, as well as current trends in bryophyte reproduction. We examined different approaches and highlighted advantages and limitations. We emphasized five key topics: the importance of understanding reproductive allocation and reproductive cost in bryophytes; the significance of bryophytes as model organisms; historical research; terminological and methodological inconsistencies; sexual dimorphism and reproductive allocation; and measurement methods. Furthermore, we provided insights into future perspectives. Based on our findings, we advocate for standardized quantification of reproductive allocation. Standardization would enhance comparability and synthesis of results, ultimately advancing our understanding of reproductive allocation and cost of reproduction in bryophytes. Keywords Biomass Allocation * Liverworts * Moss * Reproductive Effort * Reproductive Investment * Trade-off, Introduction Life history theory, an approach that investigates the timing of key events in an organism's life cycle, predicts that every resource produced by an organism is allocated to its [...]

Asteraceae are among the most abundant angiosperm families on oceanic islands. The reproductive biology of Asteraceae is reviewed and the attributes of the family contributing to their success on islands are discussed. Asteraceae are effective dispersers (the small, single-seeded fruits are moved great distances by wind and birds), and colonization is most likely limited by establishment. The pollinators of the colonizing ancestors rarely disperse with them to islands. Divorced from the pollinators of their ancestral habitats, the capitulum of aggregated small, shallow flowers typical of Asteraceae facilitates pollination of colonizers by various novel biotic visitors and by wind. Self-compatible (SC) colonizing ancestors are common, permitting establishment of sexual populations from one or few propagules. However, several large insular lineages of Asteraceae originated from functionally self-incompatible (SI) colonizers that may have also possessed the capacity to set some self-seed. Establishment may also be facilitated by dominance relationships among S-alleles in the sporophytic SI (SSI) system of Asteraceae, increasing cross-compatibility within small populations. Factors potentially promoting outcrossing in SC Asteraceae are: gynomonoecy, with temporal separation of receptive pistillate ray florets and pollen presentation in the hermaphroditic disc florets of a capitulum (interfloral protogyny); and intrafloral protandry where pollen presentation occurs before stigmata become receptive. Dioecy, gynodioecy, and monoecy are infrequent sexual systems in insular Asteraceae. Multiple paternity is similar in island composites to other Asteraceae, suggesting that neither compatible mates nor pollinators are typically limiting. Additional studies, particularly with genomic markers, are needed for more refined insights into mating systems and paternity in island Asteraceae as these results have important conservation implications. Keywords Asteraceae * Conservation biology * Oceanic islands * Reproductive biology, Introduction Flowering plants face multiple challenges in dispersal, establishment, and diversification in oceanic archipelagos (Baker, 1955; Carlquist, 1974, chapts. 1,2, 3, 11, 13; Pannell, 2015; Pannell et al., 2015). Despite [...]

The significance of maternal and progeny environment to chasmogamy (CH) and cleistogamy (CL) in perennial plants is not well known. The perennial grass Danthonia compressa produces CH spikelets capable of outcrossing on terminal panicles in summer followed by selling axillary CL spikelets in autumn. This study compared CH and CL seed mass, germination, seedling size, tillering, and reproduction in a sunny woodland edge and shaded interior habitat in the Catskill Mountains of New York State. CL seeds were significantly heavier than CH seeds. Numbers and mass of both seed types were greater in the edge. CL seeds showed much greater germination than CH seeds in both environments during spring, 2018; CL seedlings were larger than CH seedlings in the sunnier habitat. Survival was much greater in the edge than interior and higher for CL seedlings. After 27 months, maternal effects were mostly not detected and there was no significant effect of plant type (CH vs CL) on tiller production, final biomass, or reproduction via CH and CL. For this native grass, non-dispersed CL seeds may be more critical to seedling establishment and population persistence due to greater mass and germinability, and better plant survival, relative to smaller, dispersible CH seeds. Key words: Cleistogamy, light, maternal effects, mixed mating system, perennial grass, Poaceae, Introduction Cleistogamy (CL) is the production of closed, self-fertilizing flowers and occurs in almost 700 angiosperm species distributed among 50 plant families (Culley and Klooster 2007). Early descriptions of CL [...]

The reproductive ecology of the semi-serotinous species black spruce (Picea mariana (Mill.) BSP) in northern boreal forests remains poorly understood. There is a general lack of data on cone/seed production and viability as a function of biotic treelevel characteristics and abiotic variables. No studies currently exist to quantify these differences over a large gradient in temperature, elevation, and precipitation. Extensive physical, ecological, dendrometric, and reproductive data were collected from young to very old black spruce stands in northern Quebec. ANOVA and general linear mixed models were used to examine interannual cone production, and the relative importance of the biotic and abiotic explanatory factors in determining total cone production; length of the cone-bearing zone; filled seeds per cone; proportion of filled seeds; and seed viability. The results illustrate that the reproductive ecology of black spruce in northern cold forests is mainly explained by biotic variables such as age and diameter [DELTA]T breast height, and by abiotic variables related to temperature such as elevation, length of the growing season, and growing degree-days. Black spruce exhibits a lower reproductive potential in northern cold forests, making it possibly less resilient to increased fire frequency, particularly in unproductive and very young or very old stands. Key words: black spruce, reproductive ecology, cone production, seed production, germination, boreal forest, forest fire, seed viability, resilience, adaptation L'ecologie de la reproduction de l'espece semi-serotineuse, l'epinette noire (Picea mariana (Mill.) BSP) dans les forets boreales froides est encore peu documentee. Il existe un manque general de donnees sur la production des cones/graines et leur viabilite en fonction des caracteristiques biotiques au niveau de l'arbre et des variables abiotiques. Aucune etude n'existe actuellement pour quantifier ces differences sur un large gradient de temperature, d'altitude, et de precipitations. De nombreuses donnees physiques, ecologiques, dendrometriques et reproductives ont ete recueillies dans des peuplements d'epinette noire jeunes a tres ages dans le nord du Quebec. Des ANOVA et des modeles mixtes lineaires generaux ont ete utilises pour examiner la production annuelle de cones et l'importance relative des facteurs explicatifs biotiques et abiotiques dans la determination de la production totale de cones; la longueur de la cime comportant des cones; le nombre de graines pleines par cone; la proportion de graines pleines; et leur taux de germination. Les resultats indiquent que l'ecologie de la reproduction de l'epinette noire dans les forets boreales nordiques est expliquee par des variables biotiques telles que l'age et le DHP, et des variables abiotiques liees a la somme thermique regionale telles que l'altitude, la duree de la saison de croissance, et les degres-jours de croissance. L'epinette noire presente un potentiel reproductif plus faible dans les forets froides du nord, ce qui la rend moins resistante a l'augmentation de la frequence des feux, particulierement dans les peuplements improductifs et tres jeunes ou tres vieux. Mots-cles : epinette noire, ecologie de la reproduction, production des cones, production des graines, germination, foret boreale, feu de foret, taux de germination, resilience, adaptation, 1. Introduction Black spruce (Picea mariana (Mill.)) is one of the most common and commercially important conifer species in the boreal forest of eastern North America (Viereck and Johnston 1990), [...]

Sub-Antarctic giant kelp (Macrocystis pyrifera) forests have remained relatively wild and far from anthropogenic pressures. However, they are increasingly exposed to multiple stressors that might affect kelp forest persistence. The urban impact of a coastal city, Ushuaia (54° S 68° W), in the Beagle Channel, Argentina, on giant kelp forest environments was evaluated in this study and implications on morphological variability were explored. Seasonal samplings were conducted from 2019 to 2021 in two contrasting sites: an urban site directly exposed to coastal discharges, and a non-urban site. Our results indicate that the combination of coastal discharges, kelp canopy and low wave exposure increases light attenuation inside kelp forests, promoting coastal darkening. Additionally, and based on the present results, we present the first record of algal turf in the Beagle Channel. We further propose the Kelp Structure Index to describe the effect of environmental conditions on kelp structure, which highlights an increased blade surface in sites with urban impacts. These results suggest that giant kelp shows high plasticity in morphological traits under varying environmental conditions, particularly in environments exposed to coastal darkening effects. However, the presence of turf indicates that urban pressures might be severely limiting kelp forest health., Author(s): Julieta Kaminsky [sup.1] , María Bagur [sup.1] , Irene Ruth Schloss [sup.1] [sup.2] [sup.3] , Soledad Diodato [sup.1] [sup.2] , Mariano Rodríguez [sup.2] , Alejandro H. Buschmann [sup.4] , [...]

Heliotropism of flowers is thought to provide a reproductive advantage to individuals of many species; yet, there are few clear demonstrations of a fitness advantage provided by heliotropism, most of which are almost completely restricted to plants from the arctic or alpine regions where a heat gain provides an advantage to the plants. In this study, we report heliotropism in the white trillium, an early spring blooming species from the temperate forests of eastern North America. The white trillium shows horizontal seasonal heliotropism with flowers mainly facing south throughout the summer, but it also exhibits daily horizontal and vertical heliotropism with the orientation of the flower tracking the sun during the day. The study of 479 tethered plants indicated that seasonal heliotropism provides a reproductive advantage to the white trillium, with south-facing individuals showing a 12% increase in fertilized ovules compared to north-facing plants. The ecology of this long-lived perennial is, in many aspects, similar to that of alpine and arctic heliotropic species. Indeed, white trilliums are insect-pollinated and they flower when the weather is cold, before the trees leaf out. This suggests that there are potentially more species for which heliotropism is advantageous amongst early spring flowers from the temperate forest. Key words: heliotropism, white trillium, fertilized ovules, fitness, plant reproduction On pense que l'heliotropisme des fleurs procure un avantage reproductif aux individus de nombreuses especes. Pourtant, il existe peu de demonstrations claires de l'avantage de 1'heliotropisme sur le plan de la valeur adaptative, et ces demonstrations sont presque toutes limitees aux plantes des regions arctiques ou alpines, ou un gain de chaleur procure un avantage aux plantes. Dans cette etude, nous decrivons 1'heliotropisme chez le trille blanc, une espece a floraison printaniere precoce des forets temperees de Test de l'Amerique du Nord. Le trille blanc montre un heliotropisme saisonnier horizontal avec des fleurs principalement orientees vers le sud tout au long de l'ete, mais il presente egalement un heliotropisme horizontal et vertical quotidien avec l'orientation de la fleur suivant le soleil pendant la journee. L'etude de 479 plantes attachees a indique que 1'heliotropisme saisonnier procure un avantage reproductif au trille blanc, les individus orientes vers le sud presentant une augmentation de 12 % d'ovules fecondes par rapport aux plantes orientees vers le nord. L'ecologie de cette plante vivace a longue duree de vie est, sous de nombreux aspects, similaire a celle des especes heliotropes alpines et arctiques. En effet, les trilles blancs sont pollinises par les insectes et ils fleurissent lorsque le temps est froid, avant l'apparition du feuillage des arbres. Cela suggere qu'il y a potentiellement plus d'especes pour lesquelles 1'heliotropisme est avantageux parmi les fleurs printanieres precoces de la foret temperee. [Traduit par la Redaction] Mots-cles : heliotropisme, trille blanc, ovules fecondes, valeur adaptative, reproduction vegetale, Introduction The heliotropism of flowers has attracted curiosity and interest amongst evolutionary ecologists for more than 50 years (Hocking and Sharplin 1965; Hocking 1968; Kevan 1972, 1975). Heliotropism is the [...]

Abstract Apomixis is considered to be a natural mode of clonal propogation from seed to seed, in which progeny serves as a replica of maternal genotype. The process evades creation [...]

Phenology is an ecologically critical attribute that is commonly coordinated with other plant traits. Phenological shifts may be the result of evolutionary adjustments to persistently new conditions, or they may be transitory, varying with annual fluxes in abiotic conditions. In summer-dry, fire-prone Mediterranean-type climates, for example, many plant lineages have historically migrated from forests to more arid shrublands resulting in adaptive trait changes. These shifts in habitat abiotic conditions and biotic interactions influence morphology of flowers and fruits and interact with phenological timing. The Arbutoideae (Ericaceae) is one lineage that illustrates such modifications, with fruit characters evolving among genera from fleshy to dry fruit, thin to stony endocarps, and bird to rodent dispersal, among other changes. We scored herbarium collections and used ancestral trait analyses to determine phenological shifts among the five Arbutoid genera found in semi-arid climates. Our objective was to determine if phenology shifts with the phylogenetic transition to different reproductive characters. Our results indicate that phenological shifts began with some traits, like the development of a stony endocarp or dry fruits, but not with all significant trait changes. We conclude that early phenological shifts correlating with some reproductive traits were permissive for the transition to other later character changes. Key words: Ericaceae, fire regime, obligate seeding, scatter-hoarding, seed predation. La phenologie est un attribut critique d'un point de vue ecologique qui est generalement coordonne avec d'autres traits des vegetaux. Les changements phenologiques peuvent etre le resultat d'ajustements evolutifs a de nouvelles conditions persistantes, ou transitoires, qui varient avec le flux annuel des conditions abiotiques. Dans les climats mediterraneens secs en ete et sujets aux incendies, par exemple, de nombreux lignages de vegetaux ont historiquement migre des forets vers des zones arbustives plus arides, entrainant des changements en matiere de traits adaptatifs. Ces changements dans les conditions abiotiques de l'habitat et les interactions biotiques influencent la morphologie des fleurs et des fruits et interagiront avec le calendrier phenologique. Les Arbutoideae (Ericaceae) constituent un lignage qui illustre de telles modifications, les caracteres des fruits evoluant parmi les genres, de fruits charnus a secs, d'endocarpes minces a pierreux, et de dispersion par les oiseaux a une dispersion par les rongeurs, entre autres changements. Les auteurs ont analyse des collections d'herbiers et utilise l'analyse de traits ancestraux pour caracteriser les changements phenologiques parmi les cinq genres d'Arbutoides trouves dans des climats semi-arides. Leur objectif consistait a determiner si la phenologie change avec la transition phylogenetique vers des caracteres reproducteurs differents. Leurs resultats indiquent que les changements phenologiques ont commence avec certains traits, comme le developpement d'un endocarpe pierreux ou de fruits secs, mais pas avec tous les changements de traits significatifs. Ils concluent que les changements phenologiques precoces en correlation avec certains caracteres reproducteurs etaient permissifs pour la transition vers d'autres changements de caracteres ulterieurs. [Traduit par la Redaction] Mots-cles : Ericaceae, regime des incendies, semis obligatoire, eparpillement, predation des graines., Introduction Phenological changes that occur in coordination with fruit types is an understudied dimension of fruit evolution compared with dispersal or other traits (Forrest and Miller-Rushing 2010). Most studies investigating [...]

Phenological responses of plants to temperature dynamics are receiving attention due to the ongoing challenge with climate change. Most previous phenological studies have focused on flowering phenology rather than fruiting phenology. However, at mid-latitudes, the air temperature periodically changes during the growing period of plants. Hence, cool temperatures early and late in the growing period may affect reproductive success through pollination and fruit-development processes. To evaluate the linkages between reproductive phenology and success, we compared the phenologies, photosynthetic capacities, and fruit-set rates among 25 species within a cooltemperate community in northern Japan. The ambient temperature during the flowering periods of individual species increased with delays in flowering-onset time, whereas the ambient temperature during fruit-development periods was highest for species which bloomed in July. Fruit-set success among species was positively correlated with the ambient temperatures during the reproductive periods and with the photosynthetic capacity. Fruit production of early blooming species was limited by cool temperatures during the flowering period, presumably because of low pollinator activity, whereas that of late-blooming species was limited by cool temperatures during the fruit-development period because of slow fruit-development (i.e., sink limitation). Thus, limiting factors of fruit production varied depending on the flowering phenology of individual species within a community. Key words: air temperature, pollen limitation, pollinator, seasonality, sink limitation. Les réponses phénologiques des plantes à la dynamique de la température font l'objet d'une attention particulière en raison des changements climatiques en cours. La plupart des études phénologiques précédentes se sont concentrées sur la phénologie de la floraison plutôt que sur la phénologie de la fructification. Toutefois, aux latitudes moyennes, la température de l'air change périodiquement pendant la période de croissance des plantes. Par conséquent, des températures fraîches au début et à la fin de la période de croissance peuvent affecter le succès de la reproduction à travers les processus de pollinisation et de développement des fruits. Afin d'évaluer les liens entre la phénologie et le succès de la reproduction, les auteurs ont comparé les phénologies, les capacités photosynthétiques et les taux de fructification de 25 espèces à l'intérieur d'une communauté tempérée froide du nord du Japon. La température ambiante pendant les périodes de floraison des espèces individuelles augmentait avec le retard de l'apparition de la floraison, tandis que la température ambiante pendant les périodes de développement des fruits était la plus élevée pour les espèces qui fleurissaient en juillet. Le succès de la fructification des différentes espèces était positivement corrélé avec les températures ambiantes pendant les périodes de reproduction et avec la capacité photosynthétique. La production de fruits des espèces à floraison précoce était limitée par les températures fraîches pendant la période de floraison, probablement en raison de la faible activité des pollinisateurs, tandis que celle des espèces à floraison tardive était limitée par les températures fraîches pendant la période de développement des fruits en raison de la lenteur du développement des fruits (c'est-à-dire la limitation du puits). Ainsi, les facteurs limitants de la production de fruits varient en fonction de la phénologie de floraison des espèces individuelles au sein d'une communauté. [Traduit par la Rédaction] Mots-clés : température de l'air, limitation du pollen, pollinisateur, saisonnalité, limitation du puits., Introduction When should plants bloom and develop fruits? This issue is critical for plants to adapt to local abiotic and biotic environments, and it is one of their most important [...]

Masting behavior--variable and synchronized reproduction by a population of plants--has long been recognized as correlating with weather. How and why weather conditions influence seed production is, however, poorly understood. We investigated the relationships between acorn production and both local weather and long-term climate in 10 populations across the geographic range of the valley oak (Quercus lobata Nee), a California endemic that matures acorns in a single season. Acorn production was larger following a cold spring in the prior year and dry conditions in the winter and spring immediately preceding acorn maturation; similar patterns were also found, with minor differences, at all 10 individual sites. The strength of the relationships varied geographically in the case of the correlation between winter rainfall and annual acorn production, which was stronger (more negative) at wetter sites. Thus, in contrast to a recent study in Quercus petraea (Matt.) Liebl., weather had generally similar effects on acorn production throughout the range of Q. lobata. Similar to Q. petraea, however, the strength of the relationship between site-level annual acorn production and one of the weather factors affecting acorn production (winter rainfall in the case of Q. lobata) varied geographically in ways that may be related to differences among sites in the degree of pollen limitation. Understanding the mechanisms by which weather affects seed production is challenging but critical if we are to understand how climate change will affect masting behavior in the future. Key words: acorn production, masting, Quercus lobata, valley oak, variable reproduction. Il est depuis longtemps reconnu que la reproduction synchronisee et variable dans une population de plantes (<>) est correlee avec les conditions meteorologiques. Cependant, on comprend mal comment et pourquoi les conditions meteorologiques influencent la production de semences. Nous avons etudie les relations entre la production de glands et les conditions meteorologiques locales ainsi que le climat a long terme chez 10 populations dans l'aire de repartition du chene lobe (Quercus lobata Nee), un chene endemique de la Californie dont les glands arrivent a maturite en une seule saison. La production de gland etait plus abondante a la suite d'un printemps froid l'annee precedente et des conditions seches durant l'hiver et le printemps precedant immediatement la maturation des glands. Des patrons similaires ont ete observes, avec des differences mineures, dans l'ensemble des 10 stations individuelles. La force de la relation variait geographiquement dans le cas de la correlation entre la chute de pluie hivernale et la production annuelle de glands; la correlation etait plus forte (plus negative) dans les stations plus humides. Par consequent, contrairement a une etude recente qui portait sur Quercus petraea (Matt.) Liebl., les conditions meteorologiques avaient generalement des effets similaires sur la production de glands partout dans l'aire de repartition de Q. lobata. Comme avec Q. petraea cependant, la force de la relation entre la production annuelle de glands a l'echelle de la station et un des facteurs meteorologiques qui influencent la production de glands (chute de pluie hivernale dans le cas de Q. lobata) variait d'un endroit a l'autre. Cette variation pouvait etre reliee a des differences entre les stations concernant la disponibilite du pollen. Il est difficile mais essentiel de comprendre les mecanismes par lesquels les conditions meteorologiques influencent la production de semences si nous voulons comprendre de quelle facon le changement climatique affectera la reproduction synchronisee dans le futur. [Traduit par la Redaction] Mots-cles: production de glands, masting, Quercus lobata, vallee du chene, reproduction variable., Introduction Variable, synchronized seed production, known as mast-fruiting or masting behavior, is commonly observed in many taxa of plants and is particularly widespread among temperate and boreal trees. The evolutionary [...]

Species that propagate by sexual reproduction actively guard against the fertilization of an egg by multiple sperm (polyspermy). Flowering plants rely on pollen tubes to transport their immotile sperm to fertilize the female gametophytes inside ovules. In Arabidopsis, pollen tubes are guided by cysteine-rich chemoattractants to target the female gametophyte.sup.1,2. The FERONIA receptor kinase has a dual role in ensuring sperm delivery and blocking polyspermy.sup.3. It has previously been reported that FERONIA generates a female gametophyte environment that is required for sperm release.sup.4. Here we show that FERONIA controls several functionally linked conditions to prevent the penetration of female gametophytes by multiple pollen tubes in Arabidopsis. We demonstrate that FERONIA is crucial for maintaining de-esterified pectin at the filiform apparatus, a region of the cell wall at the entrance to the female gametophyte. Pollen tube arrival at the ovule triggers the accumulation of nitric oxide at the filiform apparatus in a process that is dependent on FERONIA and mediated by de-esterified pectin. Nitric oxide nitrosates both precursor and mature forms of the chemoattractant LURE1.sup.1, respectively blocking its secretion and interaction with its receptor, to suppress pollen tube attraction. Our results elucidate a mechanism controlled by FERONIA in which the arrival of the first pollen tube alters ovular conditions to disengage pollen tube attraction and prevent the approach and penetration of the female gametophyte by late-arriving pollen tubes, thus averting polyspermy. FERONIA prevents polyspermy in Arabidopsis by enabling pectin-stimulated nitric oxide accumulation at the filiform apparatus after the first pollen tube arrives, which disengages LURE1 chemoattraction to prevent late-arriving pollen tubes from entering the ovule., Author(s): Qiaohong Duan [sup.1] [sup.2] , Ming-Che James Liu [sup.1] [sup.3] , Daniel Kita [sup.1] [sup.4] [sup.7] , Samuel S. Jordan [sup.1] , Fang-Ling Jessica Yeh [sup.1] , Robert Yvon [...]

Silene latifolia Poiret of Eurasia has established in North America, prompting this structural study of its mature unisexual buds and flowers. Floral nectaries, anther and stigma changes, and vestigial reproductive structures were studied using light and scanning electron microscopy. In staminate flowers, anthers dehisced before anthesis and >90% of their pollen was liberated within 36 h. Accumulated in the tubular calyx, nectar descended an anthophore from the stomatal-bearing nectary at the stamen bases. Nectary tissue surrounded the pistillode, a central filamentous organ lacking ovules but tipped by hairs resembling stigmatic papillae. In pistillate flowers, nectar flowed into an inflated calyx. The annular nectary had 10 regularly spaced, stomatal-lined craters and was continuous with the adaxial surfaces of the infertile antisepalous and epipetalous staminodes. Key elements of entomophilous pollination leading to successful sexual reproduction of this invasive species include secondary nectar presentation from disparate floral nectaries that, for pistillate flowers, also incorporate the staminodes; rapid pollen release from anthers; and elongation of papillae by tip growth that enhances each stigma's receptive surface. Context is also provided for future studies of floral nectary development in this model dioecious species. Keywords: anther, dioecy, floral nectary, invasive species, pistillode, staminode, stigma, nectary stomata, unisexual flowers. Silene latifolia Poiret d'Eurasie s'est établie en Amérique du Nord, incitant de ce fait les auteurs à réaliser cette étude structurale de ses bourgeons et ses fleurs matures unisexuées. Les changements des nectaires floraux, des anthères et des stigmates, et les structures reproductives vestigiales ont été étudiés en microscopie optique et en microscopie électronique à balayage. Chez les fleurs staminées, les anthères entraient en déhiscence avant l'anthèse et >90% de leur pollen était libéré en moins de 36 h. Accumulé dans le calice tubulaire, le nectar amenait un anthophore du nectaire portant les stomates vers les bases des étamines. Le tissu du nectaire entourait le pistillode, un organe filamenteux central dépourvu d'ovules, mais portant des poils ressemblant à des papilles stigmatiques. Chez les fleurs pistillées, le nectar s'écoulait dans un calice gonflé. Le nectaire annulaire comportait dix creux régulièrement espacés, bordés de stomates et il était continu avec des surfaces adaxiales de staminodes infertiles antisépales et épipétales. Les éléments clés de la pollinisation entomophile donnant lieu à une reproduction sexuée fructueuse chez cette espèce envahissante comprennent la présentation de nectar secondaire à partir de nectaires floraux disparates qui, chez les fleurs pistillées, intègrent aussi les staminodes; une libération rapide de pollen à partir des anthères et l'élongation des papilles par une croissance apicale qui accroît la surface réceptrice de chaque stigmate. Les auteurs contextualisent aussi les études futures du développement des nectaires floraux grâce à ce modèle d'espèce dioïque. [Traduit par la Rédaction] Mots-clés : anthère, dioécie, nectaire floral, espèce envahissante, pistillode, staminode, stigmate, stomate du nectaire, fleurs unisexuées., Introduction Only 6% of angiosperm species feature dioecy (Renner and Ricklefs 1995), an extreme strategy for sexual reproduction, being reliant on proximity of male and female plants, synchronicity in flowering [...]

Abstract: Distylous species typically experience self-incompatibility with one morph often having partial selfcompatibility Small populations may therefore experience greater rates of selfing/intramorph crosses leading to skewed morph ratios and reduced [...]

Flower size is a key trait in the reproductive ecology of animal-pollinated plants. However, pollinator-mediated selection does not always modulate this trait and environmental conditions and/or antagonist interactions may favor smaller flowers. We evaluate the occurrence of a large-flowered family in a hot and dry Mediterranean environment, mediated by a cost-benefit balance and a male-female conflict. Large flowers have sizeable benefits in terms of pollination and reproductive success and pollinators mediate selection through male function, but female fitness is context-dependent. High floral production and maintenance costs and florivore incidence in large flowers limit female function, which counteracts pollinator-mediated selection. Large flowers are highly costly in the Mediterranean and flower size is mediated by a sexual conflict between the benefits of male function and the costs of the female one. However, a short floral longevity, occasional pollen limitation and selection through maleness keep the existence of large flowers in these environments. Keywords Cistaceae * Floral costs * Flower size * Pollinators * Male fitness * Female fitness, Introduction Animal-pollinated plants include a large diversity of flowers, varying in color spectrum, shape and design, scent, longevity, size and display. Historically, numerous botanists and evolutionary biologists have greatly been [...]

Recent concern regarding the potential decline of quaking aspen (Populus tremuloides Michx.) forests in the western United States has sparked concern over whether the species can be effectively regenerated. Using a retrospective approach, we quantified the response of regenerating aspen stems to an ordinary set of silvicultural treatments conducted over approximately the past decade in southern Utah, USA. A suite of variables describing stand structure and composition, stand vigor, physiographic factors, herbivore pressure, and treatment types were measured to predict the possible controls, as well as their relative importance, on aspen regeneration. Results suggested that aspen regeneration was most strongly related to browsing pressure, site preparation technique, and the presence of advance reproduction before treatment, which is a novel finding. Secondary predictors included elevation, site index, and overstory conditions, which are generally characteristics of stand vigor. Management recommendations based on our results should recognize the strong primary control that browsing pressure exerts on regeneration. First, the height of advance reproduction is inherently dependent on antecedent herbivory and also indicative of present browsing and should be assessed before treatment. Second, the most effective site preparation techniques, namely broadcast burning and browsing reduction, will directly reduce browsing pressure, assuming ungulate populations are not too large. Any management targeting timely and effective aspen regeneration should incorporate monitoring and (or) controlling browsing pressure, both before and after treatment. Key words: browsing, coppice, herbivory, Populus tremuloides, silviculture. L'inquietude recente face au deperissement apprehende des forets de peuplier faux-tremble (Populus tremuloides Michx.) dans l'ouest des Etats-Unis a suscite un questionnement concernant la possibilite de regenerer efficacement cette espece. A l'aide d'une approche retrospective, nous avons quantifie la reponse de tiges de peuplier faux-tremble au stade de la regeneration a un ensemble ordinaire de traitements sylvicoles realises au cours de la derniere decennie dans le sud de l'Utah, aux Etats-Unis. Une serie de variables decrivant la composition et la structure du peuplement, la vigueur du peuplement, les facteurs physiographiques, la pression des herbivores et les types de traitement ont ete mesurees dans le but de determiner quels facteurs pourraient influencer la regeneration du peuplier faux-tremble ainsi que leur importance relative. Les resultats indiquent que la regeneration du peuplier faux-tremble est surtout influencee par la pression des herbivores, la preparation technique du terrain, et la presence de regeneration preetablie, c'est-a-dire avant le traitement, ce qui constitue un resultat inedit. Les predicteurs secondaires incluent l'altitude, l'indice de qualite de station et l'etat de l'etage dominant: generalement les caracteristiques de vigueur du peuplement. Selon nos resultats, les recommandations d'amenagement devraient reconnaitre que la regeneration est controlee principalement par la pression des herbivores. Premierement, la hauteur de la regeneration preetablie depend intrinsequement du broutage passe mais peut aussi donner une idee de l'impact actuel du broutage; elle devrait etre evaluee avant d'appliquer un traitement. Deuxiemement, les techniques de preparation de terrain les plus efficaces: le brulage extensif et la reduction du broutage, reduiront directement la pression des herbivores a condition que les populations d'ongules ne soient pas trop importantes. Tout amenagement visant a etablir une regeneration en temps opportun et efficace du peuplier fauxtremble devrait comprendre le suivi ou le controle de la pression des herbivores, ou les deux, avant et apres le traitement. [Traduit par la Redaction] Mots-cles: broutage, taillis, herbivorisme, Populus tremuloides, sylviculture., Introduction Quaking aspen (Populus tremuloides Michx.; hereafter, aspen) is an ecologically and economically important forest species throughout its range (Baker 1925). A prevalent theme in the aspen literature is concern [...]

The differential temperature (ΔT) model, based on the assumption that masting plants respond to the difference in the temperatures during the growing seasons 1 and 2 years prior to seed production, has recently been proposed to explain the proximate factor of masting. In this study, we used a 28-year series of data on pollen cone and seed production in Cryptomeria japonica D. Don in Japan and compared several models based on temperatures and resources to test whether ΔT acts as a cue or is a proxy for resource limitation. Of all the models tested, models including ΔT, previous summer absolute temperature [T.sub.n-1], and reproduction in the previous year provided the best fit. The number of pollen cones and seeds produced was proportional to the difference in the mean daily maximum temperature during June to August between the preceding two years. In addition, to test whether the double mast events in consecutive years was less common than consecutive warm summers, we used our dataset and 12 datasets of pollen dispersal of 17 years or longer of C. japonica in Japan. Although consecutive warm summers occurred in 4.4% of pairs, double mast events occurred in 1.0%. The ΔT model was a considerably better predictor of the rare phenomenon of double mast events, which occur only after a specific sequence of cold-moderate-hot absolute summer temperatures. Thus, ΔT acts as cue for masting in C. japonica. Key words: climate cue, Cryptomeria japonica, ΔT model, Japanese cedar, masting. Le modele de temperature differentielle (ΔT), fonde sur l'hypothese que les plantes reagissent a la difference de temperature entre les deux saisons de croissance qui ont precede une annee semenciere, a recemment ete propose pour expliquer la cause directe de ce phenomene. Dans cette etude, nous avons utilise une serie de donnees portant sur 28 annees de production de cones males et de graines chez Cryptomeria japonica D. Don au Japon et nous avons compare plusieurs modeles fondes sur les temperatures ainsi que les ressources pour verifier si le modele ΔT agit comme un signal ou est un indice de ressources limitees. De tous les modeles testes, les modeles qui incluaient ΔT, la temperature absolue de l'ete precedent [T.sub.n-1] et la reproduction au cours de l'annee precedente donnaient le meilleur ajustement. Le nombre de cones males et de graines produits etait proportionnel a la difference de temperature journaliere maximum moyenne durant les mois de juin et aout entre les deux annees precedentes. De plus, pour determiner si les annees semencieres doubles consecutives etaient moins frequentes que les etes chauds consecutifs, nous avons utilise notre base de donnees et 12 bases de donnees sur la dispersion du pollen sur 17 annees ouplus pour C. japonica au Japon. Bienque des etes chauds consecutifs soient survenus dans 4,4% des paires, les annees semencieres doubles sont survenues dans 1% des cas. Le modele ΔT predisait beaucoup mieux le phenomene rare des annees semencieres doubles qui survenaient seulement a la suite d'une sequence specifique de temperatures estivales absolues: froides-moderees-chaudes. Par consequent, ΔT agit comme un signal pour les annees semencieres chez C. japonica. [Traduit par la Redaction] Mots-cles: signal climatique, Cryptomeria japonica, modele ΔT, cedre du Japon, annee semenciere., Introduction Population-level fluctuations of large crops of seeds or flowers, known as masting or mass flowering, are common and important phenomena in plants (Silvertown 1980, Kelly and Sork 2002). Masting [...]

Diploid Daucus pusillus Michx. (x = 11) and hexaploid Daucus montanus Humb. et Bonpl. ex Schult. (x = 11) are wild taxonomic carrot species, closely related to diploid Daucus carota L. (x = 9), spontaneous in Argentina. For efficient ex situ conservation and potential use in breeding, we investigated their reproductive behavior by (i) carrying out controlled pollinations among D. pusillus accessions from a wide distribution area in the country and between these and one plant of D. montanus that overlapped in flowering, and (ii) bagging a few inflorescences to prevent outcrossings. Part of the pollinated pistils were analyzed by fluorescence microscopy; others were left on the plant. Pollen viability was high (>87%) in all accessions, but heterogeneity for size and shape was observed. Seed formation in bagged inflorescences confirmed that D. pusillus is autogamous and revealed that D. montanus is self-compatible. Fully developed mericarps were obtained only in intraspecific combinations. It is concluded that populations classified as the taxonomic species D. pusillus constitute a biological species as well, and that they are closely related to the taxonomic species D. montanus because they share the basic chromosome number and are reproductively isolated mainly by post-zygotic barriers, which could be eventually circumvented via 2n gametes. Key words: hybridization, breeding barriers, taxonomic species, biological species. Resume: Daucus pusillus Michx. (x = 11) diploide et Daucus montanus Humb. et Bonpl. ex Schult. (x = 11) hexaploide sont des especes taxonomiques de carottes sauvages, etroitement reliees a Daucus carota L. (x = 9) diploide, spontanee en Argentine. Les auteurs ont examine leurs comportement reproducteur a des fins de conservation efficiente ex situ et d'utilisation potentielle en reproduction, (i) en realisant des pollinisations controlees parmi des accessions de D. pusillus provenant d'une large zone de distribution dans le pays, et entre elles et un plant de D. montanus dont les floraisons se chevauchaient, et (ii) en enveloppant quelques inflorescences afin de prevenir les croisements heterogenes. Une partie des pistils pollinises ont ete analyses par microscopie en fluorescence, les autres etant laisses sur la plante. La viabilite du pollen etait elevee (>87 %) chez toutes les accessions, mais une heterogeneite sur le plan de la taille et de la forme a ete observee. La grenaison des inflorescences enveloppees a confirme que D. pusillus est autogame et revele que D. montanus est auto-compatible. Des mericarpes pleinement developpes ont ete obtenus uniquement lors de combinaisons intraspecifiques. Les auteurs concluent que les populations attribuees a l'espece taxonomique D. pusillus constituent une egalement une espece biologique, et qu'elles sont etroitement reliees a l'espece taxonomique D. montanus car elles partagent le nombre de base de chromosomes et sont isolees sur le plan reproducteur principalement par des barrieres post-zygotiques, qui pourraient eventuellement etre contournees via un nombre diploide de gametes. [Traduit par la Redaction] Mots-cles: hybridation, barrieres reproductrices, espece taxonomique, espece biologique., Introduction Three to four wild Daucus species (according to different authors), closely related to the edible carrot (D. carota L.), have been reported in Argentina: naturalized Daucus carota L., Daucus [...]

The study of floral traits and pollination for the plant genus Phlox has historically been focused on either surveys of general pollinator affinities across the genus or detailed research on pollinator-mediated evolution of floral color in a single species (Phlox drummondii). The purpose of this study was to explore a different kind of trait--floral scent in Phlox divaricata, a species noted for its strong scent. Specifically, we predicted the diel emission patterns of floral scent might covary with the daily abundance of diurnal moths, identified in a previous study as the most important pollinators in a Konza Prairie population of P. divaricata. Consistent with this prediction, we documented peaks in median floral scent emissions at 1000-1200 and 1930-2130, coinciding with peaks in moth visitation and resulting seed production. Two groups of scent compounds contributed to this pattern; linalool and its associated lilac aldehyde/alcohol compounds (especially lilac aldehyde B) contributed a greater proportion to scent at 1000-1200, while aromatic compounds (including benzaldehyde and benzyl acetate) contributed a greater proportion to scent at 1930-2130 and other afternoon time periods. These volatiles are known floral attractants for several lepidopteran pollinators, including noctuid moths. However, there is an additional peak in pollinator abundance (Hemaris diurnal hawkmoths) and seed set at a time when scent production is relatively low (1400-1600) suggesting additional factors mediate both pollinator behavior and floral volatile emissions. Future studies of P. divaricata should test for the presence of destructive floral enemies that might be attracted by floral volatiles during mid-afternoon periods, as well as the importance of visual floral traits (color, shape) in attracting diurnal moths, an important functional group of pollinators that has received minimal attention in North America., INTRODUCTION Studies of unique floral forms and functions for a number of different plant species have led to a greater understanding of the evolutionary history of relationships between plants and [...]

Numerous factors contribute to the variability in treeline change; however, the potential role of insect predation in limiting seed productivity is not well documented. Conditions for seed germination, establishment, and survival are not limiting at the Mealy Mountains treeline (Labrador, Canada), but seedlings are rarely encountered, suggesting a seed-related bottleneck to recruitment. Mature cones were collected in 2008 from four tree species (black spruce (Picea mariana (Mill.) Britton, Sterns & Poggenb.), balsam fir (Abies balsamea (L.) Mill.), eastern larch (Larix laricina (Du Roi) K. Koch), and white spruce (Picea glauca (Moench) Voss)) across three treeline zones (forest, transition, and krummholz) to assess potential seed limitation. During that year, an unexpectedly high diversity of insect larvae caused extensive reproductive loss and damaged the cones of ~85% of trees sampled, confirming that treeline change models should include seed predation. Seed germination was low and variable in all treeline zones, although significantly higher in black spruce and eastern larch. Most reproductive quality measures decreased significantly with elevation, although no differences among zones or tree species in the percentages of seeds damaged by insects were found (mean ± standard deviation: 31% [+ or -] 23%). Based on tree density and seed production, black spruce is predicted to lead the treeline expansion in the Mealy Mountains. Although climate warming may create conditions conducive for increased seed production, predispersal seed predation may limit future treeline expansion. Key words: climate change, forest-tundra ecotone, insect herbivory, multispecies, predispersal seed predation, reproductive bottleneck. Plusieurs facteurs contribuent a la variabilite de la modification de la limite des arbres mais le role potentiel des epidemies d'insecte dans la reduction de la productivite des graines a ete peu etudie. A la limite des arbres dans les montagnes Mealy (Labrador, Canada), les conditions sont adequates pour la germination, l'etablissement et la survie mais on trouve rarement des semis. Cela indique qu'il y a un probleme de recrutement relie aux graines. Des cones matures ont ete collectes en 2008 chez quatre especes (epicea noir (Picea mariana (Mill.) Britton, Sterns & Poggenb.), sapin baumier (Abies balsamea (L.) Mill.), meleze laricin (Larix laricina (Du Roi) K. Koch) et epicea blanc (Picea glauca (Moench) Voss)) dans trois zones de la limite des arbres (foret, transition et krummholz) pour evaluer les problemes potentiels relies aux graines. Durant cette annee, une diversite etonnamment elevee de larves d'insecte ont cause des pertes importantes en endommageant les cones d'environ 85 % des arbres echantillonnes. Cela a confirme que les modeles qui simulent les variations de la limite des arbres devraient inclure la predation par les insectes. La germination des graines etait faible et variable dans toutes les zones a la limite des arbres quoique significativement meilleure chez l'epicea noir et le meleze. La plupart des mesures de qualite de la reproduction diminuaient significativement avec l'altitude bien qu'aucune difference dans le pourcentage de graines endommagees par les insectes entre les zones ou les especes d'arbre n'ait ete observee (moyenne : 31% ± 23%ET). Sur la base de la densite des arbres et de la production de cones ou de graines, on prevoit que l'epicea noir dominera l'expansion de la limite des arbres dans les montagnes Mealy. Bien que le rechauffement du climat puisse creer des conditions favorables a l'augmentation de la production de graines, la predation des graines avant qu'elles n'aient ete dispersees pourrait limiter l'expansion future de la limite des arbres. [Traduit par la Redaction] Mots-cles : changements climatiques, ecotone entre la foret et la toundra, insectes herbivores, multiespeces, predation des graines avant leur dispersion, problemes de reproduction., Introduction At the global scale, upslope and northward advance of the thermally constrained forest-tundra ecotone (treeline; sensu Scott (1995)) is expected given projected warming scenarios associated with climate change (Grace [...]

Ranunculus ficaria is an invasive plant species in the northeastern United States, especially in urban riparian habitats. Changes in the frequency and intensity of flooding events in these urban riparian corridors create patches of heavy litter and patches of bare ground. Many plant species either cannot penetrate deep litter, or they are susceptible to freezing temperatures and drying conditions on bare ground. This can result in competitive advantages for invasive species that are adapted to these varying conditions. We conducted a field experiment to test the effects of leaf litter depth on R. ficaria biomass, bulbil production, flower production, and seed production under deep (20 cm) litter, intermediate (10 cm) litter, shallow (5 cm) litter, and bare ground along an urban stream in Louisville, Kentucky. Deep litter and lack of litter decreased plant biomass compared with shallow litter. Bulbil production was not significantly different across treatments. Flower and seed production were only reduced in deep litter. Ranunculus jicaria's ability to maintain production across a large range of litter depths may provide a competitive advantage over plant species not adapted to varying litter depths., INTRODUCTION Invasive plant species are important economic and environmental pests, posing threats to endangered species, altering native habitats, decreasing biodiversity, and facilitating the establishment of other invasive species (Pimentel et [...]

This article introduces the concept of 'robust selection', which proposes tree selection based on the stochastic simulation of economic values to account for the inherent uncertainty of economic weights used in tree selection for breeding programs. The proposed method uses both median ranking and ranking variability as criteria for breeding selection. Using consensus genetic and economic parameters from the New Zealand Radiata Pine Breeding Company program, we compare three selection strategies: deterministic application of economic weights from a vertically integrated bioeconomic model, an equal-weight index often used in operations, and robust selection. All strategies aim to increase value for a breeding objective that includes four traits, i.e., volume, stem sweep, branch size, and wood stiffness (measured as modulus of elasticity), based on a selection index that considers five criteria, i.e., stem diameter at breast height (1.3 m), straightness, branching score, wood density, and modulus of elasticity. Two-thirds of the selected trees were unique for each of the selection strategies. Robust selection achieved the best realised gain for three of the four selection criteria and was the middle performer in the last selection criteria. Considering the high intrinsic uncertainty of economic weights, we suggest that the relevant criterion for the selection of individuals is the maximum median ranking, subject to an acceptable level of variation in that ranking, rather than their narrow performance under a single economic scenario. This will lead to tree selections that perform well under a wide range of economic circumstances. Key words: breeding objectives, economic weights, simulation, economic evaluation, risk analysis. Cet article introduit le concept de << selection robuste >> qui propose une selection fondee sur la simulation stochastique de la valeur economique pour tenir compte de l'incertitude inherente du poids economique utilise pour la selection des arbres dans les programmes d'amelioration. La methode qui est proposee utilise le classement median et la variabilite du classement comme criteres pour la selection. A l'aide de parametres genetiques et economiques du programme de la New Zealand Radiata Pine Breeding Company qui font consensus, nous avons compare trois strategies de selection : l'application deterministique du poids economique provenant d'un modele bioeconomique verticalement integre, un indice de poids equivalent souvent utilise dans les operations et la selection robuste. Toutes les strategies visent a augmenter la valeur d'un objectif d'amelioration qui inclut le volume, la courbure du tronc, la dimension des branches et la rigidite du bois a partir d'un indice de selection qui tient compte du diametre du tronc, de sa rectitude, de la note de branchaison, de la densite du bois et du module d'elasticite. Les deux tiers des arbres selectionnes avec chacune des strategies etaient uniques. La selection robuste a produit le meilleur gain pour trois des quatre criteres de selection et occupe la position intermediaire pour l'autre critere. En tenant compte de l'importante incertitude intrinseque du poids economique, nous suggerons que le critere pertinent pour la selection des individus soit le classement median maximum, qui est sujet a un degre acceptable de variation dans ce classement, plutot que leur performance etroite dans le cadre d'un seul scenario economique. Cela va engendrer la selection d'individus qui performent bien dans une vaste gamme de conditions economiques. [Traduit par la Redaction] Mots-cles : objectifs d'amelioration, poids economique, simulation, evaluation economique, analyse de risques., Introduction The selection of superior trees is central to breeding programs, aiming to identify individuals with maximum economic-genetic value for a combination of characteristics of economic importance. These trees are [...]

Exponential fertilization has been shown to be a useful technique for improving seedling quality during nursery production. In this study, we evaluated (i) the impact of exponential vs. conventional fertilization on trembling aspen (Populus tremuloides Michx.) and white spruce (Picea glauca (Moench) Voss) seedlings during nursery production and (ii) the growth performance and nitrogen (N) utilization of those seedlings in response to foxtail barley (Hordeum jubatum L.) competition after the transplantation of seedlings in a greenhouse experiment. Exponential fertilization with an application rate higher than the conventional fertilization increased the internal N reserve in trembling aspen and white spruce seedlings during nursery production and also increased new leaf, new stem, and old stem biomass and N retranslocation rates in trembling aspen seedlings but not in white spruce seedlings after transplantation. Foxtail barley competition decreased N concentrations in seedlings and soil N uptake by the seedlings; however, increased N retranslocation rates with foxtail barley competition were observed in white spruce seedlings but not in trembling aspen seedlings. Our results suggest that the growth performance of seedlings was improved by N loading, whereas the impact of vegetation management was species specific. Key words: exponential fertilization, internal N reserve, N-loaded seedling, net N retranslocation rate, vegetation competition. La fertilisation exponentielle s'est averee utile pour ameliorer la qualite des semis lors de la production en pepiniere. Dans cette etude, nous avons evalue (i) l'impact de la fertilisation exponentielle vs conventionnelle sur les semis de peuplier faux-tremble (Populus tremuloides Michx.) et d'epicea blanc (Picea glauca (Moench) Voss) lors de la production en pepiniere, et (ii) la croissance de ces semis et leur utilisation de N en reaction a la competition de l'orge queue-d'ecureuil (Hordeum jubatum L.) apres les avoir transplantes en serre suivant un dispositif experimental. La fertilisation exponentielle, dont le taux d'application est plus eleve que la fertilisation conventionnelle, a augmente les reserves internes de N chez les semis de peuplier faux- tremble et d'epicea blanc durant la production en pepiniere et a augmente la biomasse des nouvelles feuilles, des nouvelles et des vieilles tiges ainsi que le taux de retranslocation de N apres la transplantation chez les semis de peuplier faux-tremble mais pas chez les semis d'epicea blanc. La competition de l'orge queue-d'ecureuil a reduit les concentrations de N dans les semis et l'absorption de N dans le sol par les semis; cependant, en presence de l'orge queue-d'ecureuil une augmentation du taux de retranslocation de N a ete observee chez les semis d'epicea blanc mais pas chez les semis de peuplier faux-tremble. Nos resultats indiquent que la croissance des semis a ete amelioree par une surcharge de N tandis que l'impact de la maitrise de la vegetation dependait de chaque espece. [Traduit par la Redaction] Mots-cles : fertilisation exponentielle, reserves internes de N, semis surcharges en N, taux net de retranslocation, competition de la vegetation., Introduction Vegetation management is one of the most critical silvicultural practices for maximizing postplanting tree seedling survival and growth during the early establishment phase of plantations (Lowery et al. 1993; [...]

Author(s): Wudan Yan [1] Nathan Lakey practically has to shout to be heard over the whirring machinery in the laboratory at Orion Biosains near Kuala Lumpur. One source of the [...]