Relationships among Flowering Phenology, Insect Visitors, and Seed-Set of Individuals: Experimental Studies on Four Co-occurring Species of Goldenrod (Solidago: Compositae)

1983 ◽  
Vol 53 (1) ◽  
pp. 95-117 ◽  
Author(s):  
Ronald S. Gross ◽  
Patricia A. Werner
Botany ◽  
2010 ◽  
Vol 88 (3) ◽  
pp. 241-249 ◽  
Author(s):  
Diana Bizecki Robson

Flower-visiting insect activity to the rare Symphyotrichum sericeum (Vent.) G.L. Nesom and the common Solidago nemoralis Ait. var. longipetiolata (Mack. & Bush) Pal. & Steyerm. was examined to detect compositional and temporal similarities. A hand pollination experiment was conducted to determine whether pollen was limiting seed set. Of the 31 insect taxa that visited these plants, Bombus bifarius Cresson was the most common visitor to both species. More insect visitors of the Halictidae and Bombyliidae were received by S. sericeum than S. nemoralis, which received more visitors of the Syrphidae and Tachinidae. The insect visitation rate was not significantly different between the two plant species. Solidago nemoralis was visited by fewer insect taxa per day than S. sericeum, but the constancy of its visitors was higher. The insect visitor composition changed over time, with B. bifarius ignoring S. sericeum plants initially, then visiting them more frequently as the number of receptive S. nemoralis capitula declined. Hand pollination increased seed set in the earliest flowering capitula of S. sericeum, but not for those flowering during the peak. This research shows that the quantity of insect visits to the rare plant is comparable with that of the common plant but that pollination quality may be lower, particularly for early blooming capitula.


1993 ◽  
Vol 71 (8) ◽  
pp. 1072-1079 ◽  
Author(s):  
Ørjan Totland

Pollination studies in European alpine communities are few. The objective of this study was to describe the pollination ecology in two alpine plant communities at Finse, southwestern Norway. Because of late snowmelt and early winter at Finse, the time available for flowering and seed maturation is restricted. Flowering was concentrated at the beginning of the season in both communities, and large overlaps in flowering time were found for most species. In one of the communities, flowering peaks were significantly clumped, whereas in the other they were randomly distributed through the season. However, in this community, five insect-pollinated species flowered simultaneously early in the season. Diptera almost exclusively dominated the visitor assemblage. Most plant species pairs had high overlaps in flower visitor species. Species flowering simultaneously attracted the same visitor species. In one community, eight species pairs flowered sequentially and shared visitors. Visitation rates were highest at the lowest elevated site. The results are compared with those obtained in other alpine areas. It is argued that selection for an early flowering is probably stronger than selection pressures resulting from interspecific interactions. Key words: alpine, Diptera, flowering phenology, flower visitors, season length, visitation rate.


1982 ◽  
Vol 60 (2) ◽  
pp. 210-219 ◽  
Author(s):  
Robert I. Bertin

The Ruby-throated Hummingbird (or rubythroat, Archilochus colubris) and several of its major food plants were examined to assess the importance of rubythroat versus insect pollination, the overlap of geographical ranges, and the synchrony between migration and flowering times. Seed set of Impatiens biflora was increased 8–17% by rubythroat and insect visitation over the level achieved by insects alone. The rubythroat's range is not contiguous with that of any of 22 putative food plants examined, but is nearly coincident with the range of certain forest types, perhaps reflecting the importance of sap for food. A new method was developed to estimate peak flowering times of plants from herbarium data. Based on these data and field observations, only one rubythroat food plant (Impatiens biflora) had peak flowering times close to peak rubythroat migration times throughout their shared range. Rubythroats and their North American food plants are facultative mutualists, with the plants apparently having been evolutionarily more labile.


2000 ◽  
Vol 40 (5) ◽  
pp. 755 ◽  
Author(s):  
M. Aleemullah ◽  
A. M. Haigh ◽  
P. Holford

Little attention has been paid to the events associated with fruit production such as flowering and seed set in chilli peppers despite this species being a major horticultural crop. To address this deficit, we examined flowering phenology in the cv. Red Hot Glory, a representative of the Longum group of peppers. Measurements of bud length and width showed that these characteristics can provide an effective index of the number of days required by a bud to reach anthesis. Anthesis itself mainly occurred during the morning with a second, smaller peak of flower opening in the afternoon. Measurements made in spring and summer suggested that the daily start of anthesis is controlled by daylength. In flowers that opened before 1700 hours, anther dehiscence took place 1 h after the buds opened; in flowers that opened later, dehiscence was delayed until the following morning. This pattern of anther dehiscence suggests that this event is partially controlled by the flower’s endogenous rhythms. Controlled pollinations showed that the period of female receptivity, as judged by seed set, lasted from 5 days before anthesis to 3 days after anthesis with maximum fertility occurring on the day of anthesis. Therefore, bud pollinations are possible, and, for maximum seed set, should be made as close to the day of anthesis as possible. This study has provided baseline data that will aid the production of new, hybrid cultivars and will facilitate further studies on the factors affecting fertility in this species.


2021 ◽  
Vol 78 (4) ◽  
Author(s):  
Clément Larue ◽  
Teresa Barreneche ◽  
Rémy J. Petit

Abstract Key message Pollination is a key step for fruit production. To provide a tool for future in-depth analysis of pollination in chestnut, we describe in detail a chestnut orchard (location, genotype, phenotype and seed-set of all trees). Context Chestnuts, which are insect-pollinated trees, have been massively planted around the world for nut production. Orchards are planted with clonal varieties selected from crosses between the European chestnuts (Castanea sativa) and Japanese chestnuts (C. crenata) or Chinese chestnuts (C. mollissima) because these two last species are tolerant to blight and ink diseases. Aims To characterize chestnut genetic resources and accurately model male and female fitness as well as pollen exchanges in orchards, we characterized all chestnuts of the INRAE chestnut germplasm collection located near Bordeaux (France). Methods All chestnut trees were geolocated and genotyped using 79 SNP and 98 SSR loci. We scored their flowering phenology using chestnut BBCH scale and precisely described their phenotype (height, diameter a breast height (DBH), canopy diameter…), their capacity to produce pollen (flower type, catkins length…) and their fruit production (number of burrs, seed-set…). Results We geolocated 275 trees and genotyped 273 of them. We identified 115 unique genotypes and assigned each genotype to species. To assess phenology, we evaluated 244 trees twice a week, for 6 weeks from early June to mid-July. We also described tree phenotypes with 11 variables, pollen production with 5 variables and fruit production with 3 variables. All measures were recorded in 2018 except seed set that was measured two consecutive years, in 2018 and 2019. Conclusion The data collected is very detailed and allows modelling precisely pollen exchanges between trees. Parts of this data have been successfully published in scientific articles. Data are available at: https://data.inrae.fr/dataset.xhtml?persistentId=doi:10.15454/GSJSWW Associated metadata are available at:https://metadata-afs.nancy.inra.fr/geonetwork/srv/fre/catalog.search#/metadata/02c5ca07-1536-4f89-9a0c-9e8d44a91287


2018 ◽  
Vol 285 (1884) ◽  
pp. 20181072 ◽  
Author(s):  
Shiyun Qiu ◽  
Xiao Xu ◽  
Shuangshuang Liu ◽  
Wenwen Liu ◽  
Jing Liu ◽  
...  

Flowering synchrony can play an important role in plants' reproductive success, which is essential for the successful establishment and spread of invasive plants. Although flowering synchrony has been found to be closely related to climatic factors, the effects of variation in such factors along latitudinal gradient on flowering synchrony and the role of flowering synchrony in the reproductive success of invading populations remain largely unexplored. In a 2-year field study, we examined the latitudinal variation of flowering phenology, especially flowering synchrony, in an invasive plant, Spartina alterniflora , along coastal China, and its relationship with population seed set across three climatic zones. We found that first flowering date was delayed, and flowering synchrony increased with increasing latitude. Flowering synchrony was negatively related to temperature during flowering season but not to soil properties or precipitation, suggesting that climate has shaped the latitudinal pattern of flowering synchrony. Moreover, a positive correlation between flowering synchrony and seed set across latitudes indicates the possible role of flowering synchrony in the latitudinal pattern of sexual reproduction in S. alterniflora . These results suggest that, in addition to the effects of climate on the growth of invasive species, climatic factors can play an important role in the invasion success of alien plants by regulating the flowering synchrony and thus the reproductive success of invasive plants.


1972 ◽  
Vol 20 (4) ◽  
pp. 225-231
Author(s):  
J.G. Boonman

Effects of date of applying top-dressings of N to early-season and late-season seed crops of Setaria sphacelata cv. Nandi were studied in 4 trials in 1967-71. Highest seed yields were obtained when N was applied as soon as possible after the onset of the rainy season; a delay of 4 weeks reduced yields of pure germinating seed by >60%. Total yields of herbage DM and number of heads were also reduced, but to a lesser extent; the main adverse effect was on seed set/head. In late-season crops, applying N 2 weeks after the earliest possible date proved beneficial in 2 out of 3 years. (Abstract retrieved from CAB Abstracts by CABI’s permission)


2000 ◽  
Vol 48 (2) ◽  
pp. 261 ◽  
Author(s):  
Andrew J. Denham ◽  
Robert J. Whelan

Lomatia silaifolia (Smith) R.Br. (Proteaceae) is a common shrub in southeastern Australian bushland that generally flowers only once after each fire. However, little is known of the details of this post-fire flowering. Lomatia silaifolia has flowers well-spaced along its conflorescence axis, unlike many other Proteaceae species, thus allowing close examination of the influence of flower position, mate choice and flowering sequence on fruit production. We examined breeding system, flowering phenology and spatial patterns of fruit set in the species, after a fire in September 1992 at Bulli Tops, New South Wales. Flowering occurred in December–January, but only in the first and second summers after the fire. The species is partially self-compatible: only 25% of self-pollinated conflorescences initiated fruits compared with 100% of cross-pollinated conflorescences. Fewer flowers initiated fruits after hand self-pollination (3.0%) than after cross-pollination (35.4%). Self-pollinated flowers produced fewer viable seeds (22.2% viable) than cross-pollinated flowers (62.9% viable). Pollen tubes were found in 72% of the self-pollinated flowers examined, suggesting that there is no early stylar self-incompatibility in the species. There was a high level of herbivory on flowering and fruiting branches, with 69% of unbagged branches completely destroyed. This may significantly affect recruitment in the species, given the limited opportunities for reproduction in the post-fire environment. In this study, fruits were evenly distributed along the conflorescence axis unlike some other species in the Proteaceae with more compressed, spike-like flowering structures where fruits are typically concentrated in some parts of the conflorescence axis (e.g. Telopea and some Banksia spp.). No bird visitors to flowers were observed, but a variety of insect visitors were identified.


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