Pollination and seed production in five boreal species of Vaccnium and Andromeda (Ericaceae)

1996 ◽  
Vol 74 (9) ◽  
pp. 1363-1368 ◽  
Author(s):  
Heléne Fröborg

Using experimental manipulations, I examined if pollen quality affected fruit and seed production in five ericaceous understory shrubs in a coniferous forest in central Sweden. Flowers of Vaccinium myrtillus L., Vaccinium uliginosum L., Vaccinium vitis-idaea L., Vaccinium oxycoccos Gil., and Andromeda polifolia L. were (treatment 1) open-pollinated, (treatment 2) bagged without further treatment, (treatment 3) bagged and self-pollinated, (treatment 4) cross-pollinated with pollen from neighbouring plants, or (treatment 5) supplied with pollen from distant plants. Finally, flowers were (treatment 6) open-pollinated with a supply of extra pollen of distant origin. To investigate pollen or resource limitations to fruit and seed production, V. vitis-idaea was subjected to partial flower removal followed by open- and hand-pollination. Fruit and seed set were estimated for each treatment. The main conclusion is that natural levels of outcrossing are sufficiently high for full seed production and that the availability of pollen is not limiting in natural habitats. There were significant reductions in fruit and seed set after self-pollination in V. myrtillus. Fruit set was reduced in V. vitis-idaea, and V. uliginosum failed to set fruit after self-pollination. Self-pollination caused a decreased seed set in A. polifolia. There was no significant variation across treatments in V. oxycoccos. Since fruits tend to develop regardless of seed number, resources are likely to limit seed production in species with costly fruits. Keywords: self-fertility, pollination, Vaccinium, fruit set, seed set.

1994 ◽  
Vol 119 (1) ◽  
pp. 84-89 ◽  
Author(s):  
Richard E. Harrison ◽  
James J. Luby ◽  
Peter D. Ascher

Pollination of the half-high blueberry (Vaccinium corymbosum L./V. anugustifolium Ait.) cultivars St. Cloud, Northsky, Northcountry, and Northblue with self, outcross, and outcross/self pollen mixtures suggests that outcross fertilization maximizes percent fruit set, berry weight, seeds per berry, and seeds per pollination while minimizing days to harvest. Based on these results, mixed plantings of at least two blueberry cultivars are recommended for these cultivars. Fruit and seed set were negatively associated with increased percentages of self pollen in outcross/self pollen mixtures. These responses were linear for `Northblue' due to a tendency to parthenocarpy, and nonlinear for `St. Cloud', `Northsky', and `Northcountry', due to low fruit set following self-pollination. These data indicate that post-fertilization abortion affected seed formation, which was, in turn, correlated positively with fruit set.


PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0250203
Author(s):  
Agneta Colda ◽  
Sofie Bossaert ◽  
Christel Verreth ◽  
Bart Vanhoutte ◽  
Olivier Honnay ◽  
...  

Currently, one of the most important challenges is to provide sufficient and affordable food and energy for a fast-growing world population, alongside preserving natural habitats and maintaining biodiversity. About 35% of the global food production depends on animals for pollination. In recent years, an alarming worldwide decline in pollinators has been reported, putting our food production under additional pressure. Therefore, there is an urgent need to find sustainable ways to ensure this crucial ecosystem service. Recent studies have shown that floral nectar is generally colonized by microorganisms, specifically yeasts and bacteria, which may alter nectar chemistry and enhance attraction of pollinators. In this study, we investigated changes in pollinator foraging behavior and pollination success in European pear (Pyrus communis L.) cultivars ‘Regal Red’ and ‘Sweet Sensation’ (red sports of ‘Doyenné de Comice’) after flower inoculation with the typical nectar-inhabiting microorganisms Metschnikowia reukaufii and Acinetobacter nectaris, and a combination of both. Pollination success was monitored by measuring the number of flower visits, fruit set and seed set in two consecutive years, 2019 and 2020. Results revealed that application of a mixture of M. reukaufii and A. nectaris resulted in significantly higher visitation rates of honeybees and hoverflies. By contrast, no effects on flower visits were found when yeasts and bacteria were applied separately. Fruit set and seed set were not significantly affected by any of the inoculation treatments. The only factors affecting fruit set were initial number of flower clusters on the trees and the year. The absence of treatment effects can most likely be attributed to the fact that pollination was not a limiting factor for fruit set in our experiments. Altogether, our results show that inoculation of flowers with nectar microbes can modify pollinator foraging patterns, but did not lead to increased pollination success under the conditions tested.


Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 815
Author(s):  
Sandra V. Rojas-Nossa ◽  
José María Sánchez ◽  
Luis Navarro

Floral development depends on multifactor processes related to genetic, physiological, and ecological pathways. Plants respond to herbivores by activating mechanisms aimed at tolerating, compensating, or avoiding loss of biomass and nutrients, and thereby survive in a complex landscape of interactions. Thus, plants need to overcome trade-offs between development, growth, and reproduction vs. the initiation of anti-herbivore defences. This study aims to assess the frequency of phloem-feeding herbivores in wild populations of the Etruscan honeysuckle (Lonicera etrusca Santi) and study their effects on floral development and reproduction. The incidence of herbivory by the honeysuckle aphid (Hyadaphis passerinii del Guercio) was assessed in three wild populations of the Iberian Peninsula. The effect of herbivory on floral morphology, micromorphology of stigmas and pollen, floral rewards, pollination, and fruit and seed set were studied. The herbivory by aphids reduces the size of flowers and pollen. Additionally, it stops nectar synthesis and causes malformation in pollen and microstructures of stigmas, affecting pollination. As a consequence, fruit set and seed weight are reduced. This work provides evidence of the changes induced by phloem-feeding herbivores in floral development and functioning that affect the ecological processes necessary to maintain the reproductive success of plants.


2016 ◽  
Vol 69 (1) ◽  
Author(s):  
Matthew Oziegbe ◽  
Temitope Olatayo Kehinde ◽  
Joshua Olumide Matthew

<em>Ocimum</em> species have a combination of reproductive system which varies with the locality and cultivar. We have studied here the reproductive mechanisms of five variants of three <em>Ocimum</em> species in Nigeria, namely: <em>Ocimum canum</em> Sims., <em>O. basilicum</em> L., and <em>O. americanum</em> L. Flowers from each variant were subjected to open and bagged pollination treatments of hand self-pollination, spontaneous self-pollination and emasculation. All open treatments of the five <em>Ocimum</em> variants produced more fruit and seed than the corresponding bagged treatments. The two <em>O. canum</em> variants and <em>O. basilicum</em> ‘b<span><sub>1</sub></span>’ produced high fruit and seed set in the open and bagged treatments of spontaneous self-pollination. <em>Ocimum basilicum</em> ‘b<span><sub>2</sub></span>’ and <em>O. americanum</em> produced higher fruit and seed set in the self-pollination open treatment but significantly lower fruit and seed set in the bagged treatment. Fewer fruit and seeds were produced in the emasculated open treatments but none in the emasculated bagged treatments of the five <em>Ocimum</em> variants. The floral foragers comprising of bees, wasps and butterflies visited the <em>Ocimum</em> species to collect pollen or nectar in the open treatments. The two <em>O. canum</em> variants and <em>O. basilicum</em> ‘b<span><sub>1</sub></span>’ variant reproduced mainly through autogamy but <em>O. basilicum</em> ‘b<span><sub>2</sub></span>’ and <em>O. americanum</em> showed mixed reproduction of autogamy and outcrosssing. Insect visitation to the flowers enhanced pollination resulting in higher fruit and seed set in all the <em>Ocimum</em> species studied.


2021 ◽  
Vol 154 (1) ◽  
pp. 39-48
Author(s):  
Olga V. Nakonechnaya ◽  
Olga G. Koren ◽  
Vasilii S. Sidorenko ◽  
Sergey A. Shabalin ◽  
Tatyana O. Markova ◽  
...  

Background and aims – Interactions of insects with trap flowers of Aristolochia manshuriensis, a relic woody liana with fragmented natural populations from south-eastern Russia, were studied. Pollination experiments were conducted to identify the causes of the poor fruit set in this plant.Material and methods – The study was carried out at two ex situ sites within the natural range of A. manshuriensis in the suburban zone of the city of Vladivostok (Russia). The floral morphology was examined to verify how it may affect the process of pollination in this species. To test for a probability of self-pollination, randomly selected flowers at the female phase of anthesis (day 1 of limb opening) were hand-pollinated with pollen from the same plant. The daily insect visitation was studied. The pollen limitation coefficient and the number of visitors to the flowers were determined. To identify insects that lay eggs on the flowers, the insects were reared from eggs collected from fallen flowers. Both caught and reared insects were identified.Key results – The floral morphology and the colour pattern of A. manshuriensis are adapted to temporarily trap insects of a certain size. The hand-pollination experiment showed that flowers of this plant are capable of self-pollination by geitonogamy and require a pollinator for successful pollination. The positive value (2.64) for the pollen limitation coefficient indicates a higher fruit set after hand-pollination compared to the control without pollination. The number of visitors to the flowers was low (0.17 visitors per flower per day). Insects from three orders were observed on the flowers: Diptera (up to 90.9%), Coleoptera (8.3%), and Hymenoptera (0.8%). Four species of flies (Scaptomyza pallida, Drosophila transversa (Drosophilidae), Botanophila fugax, and Botanophila sp. 1 (Anthomyiidae)) are capable of transferring up to 2500–4000 pollen grains on their bodies and can be considered as pollinators of A. manshuriensis. Data of the rearing experiment indicate that flies of the families Drosophilidae (S. pallida, D. transversa), Chloropidae (Elachiptera tuberculifera, E. sibirica, and Conioscinella divitis), and Anthomyiidae (B. fugax, B. sp. 1) use A. manshuriensis flowers to lay eggs. Beetles were also collected from the flowers, but they were probably not involved in pollination, because no pollen grains were observed on them during our study.Conclusions – Pollinators of A. manshuriensis include mainly Diptera that lay eggs on the flowers. The poor fruit set (2%) in A. manshuriensis is associated with pollen limitation due to the lack of pollinators, as the number of visitors to flowers was extremely low. This may be due to the fact that the flowers of this species are highly specialized on insects of a certain size for pollination.


2003 ◽  
Vol 81 (1) ◽  
pp. 24-27 ◽  
Author(s):  
José L Vesprini ◽  
Leonardo Galetto ◽  
Gabriel Bernardello

Dyckia floribunda is a perennial herb from the Argentinian Chaco with extrafloral nectaries. Ants visited these nectaries while patrolling inflorescences and infructescences. We anticipated that ants attracted to extrafloral nectaries might protect the reproductive organs, increasing plant reproductive output. To evaluate the possibility of mutualism between D. floribunda and ant visitors, we determined whether ant-accessible plants showed a higher seed production than ant-excluded plants. Experimental fieldwork suggested a decrease in fruit set of ant-excluded plants compared with ant-accessible plants but the seed number per fruit was not affected by ant exclusion. Thus, total seed number per plant was highly reduced in treated spikes. Analyses of covariance confirmed these trends, indicating that total seed production per plant was strongly affected by ant exclusion. This study marks the first experimental report of this mutualistic association in Bromeliaceae.Key words: ant–plant interaction, Bromeliaceae, Chaco, Dyckia floribunda, fruit set, seed set, mutualism.


1988 ◽  
Vol 66 (1) ◽  
pp. 173-178 ◽  
Author(s):  
Terence M. Laverty ◽  
R. C. Plowright

The breeding system and determinants of fruit and seed production in a population of 114 patches of Mayapple (Podophyllum peltatum L.) were examined. Experimental crosses indicated that Mayapple patches are self-incompatible (clones) and that fruit and seed set were pollinator limited. Mayapple flowers are nectarless yet depend primarily on infrequent visits by nectar-searching bumblebees for pollination. The proportion of flowers setting fruit and ovules setting seed in Mayapple clones was inversely associated with the distance to neighboring clones and the distance to Pedicularis canadensis L. plants. Clones within 45 m of P. canadensis plants (which are heavily visited by bumblebees) showed significant increases in fruit and seed production compared with a similar group of more distant clones. This effect is interpreted as evidence for a facilitative interaction between Mayapple and P. canadensis.


2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
R. W. M. U. M. Wanigasekara ◽  
W. A. I. P. Karunaratne

Plant-pollinator interactions are often considered as tightly coevolved, mutualistic relationships. The present study aimed at determining the flower visiting bees of the vegetable crop,Solanum violaceum, and the efficiency of buzz pollination by bees on fruit and seed production in Sri Lanka. Seven bee species:Hoplonomia westwoodi,Amegilla comberi,Patellapis kaluterae,Xylocopa tenuiscapa,Apis dorsata,Trigona iridipennis, andCeratina hieroglyphicavisited the flowers ofS. violaceum, and the first four species were buzzing bees. Buzzing bees were the first to visitSolanumflowers and were followed by nonbuzzing bees. Handling time ofH. westwoodiandP. kaluteraevaried with the availability of pollen in anthers that deplete with the age of flower and stayed longer at new flowers than at old flowers. Handling time of the larger buzzing bee,H. westwoodi, was higher than that of the smallerP. kaluterae. The fruit set, seed set, and seed germinability in flowers visited by buzzing bees were significantly higher than those of the flowers bagged to exclude pollinators.


1999 ◽  
Vol 5 (3-4) ◽  
Author(s):  
Z. Szabó ◽  
J. Nyéki

The peach is though considered to be a self fertile fruit species, also some self sterile and male sterile varieties have been registered. The latter type seems to be frequently met in Asian varieties, whereas in the USA and Europe, J. H. Hale and Flaminia are grown. The purpose of the present study was the assessment of fertility relations of peaches and nectarines grown in Hungary. The authors studied, since 1974, more than 100 different peach and nectarine varieties as for fertility relations, especially their autogamous or geitonogamous fruit set on isolated, i.e. bagged flowers at bud stage, then set free after blooming finished. Isolated flowers of some varieties were also self pollinated, artificially. According to the results the varieties have been assigned to four alternative groups. Self sterile varieties in the proper sense have not been found, but partial self sterility (less than 10% fruit set), self fertility (10 to 20% fruit set) and high self fertility (more than 20% fruit set on selfed flovters) was generally met. The majority of the varieties belonged to the last two groups, nevertheless. the rate of fruit set displayed seasonal variation, the maximum was in one case 89.9%. The purposeful self (hand)pollination of the isolated flowers increased fruit set, substantially. Varieties rated as partially self-sterile are J. H. Hale and Fuzador (the former being partially male sterile too). Although in some years and some varieties, fruit set legged below 10% but according to the means the majority of nectarines are assigned to the self fertile category whereas most peach varieties, either for fresh consumption or industrial types, were highly self fertile.  


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