Buzz pollination in the Epacridaceae

2002 ◽  
Vol 50 (1) ◽  
pp. 83 ◽  
Author(s):  
T. F. Houston ◽  
P. G. Ladd
Keyword(s):  
Seed Set ◽  
Corolla Tube ◽  
Pollen Tubes ◽  
Pollination Syndrome ◽  
Native Bees ◽  
Buzz Pollination ◽  
The Family

Conostephium (Epacridaceae) has flowers that conform with a buzz-pollination syndrome but, unlike most plants with this form of pollination, the anthers are hidden within the corolla tube. Vibrations generated by bees grasping the apices of the corolla tubes must be transferred via short broad filaments to the anthers. The anthers do not have pores but each dehisces from the apex by a slit that elongates over the time the flowers take to senesce (up to 10 days). This may limit self-fertilisation as the stigma is receptive as soon as it appears from between the very short corolla lobes, so little pollen is released at first but later this would increase as the slit elongates. Visitation by pollinators has rarely been seen but several observations of native bees (Leioproctus and Lasioglossum) working the flowers are presented. The bees visit the nectarless flowers of Conostephium only for pollen and must forage at other kinds of flowers to obtain nectar. Pollen tubes occurred in the stigmas of most older flowers of C. pendulum, so pollen delivery does not seem to limit seed set. Despite this, the species sets few fruit. From examination of the taxonomic positions of likely buzz-pollinated taxa in the family, it appears that pollination by sonication has arisen independently several times in the Epacridaceae, with primarily two different floral configurations.

scholarly journals Reproductive systems and post-pollination barriers between two closely related eu-bromelioids (Bromeliaceae) in the Atlantic Forest of Brazil

2019 ◽  
Vol 192 (4) ◽  
pp. 828-839
Author(s):  
Brayan Paiva Cavalcante ◽  
Everton Hilo De Souza ◽  
Joseph Hill Williams ◽  
Leonardo M Versieux
Keyword(s):  
Seed Set ◽  
Rapid Evolution ◽  
Pollen Tubes ◽  
Breeding Systems ◽  
Intergeneric Hybridization ◽  
Reproductive Barriers ◽  
Closely Related Species ◽  
Heterospecific Pollen ◽  
The Family ◽  
Self Compatibility

Abstract The eu-bromelioid clade provides a classic example of an exceptionally rapid radiation, in which many closely related species are found in sympatry. In this respect, species cohesion may be due to the rapid evolution of strong reproductive barriers, although interspecific and intergeneric hybridization is observed in the family. The objective of this study was to characterize the breeding systems and post-pollination reproductive barriers in Wittmackia patentissima and Hohenbergia ridleyi. Previously included in Aechmea, they show an almost complete absence of pre-pollination barriers, although their recent divergence may not have allowed time for complete ecological/reproductive isolation to have evolved. In manual pollinations, both species had > 40% fruit set in self and outcross treatments, but seed set from manual self-pollinations was < 50% that of outcrosses, and spontaneous self-pollination produced fewer than three seeds per fruit. Self-pollen and pollen tubes showed no evidence of self-incompatibility, but heterospecific pollen tubes were arrested in the lower part of the style and heterospecific seed set was zero in both species. The combination of self-compatibility and strong post-pollination, pre-fertilization reproductive barriers is consistent with the involvement of breeding system reproductive barriers in allowing closely related bromeliad species to occur in sympatry.

Early events in the embryo sac after intraspecific and interspecific pollinations in Rhododendron kawakamii and R. retusum

1986 ◽  
Vol 64 (2) ◽  
pp. 282-291 ◽  
Author(s):  
V. Kaul ◽  
J. L. Rouse ◽  
E. G. Williams
Keyword(s):  
Seed Set ◽  
Embryo Sac ◽  
Pollen Tubes ◽  
Interspecific Crosses ◽  
Primary Endosperm Nucleus ◽  
Kalmia Latifolia ◽  
Taxonomic Grouping ◽  
Similarities And Differences ◽  
Normal Fertilization

Early events in the embryo sac of Rhododendron kawakamii and R. retusum have been studied after compatible self-pollinations and eight interspecific crosses, using sectioned ovaries, pistil squashes, and seed-set data. Ovules of Rhododendron kawakamii and R. retusum are anatropous, unitegmic, and tenuinucellate, with a typical eight-nucleate, seven-celled embryo sac. Fertilization normally occurs 4–5 days after pollination. The zygote lays down a callose wall but remains undivided during the first 13–15 days after pollination. The primary endosperm nucleus divides soon after fertilization, and development is cellular ab initio. Crosses of R. kawakamii (♂) with R. santapaui and R. retusum and crosses of R. retusum (♂) with R. kawakamii, R. santapaui, R. ovatum, and R. tashiroi showed apparently normal fertilization in a majority of ovules entered by pollen tubes. In crosses of R. kawakamii (♂) with R. quadrasianum and Kalmia latifolia entry of pollen tubes into ovules was delayed and frequently abnormal. Apart from compatible self-pollinations of R. kawakamii an R. retusum, only the cross of R. kawakamii (♂) with R. santapaui produced healthy seedlings. Of the remaining seven interspecific crosses only three showed significant embryo development in control pistils left to mature in situ. Similarities and differences in the breeding behaviour of R. kawakamii and R. retusum are discussed with reference to their taxonomic grouping within subsection Pseudovireya.

The possible role of embryo sac degeneration in yield reduction of summer turnip rape cultivar Candle

1995 ◽  
Vol 75 (3) ◽  
pp. 595-598
Author(s):  
Xiuying Tian ◽  
L. Van Caeseele ◽  
M. J. Sumner
Keyword(s):  
Brassica Rapa ◽  
Seed Set ◽  
Embryo Sac ◽  
Pollen Tubes ◽  
Yield Reduction ◽  
Turnip Rape ◽  
Key Words:Brassica

When pollination occurred within 24 h after anthesis, 69.2% of the pods of Brassica rapa cultivar Candle contained at least 50% fertilized ovules. If pollination occurred later than 4 d after anthesis, an occasional ovule near the base of the pistil was fertilized; however, no significant seed set was observed. Pollen tubes were observed entering the locules of the ovary from pollinations carried out as late as 5 d after anthesis. At 3 d after anthesis, in unpollinated flowers, a general deterioration of the embryo-sac contents began and gradually increased to include integumentary cells by 6 d after anthesis. Some ovules swelled as though they were fertilized, but no embryos were present. The results suggest that yield reductions in this species may occur because of the reduction of fertilization potential through rapid degeneration of embryo sacs following anthesis. Key words:Brassica rapa, embryo sac, yield

Breeding Systems of Disjunct Populations of Christmas Bells (Blandfordia grandiflora R.Br., Liliaceae): Variation in Self-Fertility and an Ovular Mechanism Regulating Self-Fertilisation

1993 ◽  
Vol 41 (1) ◽  
pp. 35 ◽  
Author(s):  
M Ramsey ◽  
N Prakash ◽  
S Cairns
Keyword(s):  
Seed Set ◽  
Pollen Tubes ◽  
Breeding Systems ◽  
Seed Abortion ◽  
Self Incompatibility ◽  
Coastal Plants ◽  
Hand Pollination ◽  
Disjunct Populations ◽  
Pollen Vectors ◽  
Blandfordia Grandiflora

The breeding systems of disjunct tableland and coastal populations of Christmas bells were determined using hand-pollination experiments. In both populations, 90% or more of self-pollinated plants produced seeds. Tableland plants were significantly more self-fertile than coastal plants (ratio of self seed set to cross seed set: tableland, 0.55 ± 0.03; coast, 0.08 ± 0.02). Significant variation among plants for self-fertility was found in both populations. Autofertility was 1.6% or less in both populations indicating that pollen vectors are necessary for seed set. Seed set by agamospermy in both populations was less than 0.1%. Percentage seed abortion was greater in self-pollinated plants than cross-pollinated plants in both populations. In both self- and cross-pollinated plants, seed abortion was twice as great in the coastal population than in the tableland population. No evidence was found for stigmatic or stylar self-incompatibility. Self and cross pollen adhered to and germinated equally well on stigmas in both populations (72 - 77% germination). Similarly, there were no differences between pollination treatments or populations in the percentage of ovules penetrated by pollen tubes (82 - 89% penetration). When self-pollination preceded cross-pollination by 24 h or longer seed set was significantly reduced compared to flowers that were cross-pollinated only, suggesting ovules were pre-empted by self pollen tubes. Collectively these results strongly suggest that self seed set was reduced by a mechanism operating at the ovule level, such as early-acting inbreeding depression due to recessive seed-aborting genes, although incomplete late-acting self-incompatibility cannot be ruled out. For coastal plants, this ovular mechanism largely prevents selfing, indicating plants were predominantly outcrossing although most produced some self seed. For tableland plants, substantial seed set by selfing may occur under natural conditions.

scholarly journals Self-incompatibility in Cornus florida

HortScience ◽  
2004 ◽  
Vol 39 (2) ◽  
pp. 335-338 ◽  
Author(s):  
Sandra M. Reed
Keyword(s):  
Growth Rate ◽  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Seed Set ◽  
Pollen Tubes ◽  
Cornus Florida ◽  
Self Incompatibility ◽  
Flowering Dogwood ◽  
Pollen Tube Growth Rate ◽  
Upper Third

Low seed set has been reported following self-pollinations of flowering dogwood (Cornus florida L.). The objective of this study was to verify the presence of self-incompatibility in C. florida. `Cherokee Princess' stigmas and styles were collected 1, 2, 4, 8, 12, 24, 48, and 72 hours after cross- and self-pollinations, stained with aniline blue and observed using a fluorescence microscope. Pollen germinated freely following self-pollinations, but self-pollen tubes grew slower than those resulting from cross-pollinations. By 48 hours after cross-pollination, pollen tubes had reached the bottom of the style while pollen tubes in self-pollinated flowers had only penetrated the upper third of the style. Evidence of reduced pollen tube growth rate in self-pollinations of `Cherokee Chief' and `Cherokee Brave' was also obtained. This study provides evidence of a gametophytic self-incompatibity system in C. florida. It was also determined that stigmas of C. florida `Cherokee Princess' are receptive to pollen from 1 day prior to anthesis to 1 day after anthesis.

scholarly journals Bee Visitation on Flowers in Maine, United States, Reveals the Relative Attractiveness of Plants Through Space and Time: Part I

2020 ◽  
Vol 49 (3) ◽  
pp. 726-737
Author(s):  
Alison C Dibble ◽  
Francis A Drummond ◽  
Lois Berg Stack
Keyword(s):  
Apis Mellifera ◽  
Habitat Restoration ◽  
Native Bees ◽  
Borago Officinalis ◽  
Melilotus Officinalis ◽  
Species Analysis ◽  
The Family ◽  
Relative Attractiveness ◽  
Plant Taxon ◽  
Time Part

Abstract Bee reservoirs can be effective in agricultural and habitat restoration projects, but the relative attractiveness of plants is not fully understood. To improve plant selection with better knowledge of spatial, temporal, and competition aspects, we tested up to 90 plant subjects from 2012 to 2015 at four sites in Maine. We recognized Apis mellifera L., Bombus ternarius Say, 1837, ‘Most Bombus’ (except B. ternarius), ‘Halictidae’ and ‘Other Bees’ (collectively the so-called ‘bee groups’) on open flowers in three 1-min periods per site and day, with numerous repeated observations per plant taxon. In 14,311 observations, we recorded 17,792 bees in 61 species. Most-visited plants included Asclepias tuberosa, Borago officinalis, Clethra alnifolia cv. Hummingbird (especially by A. mellifera), Melilotus officinalis, Origanum vulgare, Rosa palustris (especially before 1400 hours), Spiraea alba var. latifolia, and taxa in the family Asteraceae. Early-flowering shrubs were visited, especially by ‘Other Bees’. Bee groups each ranked plants uniquely, with some overlap, and differed in most-visited of six plant taxa that we had included in all 4 yr and sites. For ‘All Bees’ among 84 plant taxa, the most-visited plants were M. officinalis (June), A. tuberosa (July), and C. alnifolia (August). Indicator Species Analysis revealed low bee fidelity to host plants for all but a few plant taxa. Apis mellifera differed from native bees in plants it visited intensively, with some overlap (e.g., A. tuberosa), and was associated with increased visitation on seven plant taxa by ‘Most Bombus’ and B. ternarius.

Hedyotis dinganensis, a new species of Rubiaceae from Hainan, China

Phytotaxa ◽  
2019 ◽  
Vol 399 (1) ◽  
pp. 44
Author(s):  
QINGLONG WANG ◽  
LANGXING YUAN ◽  
HUAN TANG ◽  
ZHUNIAN WANG ◽  
MAOYUAN WANG ◽  
...  
Keyword(s):  
New Species ◽  
Corolla Tube ◽  
Critically Endangered ◽  
Iucn Categories ◽  
The Family ◽  
Inflorescence Terminal ◽  
A New Species

Hedyotis dinganensis, a new species of the family Acanthaceae is described and illustrated from Hainan, China. It is most similar to H. yazhouensis and H. paridifolia, but can be easily distinguished from the latter by the inflorescence terminal or upper axillary congested-cymose, capitate, or fasciculate, the calyx 7–8 mm long, the corolla tube ca. 8 mm, the stipules triangular to broadly triangular ca.10 mm long, marginally entire to glandular-serrate, acuminate or with 8–10 narrowly triangular to linear lobes or bristles 1–7 mm long, the stigmas exserted ca. 1.2 mm. The new species is accessed as as ‘Critically Endangered’ (CR) according to IUCN categories and criteria.

scholarly journals Morphology of Anemone sylvestris L. flower (Ranunculaceae)

2016 ◽  
Vol 75 (1) ◽  
pp. 74-80 ◽  
Author(s):  
Bożena Denisow ◽  
Sebastian Antoń ◽  
Małgorzata Wrzesień
Keyword(s):  
Seed Set ◽  
Pollen Dispersal ◽  
Pollen Grains ◽  
Starch Accumulation ◽  
Pollination Syndrome ◽  
Wind Pollination ◽  
Intermediate Form ◽  
Protected Species ◽  
Large Size ◽  
Opening And Closing

Abstract During the monitoring of populations of Anemone sylvestris L. (Ranunculaceae), a protected species in Poland, we found that the seed set is impaired. The flower is considered an adaptation that has coevolved to achieve effective pollination and successful fertilization. Therefore we have focused on the morphological and anatomical characteristics of the flowers of A. sylvestris L. as a prelude to the study of the species’ pollination biology and plant breeding system. The large size of the flower (50.6 ± 16.4 mm in dimensions) and its bowl shape fulfil both the biotic pollination syndrome and the aerodynamic requirements for pollen dispersal and capture. The opening and closing of the perianth provide a shelter for beetles. The odourless perianth, absence of nectar, scarcity of pollen (approximately 200 000 pollen grains per flower) and its traits - small size (axis P = 18.52 ± 1.0 μm; E = 16.59 ± 0.9 μm), lack of balsam on the exine surface, starch accumulation in more than 95% of pollen grains correspond to the specialization in anemophily. The stigma is papillous, the dense hairs are situated between single carpels indicating adaptation to capturing dry pollen and specialization in the wind pollination syndrome. The flower of A. sylvestris is an example for an intermediate form between entomophily and anemophily, i.e. a secondary and more advanced feature among Ranunculaceae.

scholarly journals Efficiency of Buzzing Bees in Fruit Set and Seed Set ofSolanum violaceumin Sri Lanka

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
R. W. M. U. M. Wanigasekara ◽  
W. A. I. P. Karunaratne
Keyword(s):  
Sri Lanka ◽  
Seed Production ◽  
Fruit Set ◽  
Seed Set ◽  
Handling Time ◽  
Apis Dorsata ◽  
Buzz Pollination ◽  
Vegetable Crop ◽  
Flower Visiting ◽  
Plant Pollinator

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.

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