The Relationship between Transmitting Tissue, Pollen Tube, and Ovule Number: A Study across 10 Angiosperm Families

1999 ◽  
Vol 160 (4) ◽  
pp. 673-681 ◽  
Author(s):  
M. L. Matthews ◽  
J. Gardner ◽  
M. Sedgley
Keyword(s):  
Pollen Tube ◽  
Transmitting Tissue ◽  
Ovule Number ◽  
The Relationship

scholarly journals The synstigma turns the fig into a large flower

2020 ◽  
Vol 195 (1) ◽  
pp. 93-105
Author(s):  
Simone P Teixeira ◽  
Marina F B Costa ◽  
João Paulo Basso-Alves ◽  
Finn Kjellberg ◽  
Rodrigo A S Pereira
Keyword(s):  
Pollen Tube ◽  
Pollen Grains ◽  
Pollen Tubes ◽  
Live Cells ◽  
Fig Wasp ◽  
Fig Wasps ◽  
Floral Structure ◽  
Transmitting Tissue ◽  
Transmission Electron ◽  
Large Flower

Abstract The synstigma is a structure formed by clusters of two to several stigmas, whether in the same or between different flowers. Although rare in angiosperms, synstigmas are found in c. 500 out of the c. 750 Ficus spp. (Moraceae). This floral structure is associated with fig-fig wasp pollinating mutualism. The synstigma structure and pollen tube pathways were studied in six Ficus spp. from Ficus section Americanae to test the hypothesis that the synstigma allows pollen grains deposited on a stigma to emit pollen tubes that can grow laterally and fertilize surrounding flowers. Syconia containing recently pollinated stigmas were collected and dissected, and the stigmas were processed for analyses with light and scanning and transmission electron microscopy. The arrangement of the synstigmas across species can be spaced or congested, with the number of stigmas per synstigma ranging from two to 20. Contact between the stigmas in a synstigma occurs by the intertwining of the stigmatic branches and papillae; their union is firm or loose. The pollen tube grows through live cells of the transmitting tissue until reaching the ovule micropyle. Curved pollen tubes growing from one stigma to another were observed in five out of the six species studied. The curvilinear morphology of pollen tubes probably results from competition by pollen between the stigmas composing a synstigma via chemotropic signals. The synstigma appears to be a key adaptation that ensures seed production by flowers not exploited by the fig wasps in actively pollinated Ficus spp.

scholarly journals Localised and non-localised promotion of fruit development by seeds in Arabidopsis

2006 ◽  
Vol 33 (1) ◽  
pp. 1 ◽  
Author(s):  
Catherine M. Cox ◽  
Stephen M. Swain
Keyword(s):  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Seed Set ◽  
Fruit Size ◽  
Fruit Growth ◽  
Tube Growth ◽  
Gene Encoding ◽  
Pollen Tube Elongation ◽  
The Relationship ◽  
Silique Length

In Arabidopsis, as in the majority of flowering plants, developing seeds promote fruit growth. One method to investigate this interaction is to use plants with reduced seed set and determine the effect on fruit growth. Plants homozygous for a transgene designed to ectopically express a gene encoding a gibberellin-deactivating enzyme exhibit reduced pollen tube elongation, suggesting that the plant hormone gibberellin is required for this process. Reduced pollen tube growth causes reduced seed set and decreased silique (fruit) size, and this genotype is used to explore the relationship between seed set and fruit elongation. A detailed analysis of seed set in the transgenic line reveals that reduced pollen tube growth decreases the probability of each ovule being fertilised. This effect becomes progressively more severe as the distance between the stigma and the ovule increases, revealing the complex biology underlying seed fertilisation. In terms of seed-promoted fruit growth, major localised and minor non-localised components that contribute to final silique length can be identified. This result demonstrates that despite the relatively small size of the fruit and associated structures, Arabidopsis can be used as a model to investigate fundamental questions in fruit physiology.

scholarly journals Effect of pistil age on pollen tube growth, fruit development and seed set in Cucurbita pepo L.

2014 ◽  
Vol 70 (3) ◽  
pp. 165-172 ◽  
Author(s):  
Ettore Pacini ◽  
Massimo Nepi
Keyword(s):  
Pollen Tube ◽  
Fruit Development ◽  
Pollen Tube Growth ◽  
Cucurbita Pepo ◽  
Seed Set ◽  
Fruit Weight ◽  
Tube Growth ◽  
Transmitting Tissue ◽  
Stigma Receptivity ◽  
Different Parts

The effects of pistil age on pollen tube growth, fruit development and seed set were studied in <em>Cucurbita pepo</em> L., the flower of which opens for only six hours. Stigma receptivity lasts four days, from one day before until two days after anthesis. Style receptivity lasts three days, from the day before to the day after anthesis. Ovule receptivity lasts two days: the day of anthesis and the day before. The rate of pollen tube growth varies in different parts of the pistil and in relation to pistil age. In the stigmatic and stylar region, the tubes grow faster if pollination occurs the day before anthesis; in the ovary they grow faster when pollination occurs at anthesis. In the receptacle region, where the transmitting tissue is reduced, the growth rate decreases independently of the time of pollination. The fruits are larger and heavier with more seeds when pollination occurs at anthesis. There is a positive correlation between seed number and fruit weight when pollination occurred at anthesis and the day before.

Pseudo-self-compatibility in Ultraviolet-irradiated Plants of Primula Acaulis (‘pin’ morph)

1990 ◽  
Vol 95 (4) ◽  
pp. 659-665
Author(s):  
LUISA CARRARO ◽  
P. D. GEROLA ◽  
GIULIANA LOMBARDO ◽  
F. M. GEROLA
Keyword(s):  
Pollen Tube ◽  
Peroxidase Activity ◽  
Central Portion ◽  
Transmitting Tissue ◽  
Incompatible Pollen ◽  
Self Pollination ◽  
Rejection Mechanism ◽  
Self Compatibility ◽  
Apoplastic Peroxidase ◽  
Incompatible Pollen Tube

Apoplastic peroxidase distribution in transmitting tissue of the stylar ‘neck’ was investigated using the DAB cytochemical reaction applied to electron microscopy in non-, self- and cross-pollinated pistils of Primula acaulis (‘pin’ morph) exposed or not to ultraviolet (u.v.) irradiation. In non-irradiated flowers, apoplastic peroxidase activity, which is present in non-pollinated pistils, is increased by self-pollination, whereas cross-pollination causes its disappearance from the central portion of the transmitting tissue. Apoplastic peroxidases localized in the central portion of the transmitting tissue are supposed to play a role in the predisposition of the pistil to reject incompatible pollen tubes and in the rejection mechanism itself. Pistil irradiation with u.v., which induces pseudo-self-compatibility, modified the aforementioned apoplastic peroxidase distribution. Shortly after u.v. irradiation of nonpollinated styles, apoplastic peroxidase activity was absent from the central portion of the transmitting tissue; some hours later peroxidase activity was restored, and 40 h after treatment, the ‘normal’ peroxidase distribution was observed. Our data suggest an u.v.-induced temporary removal of the ‘predisposition for incompatible pollen tube rejection. Moreover, soon after irradiation, the usually observed peroxidase production due to self-pollination was inhibited. Pseudo-self-compatibility, observed when self-pollination was carried out immediately after u.v. irradiation, was due to incompatible pollen tube elongation in a transmitting tissue devoid of apoplastic peroxidases and hindered in the rejection mechanism. However, pseudo-self-compatible pollen tube growth was not accompanied by the dramatic changes in transmitting tissue ultrastructure observed after compatible cross-pollination. The data indicate that, even if incompatible pollen tubes are not ‘rejected’, they are still ‘recognized’ and hindered in their absorption of cellular reserves from the transmitting tissue.

Pollen load, capsule weight, and seed production in three orchid species

1994 ◽  
Vol 72 (2) ◽  
pp. 249-255 ◽  
Author(s):  
H. C. Proctor ◽  
L. D. Harder
Keyword(s):  
Reproductive Success ◽  
Seed Production ◽  
Pollen Deposition ◽  
Pollen Load ◽  
Seed Number ◽  
Orchid Species ◽  
Liquid Suspension ◽  
Ovule Number ◽  
Cypripedium Calceolus ◽  
The Relationship

Relationships between pollen load, seed production, and capsule weight in orchids are important both theoretically and pragmatically. It has been hypothesized that pollen packets (pollinia) evolved in orchids because of selection to produce packages capable of fertilizing all ovules in an ovary; testing this hypothesis requires information about the relationship between pollen load and seed production. As well, because capsules contain thousands to millions of seeds, an easily measured correlate of seed number, such as capsule weight, would be valuable for studies of reproductive success. We hand-pollinated Cypripedium calceolus, Amerorchis rotundifolia, and Calypso bulbosa with different pollen loads, weighed capsules, and estimated seed number by subsampling from liquid suspension. Pollen load affected seed number in Calypso but had no significant effect in Cypripedium or Amerorchis. Capsule weight was positively associated with seed number in all species, but there was considerable variation in R2 across species (from 0.40 to 0.85), indicating that it is unwise to assume that capsule weight is a good measure of relative reproductive success. As well, our data suggest that size of the typical unit of pollen deposition rather than that of the entire pollinarium evolved to match ovule number in orchids. Key words: Orchidaceae, pollen load, capsule weight, seed set.

Pollen Tube Growth and Early Seed Development in Eucalyptus regnans F. Muell. (Myrtaceae) in Relation to Ovule Structure and Preferential Outcrossing

1989 ◽  
Vol 37 (5) ◽  
pp. 397 ◽  
Author(s):  
M Sedgley ◽  
FC Hand ◽  
RM Smith ◽  
AR Griffin
Keyword(s):  
Pollen Tube ◽  
Phase Contrast ◽  
Pollen Tubes ◽  
Central Canal ◽  
Transmitting Tissue ◽  
Bright Field ◽  
Eucalyptus Regnans ◽  
Cross Pollination ◽  
Early Seed Development ◽  
Scanning Electron

Pistils of Eucalyptus regnans were observed by bright field, fluorescence, phase contrast, Nomarski, and scanning electron microscopy from 4 weeks prior to anthesis to 16 weeks after self- and cross- pollination. The transmitting tissue of the style had a central canal which extended for half its length. The unfertilised ovary contained a mean of 30.5 ovular structures with 16.5 normal ovules, 2.5 abnor- mal ovules, and 11.5 sterile ovulodes. The ovules were arranged in two rows in three (occasionally four) locules. The ovulodes always occupied positions at the stylar end of the ovary, but with this exception there was no pattern to the occurrence of the abnormal ovules. Pollen tubes grew between the cells'of the transmitting tissue, and not in the stylar canal. Penetration of the ovules had commenced by 5 days after both self- and cross-pollination. The early fertilised ovule contained a zygote and free-nuclear endosperm, and embryos with between 1 and 16 cells were present at 16 weeks after pollination. Not all normal ovules were fertilised, despite adequate numbers of pollen tubes. Ovulodes were never observed to be penetrated by a pollen tube, but with this exception there was no relationship between position on the placenta and either the penetration of ovules by a pollen tube or the occurrence of fertilised ovules. There was no difference between self- and cross-pollination in either the number of ovules penetrated by a pollen tube, or the number of fertilised ovules up to 16 weeks following pollination.

Timetable of Stigmatic Receptivity and Development and Pollen Tube Growth in Chamelaucium uncinatum (Myrtaceae)

1996 ◽  
Vol 44 (6) ◽  
pp. 649 ◽  
Author(s):  
SP Obrien
Keyword(s):  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Pollen Tubes ◽  
The Self ◽  
Transmitting Tissue ◽  
Short Side ◽  
Secondary Pollen Presentation ◽  
Pollen Presentation ◽  
Days After Anthesis ◽  
Chamelaucium Uncinatum

The stigma of Chamelaucium uncinatum Schauer is small and unreceptive at anthesis, but increases in size and becomes fully receptive 7 days after anthesis. After germination, pollen tubes grow intercellularly through the stigma and transmitting tissue of the style. Chamelaucium uncinatum has a single loculus containing six ovules with axile placentation. The transmitting tissue skews to one side within the ovary and the pollen tubes grow into the placenta via an invagination along one end of the loculus. Pollen tubes are smooth-walled in the transmitting tissue of the style and ovary, but within the loculus pollen tubes produce short side branches. Secondary pollen presentation occurs in C. uncinatum with the stigmatic region being used as a pollen presenter. If the self-pollen is not removed from the stigma prior to the onset of receptivity self-pollination may occur.

scholarly journals Are obligatory apomicts invested in the pollen tube transmitting tissue? Comparison of the micropyle ultrastructure between sexual and apomictic dandelions (Asteraceae, Lactuceae)

PROTOPLASMA ◽  
2015 ◽  
Vol 252 (5) ◽  
pp. 1325-1333 ◽  
Author(s):  
Bartosz J. Płachno ◽  
Piotr Świątek ◽  
Małgorzata Kozieradzka-Kiszkurno ◽  
Ľuboš Majeský ◽  
Jolanta Marciniuk ◽  
...  
Keyword(s):  
Pollen Tube ◽  
Transmitting Tissue

Interspecific and Intergeneric Pistil - Pollen Compatibility of Banksia coccinea (Proteaceae)

1998 ◽  
Vol 46 (4) ◽  
pp. 453 ◽  
Author(s):  
T. L. Maguire ◽  
M. Sedgley
Keyword(s):  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Tube Growth ◽  
Related Genus ◽  
Reciprocal Effect ◽  
Pollination Success ◽  
Intergeneric Crosses ◽  
Close Relationship ◽  
Species Groups ◽  
The Relationship

Interspecific and intergeneric pollen-tube growth was investigated using controlled hand pollinations of Banksia coccinea R.Br., 35 species of Banksia L.f., and three species of the related genus Dryandra R.Br. Currently, the relationship between B. coccinea and other species groups within Banksia is unclear. Some species supported no germination of B. coccinea pollen, some supported normal pollen-tube growth and others produced pollen-tube abnormalities including thickened walls, bulbous swellings, directionless growth, burst tips and branched tubes. Control of pollen-tube growth in the pistil was imposed in the pollen presenter and upper style. There was no significant reciprocal effect on pollination success in the lower style. The results of pollen-tube compatability in the lower style indicated that B. coccinea has a closer affinity to the section Oncostylis, than the section Banksia where it is currently placed. Intergeneric crosses of B. coccinea with Dryandra species resulted in some compatibility, with one cross having low numbers of pollen-tubes in the pollen presenter and upper style region. These results indicate a close relationship between Banksia and Dryandra, which are sister genera in the tribe Banksiae, family Proteaceae.

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