scholarly journals Self-incompatibility and Time of Stigma Receptivity in Two Species of Hydrangea

HortScience ◽  
2004 ◽  
Vol 39 (2) ◽  
pp. 312-315 ◽  
Author(s):  
Sandra M. Reed
Keyword(s):  
Seed Set ◽  
Pollen Tubes ◽  
Tube Length ◽  
Self Incompatibility ◽  
Stigma Receptivity ◽  
Self Pollination ◽  
Incompatibility System ◽  
Self Compatibility ◽  
Days After Anthesis ◽  
Pollen Tube Length

The objectives of this study were to evaluate self-incompatibility in Hydrangea paniculata Sieb. and H. quercifolia Bartr. and to determine optimum time for pollination of these two species. Flowers from three genotypes of each species were collected 1, 2, 4, 8, 24, 48, and 72 hours after cross- and self-pollination, stained with aniline blue and observed using a fluorescence microscope. In both species, pollen germination was observed on stigmas of over half of the flowers collected 4 to 72 hours after cross- or self-pollination. Differences in pollen tube length between cross- and self-pollinated flowers were noted from 8 to 72 hours after pollination in H. paniculata and from 24 to 72 hours after pollination in H. quercifolia. By 72 hours after pollination, most self-pollen tubes had only penetrated the top third of the style but cross-pollen tubes had grown to the base of the style and entered 40% to 60% of the ovules. Stigmas of H. paniculata were receptive to pollen from anthesis to 5 days after anthesis, while stigmas of H. quercifolia were receptive from 1 to 5 days after anthesis. This study provides evidence of a gametophytic self-incompatibility system in H. paniculata and H. quercifolia. Occasional self-seed set previously observed in these species was theorized to have been due to pseudo-self compatibility.

scholarly journals Reproductive Biology of Clethra alnifolia

HortScience ◽  
2006 ◽  
Vol 41 (3) ◽  
pp. 567-570
Author(s):  
Sandra M. Reed
Keyword(s):  
Seed Set ◽  
Pollen Tubes ◽  
Self Incompatibility ◽  
Stigma Receptivity ◽  
Flower Opening ◽  
Lack Of Information ◽  
Incompatibility System ◽  
Self Compatibility ◽  
Pollen Shed ◽  
The Relationship

Breeding efforts in Clethra alnifolia L., an ornamental shrub native to the Eastern U.S., are hindered by a lack of information on the reproductive behavior of this species. The objective of this study was to evaluate self-compatibility, time of stigma receptivity, and the relationship between time of pollen shed and stigma receptivity in C. alnifolia. Stigma receptivity and changes in floral morphology were monitored over a 7-day period beginning at flower opening. Pollen germination and pollen tube growth in styles were examined following self- and cross-pollinations using fluorescence microscopy. Seed set and germination were compared following self- and cross-pollinations. Anthers began to dehisce in `Hummingbird' and `Ruby Spice' the day after flowers opened, but stigmas did not become fully receptive to pollen until 2 days later. An increase in the length of pistils was observed following flower opening. Maximum elongation of pistils occurred at approximately the same time stigmas became receptive and could be utilized as an indicator of receptivity. While self-pollen tubes appeared to grow slightly slower than cross-pollen tubes, there was no indication of a self-incompatibility system acting at the stigmatic or stylar level in C. alnifolia. Self-pollinations of `Hummingbird' and `Ruby Spice' produced fewer seeds than did cross-pollinations of these cultivars. Germination of all seed obtained from this study was too poor to allow a comparison of germination rates of the self- and cross-pollinated seed. However, because a few self-progeny were obtained, emasculation is recommended when making controlled pollinations. The presence of a late acting self-incompatibility system or early-acting inbreeding depression was proposed as being responsible for the lower seed set following self-pollination.

scholarly journals (239) Evaluation of Self-compatibility in Clethra alnifolia

HortScience ◽  
2006 ◽  
Vol 41 (4) ◽  
pp. 1040C-1040
Author(s):  
Sandra M. Reed
Keyword(s):  
Reproductive Behavior ◽  
Pollen Germination ◽  
Native Species ◽  
Seed Set ◽  
Pollen Tubes ◽  
Self Incompatibility ◽  
Lack Of Information ◽  
Incompatibility System ◽  
Self Compatibility ◽  
Deciduous Shrub

Clethra alnifolia, which is commonly known as summersweet, is an attractive deciduous shrub that produces fragrant flower in mid-summer. Breeding efforts are hampered by a lack of information on the reproductive behavior of this native species. The objective of this study was to evaluate self-compatibility in C. alnifolia. Pollen germination and pollen tube growth in styles were examined following self- and cross-pollinations using fluorescence microscopy. Seed set and germination were compared following self- and cross-pollinations. While self-pollen tubes appeared to grow slightly slower than cross-pollen tubes, there was no indication of a self-incompatibility system acting at the stigmatic or stylar level in C. alnifolia. Self-pollinations of `Hummingbird' and `Ruby Spice' produced fewer seeds than did cross-pollinations of these cultivars. Germination of all seed obtained from this study was too poor to allow a comparison of germination rates of the self- and cross-pollinated seed. However, because a few self-progeny were obtained, emasculation is recommended when making controlled pollinations. The presence of a late-acting self-incompatibility system or early acting inbreeding depression was proposed as being responsible for the lower seed set following self-pollination.

scholarly journals Pollination Biology of Hydrangea macrophylla

HortScience ◽  
2005 ◽  
Vol 40 (2) ◽  
pp. 335-338 ◽  
Author(s):  
Sandra M. Reed
Keyword(s):  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Pollen Germination ◽  
Pollen Tubes ◽  
Tube Growth ◽  
Self Incompatibility ◽  
Stigma Receptivity ◽  
Hydrangea Macrophylla ◽  
Significant Difference ◽  
Days After Anthesis

Little information is available on the reproductive behavior of Hydrangea macrophylla (Thunb. Ex J.A. Murr.) Ser. The objectives of this study were to investigate time of stigma receptivity, viability of pollen from sterile flowers, and self-incompatibility in this popular ornamental shrub. Pollen germination and pollen tube growth in styles were examined using fluorescence microscopy. Stigma receptivity was examined in cross-pollinations made from 1 day before anthesis to 8 days after anthesis. Maximum stigma receptivity for the two cultivars examined occurred from anthesis to 4 days after anthesis. Viability of pollen from sterile flowers was evaluated through pollen staining and observations of pollen tube growth. No significant difference in percent stainable pollen between fertile and sterile flowers was observed in any of the six taxa examined. Pollen germination and pollen tube growth were studied in cross-pollinations made using pollen from fertile and sterile flowers of two cultivars. For both cultivars, pollen tubes from fertile and sterile flowers grew to the same length and had entered ovules by 72 hours after pollination. Self-incompatibility was evaluated by comparing pollen germination and pollen tube growth in cross- and self-pollinations. In the five taxa examined, self pollen tubes were significantly shorter than cross pollen tubes in flowers that were examined 72 hours after pollination. This finding indicates the presence of a gametophytic self-incompatibility system in H. macrophylla.

scholarly journals Cytological Observation and Transcriptome Comparative Analysis of Self-Pollination and Cross-Pollination in Dendrobium Officinale

Genes ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 432
Author(s):  
Yaling Chen ◽  
Benchang Hu ◽  
Fantao Zhang ◽  
Xiangdong Luo ◽  
Jiankun Xie
Keyword(s):  
Pollen Tubes ◽  
The Self ◽  
Dendrobium Officinale ◽  
Self Incompatibility ◽  
Related Gene ◽  
Cytological Observation ◽  
Lectin Receptor ◽  
Cross Pollination ◽  
Self Pollination ◽  
Medicinal Value

Dendrobium officinale is a rare and traditional medicinal plant with high pharmacological and nutritional value. The self-incompatibility mechanism of D. officinale reproductive isolation was formed in the long-term evolution process, but intraspecific hybridization of different germplasm resources leads to a large gap in the yield, quality, and medicinal value of D. officinale. To investigate the biological mechanism of self-incompatibility in D. officinale, cytological observation and the transcriptome analysis was carried out on the samples of self-pollination and cross-pollination in D. officinale. Results for self-pollination showed that the pollen tubes could grow in the style at 2 h, but most of pollen tubes stopped growing at 4 h, while a large number of cross-pollinated pollen tubes grew along the placental space to the base of ovary, indicating that the self-incompatibility of D. officinale may be gametophyte self-incompatibility. A total of 63.41 G basesum of D. officinale style samples from non-pollinated, self-pollination, and cross-pollination by RNA-seq were obtained, and a total of 1944, 1758, and 475 differentially expressed genes (DEGs) in the comparison of CK (non-pollinated) vs. HF (cross-pollination sample), CK vs. SF (self-pollination sample) and SF vs. HF were identified, respectively. Forty-one candidate genes related to self-incompatibility were found by function annotation of DEGs, including 6 Ca2+ signal genes, 4 armed repeat containing (ARC) related genes, 11 S-locus receptor kinase (SRK) related genes, 2 Exo70 family genes, 9 ubiquitin related genes, 1 fatty acid related gene, 6 amino acid-related genes, 1 pollen-specific leucine-rich repeat extensin-like protein (LRX) related gene and 1 lectin receptor-like kinases (RLKs) related gene, showed that self-incompatibility mechanism of D. officinale involves the interaction of multiple genes and pathways. The results can provide a basis for the study of the self-incompatibility mechanism of D. officinale, and provide ideas for the preservation and utilization of high-quality resources of D. officinale.

Pollen flow in distylous populations of Amsinckia (Boraginaceae)

1976 ◽  
Vol 54 (22) ◽  
pp. 2530-2535 ◽  
Author(s):  
Fred R. Ganders
Keyword(s):  
Pollen Flow ◽  
Progeny Testing ◽  
Self Incompatibility ◽  
Disassortative Mating ◽  
Pollen Loads ◽  
Self Pollination ◽  
Incompatibility System ◽  
Total Pollen

Stigmatic pollen loads were analyzed from naturally pollinated pin and thrum form flowers of Amsinckia douglasiana and A. vernicosa var. furcata. Pin stigmas captured more total pollen than thrum stigmas. Pins experienced either net self-pollination or random pollination. Thrum stigmas experienced significant disassortative pollination. Comparing pollen loads from intact and emasculated thrum flowers of A. douglasiana indicated that self-pollination and geitonogamy were relatively unimportant in the pollination of the thrum form. The level of disassortative pollination of A. vernicosa var. furcata does not appear to be high enough to account for the level of disassortative mating observed by progeny testing, suggesting that this species may possess an incomplete stylar self-incompatibility system such as has been reported in A. grandiflora.

scholarly journals Overcoming Pre-Fertilization Barriers in Intertribal Crosses between Anemone coronaria L. and Ranunculus asiaticus L.

Horticulturae ◽  
2021 ◽  
Vol 7 (12) ◽  
pp. 529
Author(s):  
Emmy Dhooghe ◽  
Dirk Reheul ◽  
Marie-Christine Van Labeke
Keyword(s):  
Pollen Tube ◽  
Seed Set ◽  
Sperm Nucleus ◽  
Tube Length ◽  
Egg Cell ◽  
Dichlorophenoxyacetic Acid ◽  
Style Length ◽  
Ranunculus Asiaticus ◽  
2,4 Dichlorophenoxyacetic Acid ◽  
Pollen Tube Length

Hybridization in flowering plants depends, in the first place, on the delivery of pollen to a receptive stigma and the subsequent growth of pollen tubes through the style to the ovary, where the sperm nucleus of the pollen grain can ultimately fertilize the egg cell. However, reproductive failure is often observed in distant crosses and is caused by pre- and/or post-zygotic barriers. In this study, the reproductive pre-fertilization barriers of intertribal crosses between Anemone coronaria L. and Ranunculus asiaticus L., both belonging to the Ranunculaceae, were investigated. Despite the incongruity of intertribal crosses between A. coronaria and R. asiaticus having been of low intensity at the stigmatic level, interstylar obstructions of the pollen tube growth occurred, which confirmed the presence of pre-fertilization barriers. We show that these barriers could be partially bypassed by combining pollination with a stigma treatment. More specifically, a significantly higher ratio of the pollen tube length to the total style length and a better seed set were observed when the stigma was treated with the auxin 2,4-dichlorophenoxyacetic acid (2,4-D, 1 mg.mL−1) together with the cytokinin kinetin (KIN, 0.5 mg.mL−1) 24 h after pollination, irrespective of the cross direction. More specifically, the stigma treatments with any form of auxin (combined or not combined with cytokinin) resulted in a full seed set, assuming an apomictic fruit set, because no pollination was needed to obtain these seeds.

Onset and duration of stigma receptivity in Kunzea pomifera (Myrtaceae)

2006 ◽  
Vol 54 (6) ◽  
pp. 559 ◽  
Author(s):  
T. Page ◽  
G. M. Moore ◽  
J. Will ◽  
G. M. Halloran
Keyword(s):  
Pollen Tube ◽  
Reproductive Biology ◽  
Peroxidase Activity ◽  
Pollen Tube Growth ◽  
Seed Set ◽  
Stigma Receptivity ◽  
Controlled Pollination ◽  
Germinated Pollen ◽  
New Crop ◽  
Days After Anthesis

The onset and duration of stigma receptivity in K. pomifera was evaluated by observing stigma peroxidase activity, pollen-tube growth and seed set, following controlled pollination of flowers of different ages. Peroxidase activity was negligible from 1 day before to 4 days after anthesis, increasing to a peak of 65% at Day 13. The percentage of pistils bearing germinated pollen and ovaries exhibiting pollen-tube entry increased when pollen was applied to the stigma from the day before anthesis, to a maximum at Days 6 and 7 after anthesis, respectively, followed by a decline by Day 9. Under greenhouse conditions the optimum pollination period, measured as the level of set seed after pollination, ranged from 2 to 11 days after anthesis. The knowledge of this aspect of the species reproductive biology is of considerable value in controlled pollinations for its improvement as a new crop.

Electrophoretic evidence supporting self-incompatibility in Lotus corniculatus

1980 ◽  
Vol 58 (6) ◽  
pp. 712-716 ◽  
Author(s):  
Shirley Dobrofsky ◽  
W. F. Grant
Keyword(s):  
Gel Electrophoresis ◽  
Seed Set ◽  
Polyacrylamide Gel Electrophoresis ◽  
Lotus Corniculatus ◽  
Polyacrylamide Gel ◽  
Self Incompatibility ◽  
Banding Patterns ◽  
Protein Subunits ◽  
Self Pollination

Self-incompatibility, a prefertilization event, and self-sterility, a postfertilization event, have both been suggested as causes for differences in seed set between cross- and self-pollinated florets in Lotus corniculatus L. Ovary protein subunits of selfed, crossed, and unpollinated florets of L. corniculatus cv. Mirabel were studied using polyacrylamide gel electrophoresis. Banding patterns differed for all three conditions. Ovary protein differences were found prior to the time fertilization is known to occur, thereby providing evidence that self-incompatibility is at least partially responsible for the reduced seed set after self-pollination.

The Breeding Systems of Stylidium graminifolium and Stylidium productum (Stylidiaceae)

1990 ◽  
Vol 38 (2) ◽  
pp. 217 ◽  
Author(s):  
AJ Willis ◽  
JE Ash
Keyword(s):  
Breeding System ◽  
Seed Set ◽  
Breeding Systems ◽  
The South ◽  
Pollination Experiments ◽  
Australian Species ◽  
South West ◽  
Self Pollination ◽  
Incompatibility System ◽  
Close Relationship

The breeding systems of Stylidiurn grarninifolium and S. producturn (= S. grarninifoliurn var. caulescens) were studied by observing the phenology of individual flowers and inflorescences, and relating the data to a series of pollination experiments within and between the species. Inter-specific pollinations yielded similar levels of seed-set to crosses within the species indicating a close relationship between the taxa. Self-pollination of either species is uncommon; however, when it occurs, the majority of selfed ovules are aborted post-zygotically, probably by a system of recessive lethals, as there is no indication of an incompatibility system. It is concluded that the breeding systems of S. grarninifoliurn and S. productum, two of the few eastern Australian species, are similar to those of many Stylidiurn species from the south-west, casting doubt upon hypotheses that the breeding system has led to high rates of speciation in the south-west.

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.

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