Seed Production Enhanced by Antiauxin in the pat-2 Parthenocarpic Tomato Mutant

There is concern that high temperatures resulting from global warming could reduce fruit set of tomato (Solanum lycopersicum). However, fruit set of parthenocarpic tomato genotypes, which often bears seedless fruit, is not reduced when grown under a high temperature. The cause of seedless fruit development was studied with the aim of increasing the seed number in parthenocarpic tomato. Ovule number at anthesis in parthenocarpic and non-parthenocarpic fruit did not differ, but the proportion of undeveloped ovules increased with time after anthesis in parthenocarpic tomato, whereas most ovules in non-parthenocarpic tomato developed normally. Pollen grains germinated on the stigma and extruded pollen tubes in parthenocarpic and non-parthenocarpic tomatoes, but in parthenocarpic tomato, pollen tube elongation was markedly inhibited in the style base. Elongation of pollen tubes on agar containing indoleacetic acid (IAA) was depressed in parthenocarpic and non-parthenocarpic tomato plants. p-Chlorophenoxyisobutyric acid (PCIB), which inhibits auxin action, did not affect the fruit set and fresh weight in either type of tomato, although seed number per fruit in parthenocarpic tomato was significantly increased from 13 ± 2 to 74 ± 6 seeds by PCIB treatment. These results indicated that a high IAA concentration in the ovary of parthenocarpic tomato inhibited pollen tube elongation, and that poor fertilization resulted in failure of ovule development. Moreover, floral organs in parthenocarpic tomato were normally developed as in non-parthenocarpic tomato, and seed development could be induced in parthenocarpic tomato by PCIB treatment.

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Pollen tube incompatibility reaction on the stigma in selfpollinated Sinapis alba L.

Acta Societatis Botanicorum Poloniae ◽

10.5586/asbp.1996.017 ◽

2014 ◽

Vol 65 (1-2) ◽

pp. 101-105 ◽

Cited By ~ 1

Author(s):

Renata Śnieżko ◽

Krystyna Winiarczyk

Keyword(s):

Pollen Tube ◽

Pollen Tube Growth ◽

Pollen Grains ◽

Pollen Tubes ◽

Sinapis Alba ◽

Pollen Grain ◽

Tube Growth ◽

Sinapis Alba L ◽

Growth Changes ◽

Incompatibility Reaction

After selfpollination of <em>Sinapis alba</em> L. pollen tubes growth is inhibited on the stigma. The pollen grains germinate 3-4 hours after pollination. The pollen give rise to one or more pollen tubes. They grow along the papillae. In the place of contact between the papilla and pollen tube the pellicula is digested. Then the direction of pollen tube growth changes completely. Pollen tubes grow back on the exine of their own pollen grain, or turn into the air. The pollen tubes growth was inhibited in 6-8 hours after selfpollination. After crosspollination usually there is no incompatibility reaction.

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Two groups of Arabidopsis receptor kinases preferentially regulate the growth of intraspecies pollen tubes in the female reproductive tract

10.1101/2020.03.17.995555 ◽

2020 ◽

Author(s):

Hyun Kyung Lee ◽

Daphne R. Goring

Keyword(s):

Pollen Tube ◽

Reproductive Tract ◽

Cell Communication ◽

Pollen Grains ◽

Pollen Tubes ◽

Female Reproductive Tract ◽

Wild Type ◽

Knockout Mutant ◽

Receptor Kinases ◽

Compatible Pollen

SummaryIn flowering plants, continuous cell-cell communication between the compatible male pollen grain/growing pollen tube and the female pistil is required for successful sexual reproduction. In Arabidopsis thaliana, the later stages of this dialogue are mediated by several peptide ligands and receptor kinases that guide pollen tubes to the ovules for the release of sperm cells. Despite a detailed understanding of these processes, a key gap remains on the nature of the regulators that function at the earlier stages. Here, we report on two groups of A. thaliana receptor kinases, the LRR-VIII-2 RK subclass and the SERKs, that function in the female reproductive tract to regulate the compatible pollen grains and early pollen tube growth, both essential steps for the downstream processes leading to fertilization. Multiple A. thaliana LRR-VIII-2 RK and SERK knockout mutant combinations were created, and several phenotypes were observed such as reduced wild-type pollen hydration and reduced pollen tube travel distances. As these mutant pistils displayed a wild-type morphology, the observed altered responses of the wild-type pollen are proposed to result from the loss of these receptor kinases leading to an impaired pollen-pistil dialogue at these early stages. Furthermore, using pollen from related Brassicaceae species, we also discovered that these receptor kinases are required in the female reproductive tract to establish a reproductive barrier to interspecies pollen. Thus, we propose that the LRR-VIII-2 RKs and the SERKs play a dual role in the preferential selection and promotion of intraspecies pollen over interspecies pollen.

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The synstigma turns the fig into a large flower

Botanical Journal of the Linnean Society ◽

10.1093/botlinnean/boaa061 ◽

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.

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Comparative analyses of angiosperm secretomes identify apoplastic pollen tube functions and novel secreted peptides

Plant Reproduction ◽

10.1007/s00497-020-00399-5 ◽

2020 ◽

Author(s):

María Flores-Tornero ◽

Lele Wang ◽

David Potěšil ◽

Said Hafidh ◽

Frank Vogler ◽

...

Keyword(s):

Cell Wall ◽

Pollen Tube ◽

Turgor Pressure ◽

Pollen Grains ◽

Pollen Tubes ◽

Secreted Proteins ◽

Reproductive Tissues ◽

Small Proteins ◽

Secreted Peptides

Abstract Key message Analyses of secretomes of in vitro grown pollen tubes from Amborella, maize and tobacco identified many components of processes associated with the cell wall, signaling and metabolism as well as novel small secreted peptides. Abstract Flowering plants (angiosperms) generate pollen grains that germinate on the stigma and produce tubes to transport their sperm cells cargo deep into the maternal reproductive tissues toward the ovules for a double fertilization process. During their journey, pollen tubes secrete many proteins (secreted proteome or secretome) required, for example, for communication with the maternal reproductive tissues, to build a solid own cell wall that withstands their high turgor pressure while softening simultaneously maternal cell wall tissue. The composition and species specificity or family specificity of the pollen tube secretome is poorly understood. Here, we provide a suitable method to obtain the pollen tube secretome from in vitro grown pollen tubes of the basal angiosperm Amborella trichopoda (Amborella) and the Poaceae model maize. The previously published secretome of tobacco pollen tubes was used as an example of eudicotyledonous plants in this comparative study. The secretome of the three species is each strongly different compared to the respective protein composition of pollen grains and tubes. In Amborella and maize, about 40% proteins are secreted by the conventional “classic” pathway and 30% by unconventional pathways. The latter pathway is expanded in tobacco. Proteins enriched in the secretome are especially involved in functions associated with the cell wall, cell surface, energy and lipid metabolism, proteolysis and redox processes. Expansins, pectin methylesterase inhibitors and RALFs are enriched in maize, while tobacco secretes many proteins involved, for example, in proteolysis and signaling. While the majority of proteins detected in the secretome occur also in pollen grains and pollen tubes, and correlate in the number of mapped peptides with relative gene expression levels, some novel secreted small proteins were identified. Moreover, the identification of secreted proteins containing pro-peptides indicates that these are processed in the apoplast. In conclusion, we provide a proteome resource from three distinct angiosperm clades that can be utilized among others to study the localization, abundance and processing of known secreted proteins and help to identify novel pollen tube secreted proteins for functional studies.

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High self-pollen transfer and low fruit set in buzz-pollinated Dianella revoluta (Phormiaceae)

Australian Journal of Botany ◽

10.1071/bt03139 ◽

2004 ◽

Vol 52 (2) ◽

pp. 185 ◽

Cited By ~ 20

Author(s):

David H. Duncan ◽

Saul A. Cunningham ◽

Adrienne B. Nicotra

Keyword(s):

Pollen Tube ◽

Fruit Set ◽

Significant Proportion ◽

Pollen Tubes ◽

Common Species ◽

Pollen Transfer ◽

Direct Demonstration ◽

Floral Phenology ◽

Early Abortion ◽

To Receive

We used pollinator observation, flower manipulation, controlled pollination and pollen-tube analysis to better understand the reproductive ecology of Dianella revoluta R.Br., a common species known to have depressed fruit set at fragmented sites. This buzz-pollinated species was found to receive large quantities of self-pollen even during a single pollinator visit, but is only partially self-compatible. This may be the first direct demonstration of pollinator-facilitated, autogamous self-pollen transfer accounting for a significant proportion of stigmatic pollen load. Frequent high self-pollen transfer may account for the observed low rate of fruit development in open-pollinated flowers. Self-pollen tubes reached the base of the style in comparable numbers and at the same rate as outcross pollen tubes, with no sign of pollen-tube competition favouring outcross pollen. Barriers to greater self-fertility occur late, probably through early abortion of selfed ovules. We also investigated what impact overlapping distribution with D. longifolia may have on D. revoluta pollination and reproduction. Although these species shared pollinators, they differed in terms of frequency of visits. There was also separation of floral phenology within the course of a day.

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EFFECTS OF INDIGENOUS AND FOREIGN POLLINIZERS ON THE YIELD AND FRUIT CHARACTERISTICS OF DATE PALM CULTIVAR KHALAS

IRAQI JOURNAL OF AGRICULTURAL SCIENCES ◽

10.36103/ijas.v51i1.935 ◽

2020 ◽

Vol 51 (1) ◽

Author(s):

Munir & et al.

Keyword(s):

Saudi Arabia ◽

Date Palm ◽

Fruit Set ◽

Block Design ◽

Pollen Grains ◽

Dry Weight ◽

Soluble Solids ◽

Parthenocarpic Fruit ◽

Fruit Characteristics ◽

Palm Trees

This research was carried out at Research and Training Station, Date Palm Research Center of Excellence, King Faisal University, Al-Ahsa, Saudi Arabia during 2017 and 2018 to investigate the effects of indigenous and foreign pollinizers on the yield and physicochemical fruit characteristics of date palm cv. Khalas. Pollen grains of different date palm male pollinizers were collected from different geological locations of Saudi Arabia and Egypt. Fifteen twelve-year-old date palm trees were selected for the experiment, for which five spathes for each palm were selected per replication. The experiment was laid out as a Randomized Complete Block Design with three replicates for each treatment. The findings of the present study showed significant differences among pollinizer sources. Female date palms pollinated with indigenous male pollen grains (Al-Ahsa, Saudi Arabia) exhibited superior results regarding fruit set percentage, parthenocarpic fruit percentage, tamar fruit percentage, fruit drop percentage, total number of fruit nodes per bunch, bunch weight, pulp weight, pulp ratio, seed ratio and pulp:seed ratio, fruit fresh weight, fruit dry weight, fruit length, fruit width, fruit volume, seed weight, seed length, seed width, fruit moisture content and total soluble solids. It is can be concluded that although the response to pollination and fertilization of date palm is species dependent, however, the indigenous cultivar Khalas was more responsive to the local male types than the foreign males for better fruit set, higher yield and best fruit quality traits.

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Effects of Temperature and the Combination of Liquid Lime Sulfur and Fish Oil on Pollen Germination, Pollen Tube Growth, and Fruit Set in Apples

HortScience ◽

10.21273/hortsci.44.5.1277 ◽

2009 ◽

Vol 44 (5) ◽

pp. 1277-1283 ◽

Cited By ~ 14

Author(s):

Keith Yoder ◽

Rongcai Yuan ◽

Leon Combs ◽

Ross Byers ◽

Jim McFerson ◽

...

Keyword(s):

Pollen Tube ◽

Pollen Tube Growth ◽

Pollen Germination ◽

Fruit Set ◽

Pollen Tubes ◽

Tube Growth ◽

Pollen Tube Growth Rate ◽

Golden Delicious ◽

Effects Of Temperature ◽

Increasing Temperature

Effects of temperature and the combination of liquid lime sulfur (LLS) and fish oil (FO) applied during bloom on pollen germination and pollen tube growth in flowers and fruit set were examined in apples (Malus ×domestica Borkh.). Percent germination of pollen of ‘Manchurian’ crabapples and ‘Golden Delicious’ apple flowers on the stigmatic surface of ‘Golden Delicious’ pistils increased with increasing temperature from 13 to 29 °C in the first 24 and 48 h after pollination, respectively, but not thereafter. Pollen tube growth rate in the style increased quadratically with increasing temperature from 13 to 29 °C. ‘Manchurian’ was a more effective pollenizer of ‘Golden Delicious’ than was ‘Golden Delicious’ pollen. For example, at 24 or 29 °C, some ‘Manchurian’ pollen tubes grew to the base of ‘Golden Delicious’ styles by 24 h after pollination. On the other hand, no ‘Golden Delicious’ pollen tube grew to the base of a ‘Golden Delicious’ style regardless of temperature and time. Pollen tube growth rate in the style increased with increasing day/night temperature from 7/0 to 24/7 °C. The time required for pollen tubes to grow to the base of styles decreased with increasing day/night temperature from 13/2 to 24/7 °C. Only ≈36 h was required for pollen tubes to grow to the base of style at 24/7 °C, whereas pollen tubes grew very slowly and no pollen tubes grew to the base of style at 7/0 °C regardless of pollen source. LLS + FO, applied 4 or 24 h after pollination, inhibited pollen germination, pollen tube growth in the style, fertilization, and fruit set, but it had no effect when applied 48 h after pollination. These results suggest that LLS + FO applied at this bloom stage causes flower or fruit abscission most likely by inhibiting pollen germination, pollen tube growth in the style, and fertilization.

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Assessment of self-(in) compatibility in some sweet cherry (Prunus avium L.) genotypes

Genetika ◽

10.2298/gensr1303939r ◽

2013 ◽

Vol 45 (3) ◽

pp. 939-952 ◽

Cited By ~ 4

Author(s):

Sanja Radicevic ◽

Sladjana Maric ◽

Radosav Cerovic ◽

Milena Djordjevic

Keyword(s):

Growth Rate ◽

Pollen Tube ◽

Pollen Tube Growth ◽

Sweet Cherry ◽

Prunus Avium ◽

Fruit Set ◽

Pollen Tubes ◽

Pollen Tube Growth Rate ◽

Prunus Avium L

The paper presents results of a three-year study of self-(in)compatibility in four economically important sweet cherry genotypes - ?Karina?, ?Kordia?, ?Regina? and ?Summit?, under agro-environmental conditions of Western Serbia. Determination of S-RNase genotype, microscopic observation of the pollen tube growth rate and assaying of the fruit set level after self-pollination were used to assess the genotypes. ?Kordia? (S3S6), ?Regina? (S1S3) and ?Summit? (S1S2) are self-incompatible genotypes, with a considerable number of pollen tubes ending the growth in the middle third of the style and lack of fruit set. ?Karina?, as S3S4 genotype, behaved as self-compatible, since its pollen tubes reached the base of the style and ovary, penetrating the nucellus. In addition, fruit set for ?Karina? was recorded in all three years of study (40.26%, 18.79% and 21.81%, respectively).

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Self-incompatibility and Self-fruitfulness in Pear cv. Agua de Aranjuez

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.132.2.166 ◽

2007 ◽

Vol 132 (2) ◽

pp. 166-171 ◽

Cited By ~ 6

Author(s):

Javier Sanzol ◽

Maria Herrero

Keyword(s):

Pollen Tube ◽

Fruit Set ◽

Parthenocarpic Fruit ◽

Self Incompatibility ◽

Variable Response ◽

Self Pollination ◽

Fruit Setting ◽

Self Fertilization ◽

Growing Conditions ◽

Performance Results

Most pear (Pyrus communis L.) cultivars are impaired to set fruit under self-pollination, because self-fertilization is prevented by a gametophytic self-incompatibility system. However, accumulated information in this species shows that often for a same cultivar, after self-pollination, a variable response in fruit set can be obtained in different years or growing conditions. In this work, we characterize self-incompatibility and self-fruitfulness in ‘Agua de Aranjuez’, the main Spanish pear cultivar, which also shows a variable response to self-pollination. Two years with a different fruit setting response after self-pollination, one with no fruit set and the other with a moderate fruit set, were compared for parthenocarpic fruit development and for pollen tube performance. Results show that in both years, this cultivar behaves as self-incompatible with absence of parthenocarpy. In selfed flowers, most pollen tubes are arrested in the upper half of the style, although in a small proportion of the styles, a pollen tube can reach the base of the style and eventually effect fertilization. Self-fertilization, although occurring at a low level, can explain the fruit set levels obtained under self-pollination given that flowers with just one fertilized ovule are able to set fruit. This behavior could explain confusing results about self-fruitfulness in ‘Agua de Aranjuez’ and other pear cultivars.

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Synthetic Cytokinin-1-(2=chloro=4=pyridyl)-3-phenylurea (CPPU)-Promotes Fruit Set and Induces Parthenocarpy in Watermelon

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.120.6.997 ◽

1995 ◽

Vol 120 (6) ◽

pp. 997-1000 ◽

Cited By ~ 34

Author(s):

Yasuyoshi Hayata ◽

Yoshiyuki Niimi ◽

Naoto Iwasaki

Keyword(s):

Fruit Quality ◽

Fruit Set ◽

Fruit Growth ◽

Soluble Solids ◽

Parthenocarpic Fruit ◽

Soluble Solids Content ◽

Control Fruit ◽

Seedless Fruit ◽

Solids Content

Applying a 200 ppm solution of CPPU to pollinated ovaries of watermelon (Citrullus lunatus Matsum) at anthesis increased fruit set from 26.9% (control) to 95%. Applying CPPU solutions to nonpollinated ovaries at anthesis induced parthenocarpy, yielding 65% and 89.5% fruit set, respectively with 20 and 200 ppm applications. However, 64% of the 20 ppm CPPU-treated parthenocarpic fruit stopped growth 10 days after treatment. Growth of CPPU-treated, pollinated, and nonpollinated fruit increased significantly compared with growth of control fruit during the first 10 days after treatment, but, except for the 20 ppm CPPU parthenocarpic fruit, growth subsequently slowed, resulting in fruit equal in size to the control by harvest. CPPU application did not affect soluble solids content of pollinated fruit, but reduced content of parthenocarpic fruit treated with 20 ppm. Fructose content was generally higher than glucose and sucrose at harvest. However, in pollinated fruit treated with 20 ppm CPPU, sucrose levels were higher than glucose and fructose. These results suggest that CPPU is practical for promoting fruit set and seedless fruit without adversely affecting fruit quality and development.

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