Effective Pollination Period and Parentage Effect on Pollen Tube Growth in Apple

Flower receptivity is a limiting factor for the fertilization of several tree fruit. The effective pollination period (EPP) can be used to determine flower longevity and identify limiting factors by assessing stigmatic receptivity, pollen tube growth rate, and ovule longevity. EPPs were determined for three apple cultivars under natural field conditions in Washington State in 2019 and 2020. In addition, a greenhouse study, performed under semi-controlled conditions, evaluated the influence of six maternal parents on the pollen tube growth performance of six pollen sources. The duration of the stigmatic receptivity ranged from 6.3 to 8.1 days, depending on the cultivar and year—pollen tubes required between 5.5 and 7.0 days from the stigma to reach the ovules. Ovule longevity of non-pollinated flowers varied between 8.2 and 11.3 days. Combinations of these factors resulted in EPPs ranging from 3.0 days for ‘Rubinstar’ to 5.6 days for ‘Olsentwo Gala’ in the present experimental conditions. The greenhouse study revealed that parentage affected pollen tube growth performance. Importantly, a significant interaction between maternal and paternal factors indicated that the performance of different pollen sources depended on the maternal parent and that general recommendations on pollination need to account for the maternal parent.

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Novel Metrics to Characterize In Vitro Pollen Tube Growth Performance of Apple Cultivars

Plants ◽

10.3390/plants10071460 ◽

2021 ◽

Vol 10 (7) ◽

pp. 1460

Author(s):

Stefan Roeder ◽

Sara Serra ◽

Stefano Musacchi

Keyword(s):

Decision Tree ◽

Pollen Tube ◽

Growth Performance ◽

Pollen Tube Growth ◽

Pollen Viability ◽

Tube Growth ◽

Tree Model ◽

Apple Cultivars ◽

Screening Trials

In vitro germination assays are frequently used in screening trials to evaluate the pollen viability of pollinizers. To be effective, screening trials must have defined threshold criteria, from which individuals can then be assessed. However, despite decades of research on pollen viability, no established threshold is available to categorize apple cultivars based on their in vitro pollen tube lengths. This study aimed to identify and characterize the subgroups of cultivars based on their pollen tube growth performance. In vitro pollen tube lengths of 41 individuals were determined by incubating samples on artificial germination media at 15 and 25 °C. A six-number summary statistic was calculated, and hierarchical clustering on principal component (HCPC) analysis was used to determine and characterize subgroups. Furthermore, a decision tree model was used to predict class membership for future datasets. HCPC analysis partitioned the 41 individuals into three subgroups with different performances. The decision tree quickly predicted the cluster membership based on the second quartile at 15 °C and the third quartile at 25 °C. The thresholds from the decision tree can be used to characterize new observations. The use of the methods will be demonstrated using a case study with 29 apple accessions.

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Stigmatic Receptivity Limits the Effective Pollination Period in `Agua de Aranjuez' Pear

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.128.4.0458 ◽

2003 ◽

Vol 128 (4) ◽

pp. 458-462 ◽

Cited By ~ 13

Author(s):

Javier Sanzol ◽

Pilar Rallo ◽

María Herrero

Keyword(s):

Pollen Tube ◽

Pollen Tube Growth ◽

Fruit Set ◽

Strong Relationship ◽

Tube Growth ◽

Limiting Factor ◽

Ovule Development ◽

Fruit Crops ◽

Reproductive Process ◽

Speed Up

Apples and pears are fruit crops particularly susceptible to cropping irregularities. A strong relationship has been observed between the effective pollination period (EPP) and the general cropping of the orchard. The EPP concept has also been proven to be a useful parameter to establish a relationship between the variation in the reproductive process and cropping behaviors. For apples and pears, a slow pollen tube growth has been shown to be the main limiting factor of the EPP in the traditional cooler temperate cultivation regions. However, while higher temperatures speed up the pollen tube growth, the expansion of these crops into warmer areas often results in failures of fruit set. Thus, with the aim to ascertain the main limiting factor responsible for fruit set failures in Mediterranean conditions we have evaluated the EPP for two consecutive years in `Agua de Aranjuez' pear, the main Spanish cultivar, by studying the stigmatic receptivity, pollen tube kinetics, and ovule development. Complete flower fertility was maintained for just 2 days after anthesis in both years. Pollen tube kinetics and ovule degeneration do not appear to limit flower receptivity. However, the stigmatic receptivity expressed as flowers with at least one receptive stigma, closely matches the duration of the EPP evaluated from fruit set experiments. This was consistent over the 2 years of experiments, in spite of the differences recorded in the EPP, suggesting that stigmatic receptivity is clearly the limiting factor of flower receptivity. This is the first report for stigmatic receptivity limiting the EPP in pears and suggests that stigmatic receptivity could be an important factor limiting pear flower receptivity and hence cropping performance under warmer conditions.

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STIGMATIC RECEPTIVITY AND POLLEN TUBE GROWTH IN RABBITEYE BLUEBERRY

HortScience ◽

10.21273/hortsci.40.3.891b ◽

2005 ◽

Vol 40 (3) ◽

pp. 891b-891

Author(s):

Patricio A. Brevis ◽

D. Scott NeSmith ◽

Hazel Wetzstein

Keyword(s):

Pollen Tube ◽

Pollen Tube Growth ◽

Fruit Set ◽

Pollen Tubes ◽

Tube Growth ◽

Limiting Factor ◽

Ripe Fruit ◽

Pollen Tube Growth Rate ◽

Growth Chambers ◽

Limiting Parameters

Effective pollination period (EPP) is the number of days during which pollination is effective to produce a fruit. The EPP is determined by ovule longevity, pollen tube growth rate and length of stigmatic receptivity. The objectives of this research were to establish the EPP of rabbiteye blueberry and to further the understanding of its limiting parameters. The experiments were conducted in growth chambers using blueberry plants of the cultivars Brightwell and Tifblue. Emasculated flowers were hand-pollinated at 0, 2, 4, 6, and 8 days after anthesis (DAA). Ripe fruit were harvested to record percentage fruit set. Stigmatic receptivity was evaluated as the number of germinated tetrads on the stigma 24 hours after pollination. Under day/night temperatures of 23/10 °C, the EPP was 7 days. Stigmatic receptivity was lowest on the day of anthesis and increased as flowers aged. Stigmatic receptivity was not positively correlated to fruit set, therefore, this parameter was not the most limiting factor of the EPP. Observations of pistils pollinated 3 DAA indicated that the fastest growing pollen tubes reached the bottom of the style 2 to 3 days after pollination. Self-pollination resulted in normal pollen tube growth in the style and inside the ovary. Self-pollen tubes were seen penetrating the micropile.

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Inhibition of Pollen Tube Growth by Diffusate and Extract of Grape Pistils

Engei Gakkai zasshi ◽

10.2503/jjshs.58.515 ◽

1989 ◽

Vol 58 (3) ◽

pp. 515-521 ◽

Cited By ~ 1

Author(s):

Goro OKAMOTO ◽

Ikuo SHIBUYA ◽

Miwa FURUICHI ◽

Kazuo SHIMAMURA

Keyword(s):

Pollen Tube ◽

Pollen Tube Growth ◽

Tube Growth

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Faculty Opinions recommendation of Tip-localized receptors control pollen tube growth and LURE sensing in Arabidopsis.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.726209929.793518680 ◽

2016 ◽

Author(s):

Venkatesan Sundaresan

Keyword(s):

Pollen Tube ◽

Pollen Tube Growth ◽

Tube Growth

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IN VITRO GERMINATION AND POLLEN TUBE GROWTH OF MAIZE (ZEA MAYS L.) POLLEN. X. POLLEN SOURCE GENOTYPE AND GIBBERELLIN A3INTERACTIONS*

Acta Botanica Neerlandica ◽

10.1111/j.1438-8677.1982.tb01596.x ◽

1982 ◽

Vol 31 (1-2) ◽

pp. 105-111 ◽

Cited By ~ 3

Author(s):

P. L. Pfahler ◽

M. Wilcox ◽

D. L. Mulcahy ◽

D. A. Knauft

Keyword(s):

Zea Mays ◽

Pollen Tube ◽

Pollen Tube Growth ◽

Zea Mays L ◽

Tube Growth ◽

In Vitro Germination

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Hyperoside promotes pollen tube growth by regulating the depolymerization effect of actin-depolymerizing factor 1 on microfilaments in okra

Horticulture Research ◽

10.1038/s41438-021-00578-z ◽

2021 ◽

Vol 8 (1) ◽

Author(s):

Biying Dong ◽

Qing Yang ◽

Zhihua Song ◽

Lili Niu ◽

Hongyan Cao ◽

...

Keyword(s):

Pollen Tube ◽

Pollen Tube Growth ◽

Pollen Germination ◽

Pollen Tubes ◽

Tube Growth ◽

Actin Depolymerizing Factor ◽

Specific Mechanism ◽

Promoting Effect ◽

New Research

AbstractMature pollen germinates rapidly on the stigma, extending its pollen tube to deliver sperm cells to the ovule for fertilization. The success of this process is an important factor that limits output. The flavonoid content increased significantly during pollen germination and pollen tube growth, which suggests it may play an important role in these processes. However, the specific mechanism of this involvement has been little researched. Our previous research found that hyperoside can prolong the flowering period of Abelmoschus esculentus (okra), but its specific mechanism is still unclear. Therefore, in this study, we focused on the effect of hyperoside in regulating the actin-depolymerizing factor (ADF), which further affects the germination and growth of pollen. We found that hyperoside can prolong the effective pollination period of okra by 2–3-fold and promote the growth of pollen tubes in the style. Then, we used Nicotiana benthamiana cells as a research system and found that hyperoside accelerates the depolymerization of intercellular microfilaments. Hyperoside can promote pollen germination and pollen tube elongation in vitro. Moreover, AeADF1 was identified out of all AeADF genes as being highly expressed in pollen tubes in response to hyperoside. In addition, hyperoside promoted AeADF1-mediated microfilament dissipation according to microfilament severing experiments in vitro. In the pollen tube, the gene expression of AeADF1 was reduced to 1/5 by oligonucleotide transfection. The decrease in the expression level of AeADF1 partially reduced the promoting effect of hyperoside on pollen germination and pollen tube growth. This research provides new research directions for flavonoids in reproductive development.

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Two Expansin Genes, AtEXPA4 and AtEXPB5, Are Redundantly Required for Pollen Tube Growth and AtEXPA4 Is Involved in Primary Root Elongation in Arabidopsis thaliana

Genes ◽

10.3390/genes12020249 ◽

2021 ◽

Vol 12 (2) ◽

pp. 249

Author(s):

Weimiao Liu ◽

Liai Xu ◽

Hui Lin ◽

Jiashu Cao

Keyword(s):

Arabidopsis Thaliana ◽

Pollen Tube ◽

Pollen Tube Growth ◽

Cell Walls ◽

Root Elongation ◽

Expression Patterns ◽

Primary Root ◽

Pollen Grains ◽

Tube Growth ◽

Cell Wall Binding

The growth of plant cells is inseparable from relaxation and expansion of cell walls. Expansins are a class of cell wall binding proteins, which play important roles in the relaxation of cell walls. Although there are many members in expansin gene family, the functions of most expansin genes in plant growth and development are still poorly understood. In this study, the functions of two expansin genes, AtEXPA4 and AtEXPB5 were characterized in Arabidopsis thaliana. AtEXPA4 and AtEXPB5 displayed consistent expression patterns in mature pollen grains and pollen tubes, but AtEXPA4 also showed a high expression level in primary roots. Two single mutants, atexpa4 and atexpb5, showed normal reproductive development, whereas atexpa4atexpb5 double mutant was defective in pollen tube growth. Moreover, AtEXPA4 overexpression enhanced primary root elongation, on the contrary, knocking out AtEXPA4 made the growth of primary root slower. Our results indicated that AtEXPA4 and AtEXPB5 were redundantly involved in pollen tube growth and AtEXPA4 was required for primary root elongation.

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