scholarly journals Ovary Signals for Pollen Tube Guidance in Chalazogamous Mangifera indica L.

2021 ◽  
Vol 11 ◽  
Author(s):  
Jorge Lora ◽  
Veronica Perez ◽  
Maria Herrero ◽  
Jose I. Hormaza
Keyword(s):  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Mangifera Indica ◽  
Embryo Sac ◽  
Pollen Tubes ◽  
Tube Growth ◽  
Transmitting Tissue ◽  
Egg Apparatus ◽  
Pollen Tube Elongation

Most flowering plants show porogamy in which the pollen tubes reach the egg apparatus through the micropyle. However, several species show chalazogamy, an unusual pollen tube growth, in which the pollen tubes reach the embryo sac through the chalaza. While ovary signals for pollen tube growth and guidance have been extensively studied in porogamous species, few studies have addressed the process in chalazogamous species such as mango (Mangifera indica L.), one of the five most important fruit crops worldwide in terms of production. In this study, we characterize pollen–pistil interaction in mango, paying special attention to three key players known to be involved in the directional pollen tube growth of porogamous species such as starch, arabinogalactan proteins (AGPs), and γ-aminobutyric acid (GABA). Starch grains were observed in the style and in the ponticulus at anthesis, but their number decreased 1 day after anthesis. AGPs, revealed by JIM8 and JIM13 antibodies, were homogenously observed in the style and ovary, but were more conspicuous in the nucellus around the egg apparatus. GABA, revealed by anti-GABA antibodies, was specifically observed in the transmitting tissue, including the ponticulus. Moreover, GABA was shown to stimulate in vitro mango pollen tube elongation. The results support the heterotrophic growth of mango pollen tubes in the style at the expense of starch, similarly to the observations in porogamous species. However, unlike porogamous species, the micropyle of mango does not show high levels of GABA and starch, although they were observed in the ponticulus and could play a role in supporting the unusual pollen tube growth in chalazogamous species.

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

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.

scholarly journals Pollen Viability and Vigor in Hybrid Southern Highbush Blueberries (Vaccinium corymbosum L. ×spp.)

HortScience ◽  
1992 ◽  
Vol 27 (5) ◽  
pp. 425-427 ◽  
Author(s):  
Gregory A. Lang ◽  
E. James Parrie
Keyword(s):  
Pollen Tube ◽  
Growth Rates ◽  
Pollen Tube Growth ◽  
Pollen Viability ◽  
Pollen Tubes ◽  
Vaccinium Corymbosum ◽  
Tube Growth ◽  
Multiple Pollen ◽  
Southern Highbush

Pollen from six southern highbush blueberry cultivars derived from Vaccinium corymbosum L. and one or more other species (V. darrowi Camp, V. ashei Reade, and V. angustifolium Aiton) was incubated on nutrient agar to determine tetrad viability, pollen tube growth rates, and incidence of multiple pollen tube germinations. `Avonblue' pollen had a significantly lower tetrad germination percentage than `Georgiagem', `Flordablue', `Sharpblue', `Gulfcoast', or `O'Neal', all of which had >90% viable tetrads. The in vitro growth rate of `O'Neal' pollen tubes was significantly higher than the growth rates of `Sharpblue' and `Georgiagem pollen tubes. Of those tetrads that were viable, more than two pollen tubes germinated from 83% and 91% of the `Gulfcoast' and `Sharpblue' tetrads, respectively, while only 11% of the `Flordablue' tetrads produced more than two pollen tubes. The total number of pollen tubes germinated per 100 tetrads ranged from 157 (`Flordablue') to 324 (`Sharpblue'), resulting in actual pollen grain viabilities ranging from 39% to 81%. Genetic differences in pollen vigor, as indicated by pollen viability, pollen tube growth rates, and multiple pollen tube germinations, may influence blueberry growers' success in optimizing the beneficial effects of cross-pollination on fruit development.

scholarly journals Pollen Tube Growth in Carya and Temporal Influence of Pollen Deposition on Fertilization Success in Pecan

1992 ◽  
Vol 117 (2) ◽  
pp. 328-331 ◽  
Author(s):  
Robert D. Marquard
Keyword(s):  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Pollen Tubes ◽  
Fertilization Success ◽  
Tube Growth ◽  
In Vivo Studies ◽  
Pollen Deposition ◽  
Cape Fear

In vivo pollen tube growth of pecan [Carya illinoinensis (Wangenh.) K. Koch] was estimated to be ≈ 150 μm·hour-1 from 3 to 8 hours postpollination. Pollen tubes averaged 47, 194, 405, and 946 μm after 2, 3, 4, and 8 hours postpollination, respectively. Pollen tube growth was strongly influenced by temperature, and in vitro studies demonstrated pollen germination and tube growth were optimal at 27C for `Cape Fear' pecan. In in vivo studies, tubes of cross-pollen did not grow significantly faster than tubes of self-pollen. Pollen tubes of water hickory [C. aquatica (Michx. f.) Nutt.] grew significantly faster than those of C. illinoinensis. Bitternut [C. cordiformis (Wangenh.) K. Koch] and mockernut hickory (C. tomentosa Nutt.) pollen tubes grew significantly slower on pecan stigmas than did pecan pollen. Pollen arriving first on the stigma has a decided advantage for fertilization success of pecan. The fertilization success rate of pecan pollen arriving 24 hours after first pollen arrival was <3%.

Floral Anatomy and Pollen Tube Growth in the Quandong (Santalum acuminatum (R. Br.) A. DC.)

1982 ◽  
Vol 30 (6) ◽  
pp. 601 ◽  
Author(s):  
M Sedgley
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Floral Anatomy ◽  
Embryo Sac ◽  
Pollen Tubes ◽  
The Other ◽  
Tube Growth ◽  
Scanning Electron

Floral anatomy and pollen tube growth in the quandong were studied using light and scanning electron microscopy. The flowers had four perianth lobes and four stamens whose anthers dehisced by longitudinal slits. The pollen became caught in long unicellular hairs adjacent to the anthers. The central disc secreted nectar through raised stomata. The stigma papilla cells had a cuticle with a rough surface overlying thick PAS-positive walls. The half-inferior ovary normally contained two ovules. The embryo sac extended beyond the ovule at the micropylar end and into the placenta at the chalazal end. Half of the ovaries observed at both anthesis and 4 days following anthesis had no embryo sacs and the other half had one embryo sac. Occasional ovaries had two embryo sacs and some underdeveloped embryo sacs were observed that did not extend beyond the ovule or into the placenta. Pollen tubes had reached the ovary by 1 day following pollination and the stigma was receptive for 8 days following anthesis. Only half of the pistils had pollen tubes in the ovary. Unpollinated flowers had no pollen tube growth in the pistil.

scholarly journals Pollen tube growth through nucellus into embryo sac of Spinacia - an ultrastructural investigation

2014 ◽  
Vol 50 (1-2) ◽  
pp. 191-193 ◽  
Author(s):  
H. J. Wilms
Keyword(s):  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Embryo Sac ◽  
Pollen Tubes ◽  
Tube Growth ◽  
Ultrastructural Investigation ◽  
Nucellar Tissue

The micropylar parts of nucellus and embryo sac were studied in relation to pollen tube growth and its entrance into the embryo sac. The initially homogeneous walls of the cells of the conductive nucellar tissue disintegrate at the middle lamellae region. Pollen tubes pierce the nucellar cuticle and continue their growth into the nucellus intercellularly. Subsequently they can follow various pathways to reach the FA of the degenerated synergid. The penetration into this synergid, and the discharge of the tube contents are described and discussed.

scholarly journals Pollen tube growth in sweet cherry (Prunus avium L.) styles following fully compatible, half compatible and incompatible pollinations

2005 ◽  
Vol 11 (1) ◽  
Author(s):  
Zs. Békefi ◽  
Zs. Halász
Keyword(s):  
Fluorescence Microscopy ◽  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Sweet Cherry ◽  
Prunus Avium ◽  
Pollen Tubes ◽  
Tube Growth ◽  
In Vivo Studies

In vivo as well as in vitro pollen tube growth studies along the style were performed, each with two pairs of sweet cherry cultivar combinations by means of fluorescence microscopy. In vivo studies showed that the percentage of pollen tubes penetrating the middle and basal section of the style was higher in the fully compatible 'Margit' x 'Alex' combination than in the half compatible `Germersdorfi 3' x `Alex' cross. The year effect was significant at P=0.] probability level. All pollen tubes in vitro stopped at the upper third of the style in the incompatible 'Vera' x 'Van' cross, whereas in the half compatible 'Alex' x 'Van' 50% of the pollen tubes penetrated to the lower third of the style. By in vitro fluorescence microscopy, it was possible to distinguish half compatible combinations from incompatible ones. Results obtained by in vivo technique only were much ambiguous.

scholarly journals Two Carbohydrate-Based Natural Extracts Stimulate in vitro Pollen Germination and Pollen Tube Growth of Tomato Under Cold Temperatures

2021 ◽  
Vol 12 ◽  
Author(s):  
Ferdousse Laggoun ◽  
Nusrat Ali ◽  
Sabine Tourneur ◽  
Grégoire Prudent ◽  
Bruno Gügi ◽  
...  
Keyword(s):  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Pollen Germination ◽  
Crop Production ◽  
Extreme Temperature ◽  
Pollen Tubes ◽  
Molecular Techniques ◽  
Tube Growth ◽  
Cold Temperatures

To date, it is widely accepted by the scientific community that many agricultural regions will experience more extreme temperature fluctuations. These stresses will undoubtedly impact crop production, particularly fruit and seed yields. In fact, pollination is considered as one of the most temperature-sensitive phases of plant development and until now, except for the time-consuming and costly processes of genetic breeding, there is no immediate alternative to address this issue. In this work, we used a multidisciplinary approach using physiological, biochemical, and molecular techniques for studying the effects of two carbohydrate-based natural activators on in vitro tomato pollen germination and pollen tube growth cultured in vitro under cold conditions. Under mild and strong cold temperatures, these two carbohydrate-based compounds significantly enhanced pollen germination and pollen tube growth. The two biostimulants did not induce significant changes in the classical molecular markers implicated in pollen tube growth. Neither the number of callose plugs nor the CALLOSE SYNTHASE genes expression were significantly different between the control and the biostimulated pollen tubes when pollens were cultivated under cold conditions. PECTIN METHYLESTERASE (PME) activities were also similar but a basic PME isoform was not produced or inactive in pollen grown at 8°C. Nevertheless, NADPH oxidase (RBOH) gene expression was correlated with a higher number of viable pollen tubes in biostimulated pollen tubes compared to the control. Our results showed that the two carbohydrate-based products were able to reduce in vitro the effect of cold temperatures on tomato pollen tube growth and at least for one of them to modulate reactive oxygen species production.

scholarly journals The Arabidopsis thaliana Class II Formin FH13 Modulates Pollen Tube Growth

2021 ◽  
Vol 12 ◽  
Author(s):  
Eva Kollárová ◽  
Anežka Baquero Forero ◽  
Fatima Cvrčková
Keyword(s):  
Arabidopsis Thaliana ◽  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Tip Growth ◽  
Pollen Tubes ◽  
Class Ii ◽  
Membrane Dynamics ◽  
Tube Growth ◽  
Class I ◽  
Pollen Tube Elongation

Formins are a large, evolutionarily conserved family of actin-nucleating proteins with additional roles in regulating microfilament, microtubule, and membrane dynamics. Angiosperm formins, expressed in both sporophytic and gametophytic tissues, can be divided into two subfamilies, Class I and Class II, each often exhibiting characteristic domain organization. Gametophytically expressed Class I formins have been documented to mediate plasma membrane-based actin assembly in pollen grains and pollen tubes, contributing to proper pollen germination and pollen tube tip growth, and a rice Class II formin, FH5/RMD, has been proposed to act as a positive regulator of pollen tube growth based on mutant phenotype and overexpression data. Here we report functional characterization of the Arabidopsis thaliana pollen-expressed typical Class II formin FH13 (At5g58160). Consistent with published transcriptome data, live-cell imaging in transgenic plants expressing fluorescent protein-tagged FH13 under the control of the FH13 promoter revealed expression in pollen and pollen tubes with non-homogeneous signal distribution in pollen tube cytoplasm, suggesting that this formin functions in the male gametophyte. Surprisingly, fh13 loss of function mutations do not affect plant fertility but result in stimulation of in vitro pollen tube growth, while tagged FH13 overexpression inhibits pollen tube elongation. Pollen tubes of mutants expressing a fluorescent actin marker exhibited possible minor alterations of actin organization. Our results thus indicate that FH13 controls or limits pollen tube growth, or, more generally, that typical Class II formins should be understood as modulators of pollen tube elongation rather than merely components of the molecular apparatus executing tip growth.

Effect of spermine and cyclohexylamine on in vitro pollen germination and tube growth in Helianthus annuus

2000 ◽  
Vol 80 (2) ◽  
pp. 241-245 ◽  
Author(s):  
Ergü Çetin ◽  
Cansev Yildirim ◽  
Narçin Palavan-Ünsal ◽  
Meral Ünal
Keyword(s):  
Pollen Tube ◽  
Helianthus Annuus ◽  
Pollen Tube Growth ◽  
Pollen Germination ◽  
Germination Percentage ◽  
Tube Growth ◽  
Pollen Tube Elongation ◽  
Relationship Of

Naturally occurring polyamines (PA) are known to play a key role in growth and development of plants and animals. However, the role of these polycations in the development and germination of the pollen grain is not well understood. The effect of different concentrations of spermine (Spm) on pollen tube growth in Helianthus annuus was investigated. Spermine treatments in the 10−7 to 10−5 M range stimulated pollen tube growth starting in the first 15 min of the incubation period, while 10−4 M Spm treatment resulted in inhibition of pollen tube elongation. The effect of cyclohexylamine (CHA), an inhibitor of Spm synthesis on pollen tube growth and germination percentage was also studied. Cyclohexylamine in the 0.5 × 10−3 M to the 1.5 × 10−3 M range inhibited pollen tube elongation. The relationship of B deficiency, excess B and PA effect on pollen germination and pollen tube growth were also investigated. Key words: Polyamines, pollen, cyclohexylamine, boron

Molecular control of the glucan synthase-like protein NaGSL1 and callose synthesis during growth of Nicotiana alata pollen tubes

2008 ◽  
Vol 414 (1) ◽  
pp. 43-52 ◽  
Author(s):  
Lynette Brownfield ◽  
Sarah Wilson ◽  
Ed Newbigin ◽  
Antony Bacic ◽  
Steve Read
Keyword(s):  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Pollen Tubes ◽  
Tube Growth ◽  
Nicotiana Alata ◽  
Molecular Control ◽  
Intracellular Location ◽  
Glucan Synthase ◽  
Tobacco Pollen

The protein NaGSL1 (Nicotiana alata glucan synthase-like 1) is implicated in the synthesis of callose, the 1,3-β-glucan that is the major polysaccharide in the walls of N. alata (flowering tobacco) pollen tubes. Here we examine the production, intracellular location and post-translational processing of NaGSL1, and relate each of these to the control of pollen-tube callose synthase (CalS). The 220 kDa NaGSL1 polypeptide is produced after pollen-tube germination and accumulates during pollen-tube growth, as does CalS. A combination of membrane fractionation and immunoelectron microscopy revealed that NaGSL1 was present predominantly in the endoplasmic reticulum and Golgi membranes in younger pollen tubes when CalS was mostly in an inactive (latent) form. In later stages of pollen-tube growth, when CalS was present in both latent and active forms, a greater proportion of NaGSL1 was in intracellular vesicles and the plasma membrane, the latter location being consistent with direct deposition of callose into the wall. N. alata CalS is activated in vitro by the proteolytic enzyme trypsin and the detergent CHAPS, but in neither case was activation associated with a detectable change in the molecular mass of the NaGSL1 polypeptide. NaGSL1 may thus either be activated by the removal of a few amino acids or by the removal of another protein that inhibits NaGSL1. These findings are discussed in relation to the control of callose biosynthesis during pollen germination and pollen-tube growth.

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