Growth of barley pollen tubes in vivo. I. Ultrastructural aspects of early tube growth in the stigmatic hair

1979 ◽  
Vol 57 (4) ◽  
pp. 386-396 ◽  
Author(s):  
David D. Cass ◽  
Daniel J. Peteya
Keyword(s):  
Electron Microscopy ◽  
Pollen Tube ◽  
Hair Cell ◽  
Tube Wall ◽  
Periodic Acid ◽  
Pollen Tubes ◽  
Tube Growth ◽  
Reserve Carbohydrate ◽  
Pollen Tube Wall ◽  
Hair Surface

Barley styles were examined with transmission electron microscopy (TEM) and scanning electron microscopy (SEM) before and after pollination. Pollen tube penetration of a stigmatic hair may follow initial missing of the hair and (or) a period of growth on the hair surface. Changes in hair cell walls occur at penetration sites. Absence of demonstrable reserve carbohydrate in hair cells and styles and its abundance in pollen tubes suggest that early tube growth is largely dependent on endogenous substrates relative to its carbohydrate requirement. The pollen tube wall has an inner, somewhat reticular region and an outer, multilayered fibrillar region. Membrane-bound pollen tube vesicles containing reticular material fuse with the pollen tube membrane, contributing to development of the pollen tube wall. Vesicles and tube wall are stained by Ruthenium Red; this staining is compared with results of periodic acid–silver proteinate treatment. Two types of tube growth anomalies are reported. In the first, a tube may grow out of a hair and discharge its cytoplasm onto the hair surface through an aperture. Discharged, naked tube cytoplasm often remains appressed to hair surfaces. In the second, a tube may grow into a hair cell and discharge its contents therein through an apparently similar aperture. Vegetative nuclei appear unaltered during early pollen tube growth, but there are minor structural alterations in sperms and vegetative cell cytoplasm.

Observations of Germinating Lychnis Alba Pollen

1971 ◽  
Vol 29 ◽  
pp. 348-349
Author(s):  
Richard E. Crang ◽  
Michael A. Millay
Keyword(s):  
Electron Microscopy ◽  
Pollen Tube ◽  
Liquid Culture ◽  
Culture Medium ◽  
Tube Wall ◽  
Pollen Grains ◽  
Pharbitis Nil ◽  
Liquid Culture Medium ◽  
Transmission Electron ◽  
Pollen Tube Wall

The exine surface of Lychnis alba pollen grains is ornamented with spines and pits (Fig. 1) that are variable both in size and number. No relationship appears to exist between the relative nature of these surface features as observed by means of scanning electron microscopy (SEM) and germination potentials of the pollen. The protrusion of cytoplasm at the apertures is a common phenomenon as the grains become hydrated when placed in liquid culture medium. As swelling of the apertures occurs, the aperturate opercula, or pore plates, may be lifted to the terminal surface but frequently are displaced to one side where they become embedded in the pollen tube wall (Fig.2). Although all apertures may protrude, only a single pollen tube will normally form from each grain. The composition of the opercula appear similar to the exine in transmission electron microscopy (TEM) preparations, but is less dense than the exine when observed in SEM preparations, as indicated by surface folds suggestive of a soft composition. There is no structural evidence that enzyme degradations of the exine at germination sites is required for emergence of the pollen tube, although such may be the case when pollen germinates on the style as indicated in SEM observations of Pharbitis nil pollen.

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.

Germination and growth of sponge gourd (Luffa cylindrica) pollen tubes and FTIR analysis of the pollen tube wall

2009 ◽  
Vol 122 (4) ◽  
pp. 638-644 ◽  
Author(s):  
Bo Jiang ◽  
Zonggen Shen ◽  
Jinbo Shen ◽  
Da Yu ◽  
Xianyong Sheng ◽  
...  
Keyword(s):  
Pollen Tube ◽  
Tube Wall ◽  
Pollen Tubes ◽  
Ftir Analysis ◽  
Luffa Cylindrica ◽  
Sponge Gourd ◽  
Pollen Tube Wall ◽  
Germination And Growth

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 Testing of self-(in)compatibility in apricot cultivars from European breeding programmes

2013 ◽  
Vol 40 (No. 2) ◽  
pp. 65-71 ◽  
Author(s):  
D. Milatović ◽  
D. Nikolić ◽  
B. Krška
Keyword(s):  
Fluorescence Microscopy ◽  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Reliable Method ◽  
Pollen Tubes ◽  
Tube Growth ◽  
Self Incompatibility ◽  
Breeding Programmes

Self-(in)compatibility was tested in 40 new apricot cultivars from European breeding programmes. Pollen-tube growth in pistils from laboratory pollinations was analysed using the fluorescence microscopy. Cultivars were considered self-compatible if at least one pollen tube reached the ovary in the majority of pistils. Cultivars were considered self- incompatible if the growth of pollen tubes in the style stopped along with formation of characteristic swellings. Of the examined cultivars, 18 were self-compatible and 22 were self-incompatible. Fluorescence microscopy provides a relatively rapid and reliable method to determine self-incompatibility in apricot cultivars.      

scholarly journals NETWORKED2‐Subfamily Proteins Regulate the Cortical Actin Cytoskeleton of Growing Pollen Tubes and Polarised Pollen Tube Growth

2021 ◽  
Author(s):  
Patrick Duckney ◽  
Johan T. Kroon ◽  
Martin R. Dixon ◽  
Timothy J. Hawkins ◽  
Michael J. Deeks ◽  
...  
Keyword(s):  
Pollen Tube ◽  
Actin Cytoskeleton ◽  
Pollen Tube Growth ◽  
Pollen Tubes ◽  
Tube Growth ◽  
Cortical Actin

The growth of the pollen tube wall in Oenothera organensis

1975 ◽  
Vol 18 (3) ◽  
pp. 519-532
Author(s):  
H.G. Dickinson ◽  
J. Lawson
Keyword(s):  
Pollen Tube ◽  
Tube Wall ◽  
Wall Material ◽  
Fibrillar Material ◽  
Stage Of Development ◽  
Large Numbers ◽  
Membrane Bound ◽  
Pollen Tube Wall ◽  
Different Sources ◽  
Dictyosome Vesicles

The growth of the pollen tube wall of Oenothera is effected by the expulsion of fibrillar material from the cytoplasm into the developing wall. This material may also be seen in the cytoplasm, contained in membrane-bound vesicles. It is not clear how the content of the vesicles is discharged, but it appears not to involve the participation of microtubules. The source of the cytoplasmic fibrillar bodies depends upon the stage of development of the pollen tube. The earilest growth is derived from the inclusion into the wall of vesicles containing pre-formed materials present in the grain on pollination. During the next stage of growth the wall is derived from the content of double-membraned inclusions also present in the pollen. The content of the former vesicles is not so similar to the wall as the latter, but intermediates between the 2 types of vesicle may be seen in the cytoplasm, indicating that the former are formed from the latter. Most of the tube wall is derived from the products of dictyosomes in the pollen grain or tube. These dicytosomes are few in number and they must be exceedingly active. This, and the observation that dictyosome vesicles are frequently associated with banked complexes of mitochondria, indicates that some steps in the metabolism of the vesicular content, perhaps phosphorylation, take place distant from the dicytosomes. These different sources of fibrillar material presumably permit the rapid starting of tube growth, without any attendant metabolism. However, it would be impossible to include enough pre-formed wall material in the grain to enable the full growth of the tube, so once started, it seems that the tube then relies on the elaboration of simple reserves for the contruction of its wall. These reserves are likely to be held in the pollen, and may be the large numbers of starch grains characteristic of the pollen cytoplasm.

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

2014 ◽  
Vol 65 (1-2) ◽  
pp. 101-105 ◽  
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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