scholarly journals Pollen-pistil interactions in interspecific crosses of Populus (sections Aigeiros and Leuce): pollen adhesion, hydration and callose responses

1984 ◽  
Vol 72 (1) ◽  
pp. 173-184
Author(s):  
M. Gaget ◽  
C. Said ◽  
C. Dumas ◽  
R.B. Knox
Keyword(s):  
Pollen Tube ◽  
Cell Walls ◽  
Populus Deltoides ◽  
Pollen Tubes ◽  
Interspecific Crosses ◽  
Transmitting Tissue ◽  
Stigma Surface ◽  
The Cross ◽  
Plug Formation ◽  
Callose Plug

Intersectional crosses between species of sections Aigeiros (Populus deltoides, P. X euramericana or P. nigra) and Leuce (P. alba or P. tremuloides) are known to be reciprocally incompatible. The site of pollen tube arrest is on the stigma surface in pollinations between pistils of section Leuce and pollen of section Aigeiros; tubes failed to penetrate the stigma surface. In reciprocal matings, pollen of section Leuce germinated and tubes penetrated the stigma and style, where arrest occurred. Rejection may be accompanied by swelling of the tube tips, and callose plug formation. In the cross between P. deltoides and P. alba a callose response was detected in the cell walls of the transmitting tissue, adjacent to the rejected pollen tubes.

Overgrowth of Pollen Tubes in Embryo Sacs of Rhododendron Following Interspecific Pollinations

1986 ◽  
Vol 34 (4) ◽  
pp. 413 ◽  
Author(s):  
EG Williams ◽  
V Kaul ◽  
JL Rouse ◽  
BF Palser
Keyword(s):  
Pollen Tube ◽  
Embryo Sac ◽  
Pollen Tubes ◽  
Egg Cell ◽  
Interspecific Crosses ◽  
Main Body

Frequent overgrowths of pollen tubes within the embryo sac are characteristic of a number of interspecific crosses in the genus Rhododendron (Ericaceae). The combined techniques of sectioning, squashing and whole-ovule clearing have confirmed that in ovules showing this phenomenon the pollen tube fails to terminate growth and release sperms on entry into a synergid; instead it continues to grow beyond the synergid and egg cell, often filling the main body of the embryo sac with a coiled and distorted mass. Such ovules fail to develop further. The occurrence and possible causes of this error syndrome are discussed.

scholarly journals The synstigma turns the fig into a large flower

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.

scholarly journals Attractive and repulsive interactions between female and male gametophytes in Arabidopsis pollen tube guidance

Development ◽  
2000 ◽  
Vol 127 (20) ◽  
pp. 4511-4518 ◽  
Author(s):  
K.K. Shimizu ◽  
K. Okada
Keyword(s):  
Pollen Tube ◽  
Female Gametophyte ◽  
Inclusive Fitness ◽  
Male Gametophyte ◽  
Pollen Tubes ◽  
Interspecific Crosses ◽  
Pollen Tube Guidance ◽  
Normal Number ◽  
Mutant Female ◽  
Diploid Cells

Sexual reproduction in plants, unlike that of animals, requires the action of multicellular haploid gametophytes. The male gametophyte (pollen tube) is guided to a female gametophyte through diploid sporophytic cells in the pistil. While interactions between the pollen tube and diploid cells have been described, little is known about the intercellular recognition systems between the pollen tube and the female gametophyte. In particular, the mechanisms that enable only one pollen tube to interact with each female gametophyte, thereby preventing polysperm, are not understood. We isolated female gametophyte mutants named magatama (maa) from Arabidopsis thaliana by screening for siliques containing half the normal number of mature seeds. In maa1 and maa3 mutants, in which the development of the female gametophyte was delayed, pollen tube guidance was affected. Pollen tubes were directed to mutant female gametophytes, but they lost their way just before entering the micropyle and elongated in random directions. Moreover, the mutant female gametophytes attracted two pollen tubes at a high frequency. To explain the interaction between gametophytes, we propose a monogamy model in which a female gametophyte emits two attractants and prevents polyspermy. This prevention process by the female gametophyte could increase a plant's inclusive fitness by facilitating the fertilization of sibling female gametophytes. In addition, repulsion between pollen tubes might help prevent polyspermy. The reproductive isolations observed in interspecific crosses in Brassicaceae are also consistent with the monogamy model.

scholarly journals Pollen Tube Growth in Interspecific Crosses between Capsicum Species

HortScience ◽  
1991 ◽  
Vol 26 (5) ◽  
pp. 585-586 ◽  
Author(s):  
Sierd Zijlstra ◽  
Coen Purimahua ◽  
Pim Lindhout
Keyword(s):  
Pollen Tube ◽  
Capsicum Annuum ◽  
Pollen Tube Growth ◽  
Pollen Tubes ◽  
Tube Growth ◽  
Egg Cell ◽  
Interspecific Crosses ◽  
Capsicum Species ◽  
Pollen Tube Penetration ◽  
Capsicum Chacoense

Crossing barriers between white- and purple-flowered species were examined. Four accessions of Capsicum annuum and three of C. pubescens were reciprocally crossed with one to four accessions of C. baccatum, C. cardenasii, C. chacoense, C. chinense, C. eximium, C. frutescens, C. galapagoense, and C. praetermissum. Capsicum chacoense is the only white-flowered species that inhibits C. annuum pollen tube growth but allows C. pubescens pollen tube penetration into the egg cell. Capsicum cardenasii and C. eximium exhibit similar crossabilities with C. annuum and C. pubescens: pollen tubes of C. cardenasii and of C. eximium can penetrate the egg cells of C. annuum but not vice versa, and pollen tubes of C. pubescens can penetrate the egg cells of C. cardenasii and of C. eximium but not vice versa.

A quantitative and structural comparison of Citrus pollen tube development in cross-compatible and self-incompatible gynoecia

1986 ◽  
Vol 64 (11) ◽  
pp. 2548-2555 ◽  
Author(s):  
Tracy L. Kahn ◽  
Darleen A. DeMason
Keyword(s):  
Pollen Tube ◽  
Pollen Tubes ◽  
Citrus Paradisi ◽  
Structural Comparison ◽  
Stigma Surface ◽  
Incompatible Pollination ◽  
Compatible Cross ◽  
Incompatible Cross ◽  
Compatible Pollinations ◽  
Compatible Pollen

Pollen tube development in Orlando tangelo (Citrus paradisi Macf. × C. reticulata Blanco.) was compared within and between cross-compatible pollinations of Orlando pollen on Dancy tangerine (C. reticulata Blanco.) stigmas and self-incompatible pollinations on Orlando tangelo stigmas. Orlando and Dancy gynoecia were morphologically similar but differed slightly in stigma, style, and ovary lengths. Orlando pollen tube development was studied 1, 3, 6, 9, and 12 days after both cross- and self-pollination to record the number of pollen tubes at each of five levels: stigma surface, upper style, lower style, ovary, and entrance into ovules. In the incompatible cross (self-pollinated Orlando), the stigma was the primary region of pollen tube arrest. In the compatible cross (Orlando pollen on Dancy), some pollen tubes penetrated ovules between 9 and 12 days after cross pollination; however, other pollen tubes were arrested in the stigma. Pollen tubes that successfully penetrated ovules in the compatible cross differed morphologically from pollen tubes arrested in both the compatible and incompatible situations. Successful compatible pollen tubes were straight with thin-walled tips and regularly spaced callose plugs behind the growing tips. Many pollen tube abnormalities associated with the self-incompatible pollination of Orlando were also present among arrested pollen tubes from the compatible cross.

Pollen Tube Growth and Early Seed Development in Eucalyptus regnans F. Muell. (Myrtaceae) in Relation to Ovule Structure and Preferential Outcrossing

1989 ◽  
Vol 37 (5) ◽  
pp. 397 ◽  
Author(s):  
M Sedgley ◽  
FC Hand ◽  
RM Smith ◽  
AR Griffin
Keyword(s):  
Pollen Tube ◽  
Phase Contrast ◽  
Pollen Tubes ◽  
Central Canal ◽  
Transmitting Tissue ◽  
Bright Field ◽  
Eucalyptus Regnans ◽  
Cross Pollination ◽  
Early Seed Development ◽  
Scanning Electron

Pistils of Eucalyptus regnans were observed by bright field, fluorescence, phase contrast, Nomarski, and scanning electron microscopy from 4 weeks prior to anthesis to 16 weeks after self- and cross- pollination. The transmitting tissue of the style had a central canal which extended for half its length. The unfertilised ovary contained a mean of 30.5 ovular structures with 16.5 normal ovules, 2.5 abnor- mal ovules, and 11.5 sterile ovulodes. The ovules were arranged in two rows in three (occasionally four) locules. The ovulodes always occupied positions at the stylar end of the ovary, but with this exception there was no pattern to the occurrence of the abnormal ovules. Pollen tubes grew between the cells'of the transmitting tissue, and not in the stylar canal. Penetration of the ovules had commenced by 5 days after both self- and cross-pollination. The early fertilised ovule contained a zygote and free-nuclear endosperm, and embryos with between 1 and 16 cells were present at 16 weeks after pollination. Not all normal ovules were fertilised, despite adequate numbers of pollen tubes. Ovulodes were never observed to be penetrated by a pollen tube, but with this exception there was no relationship between position on the placenta and either the penetration of ovules by a pollen tube or the occurrence of fertilised ovules. There was no difference between self- and cross-pollination in either the number of ovules penetrated by a pollen tube, or the number of fertilised ovules up to 16 weeks following pollination.

Timetable of Stigmatic Receptivity and Development and Pollen Tube Growth in Chamelaucium uncinatum (Myrtaceae)

1996 ◽  
Vol 44 (6) ◽  
pp. 649 ◽  
Author(s):  
SP Obrien
Keyword(s):  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Pollen Tubes ◽  
The Self ◽  
Transmitting Tissue ◽  
Short Side ◽  
Secondary Pollen Presentation ◽  
Pollen Presentation ◽  
Days After Anthesis ◽  
Chamelaucium Uncinatum

The stigma of Chamelaucium uncinatum Schauer is small and unreceptive at anthesis, but increases in size and becomes fully receptive 7 days after anthesis. After germination, pollen tubes grow intercellularly through the stigma and transmitting tissue of the style. Chamelaucium uncinatum has a single loculus containing six ovules with axile placentation. The transmitting tissue skews to one side within the ovary and the pollen tubes grow into the placenta via an invagination along one end of the loculus. Pollen tubes are smooth-walled in the transmitting tissue of the style and ovary, but within the loculus pollen tubes produce short side branches. Secondary pollen presentation occurs in C. uncinatum with the stigmatic region being used as a pollen presenter. If the self-pollen is not removed from the stigma prior to the onset of receptivity self-pollination may occur.

scholarly journals KATANIN-dependent mechanical properties of the stigmatic cell wall mediate the pollen tube path in Arabidopsis

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Lucie Riglet ◽  
Frédérique Rozier ◽  
Chie Kodera ◽  
Simone Bovio ◽  
Julien Sechet ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cell Wall ◽  
Pollen Tube ◽  
Cell Walls ◽  
Cell Shape ◽  
Pollen Tubes ◽  
Mechanical Anisotropy ◽  
Cellulose Microfibrils ◽  
Cortical Microtubules ◽  
Isotropic Reorientation

Successful fertilization in angiosperms depends on the proper trajectory of pollen tubes through the pistil tissues to reach the ovules. Pollen tubes first grow within the cell wall of the papilla cells, applying pressure to the cell. Mechanical forces are known to play a major role in plant cell shape by controlling the orientation of cortical microtubules (CMTs), which in turn mediate deposition of cellulose microfibrils (CMFs). Here, by combining imaging, genetic and chemical approaches, we show that isotropic reorientation of CMTs and CMFs in aged Col-0 and katanin1-5 (ktn1-5) papilla cells is accompanied by a tendency of pollen tubes to coil around the papillae. We show that this coiled phenotype is associated with specific mechanical properties of the cell walls that provide less resistance to pollen tube growth. Our results reveal an unexpected role for KTN1 in pollen tube guidance on the stigma by ensuring mechanical anisotropy of the papilla cell wall.

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.

Pollen-Pistil Interactions as Reproductive Barriers

2021 ◽  
Vol 72 (1) ◽  
pp. 615-639
Author(s):  
Amanda K. Broz ◽  
Patricia A. Bedinger
Keyword(s):  
Pollen Tube ◽  
Mate Selection ◽  
Critical Role ◽  
Pollen Tubes ◽  
Reproductive Barriers ◽  
Transmitting Tissue ◽  
Active Systems ◽  
Heterospecific Pollen ◽  
Pollen Rejection ◽  
Cell Release

Pollen-pistil interactions serve as important prezygotic reproductive barriers that play a critical role in mate selection in plants. Here, we highlight recent progress toward understanding the molecular basis of pollen-pistil interactions as reproductive isolating barriers. These barriers can be active systems of pollen rejection, or they can result from a mismatch of required male and female factors. In some cases, the barriers are mechanistically linked to self-incompatibility systems, while others represent completely independent processes. Pollen-pistil reproductive barriers can act as soon as pollen is deposited on a stigma, where penetration of heterospecific pollen tubes is blocked by the stigma papillae. As pollen tubes extend, the female transmitting tissue can selectively limit growth by producing cell wall–modifying enzymes and cytotoxins that interact with the growing pollen tube. At ovules, differential pollen tube attraction and inhibition of sperm cell release can act as barriers to heterospecific pollen tubes.

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