scholarly journals Characterization of the role of several COPI complex isoforms during the early acceptance of compatible pollen grains in Arabidopsis thaliana

2018 ◽  
Author(s):  
Daniel A. Cabada Gomez ◽  
M. Isabella Chavez ◽  
Emily Indriolo

AbstractCOPI is a seven subunit coatomer complex, consisting of α, β, β′, γ, δ, ε, and ξ; in A. thaliana, COPI is necessary for retrograde transport from the Golgi to the Endoplasmic Reticulum, Golgi maintenance, and cell-plate formation in plant cells. Vesicle recruitment to the pollen contact point is required for pollen hydration and pollen tube penetration. To determine what other aspects of trafficking may be involved in the stigmatic papillae acceptance of compatible pollen, knock-out lines of several isoforms of the COPI complex were characterized in their roles during compatible pollination. Isoforms that were studied included α1-COPI, β-COPI, β′-COPI, γ-COPI and ε-COPI. Each mutant line was characterized in regards to pollen grain adherence, pollen tube penetration, and seed set. Of the mutant lines examined, α1-copi had the strongest phenotype with issues with compatible pollen grain adherence, tube germination and reduction in seed set while other lines had milder but visible retardation in compatible pollen acceptance. The data presented here are the first study of the role of the COPI complex in compatible pollinations and that certain subunit isoforms are required for compatible pollen acceptance.


2014 ◽  
Vol 65 (1-2) ◽  
pp. 101-105 ◽  
Author(s):  
Renata Śnieżko ◽  
Krystyna Winiarczyk

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.



2020 ◽  
Author(s):  
Hyun Kyung Lee ◽  
Daphne R. Goring

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.



2021 ◽  
Vol 74 ◽  
Author(s):  
Thomas Sawidis ◽  
Gülriz Baycu ◽  
Elżbieta Weryszko-Chmielewska ◽  
Aneta Sulborska

Abstract In vitro culture of Lilium longiflorum pollen grains was carried out to determine the role of manganese in pollen germination and pollen tube growth. Pollen germination was adversely affected by the presence of manganese (>10 −8 M), whereas low concentrations (10 −12 –10 −10 M) stimulated the process. Manganese caused morphological anomalies during tube growth, characterized by irregular pollen tube thickening and swollen tips. The main effect was the anomalous cell wall formation at the tip, in which the presence of several organelles reduced the number of secretory vesicles. A loose network of fibrillar material and spherical aggregates, mostly in the tip region, was detected, and this material was progressively loosened into the surrounding medium. As a response to potential toxicity, the excess manganese was isolated in vacuoles, which formed an internal barrier against penetration of manganese to the tip area. Elevated manganese concentrations might affect plant reproduction, resulting in anomalies in gamete development. Consequently, the loss in genetic diversity and decreased fruit set ultimately lower yield.



1984 ◽  
Vol 62 (6) ◽  
pp. 1298-1303 ◽  
Author(s):  
Joel S. Shore ◽  
Spencer C. H. Barrett

Controlled pollination experiments were performed on the self-incompatible distylous herb Turnera ulmifolia L. to investigate the effects of pollination intensity and large amounts of incompatible pollen on seed set. In the first experiment, known numbers of compatible pollen grains ranging from 1 to 100 were applied to stigmas of the floral morphs. In both morphs, increasing amounts of pollen generally resulted in increased levels of seed set, although considerable variance was observed at all pollination intensities. Approximately two to seven pollen grains are required to produce a single seed and more than 95 grains are required to achieve maximum seed set in T. ulmifolia. Regression analysis of the seed set data failed to detect a difference in the response of the floral morphs to pollination intensity. In the second experiment, known proportions of compatible and incompatible pollen were applied to stigmas at various time intervals. Most treatments involving mixtures of compatible and incompatible pollen had no significant effect on seed set when compared with the controls. Clogging was only observed in the long-styled morph when one anther of compatible pollen was applied to stigmas 1.5 and 3.0 h after pollination with five anthers of incompatible pollen. The clogging of stigmas by incompatible pollen seems unlikely to have played a major role in the evolution and maintenance of distyly in Turnera ulmifolia.



2014 ◽  
Vol 51 (3-4) ◽  
pp. 341-344 ◽  
Author(s):  
Józef Kocoń ◽  
Stanisław Muszyński

The sculpturing patterns of pollen grains in some species of the <em>Rosaceae</em> family were analyzed by SEM. Three patterns are described, typical for <em>Prunus spinosa, Pyrus elengrifolia</em> and <em>Crataegus</em> sp. The role of SEM analysis of sculpturing patterns in taxonomy can be compared to the "finger print" method in chemical plant taxonomy.



2017 ◽  
Author(s):  
Mahua Ghara ◽  
Christina Ewerhardy ◽  
Gil Yardeni ◽  
Mor Matzliach ◽  
Yuval Sapir

ABSTRACTFlorivory, the damage to flowers by herbivores can affect fitness both directly and indirectly. Flowers consumed by florivores may fail to produce fruit or produce lower seed set because of direct damage to reproductive organs. In addition, eaten flowers are less attractive to pollinators because of reduced or modified advertisement, which reduces pollination services. While observational data are abundant, experimental evidence is scarce and results are contrasting. We tested experimentally the effect of florivory on both pollinator visitation and reproductive success in three species of the Royal Irises, which have large flowers that are attractive to pollinators, and potentially also for florivores. We hypothesized that florivory will reduce pollen deposition due to reduced attractiveness to pollinators, while fruit set and seed set will depend on the extent of florivory. We performed artificial florivory in two experiments over two years. In the first experiment, each of the three floral units of a single Iris flower was subject to either low or high artificial florivory, or left un-touched as control. We counted the number of pollen grains deposited on each of the three stigmas as a measure of pollinator visitation. In the second experiment, three flowers of the same plant received low, high, or no artificial florivory and were further recorded for fruit and seed production. In 2016, high artificial florivory revealed lower number of pollen grains on stigmas of Iris atropurpurea, but in 2017 there was no difference. Similarly, number of pollen grains in high artificial was lower than low florivory in 2017 in I. petrana. No significant effect of florivory was found on pollen grain deposition, fruit set or seed set. The results remained consistent across species and across years. The results undermine the assumption that flower herbivory is necessarily antagonistic interaction and suggests that florivores may not be strong selection agents on floral reproductive biology in the Oncocyclus irises.





2017 ◽  
Vol 32 (1) ◽  
pp. 61-65 ◽  
Author(s):  
Natalia Georgieva ◽  
Ivelina Nikolova ◽  
Valentin Kosev ◽  
Yordanka Naydenova

The objective of this study was to evaluate the influence of two organic nanofertilizers, Lithovit and Nagro, on in vitro germination, pollen tube elongation and pollen grain viability of Pisum sativum L cv. Pleven 4. The effect of their application was high and exceeded data for the untreated control (44.2 and 47.23 % regarding pollen germination and pollen tube elongation, respectively), as well as the effect of the control organic algal fertilizer Biofa (17.5 and 27.9 %, respectively). Pollen grains were inoculated in four culture media. A medium containing 15% sucrose and 1% agar had the most stimulating impact on pea pollen grains. Pollen viability, evaluated by staining with 1% carmine, was within limits of 74.72-87.97%. The highest viability of pollen grains was demonstrated after the application of Nagro organic nano-fertlizer.



2011 ◽  
Vol 48 (No. 8) ◽  
pp. 368-375
Author(s):  
Tejaswini

Present study focuses on making best possible use of male gametophytic generation in carnation breeding program. Exploration of pollen population revealed the existence of variability in terms of pollen morphology and histochemical content among as well as within varieties and species of Dianthus caryophyllus and D. chinensis sufficient to make selection. Pollen grain size and histochemical content were found to be associated with germination capacity and pollen tube growth rate. In addition, pollen germination capacity and elongation of pollen tube in response to presence of culture filtrate from F. oxysporum. f.sp. dianthi causal organism of fusarium wilt in carnation was found to be governed by pollen grain size and histochemical content of pollen grains. Entire result suggests the possibility of selecting the desired pollen grains from a&nbsp;pollen population and possibility of attempting selective pollination in carnation breeding program.



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