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Pollen stigma

Ludi Wang, Zongcheng Lin, Marina Triviño, Moritz K Nowack, Vernonica E Franklin-Tong, Maurice Bosch
Self-Incompatibility (SI) is a genetically controlled mechanism that prevents self-fertilisation and thus encourages outbreeding and genetic diversity. During pollination, most SI systems utilise cell-cell recognition to reject incompatible pollen. Mechanistically, one of the best-studied SI systems is that of Papaver rhoeas (poppy), which involves the interaction between the two S-determinants, a stigma-expressed secreted protein (PrsS) and a pollen-expressed plasma-membrane localised protein (PrpS). This interaction is the critical step in determining acceptance of compatible pollen or rejection of incompatible pollen...
November 16, 2018: Journal of Experimental Botany
Yan Ning Wang, Bo Sen Wang, Qin Zheng Hou, Xue Su, Shi Hu Zhang, Kun Sun
Reproductive isolation, the key process to prevent interspecific hybridization and keep the completeness and independence of species, is crucial to the formation and maintenance of biodiversity. The forming steps, methods and intensities of reproductive isolation between different species are not completely the same. Literatures on reproductive isolation between species provide valuable evidence for speciation and its maintenance. Flowering phenology, flowering-visiting insects, and pollen-stigma compatibility were observed for Ligularia virgaurea and L...
November 2018: Ying Yong Sheng Tai Xue Bao, the Journal of Applied Ecology
J M Bennett, J A Steets, W Durka, J C Vamosi, G Arceo-Gómez, M Burd, L A Burkle, A G Ellis, L Freitas, J Li, J G Rodger, M Wolowski, J Xia, T-L Ashman, T M Knight
Plant reproduction relies on transfer of pollen from anthers to stigmas, and the majority of flowering plants depend on biotic or abiotic agents for this transfer. A key metric for characterizing if pollen receipt is insufficient for reproduction is pollen limitation, which is assessed by pollen supplementation experiments. In a pollen supplementation experiment, fruit or seed production by flowers exposed to natural pollination is compared to that following hand pollination either by pollen supplementation (i...
November 20, 2018: Scientific Data
George D Hoffman, Claire Lande, Sujaya Rao
Honey bees (Apis mellifera L. (Hymenoptera: Apidae)) are effective pollinators of many crops but are thought to be inefficient in pollinating blueberries (Vaccinium corymbosum L.) due to their inability to buzz pollinate. Nonetheless, commercial growers rent honey bee hives for pollination, resulting in the dominance of honey bee workers visiting flowers during bloom. The objective of this study was to examine where on the honey bee pollen is carried and how it is transferred from flower to bee to the stigma of other flowers...
November 19, 2018: Environmental Entomology
Yang-Yang Zheng, Xian-Ju Lin, Hui-Min Liang, Fang-Fei Wang, Li-Yu Chen
In non-cleistogamous plants, the male gametophyte, the pollen grain is immotile and exploits various agents, such as pollinators, wind, and even water, to arrive to a receptive stigma. The complex process of pollination involves a tubular structure, i.e., the pollen tube, which delivers the two sperm cells to the female gametophyte to enable double fertilization. The pollen tube has to penetrate the stigma, grow in the style tissues, pass through the septum, grow along the funiculus, and navigate to the micropyle of the ovule...
November 9, 2018: International Journal of Molecular Sciences
Alicia Armentia, Sara Martín Armentia, Rafael Álvarez-Nogal, Blanca Martín Armentia, Manuel José Gayoso, Delia Fernández-González
BACKGROUND: Eosinophilic esophagitis (EoE) is characterized by esophageal dysfunction and, histologically, by eosinophilic inflammation. There is no a clear etiologic treatment. EoE exacerbations are often seasonal. We hypothesized that the inflammatory response of the esophageal mucosa in patients with high levels of antibodies to pollen allergens and worsened seasonal EoE might be due to swallowing airborne pollen and the intrusion into the esophageal mucosa of pollen allergens and pollen tubes, which encounter a pH and humidity resembling the stigma at pollination...
November 12, 2018: Clinical and Experimental Allergy: Journal of the British Society for Allergy and Clinical Immunology
W Scott Armbruster, Juliet A Wege
Background and Aims: The Berg hypothesis proposes that specialized-flower traits experience stronger stabilizing selection than non-floral structures and predicts that variation in specialized-flower traits will be mostly uncorrelated with variation in non-floral traits. Similarly, adaptive-accuracy theory predicts lower variation (as a proportion of the mean) in floral traits than in non-floral ones. Both hypotheses can be extended to comparisons between floral traits, where different parts of the flower can be expected to experience different strengths of stabilizing selection, resulting in contrasting patterns of variation...
October 31, 2018: Annals of Botany
Juannan Zhou, Elizabeth A Zimmer, Charles B Fenster, Michele R Dudash
PREMISE OF THE STUDY: Nursery pollination systems can range from obligate to facultative. In a system where generalists provide substantial pollination service, an important question is whether the cost of seed predation outweighs the benefit provided by the nursery pollinator to cause the plant to evolve toward more generalized pollination. Using a facultative system native to North America, we tested whether nursery pollinator vs. strictly mutualistic generalists affect mating-system parameters of the host plant and explored the implications for long-term coevolution...
October 2018: American Journal of Botany
Daisuke Tsugama, Shenkui Liu, Kaien Fujino, Tetsuo Takano
Protein phosphatase 2A (PP2A) is a heterotrimeric protein complex conserved among eukaryotes. The B subunit of PP2A determines the substrate specificity of the PP2A holoenzyme, and is classified into the B, B', B″ and B‴ families. Arabidopsis thaliana has two isoforms of the B-family subunit (ATBA and ATBB). A double knockout of their genes is lethal, but which developmental process is primarily impaired by the double knockout is unclear. Identifying such a process helps understand PP2A-mediated signaling more deeply...
September 19, 2018: Biochemical and Biophysical Research Communications
Madeline A E Peters, Arthur E Weis
Coexpression of genes in plant sporophytes and gametophytes allows correlated gametic and sporophytic selection. Theory predicts that, under outcrossing, an allele conferring greater pollen competitive ability should fix within a population unless antagonistic pleiotropy with the sporophyte stage is strong. However, under strong selfing, pollen competitiveness is immaterial as superior and inferior competitors are deposited on opposite stigmas, producing assortative competition. Because many plant species have mixed-mating systems, selfing should be critical in the spread and maintenance of pollen-expressed genes affecting competitiveness...
November 2018: Evolution; International Journal of Organic Evolution
A L Teixido, M O Duarte, I Ballego-Campos, D Sanín, J S Cunha, C S Oliveira, F A O Silveira
Long-lived flowers increase pollen transfer rates, but these entail high water and carbon maintenance costs. The retention of pollinated and reward-free old flowers enhances pollinator visitation to young receptive flowers by increasing floral display size. This mechanism is associated with acropetal inflorescences or changes in flower colour and openness, but the retention of unchanging solitary flowers remains overlooked. We examined pollination-dependent variation in floral longevity and determined stigmatic receptivity, pollen viability and pollen removal rates among flower ages in Kielmeyera regalis, a Neotropical savanna shrub...
September 5, 2018: Plant Biology
Gerardo Arceo-Gómez, Conchita Alonso, Tia-Lynn Ashman, Victor Parra-Tabla
PREMISE OF THE STUDY: There is growing interest in understanding plant-plant interactions via pollen transfer at the community level. Studies on the structure and spatial variability of pollen transfer networks have been valuable to this understanding. However, there is high variability in the intensity of sampling used to characterize pollen transfer interactions, which could influence network structure. To date, there is no knowledge of how sampling effort influences the richness of pollen on stigmas and thereby transfer interactions observed, nor how this may vary across species and study sites...
September 2018: American Journal of Botany
Daniela Farinelli, Catherine Breton, Georgios Koubouris, Franco Famiani, Pierre Villemur, André Bervillé
This study was carried out to examine the validity of previous studies on the intercompatibility of olive and to compare the approach and techniques used for proposing the diallelic self-incompatibility system and the sporophytic self-incompatibility system. Analysis of the literature indicates that the mating system of the olive tree is a controversial issue and requires further studies to clearly and fully comprehend it. All possible approaches should be used to maximize reliability of the final conclusions on the olive mating system...
September 2018: Evolutionary Applications
Xianping Fang, Ya Xin, Zheliang Sheng, Hui Liu, Aili Jiang, Fang Wang, Jian Yang, Xiaojun Xi, Qian Zha, Liqing Zhang, Liangying Dai, Chengqi Yan, Jianping Chen
The various post-translational modifications of plant proteins have important regulatory roles in development. We therefore examined various modified proteins from strawberry stigmata and found that succinylation of lysine residues was the most abundant type of modification. We then subjected proteins from strawberry stigmata to an efficient enrichment method for succinylated peptides and identified 200 uniquely succinylated lysines in 116 proteins. A bioinformatics analysis revealed that these proteins are involved in important biological processes, including stress responses, vesicular transport, and energy metabolism...
August 27, 2018: Journal of Agricultural and Food Chemistry
Yunfei Jiang, Rachid Lahlali, Chithra Karunakaran, Thomas D Warkentin, Arthur R Davis, Rosalind A Bueckert
Field pea (Pisum sativum), a major grain legume crop, is autogamous and adapted to temperate climates. The objectives of this study were to investigate effects of high temperature stress on stamen chemical composition, anther dehiscence, pollen viability, pollen interactions with pistil and ovules, and ovule growth and viability. Two cultivars ("CDC Golden" and "CDC Sage") were exposed to 24/18°C (day/night) continually or to 35/18°C for 4 or 7 days. Heat stress altered stamen chemical composition, with lipid composition of "CDC Sage" being more stable compared with "CDC Golden...
August 22, 2018: Plant, Cell & Environment
Yun-Peng Song, Zhi-Huan Huang, Shuang-Quan Huang
Pollen grains can be dispersed singly or variously aggregated in groups. Whether the evolution of pollen aggregation is driven by the pollinator remains unexplored. We hypothesize that an extensive pollen aggregation is favored under a scarcity of pollinators. Variation in pollen aggregation by viscin threads in 13 Rhododendron species was measured as it is related to pollen removal in a visit. Visitation rates of functional pollinator groups that vary in their grooming behavior were investigated in each species...
August 19, 2018: New Phytologist
Anna L Johnson, Tia-Lynn Ashman
Pollination is known to be sensitive to environmental change but we lack direct estimates of how quantity and quality of pollen transferred between plant species shifts along disturbance gradients. This limits our understanding of how species compositional change impacts pollen receipt per species and structure of pollen transfer networks. We constructed pollen transfer networks along a plant invasion gradient in the Hawaiian dry tropical forest ecosystem. Flowers and stigmas were collected from both native and introduced plants, pollen was identified and enumerated and floral traits were measured...
August 7, 2018: New Phytologist
Nidhi Sehgal, Saurabh Singh
The sporophytic system of self-incompatibility is a widespread genetic phenomenon in plant species, promoting out-breeding and maintaining genetic diversity. This phenomenon is of commercial importance in hybrid breeding of Brassicaceae crops and is controlled by single S locus with multiple S haplotypes. The molecular genetic studies of Brassica ' S ' locus has revealed the presence of three tightly linked loci viz. S-receptor kinase ( SRK ), S-locus cysteine-rich protein/S-locus protein 11 ( SCR / SP11 ), and S-locus glycoprotein ( SLG )...
August 2018: 3 Biotech
Wei Liu, Maosong Pei, Anning Zhang
Peach (Prunus persica L.) generally exhibits self-pollination, however, they can also be pollinated by other varieties of pollen. Here we found two varieties that are different from other peaches: 'Daifei' and 'Liuyefeitao'. 'Daifei' produces less pollen, which needs artificial pollination, honeybee pollination, and the fruit setting depends on other varieties of peach pollen. 'Liuyefeitao' exhibits strictly self-pollination, hence pollen from other species is rejected. To explore the mechanism of this phenomenon, we performed a high-throughput sequencing of the stigma (including style) of 'Daifei' and 'Liuyefeitao' to explain the rejection mechanism of other varieties of pollen of 'Liuyefeitao' peach...
2018: PloS One
Roberto Sáyago, Mauricio Quesada, Ramiro Aguilar, Lorena Ashworth, Martha Lopezaraiza-Mikel, Silvana Martén-Rodríguez
Fragmentation of natural habitats generally has negative effects on the reproductive success of many plant species; however, little is known about epiphytic plants. We assessed the impact of forest fragmentation on plant-pollinator interactions and female reproductive success in two epiphytic Tillandsia species with contrasting life history strategies (polycarpic and monocarpic) in Chamela, Jalisco, Mexico, over three consecutive years. Hummingbirds were the major pollinators of both species and pollinator visitation rates were similar between habitat conditions...
August 2018: AoB Plants
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