Variability of pollen grain features: a plant strategy to maximize reproductive fitness in two species of Dianthus ?

Tejaswini,

doi:10.1007/s00497-002-0130-z

Cited by 22 publications

(9 citation statements)

References 24 publications

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“…Abnormal pollen may be the result of natural intraspecific variation and higher internal genetic variability of the parent plant (e.g., Lindström et al, 1997;Leitch and Leitch, 2012), but the variability is reflected most frequently in size differences (e.g., Tejaswini, 2002;Ejsmond et al, 2011).…”

Section: Aberrant Pollen Grains At the Petrified Forest National Parkmentioning

confidence: 99%

Norian vegetation history and related environmental changes: New data from the Chinle Formation, Petrified Forest National Park (Arizona, SW USA)

et al. 2017

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Fossil plant assemblages including spores and pollen grains provide useful information on past ecosystems and the response of terrestrial biotas to various environmental perturbations. New quantitative palynological data from the Chinle Formation of the American Southwest suggest that a floral turnover occurred in the middle Norian (between 217 and 213 Ma). Analysis of plant communities reveals that this turnover was followed by a complete reorganization of the riparian vegetation, driven by changes in fluvial styles and the tectonic regime of the basin, as well as a gradual transition toward a more arid climate. Marked increases in Klausipollenites gouldii, Patina sporites spp., and Froelichsporites traversei are probable indicators of environmental stress, such as increased aridity, perturbations of atmospheric pCO 2 , acid rain, and atmospheric aerosol accumulation due to volcanism in connection with the Pangean rifting and uplift of the Cordilleran arc. Comparison of the vegetation turnover with younger assemblages from the Chinle Formation in New Mexico revealed similar floral turnover patterns, suggesting two distinct drier periods as a result of multiple climatic oscillations. The climate-induced floral turnover may have contributed to the vertebrate faunal turnover as the loss of wetland habitat space and an increase in xerophytic plants may have dwindled the supply of palatable vegetation for herbivores. The onset of the floral turnover in Arizona roughly corresponds to the Manicouagan impact event, but a direct causal link is still speculative.

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Section: Aberrant Pollen Grains At the Petrified Forest National Parkmentioning

confidence: 99%

Norian vegetation history and related environmental changes: New data from the Chinle Formation, Petrified Forest National Park (Arizona, SW USA)

et al. 2017

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“…For example, Colletotrichum fungal species use pollen to spread in Citrus sinensis ( Marques et al., 2013 ). Fg and other Fusarium species are present in pollen, as noted earlier, but they are not known to be transmitted to seed ( Tejaswini, 2002 ; Kačániová et al., 2011 ; Kostić et al., 2019 ). However, we could only find one report showing pollen-mediated transmission of bacterial pathogens: specifically Pseudomonas syringae pv.…”

Section: Discussionmentioning

confidence: 77%

“…ZEA acts as a hormone that regulates fungal sexual reproduction ( Wolf and Mirocha, 1973 ). Fg , other Fusarium species and their mycotoxins present in pollen were reported to disrupt pollen tube growth ( Tejaswini, 2002 ; Kačániová et al., 2011 ; Kostić et al., 2019 ), thus directly affecting the genetic contribution of the male gamete.…”

Section: Introductionmentioning

confidence: 99%

Maize pollen carry bacteria that suppress a fungal pathogen that enters through the male gamete fertilization route

Shrestha,

Limay-Rios,

Brettingham

et al. 2024

Front. Plant Sci.

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In flowering plants, after being released from pollen grains, the male gametes use the style channel to migrate towards the ovary where they fertilize awaiting eggs. Environmental pathogens exploit the style passage, resulting in diseased progeny seed. The belief is that pollen also transmits pathogens into the style. By contrast, we hypothesized that pollen carries beneficial microbes that suppress environmental pathogens on the style passage. No prior studies have reported pollen-associated bacterial functions in any plant species. Here, bacteria were cultured from maize (corn) pollen encompassing wild ancestors and farmer-selected landraces from across the Americas, grown in a common field in Canada for one season. In total, 298 bacterial isolates were cultured, spanning 45 genera, 103 species, and 88 OTUs, dominated by Pantoea, Bacillus, Pseudomonas, Erwinia, and Microbacterium. Full-length 16S DNA-based taxonomic profiling showed that 78% of bacterial taxa from the major wild ancestor of maize (Parviglumis teosinte) were present in at least one cultivated landrace. The species names of the bacterial isolates were used to search the pathogen literature systematically; this preliminary evidence predicted that the vast majority of the pollen-associated bacteria analyzed are not maize pathogens. The pollen-associated bacteria were tested in vitro against a style-invading Fusarium pathogen shown to cause Gibberella ear rot (GER): 14 isolates inhibited this pathogen. Genome mining showed that all the anti-Fusarium bacterial species encode phzF, associated with biosynthesis of the natural fungicide, phenazine. To mimic the male gamete migration route, three pollen-associated bacterial strains were sprayed onto styles (silks), followed by Fusarium inoculation; these bacteria reduced GER symptoms and mycotoxin accumulation in progeny seed. Confocal microscopy was used to search for direct evidence that pollen-associated bacteria can defend living silks against Fusarium graminearum (Fg); bacterial strain AS541 (Kluyvera intermedia), isolated from pollen of ancestral Parviglumis, was observed to colonize the susceptible style/silk entry points of Fg (silk epidermis, trichomes, wounds). Furthermore, on style/silk tissue, AS541 colonized/aggregated on Fg hyphae, and was associated with Fg hyphal breaks. These results suggest that pollen has the potential to carry bacteria that can defend the style/silk passage against an environmental pathogen – a novel observation.

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“…The size and aperture number of a pollen grain may significantly influence the fertilization success of individual grains and, thus, individual plant fitness. The growth of the pollen tube is faster and longer in a large-sized grain (Aizen and Raffaele, 1998;Tejaswini, 2002). Four-aperturate pollen (of the genus Viola) germinated faster (positive correlation), but produced shorter pollen tubes in vitro and had reduced longevity (negative correlation) as compared to 3-aperturate pollen grains (Dajoz et al, 1991).…”

Section: Discussionmentioning

confidence: 99%

Pollen heteromorphism in Schleichera Lour. (Sapindaceae), observed in surface soil samples from central India

Quamar¹,

Thakur²,

Singh³

et al. 2021

Acta Palaeobotanica

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Angiosperms display striking variation of pollen morphological features within and between populations of the same species, as well as within individual plants. We describe and illustrate variation of pollen aperture number, which is called pollen heteromorphism, in Schleichera Lour. (Sapindaceae) from surface soil samples collected from central India, based on combined observations from light microscopy (LM) and confocal laser scanning microscopy (CLSM). Tri-zono-parasyncolporoidate pollen grains are, in general, known to occur in Schleichera Lour., but occasional tetra-zono-parasyncolporoidate pollen is also recorded, for the first time, from Chhattisgarh State, central India. Changes in ploidy level (diploidy/polyploidy), chromosome number, the C-value of DNA, completion of meiosis, as well as environmental factors and/or pollination ecology could be driving the occurrence of pollen heteromorphism. The present study could provide insights into the phylogeny and systematics, and has implications for pollen preservation as well.

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Variability of pollen grain features: a plant strategy to maximize reproductive fitness in two species of Dianthus ?

Cited by 22 publications

References 24 publications

Norian vegetation history and related environmental changes: New data from the Chinle Formation, Petrified Forest National Park (Arizona, SW USA)

Norian vegetation history and related environmental changes: New data from the Chinle Formation, Petrified Forest National Park (Arizona, SW USA)

Maize pollen carry bacteria that suppress a fungal pathogen that enters through the male gamete fertilization route

Pollen heteromorphism in Schleichera Lour. (Sapindaceae), observed in surface soil samples from central India

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