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Publication Type J
Authors Conceicao, S. I. R., A. S. Rois and A. D. Caperta
Title Nonreduction via meiotic restitution and pollen heterogeneity may explain residual male fertility in triploid marine halophyte Limonium algarvense (Plumbaginaceae)
Source Caryologia
Author Keywords Apomixis In vitro pollen germination Limonium Male sporogenesis and gametogenesis Meiotic restitution Polyploidy evolution mechanisms cytokinesis origin reproduction antioxidant polyploidy tetraspore taraxacum cytomixis
Abstract The cosmopolitan halophylic genus Limonium (Plumbaginaceae) presents high cytogenetic interest because of the natural occurrence of diploid and polyploid variants. Natural triploids are very rare in nature but common in this genus, including the widespread triploid Limonium algarvense found in the Iberian Peninsula and in Morocco. This study describes male sporogenesis and gametogenesis, pollen formation and germination, and seed production in triploid L. algarvense and diploid Limonium ovalifolium using various cytological approaches. The diploid species presented regular meiosis. The triploid species was defective in male meiosis due to unpaired chromosomes, trivalent and tetravalent pairing, unbalanced chromosome segregation in meiosis I, and meiotic restitution in both meiosis I and II. These results may be explained by indeterminate and broad first meiotic restitution. Dyads and restitution nuclei at meiosis I were the most frequent meiotic products in the triploid species. Cytomixis was observed in both species, and callose deposition did not differ among them. In the diploid species, regular, tricolpate pollen grains, which germinated in vitro were found. Contrastingly, the triploid species produced heterogeneous pollen in morphology and size, with moderate to no viability that poorly germinated in vitro. We conclude that even if most triploids male gametes are non-functional, they seem to generate small numbers of viable gametes via nonreduction of chromosomes. Flow cytometric seed screening demonstrated that the diploid species presented a diploid progeny whereas triploids only showed triploid progenies. In the triploids low pollen fertility coupled with viable seed production may assure their persistence in natural populations.
Author Address [Conceicao, Sofia I. R.; Rois, Ana Sofia; Caperta, Ana D.] Univ Lisbon, ISA, Linking Landscape Environm Agr & Food LEAF, P-1349017 Lisbon, Portugal. [Rois, Ana Sofia] ULHT, Sch Psychol & Life Sci, Campo Grande 376, P-1749024 Lisbon, Portugal. Caperta, AD (reprint author), Univ Lisbon, ISA, Linking Landscape Environm Agr & Food LEAF, P-1349017 Lisbon, Portugal. anadelaunay@isa.ulisboa.pt
ISSN 0008-7114
ISBN 0008-7114
29-Character Source Abbreviation Caryologia
Year Published 2019
Volume 72
Issue 3
Beginning Page 53-62
Digital Object Identifier (DOI) 10.13128/caryologia-761
Unique Article Identifier WOS:000516777700006
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