![]() Life-history strategies combining sexual and asexual reproduction can result in stable population structure under variable environmental conditions when the two modes of reproduction are successful in different circumstances ( Bengtsson and Ceplitis, 2000 Ofir and Kigel, 2014). Pseudovivipary, reproduction, seagrass, seed abortion, Posidonia australis, seagrass, heat wave, salinity, hybridization, somatic mutation, genetic mosaicism, clonality, evolution INTRODUCTION This may have important long-term implications as both genetic and ecological constraints may limit the ability to adapt or range-shift this seagrass meadow in Shark Bay already has low genetic diversity, no sexual reproduction and no seedling recruitment. This study documents a physiological response at the trailing edge, whereby reproductive strategy can adapt to fluctuating conditions and suggests that the lower-than-usual water temperature triggered unfertilized inflorescences to ‘switch’ to growing plantlets that were adventitious clones of their maternal parent. ![]() The genome size (2 C value) for samples from Shark Bay and from a separate site much further south was not significantly different, implying they are the same ploidy level and ruling out a complete genome duplication (polyploidy).Ĭonclusions Survival at range edges often sees the development of novel responses in the struggle for survival and reproduction. Ploidy was identical in all sampled plants. ![]() It was found that 87 % of the multilocus genotypes contained three alleles in at least one locus. Key Results All adventitious plantlets were genetically identical to the maternal plant and were therefore the product of a novel pseudoviviparous reproductive event. Ploidy and genome size were estimated using flow cytometry. Methods Polymorphic microsatellite DNA markers were used to generate multilocus genotypes to determine the origin of the adventitious inflorescence-derived plantlets. These novel plantlets are described and a combination of microsatellite DNA markers and flow cytometry is used to determine their origin. This study reports the first observations of adventitious inflorescence-derived plantlet formation in the marine angiosperm Posidonia australis, growing at the northern range edge (upper thermal and salinity tolerance) in Shark Bay, Western Australia. Extreme and prolonged fluctuations in environmental conditions, often associated with climate change and exacerbated at species’ geographical range edges, are known to trigger alternative responses in reproduction. Background and Aims Organisms occupying the edges of natural geographical ranges usually survive at the extreme limits of their innate physiological tolerances. ![]()
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