Pollination Drop in Juniperus communis: Response to Deposited Material

Mugnaini, Serena; Nepi, Massimo; Guarnieri, Massimo; Piotto, B.; Pacini, Ettore

doi:10.1093/aob/mcm253

Cited by 44 publications

(49 citation statements)

References 33 publications

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“…This simulated drop retraction occurred over a period of c . 1 min, which is faster than natural rates of drop withdrawal (Doyle & O’Leary, 1935; Mugnaini et al. , 2007).…”

Section: Resultsmentioning

confidence: 93%

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Flotation preferentially selects saccate pollen during conifer pollination

Leslie

2010

New Phytologist

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Summary• Among many species of living conifers the presence of pollen with air bladders (saccate pollen) is strongly associated with downward-facing ovules and the production of pollination drops. This combination of features enables saccate pollen grains captured in the pollination drop to float upwards into the ovule. Despite the importance of this mechanism in understanding reproduction in living conifers and in extinct seed plants with similar morphologies, experiments designed to test its effectiveness have yielded equivocal results.• In vitro and in vivo pollination experiments using saccate and nonsaccate pollen were performed using modeled ovules and two Pinus species during their natural pollination period.• Buoyant saccate pollen readily floated through aqueous droplets, separating these grains from nonbuoyant pollen and spores. Ovules that received saccate pollen, nonsaccate pollen or a mixture of both all showed larger amounts and higher proportions of saccate pollen inside ovules after drop secretion.• These results demonstrate that flotation is an effective mechanism of pollen capture and transport in gymnosperms, and suggest that the prevalence of saccate grains and downward-facing ovules in the evolutionary history of seed plants is a result of the widespread use of this mechanism.

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“…This simulated drop retraction occurred over a period of c . 1 min, which is faster than natural rates of drop withdrawal (Doyle & O’Leary, 1935; Mugnaini et al. , 2007).…”

Section: Resultsmentioning

confidence: 93%

“…A significant and potentially confounding issue that may explain some of these differences is the relatively rapid withdrawal of the pollination drop back into the ovule after it encounters pollen (Doyle & O’Leary, 1935; Owens et al. , 1998; Mugnaini et al. , 2007).…”

Section: Introductionmentioning

confidence: 99%

Flotation preferentially selects saccate pollen during conifer pollination

Leslie

2010

New Phytologist

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“…Pinus spp. pollen and inorganic particles) may reduce the probability of successful pollination (Mugnaini et al. 2007).…”

Section: Discussionmentioning

confidence: 99%

Critical phases in the seed development of common juniper (Juniperus communis)

et al. 2012

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Common juniper (Juniperus communis L.) populations in northwest European lowlands are currently declining in size and number. An important cause of this decline is a lack of natural regeneration. Low seed viability seems to be one of the main bottlenecks in this process. Previous research revealed a negative relation between seed viability and both temperature and nitrogen deposition. Additionally, the seeds of common juniper have a variable ripening time, which possibly influences seed viability. However, the underlying mechanisms remain unresolved. In order to elucidate this puzzle, it is important to understand in which phases of seed production the main defects are situated, together with the influence of ripening time. In this study, we compared seed viability of populations with and without successful recruitment. We examined three seed phases: (i) gamete development; (ii) fertilisation and early-embryo development; and (iii) late-embryo development. After the first two phases, we found no difference in the percentage viable seeds between populations with or without recruitment. After late-embryo development, populations without recruitment showed a significantly lower percentage of viable seeds. These results suggest that late-embryo development is a bottleneck in seed development. However, the complex interaction between seed viability and ripening time suggest that the causes should be in the second seed phase, as the accelerated development of male and female gametophytes may disturb the male-female synchrony for successful mating.

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“…Drops assist with pollen capture by increasing the area of the receptive surface of the ovule. The receding drop draws pollen into the ovule where it germinates (Tomlinson et al, 1997;Mugnaini et al, 2007). The post-pollination pre-fertilization drop is only found in pollination mechanisms that physically capture pollen on stigmatic hairs: the drop fills the micropyle many weeks after pollination.…”

Section: Introductionmentioning

confidence: 99%