The Influence of Paleozoic Ovule and Cupule Morphologies on Wind Pollination

Niklas, Karl J.

doi:10.1111/j.1558-5646.1983.tb05625.x

Cited by 22 publications

(8 citation statements)

References 26 publications

(42 reference statements)

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“…This suggests the extension of the salpinx, a structure for capturing pollen, is to optimize exposure of the drop to the environment for prepollen capture. Niklas (1983, 1985) shows that preovules with integumentary lobes close to the salpinx had greater numbers of simulated prepollen capture events, although this includes several other factors, such as orientation of the preovules. The long micropyles with pollination drops of modern-day Gnetales function similarly to capture pollen (El-Ghazaly et al, 1998).…”

Section: Fossil Gymnospermsmentioning

confidence: 99%

“…There is no reason to assume that such flexibility in carbohydrate production by ovule nucellus could not have existed in the past. Additional support for the presence of a PCM α style drop comes from wind pollination experiments performed on models of several early seed plants (Niklas, 1983). Several species were shown to have relatively inefficient wind-based capture based on their morphology.…”

Section: Fossil Gymnospermsmentioning

confidence: 99%

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The Evolution of Sexual Fluids in Gymnosperms From Pollination Drops to Nectar

2018

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A current synthesis of data from modern and fossil plants paints a new picture of sexual fluids, including nectar, as a foundational component of gymnosperm reproductive evolution. We review the morpho-anatomical adaptations, their accompanying secretions, and the functional compounds involved. We discuss two types of secretions: (1) those involved in fertilization fluids produced by gametophytes and archegonia of zooidogamous gymnosperms, i.e., Ginkgo and cycads, and (2) those involved in pollen capture mechanisms (PCMs), i.e., pollination drops. Fertilization fluids provide both liquid in which sperm swim, as well as chemotactic signals that direct sperm to the egg. Such fertilization fluids were probably found among many extinct plants such as ancient cycads and others with swimming sperm, but were subsequently lost upon the evolution of siphonogamy (direct delivery of sperm to the egg by pollen tubes), as found in modern gnetophytes, conifers, and Pinaceae. Pollination drops are discussed in terms of three major types of PCMs and the unique combinations of morphological and biochemical adaptations that define each. These include their amino acids, sugars, calcium, phosphate and proteins. The evolution of PCMs is also discussed with reference to fossil taxa. The plesiomorphic state of extant gymnosperms is a sugar-containing pollination drop functioning as a pollen capture surface, and an in ovulo pollen germination medium. Additionally, these drops are involved in ovule defense, and provide nectar for pollinators. Pollination drops in anemophilous groups have low sugar concentrations that are too low to provide insects with a reward. Instead, they appear to be optimized for defense and microgametophyte development. In insect-pollinated modern Gnetales a variety of tissues produce sexual fluids that bear the biochemical signature of nectar. Complete absence of fluid secretions is restricted to a few, poorly studied modern conifers, and is presumably derived. Aspects of pollination drop dynamics, e.g., regulation of secretion and retraction, are reviewed. Lastly, we discuss pollination drops’ control of pollen germination. Large gaps in our current knowledge include the composition of fertilization fluids, the pollination drops of Podocarpaceae, and the overall hydrodynamics of sexual fluids in general.

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Section: Fossil Gymnospermsmentioning

confidence: 99%

Section: Fossil Gymnospermsmentioning

confidence: 99%

The Evolution of Sexual Fluids in Gymnosperms From Pollination Drops to Nectar

2018

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“…It is possible that the defensive function of secondary metabolites of photosynthetic eukaryotes may have been triggered by one evolutionary milestone: the transition from aquatic (presumably non-vascular) plants to vascular terrestrial plants (tracheophytes) during the Silurian (but see Heath 1987Heath , 1991. Geochemical analysis shows that after the appearance of the first terrestrial vascular plants, a very rapid biochemical diversification occurred, involving in some cases fundamental biogenetic changes (Niklas 1983).…”

Section: Box 2 Secondary Metabolite Biosynthesismentioning

confidence: 99%

“…During the late Paleozoic and early Mesozoic 250 Myr, important groups of phytophagous insects such as Coleoptera and Lepidoptera appeared. Then, around 100 million years later, the angiosperms emerged and widely diversified around the world (Niklas 1983). Hence, these major patterns have contributed to the idea that diversification of plants and herbivores (particularly insects) is, in fact, a result of the biotic interactions between plants and animals (Strong et al 1984, Nylin & Janz 1999.…”

mentioning

confidence: 99%

Plant-herbivore interactions and secondary metabolites of plants: Ecological and evolutionary perspectives

Kariñho‐Betancourt¹

2018

Bot. Sci.

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AbstractBackground: Throughout disciplines including paleontology and molecular biology, hence using the fossil record or DNA sequences, ancestral and current plant-herbivore associations mediated by secondary compounds have been assessed. The coevolutionary model of “escape and radiation” predicts adaptive patterns at micro- and macro-evolutionary scale, resulted from the plant-herbivore interaction.Questions: The study of plant-herbivore interaction and secondary metabolites, has been bias for two main reasons: (1) the interdisciplinary study of the interaction has “atomized" the field. (2) The conceptual framework of coevolution favored analysis either within populations or across taxa.Methods: I review the evolutionary history of the interaction and secondary metabolites, from paleontological and palebiochemical data. Then, based on empirical evidence of quantitative genetics and comparative methods, I examine the main assumptions of micro- and macro-evolutionary postulates of the coevolutionary model. Further, I overview the analytical approach for the study of plant defense within-species and across phylogeny. Results: Within species, (1) the coevolutionary dynamics shaping plants and herbivore phenotypes, and (2) the role of plant chemistry to constraint ecological interactions, are the most stressed patterns. Across phylogeny, (1) the role of plant chemistry to constraint insect host shifts, and (2) the implications of, and mechanism behind the evolutionary novelties, are more recently assessed.Conclusion: I suggest that future research should integrate both conceptual and analytical perspectives of micro- and macro-evolutionary approaches. One promising direction relies in modern molecular techniques that may open new research avenues by providing evidence for the function of complex genetic and genomic machineries behind biotic interactions.

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“…Together, these advantages allow unparalleled opportunities to investigate the role of development and physiology in shaping morphological evolution. A strong foundation of such paleobotanical work has included investigation of the aerodynamics of wind pollination in seed and cone morphology (Niklas 1983(Niklas , 1985, ontogeny of primary (Eggert, 1961) and secondary growth (Cichan, 1985), hormonal gradients in shaping primary (Stein, 1993) and secondary (Rothwell and Lev-Yadun, 2005) xylem anatomy, and the biomechanics of whole plant architecture (Niklas, 1992) and stem structure (Speck and Rowe, 2001).…”

Section: Introductionmentioning

confidence: 99%

The Fossil Record of Plant Physiology and Development—What Leaves Can Tell Us

Boyce

2008

Paleontol. Soc. pap.

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Plants provide unmatched opportunities to evaluate long debated evolutionary patterns in terms of the detailed biology of the fossil organisms. Leaves serve here as an example of how those advantages can be exploited. Over the history of vascular plants, three important transitions in leaf evolution—the origin of laminate leaves, the progressive loss of seed plant morphological diversity, and the evolution of more angiosperm-like leaves—also represent major shifts in leaf development and physiology. These transitions often occurred in parallel in different lineages, such as the evolution of marginal growth in each of at least four independent origins of laminate leaves during the Devonian and Carboniferous. Each also entailed dramatic reorganizations of leaf hydraulics. For example, the length of the finest distributary vein order varies from up to tens of centimeters down to hundreds of microns in successive groups of dominant seed plants. Angiosperms impose an additional trend upon these patterns with the evolution of their uniquely high vein densities. Vein density strongly influences and can provide a proxy for other physiological characteristics, such as assimilation and transpiration rates. The large increase in transpiration capacity accompanying the evolution of angiosperm leaf traits may even play an important role in feeding precipitation and thereby altering local climate.

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The Influence of Paleozoic Ovule and Cupule Morphologies on Wind Pollination

Cited by 22 publications

References 26 publications

The Evolution of Sexual Fluids in Gymnosperms From Pollination Drops to Nectar

The Evolution of Sexual Fluids in Gymnosperms From Pollination Drops to Nectar

Plant-herbivore interactions and secondary metabolites of plants: Ecological and evolutionary perspectives

The Fossil Record of Plant Physiology and Development—What Leaves Can Tell Us

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