Publications by Kristina Bolinder
Grana, 2015
The Ephedra lineage can be traced at least to the Early Cretaceous. Its characteristically polypl... more The Ephedra lineage can be traced at least to the Early Cretaceous. Its characteristically polyplicate pollen is well-represented
in the fossil record and is frequently used as an indicator of paleoclimate. However, despite previous efforts, knowledge
about variation and evolution of ephedroid pollen traits is poor. Here, we document pollen morphology of nearly all extant
species of Ephedra, using a combination of scanning electron microscopy (SEM) and light microscopy (LM), and reconstruct
ancestral states of key pollen traits. Our results indicate that the ancestral Ephedra pollen type has numerous plicae
interspaced by unbranched pseudosulci, while the derived pollen type has branched pseudosulci and (generally) fewer
plicae. The derived type is inferred to have evolved independently twice, once along the North American stem branch and
once along the Asian stem branch. Pollen of the ancestral type is common in Mesozoic fossil records, especially from the
Early Cretaceous, but it is less commonly reported from the Cenozoic. The earliest documentation of the derived pollen type
is from the latest Cretaceous, after which it increases strongly in abundance during the Paleogene. The results of the present
study have implications for the age of crown group Ephedra as well as for understanding evolution of pollination syndromes
in the genus.
Papers by Kristina Bolinder
Grana, 2015
The Ephedra lineage can be traced at least to the Early Cretaceous. Its characteristically polypl... more The Ephedra lineage can be traced at least to the Early Cretaceous. Its characteristically polyplicate pollen is well-represented in the fossil record and is frequently used as an indicator of paleoclimate. However, despite previous efforts, knowledge about variation and evolution of ephedroid pollen traits is poor. Here, we document pollen morphology of nearly all extant species of Ephedra, using a combination of scanning electron microscopy (SEM) and light microscopy (LM), and reconstruct ancestral states of key pollen traits. Our results indicate that the ancestral Ephedra pollen type has numerous plicae interspaced by unbranched pseudosulci, while the derived pollen type has branched pseudosulci and (generally) fewer plicae. The derived type is inferred to have evolved independently twice, once along the North American stem branch and once along the Asian stem branch. Pollen of the ancestral type is common in Mesozoic fossil records, especially from the Early Cretaceous, but it is less commonly reported from the Cenozoic. The earliest documentation of the derived pollen type is from the latest Cretaceous, after which it increases strongly in abundance during the Paleogene. The results of the present study have implications for the age of crown group Ephedra as well as for understanding evolution of pollination syndromes in the genus.
Ephedra (Gnetales) is a gymnosperm genus with a long evolutionary history; the first dispersed po... more Ephedra (Gnetales) is a gymnosperm genus with a long evolutionary history; the first dispersed pollen grains with affinity to the group are known already from the Permian. This thesis focuses on th ...
Botanical Journal of the Linnean Society, 2016
Pollination in gymnosperms is usually accomplished by means of wind, but some groups are insect-p... more Pollination in gymnosperms is usually accomplished by means of wind, but some groups are insect-pollinated. We show that wind and insect pollination occur in the morphologically uniform genus Ephedra (Gnetales). Based on field experiments over several years, we demonstrate distinct differences between two Ephedra species that grow in sympatry in Greece in pollen dispersal and clump formation, insect visitations and embryo formation when insects are denied access to cones. Ephedra distachya, nested in the core clade of Ephedra, is anemophilous, which is probably the prevailing state in Ephedra. Ephedra foeminea, sister to the remaining species of the genus, is entomophilous and pollinated by a range of diurnal and nocturnal insects. The generalist entomophilous system of E. foeminea, with distinct but infrequent insect visitations, is in many respects similar to that reported for Gnetum and Welwitschia and appears ancestral in Gnetales. The Ephedra lineage is well documented already from the Early Cretaceous, but the diversity declined dramatically during the Late Cretaceous, possibly to near extinction around the Cretaceous–Palaeogene boundary. The clade imbalance between insect-and wind-pollinated lineages is larger than expected by chance and the shift in pollination mode may explain why Ephedra escaped extinction and began to diversify again.
Grana, 2015
The Ephedra lineage can be traced at least to the Early Cretaceous. Its characteristically polypl... more The Ephedra lineage can be traced at least to the Early Cretaceous. Its characteristically polyplicate pollen is well-represented in the fossil record and is frequently used as an indicator of paleoclimate. However, despite previous efforts, knowledge about variation and evolution of ephedroid pollen traits is poor. Here, we document pollen morphology of nearly all extant species of Ephedra, using a combination of scanning electron microscopy (SEM) and light microscopy (LM), and reconstruct ancestral states of key pollen traits. Our results indicate that the ancestral Ephedra pollen type has numerous plicae interspaced by unbranched pseudosulci, while the derived pollen type has branched pseudosulci and (generally) fewer plicae. The derived type is inferred to have evolved independently twice, once along the North American stem branch and once along the Asian stem branch. Pollen of the ancestral type is common in Mesozoic fossil records, especially from the Early Cretaceous, but it is less commonly reported from the Cenozoic. The earliest documentation of the derived pollen type is from the latest Cretaceous, after which it increases strongly in abundance during the Paleogene. The results of the present study have implications for the age of crown group Ephedra as well as for understanding evolution of pollination syndromes in the genus.
Biology letters, 2015
Most gymnosperms are wind-pollinated, but some are insect-pollinated, and in Ephedra (Gnetales), ... more Most gymnosperms are wind-pollinated, but some are insect-pollinated, and in Ephedra (Gnetales), both wind pollination and insect pollination occur. Little is, however, known about mechanisms and evolution of pollination syndromes in gymnosperms. Based on four seasons of field studies, we show an unexpected correlation between pollination and the phases of the moon in one of our studied species, Ephedra foeminea. It is pollinated by dipterans and lepidopterans, most of them nocturnal, and its pollination coincides with the full moon of July. This may be adaptive in two ways. Many nocturnal insects navigate using the moon. Further, the spectacular reflection of the full-moonlight in the pollination drops is the only apparent means of nocturnal attraction of insects in these plants. In the sympatric but wind-pollinated Ephedra distachya, pollination is not correlated to the full moon but occurs at approximately the same dates every year. The lunar correlation has probably been lost in...
American journal of botany, 2015
• Pollen dispersal is affected by the terminal settling velocity (Ut) of the grains, which is det... more • Pollen dispersal is affected by the terminal settling velocity (Ut) of the grains, which is determined by their size, bulk density, and by atmospheric conditions. The likelihood that wind-dispersed pollen is captured by ovulate organs is influenced by the aerodynamic environment created around and by ovulate organs. We investigated pollen ultrastructure and Ut of Ephedra foeminea (purported to be entomophilous), and simulated the capture efficiency of its ovules. Results were compared with those from previously studied anemophilous Ephedra species.• Ut was determined using stroboscopic photography of pollen in free fall. The acceleration field around an "average" ovule was calculated, and inflight behavior of pollen grains was predicted using computer simulations. Pollen morphology and ultrastructure were investigated using SEM and STEM.• Pollen wall ultrastructure was correlated with Ut in Ephedra. The relative proportion and amount of granules in the infratectum determine pollen bulk densities, and (together with overall size) determine Ut and thus dispersal capability. Computer simulations failed to reveal any functional traits favoring anemophilous pollen capture in E. foeminea.• The fast Ut and dense ultrastructure of E. foeminea pollen are consistent with functional traits that distinguish entomophilous species from anemophilous species. In anemophilous Ephedra species, ovulate organs create an aerodynamic microenvironment that directs airborne pollen to the pollination drops. In E. foeminea, no such microenvironment is created. Ephedroid palynomorphs from the Cretaceous share the ultrastructural characteristics of E. foeminea, and at least some may, therefore, have been produced by insect-pollinated plants.
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Publications by Kristina Bolinder
in the fossil record and is frequently used as an indicator of paleoclimate. However, despite previous efforts, knowledge
about variation and evolution of ephedroid pollen traits is poor. Here, we document pollen morphology of nearly all extant
species of Ephedra, using a combination of scanning electron microscopy (SEM) and light microscopy (LM), and reconstruct
ancestral states of key pollen traits. Our results indicate that the ancestral Ephedra pollen type has numerous plicae
interspaced by unbranched pseudosulci, while the derived pollen type has branched pseudosulci and (generally) fewer
plicae. The derived type is inferred to have evolved independently twice, once along the North American stem branch and
once along the Asian stem branch. Pollen of the ancestral type is common in Mesozoic fossil records, especially from the
Early Cretaceous, but it is less commonly reported from the Cenozoic. The earliest documentation of the derived pollen type
is from the latest Cretaceous, after which it increases strongly in abundance during the Paleogene. The results of the present
study have implications for the age of crown group Ephedra as well as for understanding evolution of pollination syndromes
in the genus.
Papers by Kristina Bolinder
in the fossil record and is frequently used as an indicator of paleoclimate. However, despite previous efforts, knowledge
about variation and evolution of ephedroid pollen traits is poor. Here, we document pollen morphology of nearly all extant
species of Ephedra, using a combination of scanning electron microscopy (SEM) and light microscopy (LM), and reconstruct
ancestral states of key pollen traits. Our results indicate that the ancestral Ephedra pollen type has numerous plicae
interspaced by unbranched pseudosulci, while the derived pollen type has branched pseudosulci and (generally) fewer
plicae. The derived type is inferred to have evolved independently twice, once along the North American stem branch and
once along the Asian stem branch. Pollen of the ancestral type is common in Mesozoic fossil records, especially from the
Early Cretaceous, but it is less commonly reported from the Cenozoic. The earliest documentation of the derived pollen type
is from the latest Cretaceous, after which it increases strongly in abundance during the Paleogene. The results of the present
study have implications for the age of crown group Ephedra as well as for understanding evolution of pollination syndromes
in the genus.