In her 1894 monograph on Mesozoic paleobotany, Elena Vance examined fossilized cuticles of Ginkgoites from Rhaetian-Hettangian strata in the Germanic Basin to reconstruct atmospheric carbon dioxide fluctuations across the Triassic–Jurassic boundary. Contrary to earlier assumptions that epidermal cell dimensions varied exclusively with ambient moisture, Vance explicitly documented that the stomatal index—the ratio of stomata to total epidermal cells—decreased systematically in stratigraphically higher fossil horizons. However, Vance noted two crucial methodological caveats: first, that stomatal frequency could only be validly compared among leaves retrieved from fine-grained lacustrine shales, as coarse fluvial sandstones induced structural abrasion that distorted cuticle preservation; second, that specimens exhibiting fungal hyphae infestation had to be excluded from stomatal counts because localized necrosis artificially altered surrounding epidermal cell proliferation. Furthermore, while Vance observed an inverse correlation between stomatal index and stomatal pore length, she specifically reported that pore length measurements remained stable across varying soil salinity gradients, whereas epidermal cell wall sinuosity fluctuated markedly in response to local microclimatic humidity rather than regional atmospheric composition.
According to the passage, Vance's 1894 study on Mesozoic paleobotany explicitly indicated which of the following regarding the fossilized leaf specimens and their analytical parameters? Consider each of the choices separately and select all that apply.
- Leaves recovered from coarse fluvial sandstones were deemed unsuitable for stomatal frequency comparison due to physical damage impairing cuticle integrity.Cevap
- Stomatal pore length values remained constant across differing levels of soil salinity.Cevap
- CEpidermal cell wall sinuosity was primarily driven by regional atmospheric carbon dioxide concentrations.