Month: September 2022

THIRD SURPRISE. "Thirdly, the tiny deeply incised megaphylls of the rare early-Devonian plant Eophyllophyton bellum from Chinese rocks shows that plants had the capacity to produce a simple megaphyll. Why were plants unable to release this morphogenetic potential?" http://aob.oxfordjournals.org/content/96/3/345.full.pdf View in LinkedIn

NEW PARADIGM. "This Botanical Briefing provides an overview of a new mechanistic explanation linking atmospheric CO2 decline with the delayed widespread appearance of megaphylls, and ideas concerning its molecular genetic basis and the resulting global environmental and evolutionary consequences." http://aob.oxfordjournals.org/content/96/3/345.full.pdf View in LinkedIn

NEW DATA, NEW FRAMEWORK. "Developmental genetic mechanisms underpinning aspects of stomatal and leaf formation provide additional new insight allowing progress towards a unified framework for understanding leaf evolution." http://aob.oxfordjournals.org/content/96/3/345.full.pdf View in LinkedIn

BIG LEAVES AND DROP IN CO2. "The mechanistic hypothesis of Beerling et al. (2001) links the gap between the earliest vascular plants and the advent of large megaphylls with a dramatic 90% drop in the atmospheric CO2 concentration during the late Palaeozoic." http://aob.oxfordjournals.org/content/96/3/345.full.pdf View in LinkedIn

INCREASED RESPIRATORY CHANNELS. "The large fall in CO2 corresponded with a marked rise in the stomatal density of vascular land plants, with densities increasing a 100-fold from 5–10mm (-2) on early vascular plant axes to 800–1000 mm (-2) on the cuticles of late Carboniferous megaphylls." http://aob.oxfordjournals.org/content/96/3/345.full.pdf View in LinkedIn

GLOBAL SUCCESS. "Evidently, leaves are a global success. However, the advent of large megaphylls took place some 40–50 million years (Myr) after the origination of vascular land plants, suggesting that they were far from an evolutionary inevitability." http://aob.oxfordjournals.org/content/96/3/345.full.pdf View in LinkedIn

"STOMATA are microscopic valves on plant surfaces that originated over 400 million years (Myr) ago and facilitated the greening of Earth's continents by permitting efficient shoot–atmosphere gas exchange and plant hydration." https://lnkd.in/ehcV6zt View in LinkedIn

GLOBAL SUCCESS. "Evidently, leaves are a global success. However, the advent of large megaphylls took place some 40–50 million years (Myr) after the origination of vascular land plants, suggesting that they were far from an evolutionary inevitability." http://aob.oxfordjournals.org/content/96/3/345.full.pdf View in LinkedIn

AVOIDING LETHAL OVER-HEATING. "The rise in stomatal density held special significance for the evolution of leaves by permitting greater evaporative cooling and alleviating the requirement for convective heat loss. Simulations indicate that archaic land plants with axial stems, few stomata, and low transpiration rates only avoided lethal over-heating because they intercepted a minimal quantity of solar energy." http://aob.oxfordjournals.org/content/96/3/345.full.pdf View in LinkedIn

BIG LEAF PROBLEM. "In contrast, a megaphyll intercepting at least twice as much solar energy (per unit area of the photosynthetic organ) reached temperatures approaching the highly conserved lethal threshold of extant tropical taxa because the same limited evaporative cooling was inadequate to dissipate the absorbed thermal energy." http://aob.oxfordjournals.org/content/96/3/345.full.pdf View in LinkedIn