Drought impact on water use efficiency and intra-annual density fluctuations in Erica arborea on Elba (Italy).

Erica arborea (L) is a widespread Mediterranean species, able to cope with water stress and colonize semiarid environments. The eco-physiological plasticity of this species was evaluated by studying plants growing at two sites with different soil moistures on the island of Elba (Italy), through dendrochronological, wood-anatomical analyses and stable isotopes measurements. Intra-annual density fluctuations (IADFs) were abundant in tree rings, and were identified as the key parameter to understand site-specific plant responses to water stress.

Variations of vessel diameter and δ13C in false rings of Arbutus unedo L. reflect different environmental conditions.

Woody species in Mediterranean ecosystems form intra-annual density fluctuations (IADFs) in tree rings in response to changes in environmental conditions, especially water availability. Dendrochronology, quantitative wood anatomy and high-resolution isotopic analysis (using a laser ablation technique) were used to characterize IADFs in Arbutus unedo shrubs grown on two sites with different water availability on the island of Elba (Italy). Our findings show that IADF characterization can provide information about the relationship between environmental factors and tree growth at the seasonal level.

Laser ablation-combustion-GC-IRMS--a new method for online analysis of intra-annual variation of delta13C in tree rings.

We present a new, rapid method for high-resolution online determination of delta13C in tree rings, combining laser ablation (LA), combustion (C), gas chromatography (GC) and isotope ratio mass spectrometry (IRMS) (LA-C-GC-IRMS). Sample material was extracted every 6 min with a UV-laser from a tree core, leaving 40-microm-wide holes. Ablated wood dust was combusted to CO2 at 700 degrees C, separated from other gases on a GC column and injected into an isotope ratio mass spectrometer after removal of water vapor.

Pythons metabolize prey to fuel the response to feeding.

We investigated the energy source fuelling the post-feeding metabolic upregulation (specific dynamic action, SDA) in pythons (Python regius). Our goal was to distinguish between two alternatives: (i) snakes fuel SDA by metabolizing energy depots from their tissues; or (ii) snakes fuel SDA by metabolizing their prey. To characterize the postprandial response of pythons we used transcutaneous ultrasonography to measure organ-size changes and respirometry to record oxygen consumption.