Microcosm experiment data

File contains experimental data from the microcosm experiment, namely: flask ID, author initials, date, initial microcosm richness (species), initial microcosm richness (groups), presence dummies for all 8 species, total biovolume, cell counts for each of the 5 groups, temperature before exposure (TB), minimum, maximum, standard deviation (sd) of TB within Petri dish, time of measurement of TB, temperature after exposure to light (TA), minimum, maximum, sd of TA, time of measure of TA, temperature difference (TA-TB), mean, sd, minimum, maximum RGB, "second batch" dummy, time trend for the first batch, time (in hours, minutes), time trend of the second batch, dummy for the presence of the IG (isomorphic group), complementarity and sampling effects (and intermediary calculations) within each microcosm. Volumes are in 10e-6 m3, temperatures in °C

Microcosm experiment data

File contains experimental data from the microcosm experiment, namely: flask ID, author initials, date, initial microcosm richness (species), initial microcosm richness (groups), presence dummies for all 8 species, total biovolume, cell counts for each of the 5 groups, temperature before exposure (TB), minimum, maximum, standard deviation (sd) of TB within Petri dish, time of measurement of TB, temperature after exposure to light (TA), minimum, maximum, sd of TA, time of measure of TA, temperature difference (TA-TB), mean, sd, minimum, maximum RGB, "second batch" dummy, time trend for the first batch, time (in hours, minutes), time trend of the second batch, dummy for the presence of the IG (isomorphic group), complementarity and sampling effects (and intermediary calculations) within each microcosm. Volumes are in 10e-6 m3, temperatures in °C

Stomatal closure, basal leaf embolism and shedding protect the hydraulic integrity of grape stems

The time scale of stomatal closure and xylem cavitation during plant dehydration, as well as the fate of embolised organs, is under debate, largely due to methodological limitations in the evaluation of embolism. While some argue that complete stomatal closure precedes the occurrence of embolism, others believe that the two are contemporaneous processes that are accompanied with daily xylem refilling. Here we utilize an optical light transmission method, to continuously monitor xylem cavitation in leaves of dehydrating grapevines (Vitis vinifera L.) in concert with stomatal conductance and stem and petiole hydraulic measurements. Magnetic resonance imaging (MRI) was used to continuously monitor xylem cavitation and flow rates in the stem of an intact vine during 10 days of dehydration. The results showed that complete stomatal closure preceded the appearance of embolism in the leaves and the stem by several days. Basal leaves were more vulnerable to xylem embolism than apical leaves and, once embolised, were shed, thereby preventing further water loss and protecting the hydraulic integrity of younger leaves and the stem. As a result, embolism in the stem was minimal even when drought led to complete leaf shedding. These findings suggest that grapevines avoid xylem embolism rather than tolerate it

Growth and physiology of a dominant understory shrub, Hamamelis virginiana, following canopy disturbance in a temperate hardwood forest

As global climatic changes increase plant susceptibility to large-scale disturbances like drought and pathogens, understory responses to these disturbances will become increasingly important to long-term forest dynamics. To better understand understory responses to canopy disturbance, we measured changes in the growth and physiology of the dominant understory shrub, American witch-hazel (Hamamelis virginiana), in response to girdling of canopy oaks in a northeastern U.S. temperate hardwood forest. Changes in the growth and physiology of H. virginiana may be important to the regeneration of northeastern temperate forests, as this common shrub largely shapes the microenvironment for seedlings on the forest floor where it occurs. Canopy disturbance by girdling resulted in significant increases in light and soil nitrogen availability. In response to these environmental changes, basal-area growth of H. virginiana increased by an average 334%. This growth increase corresponded to significant increases in foliar nitrogen, respiration, and leaf chlorophyll and carotenoid concentrations. These findings indicate improved environmental conditions and increased growth for this understory shrub following the loss of dominant canopy trees. This study suggests that following large-scale canopy disturbance, H. virginiana and shrubs like it may play an important role in competing for soil N and shading seedlings of regenerating canopy species.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author