Leaf metabolic traits reveal hidden dimensions of plant form and function

International audienceThe metabolome is the biochemical basis of plant form and function, but we know little about its macroecological variation across the plant kingdom. Here, we used the plant functional trait concept to interpret leaf metabolome variation among 457 tropical and 339 temperate plant species. Distilling metabolite chemistry into five metabolic functional traits reveals that plants vary on two major axes of leaf metabolic specialization—a leaf chemical defense spectrum and an expression of leaf longevity. Axes are similar for tropical and temperate species, with many trait combinations being viable. However, metabolic traits vary orthogonally to life-history strategies described by widely used functional traits. The metabolome thus expands the functional trait concept by providing additional axes of metabolic specialization for examining plant form and function

Leaf metabolic traits reveal hidden dimensions of plant form and function

The metabolome is the biochemical basis of plant form and function, but we know little about its macroecological variation across the plant kingdom. Here, we used the plant functional trait concept to interpret leaf metabolome variation among 457 tropical and 339 temperate plant species. Distilling metabolite chemistry into five metabolic functional traits reveals that plants vary on two major axes of leaf metabolic specialization—a leaf chemical defense spectrum and an expression of leaf longevity. Axes are similar for tropical and temperate species, with many trait combinations being viable. However, metabolic traits vary orthogonally to life-history strategies described by widely used functional traits. The metabolome thus expands the functional trait concept by providing additional axes of metabolic specialization for examining plant form and function

Construire: les défis du génie civil du LHC

Dans les années 80, le CERN a vécu la formidable aventure de la construction du tunnel de 27 kilomètres de circonférence. Ces dernières années, les équipes du génie civil se sont lancées dans l’excavation d’immenses cavernes souterraines et de kilomètres de galeries pour le LHC. Ces travaux ont exigé de véritables prouesses techniques

Tropopause characteristics over a southern subtropical site, Reunion Island (21°S, 55°E): Using radiosonde-ozonesonde data

International audienceIn this paper, we present tropopause characteristics using in situ radiosonde-ozonesonde observations carried out over the past 13 years (September 1992 to February 2005) from a southern subtropical site, Reunion Island (21°S, 55°E). Three kinds of tropopause definitions, namely, cold-point tropopause (CPT), lapse rate tropopause (LRT), and ozone tropopause (OT), are characterized. The ozone tropopause for Reunion is appropriately defined as the height at which the vertical gradient of the ozone mixing ratio exceeds 55 ppbv/km and the ozone mixing ratio is over 75 ppbv. The overall height distribution of the three kinds of tropopause ranges in between 12.5 and 18.5 km. Of the three definitions, CPT follows higher heights of distribution, followed by LRT and then OT. The sharpness of tropopause height detection for LRT and OT has been examined, and it has been found that the detection frequency of a definite OT is larger than that for LRT. The results also showed no indefinite OT for a subtropical station in comparison to the results obtained for Northern Hemisphere midlatitude and high-latitude stations. After adopting a few modifications in the sharpness of ozone tropopause detection, the result remains the same, with a single indefinite case. The indefinite ozone tropopause case was identified when Reunion Island was located nearer to the divergence zone of wind as well as in the anticyclonic region of jet stream entrance. The LRT sharpness results are found to be in good agreement with the other published definitio