Branchlets abscission in Quercus cerris L. related to oak decline: anatomical studies

The basic anatomy of lateral twig insertion onto the main branch in both healthy and damaged Quercus cerris L. trees was studied. An abscission zone is always present: in healthy trees it is formed by a smaller number of cell layers than in damaged ones, where it is more evident with many layers of cells. Cells of the abscission zone are roundish, with many intercellular spaces between them; cell walls are thin, non-lignified and without secondary walls. No starch was found in cells of the abscission zone, where, instead, a few scattered calcium oxalate druses are seen

Preliminary dendroecological survey on pedunculate oak (Quercus robur L) stands in Tuscany (Italy)

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Preliminary dendroecological survey on pedunculate oak (Quercus robur L) stands in Tuscany (Italy)

This paper studies the influence of climate on pedunculate oak radial growth in some stands of central Mediterranean Italy. Three populations growing along the course of the River Arno were selected. Core samples were measured, and their growth curves standardized and modellized, in order to isolate the climate signal. The response functions were calculated by orthogonal regression of the variables of the tree ring (dependent variables) and the climate (explicative variables). This paper provides an eco-physiological analysis of the results This study helps us understand how the ecotype of the pedunculate oak has adapted to a Mediterranean climate where water supply is a strong limiting factor.Observations dendroécologiques préliminaires sur des peuplements de chênes pédonculés en Toscane (Italie). Le travail concerne l'étude de l'influence du climat sur la croissance radiale du chêne pédonculé dans l'Italie centrale. On a choisi et échantillonné 3 peuplements le long de l'Arno. Les échantillons ont été mesurés et les courbes d'accroissement ont été standardisées et modélisées dans le but d'isoler le signal climatique. Les fonctions de réponse ont été calculées par régression orthogonalisée entre la variable cerne (variable dépendante) et les variables climatiques (variable explicative). Les résultats sont discutés du point de vue écophysiologique. Cette étude aide à comprendre comment des écotypes de chêne pédonculé se sont adaptés au climat méditerranéen où la disponibilité de l'eau est le facteur limitant le plus important

Umbilical blood flow and placental pathology

The aim of the study was to establish whether or not placental morphostructural damage correlates with umbilical artery Doppler waveform and neonatal condition. To this end, seriated ultrasonographic monitoring, flowmeter tests on the cord artery and computerized cardiotocography were carried out in a population of 93 pregnant women in the second half of pregnancy. After birth placentas were subjected to macroscopic and microscopic examination. The Resistance Index showed a good correlation with placental vascular lesions, characterized by a distinct reduction in terminal villi and muscular wall arterioles. Two types of intrauterine growth retardation were discernible, the first of genetic origin with a low-profile growth curve and therefore not amenable to treatment, but with a positive fet l-neonatal prognosis, and the second with a pathologic placental component, presenting a late flattening growth curve with evolution towards fetal distress and a negative fetal-neonatal prognosis