Preliminary results on the use of a modified point quadrat method for estimating canopy structure of grapevine training systems

The reliability of a modified point quadrat method designed to describe the structure and seasonal canopy dynamics of the training systems simple curtain (SC) and traditional spur-pruned cordon (SPC) was tested in a two-year study. The method relies upon an unbiased sampling procedure as each canopy insertion is first identified within a ground-projected area by a random number generation routine (RND). From each insertion, the height of each contact with either leaves or clusters is then recorded along the vertical axis. Although the method suffered from a somewhat low percentage of effective insertions early in the season, the total leaf area-to-surface area ratio and the leaf layer number calculated for both canopy types are in accordance with those reported by others for high vigour canopies. Canopy dynamics showed an asymmetric growth in the SC starting at bloom. Both trellises resulted in similar canopy density indices and a high correlation was found between total leaf area and total number of leaf contacts

Row orientation effects on whole-canopy gas exchange of potted and field-grown grapevines

The effects of canopy orientation (North-South vs. East-West) on total canopy assimilation (TCA) and transpiration (TCE) were evaluated on potted grapevines mounted on wheeled platforms for full swivel relation. Eight vines were assembled in pairs to form four canopy walls 2 m long, 1.1 m tall and 0.25-0.30 m wide. TCA and TCE readings were also taken in the field on four NS-oriented, hedgerow cordon-trained grapevines. Diurnal trends of TCA recorded on potted vines showed little variability when related to row orientation. The TCE pattern for EW followed essentially that of light intensity, whereas a NS orientation induced a marked decrease in TCE at midday before recovering in mid-afternoon. As a result, water use efficiency (WUE) in NS rows was higher during the midday hours. Total canopy water loss in NS was linearly correlated with estimates of intercepted light, suggesting that water use was a function of both, light intensity and canopy geometry (i.e. more light lost to the ground at noon, hence less transpiration). The results for the NS-oriented field-grown canopies differed to some extent from those of the pot experiments. TCA showed a more marked afternoon decline and TCE flattened at noon, though with no apparent decrease. WUE efficiency was lowest at the highest evaporative demand. The daily water loss of field vines could not be predicted by total light interception estimates only, indicating a more complex regulation of canopy transpiration than recorded on potted plants

Effects of canopy manipulations on whole-vine photosynthesis: Results from pot and field experiments

A two-year study was conducted with potted and field-grown grapevines to examine the effects of canopy restriction and leaf removal on total vine assimilation (TVA). TVA was measured using a flow-through gas exchange system equipped with flexible plastic chambers enclosing the entire canopy. Canopy restriction was applied to potted bush-shaped (BS) and field-grown spur-pruned cordon (SPC) vines on trellises to force the foliage into the smallest canopy volume. Leaf removal was performed on free cordon (FC) and SPC-trained vines at different dates to eliminate internal leaves shaded to varying extent. Canopy restriction reduced TVA more severely in the BS canopies than in the trellised SPC vines. Leaf removal elicited varying responses depending upon canopy shape, initial canopy density and leaf/fruit ratio. The FC vine showed no decrease in TVA after 27 % of its total leaf area had been removed, suggesting the occurrence of active photosynthetic compensation. TVA decreased with defoliation in the SPC vine, although the effect was mostly due to the leaf removal applied earlier in the season. In the FC vine a regression of total leaf area versus TVA showed maximum TVA at 6.0-6.5 m(2) of leaf area per meter of canopy. In SPC vines this relationship indicated a linear increase of TVA with leaf area and the lack of a saturation threshold under our experimental conditions. Sugar accumulation in the grapes of SPC vines correlated closely to the ratios leaf area/fruit and TVA/yield

Laser scanning estimation of relative light interception by canopy components in different grapevine training systems

The fractional light interception by different parts of vines trained to various systems was estimated by a modified point-quadrat method using an over-row solar are positioning device equipped with a laser to simulate sunbeam position and angle at any latitude and time of the day. Laser readings were also combined with total vine light interception estimates via a line sensor to calculate the total light intercepted by specific canopy components. At each sampling date (late June and September, corresponding to fruit set and full canopy), type and position of organs were directly detected by the laser beam. Regardless of sampling date, the relative amount of light captured by the renewal-fruiting area (nodes 1 to 6) of simple cordon (SC) and double curtain (GDC) was considerably higher than that of spur-pruned cordon (SPC), whose vegetative area (distal to node 6) received about two-thirds of the incoming light. Relative light interception by main and lateral leaves was rather constant for GDC, thus reflecting the negligible regrowth after topping. By contrast, SC and SPC showed a much stronger response to topping which caused an increase of light interception by laterals (19 % for SC and +21 % for SPC). Frequencies of relative intercepted light by main leaves as a function of node position showed a peak around nodes 6-8, a zone where maximum leaf size is attained in all systems and on all dates. Instead, lateral leaves predominantly exposed to light were within the three basal nodes of the lateral shoots. Estimates of relative and total light for different vine parts at any time during the season as detected by laser scanning can objectively assess important characteristics of grapevine training systems, e.g. cluster and basal node exposure to light

Osservatorio territoriale droga e tossicodipendenze. Il Fenomeno delle dipendenze sul territorio della ASL MI 3. Anno 2007.

Report on the state of legal and illegal substances use in the territory of the Local Healthcare Service-Mi 3, Province of Milan.Il report analizza il fenomeno delle dipendenze nel territorio della ASL Milano 2. La descrizione del fenomeno si sviluppa intorno all\u27analisi degli indicatori individuati dall\u27Osservatorio Europeo delle Dipendenze di Lisbona (OEDT): 1-uso di sostanze nella popolazione generale (questo indicatore va a rilevare i comportamenti nei confronti di alcol e sostanze psicoattive da parte della popolazione generale); 2-prevalenza d\u27uso problematico delle sostanze psicoattive; 3-domanda di trattamento degli utilizzatori di sostanze; 4-mortalit? degli utilizzatori di sostanze; 5-malattie infettive. Altri due importanti indicatori che si stanno sviluppando, e che vengono qui illustrati, sono l\u27analisi delle Schede di Dimissione Ospedaliera (SDO) e gli indicatori relativi alle conseguenza sociali dell\u27uso di droghe (criminalit? droga correlata). Inoltre sono state applicate diverse metodologie standard di stima sia per quantificare la quota parte sconosciuta di utilizzatori di sostanze che non afferiscono ai servizi, sia per identificarne alcune caratteristiche