Federica Rossi

Leaf characteristics and optical properties of different woody species

Abstract Light partition has been examined and evaluated on five woody species (Olea europaea, Ficus carica, Pittosporum tobira, Hedera helix maculata, Persica vulgaris) in relation to their leaf morpho-histological characteristics, water and chlorophyll contents. Leaf parameters and optical properties (reflectance, transmittance, absorbance) in PAR, FR and NIR wavebands (400–1100 nm) were preliminarily submitted to a canonical correlation analysis where lamina thickness and water content showed a leading role in determining all the optical properties, while chlorophyll, influential in the PAR region, was remarkably effective only in an extreme pigment situation when green and albino patches of ivy leaves were compared. Transmittance appeared inversely related to lamina thickness in accordance with the Lambert Beer law. Significant correlations were found also between mesophyll water content and both transmittance (positive) and reflectance (negative). Olive leaves showed peculiar optical patterns because of the dense and continuous trichome layer on their abaxial surface.

Photomorphogenic effects on in vitro rooting of Prunus roostock GF 655-2

The morphogenic effect of different light wavelengths on in vitro rooting of Prunus insititia GF655-2 in relation to the presence of napthaleneacetic acid (NAA) in the culture medium was investigated. Results of experiments in which plantlets were rooted in NAA enriched medium showed that the presence of auxin induced rooting even in the dark after an initial lag period. Illumination of the cultures with Red light was as effective in promoting rooting as treatment with 0.5 μM NAA; Red was more active in stimulating rooting in the short term than was NAA. The pattern of root formation resulting from the addition of NAA appeared to dominate development under White, Blue and Far Red treatments. Although it was possible to correlate the rooting response to the phytochrome photoequilibrium induced by the light treatments used, there arises a possible interference of specific Blue absorbing photoreceptors.

Characterisation of Emilia-Romagna region in relation with late frost risk

Abstract This paper describes a topoclimatic analysis that was carried out during the first year of the DIsGELO project. A climatological study and an orographical analysis were carried out, in order to identify frost-prone areas in Emilia-Romagna region (Italy). The former was used to identify and characterise the frost events in the period March–April 1987–2000 for 161 meteorological stations. A synthetic frost risk index, taking into account both temperatures and phenological conditions (expressed by decade number) was devised. For every station we computed both the synthetic frost risk index and the mean minimum temperature. The analysis of the digital elevation model provided some orographical variables: slope, aspect, absolute and relative altitude above valley bottom, valley width, closeness to the sea, and new variables specifically devised to evaluate surface roughness in the plain areas. Maps were then created for every variable and values were obtained for every station by means of a geographic information system. The study area was divided into two domains, the hill zone and the plain, and for each the correlation between the climatological and orographical variables was computed and geostatistical techniques were applied to create some temperature and frost risk climatological maps. For the hills of Emilia-Romagna, a significant correlation was found between the mean minimum temperature during frost events and two orographical factors: the relative altitude above the valley bottom and the closeness to the sea. For the plain no significant correlation was found up to now, probably due to the insufficient detail in the data, so some arbitrary coefficients, based on former practical experience, were added in order to take into account two other orographical factors describing the presence of hollows and knolls. An exponential relationship between the mean minimum temperature and the synthetic frost index was then used to obtain a preliminary frost risk map.

Micrometeorological test of microsprinklers for frost protection of fruit orchards in Northern Italy

Microclimate modification induced by intermittent water sprinkling at ground level has proven to be suitable to enhance protection against spring hoarfrosts in orchards. This research investigates about the efficiency of different sprinkler types and water volumes in enhancing air temperature in the canopy layer and to optimise the amount and the cycling of the water applied. Tests have been done over three consecutive years in purpose-built boxes delimited by polyethylene film where different sprinklers and sprayers tested were positioned along two pipes. Microsprinklers and microsprayers with different characteristics and outflow capacity were compared to evaluate whether the size of the drops can induce modification of energy balance at the surface. The impact of below-tree water sprinkling on the temperature profile appeared to be evident independently on the irrigation device and of the outflow tested. While no substantial differences between sprinklers and sprayers did not arise when the temperatures kept above 3 C, when temperatures fell below 3 C (even down to 7/)8 C), a better performance of the microsprinklers with respect to microsprayers was observed. Differences tend to fade out with height. In the same temperature conditions, a better performance of the microsprinklers with higher outflow (65 l/h) with respect to the same model characterised by a lower outflow (45 l/h) clearly emerged.

Meteorological and micrometeorological applications to frost monitoring in northern Italy orchards

Abstract Late frost are dangerous climatic hazards that can be responsible of fruit trees yield losses. Late frost potential hazard is, in particular, increased by the enhancement of low-temperature episodes in spring and to the concomitant early-blooming consequent to higher winter temperatures induced by the earth global warming. This paper reports observations on the micrometeorological features associated to frost occurrence in a representative area of the Po valley in order to characterize the atmospheric physics during frost formation episodes, to understand the frequency and the type of risk and to develop the most suitable protection practices. Energy balance and soil radiation balance are reported together with the main atmospheric features (air turbulence included), and the data-set collected are verified against the similarity equations. The computation of the surface roughness and the friction velocity, fundamental to the definition of the distinctive features of the site, has been also done by applying the similarity theory.

Parameter estimation of surface layer turbulence from wind speed vertical profile

Abstract The present work presents an iterative method for estimating the characteristic parameters of surface layer turbulence, based exclusively on the knowledge of the roughness length z0 and of the mean wind speed vertical profile. The method is a ‘specialised’ version of the well known Gauss–Newton non-linear optimisation method and its extreme simplicity allows the direct use of the latter in a real-time data acquisition system of limited potential. Comparison of the estimates derived from the proposed method with those obtained using the gradient method shows an excellent agreement between the two methods. In addition, numerical analysis has revealed excellent characteristics of speed and convergence.

Monitoring the physiological activity of plants by means of EPR spectroscopy. Mn(II) signals in Pinus nigra Arnold.

Abstract Differently aged needles from a Pinus nigra Arnold tree growing in a typical urban area have been examined by means of electron paramagnetic resonance (EPR) spectroscopy, and the variation of the observed six-line Mn (II) signal was monitored for 1 year. An inverse trend has been established between the photosynthetic efficiency of the plant and the measured content of Mn (II). The possibility of using EPR spectroscopy in studying ageing and in assessing stress situations in plants is considered.

Optical properties of juniper and lentisk canopies in a coastal Mediterranean macchia shrubland

Abstract. Light absorbance and reflectance were measured on representative shrubs of two dominant shrub species (Pistacia lentiscus and Juniperus phoenicea) of coastal Mediterranean macchia ecosystems in Sardinia (Italy). An array of 64 calibrated photodiodes was adopted for both calculations of leaf area index (LAI) and canopy transmittance of photosynthetic active radiation (PAR). PAR and NIR reflectance of canopies having similar LAI allowed us to establish the particular optical properties of each species. Lentisk reflected twice as much as juniper in the 700–1,100 spectral region. Water indexes of the two species were also different in relation to leaf water content and red edge amplitude appeared to be related to chlorophyll content. Epidermis and mesophyll structures of both species are shown.

Dry deposition of pollutants and effects on vegetation

SummaryDry deposition of gases and airborne particles is reviewed in particular relation to their interaction with vegetation. Once deposited, pollutants overcome the system of resistances (air, cuticular, stomatal and mesophyll) and penetrate key physiological points that affect the plants biochemistry. Strong relationships have been found between gases in the environment and the chlorophyll content of leaves, production and partitioning of dry matter, relative growth rate and net assimilation rate.Physical modes of dry deposition involving anthropogenic pollutants present in the surface layer and micrometeorological conditions allowing their diffusion in the canopy are also discussed, with emphasis on measurement techniques.

Older adults involvement in developing satisfactory pasta sauces with healthy ingredients

Purpose The third age can be a period of major food consumption changes. Either voluntary or imposed by health issues, they may be accompanied by alterations in sensory acuity. This research investigated how lifelong food habits, health-age issues affect food choice at a later age, with the aim of developing strategies to direct aged people towards healthier food habits. Design/methodology/approach A survey, aimed to investigate differences between current and past food habits, was carried out in a group of 170 Italian older adults. Questions focused on the composition of the main meal, asking participants to describe its actual structure and to highlight differences in previous years’ food habits. A Discrete Choice Experiment (DCE) was planned, during which participants were asked to help formulating innovative pasta sauces with healthy ingredients. Findings This survey clearly illustrated gender-related differences: women were characterized by a higher consumption of vegetables, while men revealed a mor...