Osvaldo Facini

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.

Seasonal variation of monoterpene emission from Malus domestica and Prunus avium

Emission rates of monoterpenes released by apple (Malus domestica Borkh) and cherry (Prunus avium L.) were estimated at different phenological stages. These measurements employed a dynamic flow-through Teflon chamber, sample collection onto cartridges filled with graphitized carbon and thermal desorption gas chromatography-mass spectrometry (GC-MS) for identification and quantification of the emitted volatiles. At full bloom the release of monoterpene hydrocarbons from cherry flowers was 1213 ng g(-1) dry weight (DW) h(-1), exceeding by approximately three-fold the emission rate of apple flowers (366 ng g(-1) DW h(-1)). Observed seasonal variations in biogenic volatile organic compound (VOC) emissions ranged over several order of magnitudes. At fruit-set and ripening stages, in fact, the hydrocarbon emission dramatically decreased reaching the lowest values at harvest time when leaves were fully mature (3-9 ng g(-1) DW h(-1)). Wide diversity in the composition of compounds from the species studied was also recorded. At blooming, linalool contributed significantly to the monoterpene emission from apple (94% of the emitted carbon) while alpha-pinene and camphene represented on average more than 60% of the total emitted volatiles from cherry flowers. Among the monoterpenes identified in flowers, alpha-pinene, camphene and limonene were also found in the foliage emission of both species. Fruit trees are relevant monoterpene emitters only at blooming and thus for a short period of the vegetative cycle. When leaves are fully developed, the carbon loss due to monoterpene emissions related to the photosynthetically carbon gain is negligible.

Annual and monthly carbon balance in an intensively managed Mediterranean olive orchard

At present, research activities on the role of orchard systems in sequestering atmospheric CO2 remain scarce. This paper aimed to contribute to assessing the carbon balance of a Mediterranean olive (Olea europea) orchard. The net ecosystem exchange, the ecosystem respiration and the gross primary production were computed for two consecutive years through eddy covariance, and the different biomass accumulation terms were also inferred in the same period through an inventorial method. The net carbon exchange ranged from 13.45 t(C) ha−1 year−1 to 11.60 t(C) ha−1 year−1. Very similar values [12.2 and 11.5 t(C) ha−1 year−1] were found with the direct carbon accumulation inventory. The intensive farming management (irrigation included) and the young age of the plants (12–16 years old), still in an active growing phase, led the olive plantation to be a higher carbon sink with respect to other evergreen orchards reported in the literature.

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.

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.

Light transmittance and sunlit leaf area estimation in a peach canopy

SummaryA preliminary analysis was performed to evaluate the structural differences in the different parts of a representative peach tree trained to palmette. The shoot inclination angles showed a spherical and planophile distribution at the top and at the bottom, respectively. The measured canopy transmittance was found to depend on the LAI and solar elevation angle. An empirical model, using an extinction coefficient as a function of the solar elevation angle, was tested to determine the light transmittance in a peach orchard. A good agreement was found between the daily means measured and predicted by the model at three heights in the canopy. The model proved to be useful for estimating diurnal and seasonal variation in the total sunlit leaf area.

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.

Determination of peach leaf area index by radiation measurements

SummaryThe leaf area index (LAI) of trees at any given time is an important parameter in light interception, photosynthetic productivity and ecophysiological studies. An indirect method based on photosynthetic irradiance measurements is here used to infer the LAI of a peach tree trained to flat palmette. Between the possible probability distributions, the negative binomial distribution appears the more suitable to represent the light penetration inside the canopy throughout the whole growing period, and the specific clumping coefficient of 16.2 is found.

Composition and emission of VOC from biogas produced by illegally managed waste landfills in Giugliano (Campania, Italy) and potential impact on the local population

The composition in Volatile Organic Compounds (VOC) of the biogas produced by seven landfills of Giugliano (Naples, Campania, Italy) was determined and VOC emission rates assessed to verify if these compounds represent a potential threat to the population living nearby. VOC composition in the biogas could not be predicted, as heterogeneous waste was dumped from the late 1980s to the early 2000s and then underwent biological degradation. No data are available on the amount and composition of VOC in the biogas before the landfills closure as no operational biogas collection system was present. In this study, VOC composition was determined by gas chromatography-mass spectrometry (GC-MS), after collecting samples from collection pipes and from soil fractures in cover soil or capping. Individual VOC were quantified and data compared with those collected at two landfills in Latium, when they were still in operation. Relevant differences were observed, mainly due to waste aging, but no specific VOC revealing toxic waste dumping was found, although the concurrent presence of certain compounds suggested that dumping of industrial wastes might have occurred. The average VOC emission was assessed and a dispersion model was run to find out if the emitted plume could affect the health of population. The results suggested that fugitive emissions did not represent a serious danger, since the concentrations simulated at the neighboring cities were below the threshold limits for acute and chronic diseases. However, VOC plume could cause annoyance at night when the steady state conditions of the atmosphere enhance pollutants accumulation in the lower layers. In addition, some of the emitted VOC, such as alkylbenzenes and monoterpenes, can contribute to tropospheric ozone formation.