Francesco Paolo Nicese

Comparing fractal analysis, electrical impedance and electrolyte leakage for the assessment of cold tolerance in Callistemon and Grevillea spp.

Summary Lethal low temperatures were examined in two species of Grevillea and four species of Callistemon, two taxa originating from Australia. The demand in Europe and America for Australian plants is increasing both as cut flowers and as potted or landscape plants, but there is little information available on the cold hardiness of these species. LT50 (lethal temperature at which 50% of damage occurs) was determined by measuring electrical conductivity (electrolyte leakage), impedance spectroscopy and fractal spectrum of leaf colour. All the experiments were conducted on non-acclimated and cold-acclimated plants. LT50 calculated on non-acclimated plants were about 2–3°C higher than in acclimated plants, except for G. olivacea. In every case, the LT50 estimated by the three methods were very similar and ranged from –4.6°C for G. olivacea, the species most sensitive to freezing, to about –9.5°C for C. salignus, the most resistant to freezing among the species tested.

Reuse of industrial wastewater for the irrigation of ornamental plants

This paper describes the results of experimental activities carried out for verifying the possibility of reusing reclaimed wastewater originated from textile (70%) and domestic (30%) activities for the irrigation of container-grown ornamental shrubs. Aspects that concern the refinery treatment of reclaimed wastewater and the effect of irrigation on some ornamental plant species were investigated. An experimental site consisting of a refinery treatment pilot plant (filtration and disinfection) and an agronomic experimental area was set-up. The combined treatment of PAA and UV, used for the disinfection, showed to be very effective for inactivation of E. coli with most of PAA and UV dose combinations able to assure total inactivation. The plants (Buxus, Photinia, Pistacia and Viburnum), sprinkle and drip irrigated with well water (WW), reclaimed wastewater (RW) and a water mixed (MW) between reclaimed wastewater and well water (1:1 by vol), showed interesting results. A similar growth among different treatments was achieved for Buxus and Pistacia, while Viburnum and Photinia plants showed a higher sensibility to MW and RW. Photinia, in particular, turned out to be very sensitive to sprinkle irrigation with the reclaimed water, while the drip irrigation had no such bad effects, as reported in previous works.

Use of phytoremediated sediments dredged in maritime port as plant nursery growing media

We evaluated the potential of a phytoremediated sediment (TR) dredged from maritime port as peat-free growth substrate for seven ornamental plants, in comparison with an untreated sediment (NT), in a greenhouse experiment. The studied plants were Quercus ilex, Photinia x fraseri, Viburnum tinus, Cistus albidus, Raphiolepis indica, Westringia fruticosa and Teucrium fruticans. Plant growth was monitored for ten months, and the changes in the physico-chemical properties, toxicity, microbial biomass and enzyme activities involved in the C, P and N cycles were also monitored during the plant growth period. The results showed that the studied ornamental plants could grow on both NT and TR sediments, but that the growth was higher on TR sediment. The plant growth induced changes in the sediment chemical functional groups, with clear separation between NT and TR sediments for each of the studied plant. Microbial biomass and enzyme activities significantly increased during the plant growth, more in TR than in NT sediment. Toxicity was detected in NT sediments during the plant growth whereas it was not observed in NT sediments during the whole growth period. We concluded that phytoremediation converted the dredged maritime sediments into suitable substrates for growing ornamental plants, and that the re-use by plant nursery industry can be a sustainable management and valorization for remediated sediments.

The fractal spectrum of leaf colour as a tool for measuring frost hardiness in plants

Summary An image analysis method, based on the calculation of the fractal spectrum of leaf colour, was evaluated for its potential use in assessing frost hardiness in plants. The technique developed consisted of a) digitization of the leaves after freezing treatments, b) splitting of the images obtained into the three components of the RGB (red, green and blue) colour system and c) calculation of the fractal spectrum for each colour component of the leaf. It was then tested to assess the freezing hardiness of acclimated and non-acclimated Callistemon linearis plants. The analysis system consisted of a scanning device, a personal computer and the image analysis algorithm. All the fractal parameters showed a sigmoidal relationship with temperature. From the inflection point, the LT50 calculated for acclimated and non-acclimated plants, was –7.5 and –4.8°C, respectively. The LT50 calculated from the electrolyte leakage test on the same material was about 2°C warmer than the LT50 obtained from fractal analysis. The role of fractal analysis of leaf colour as an additional, rapid and inexpensive method for identifying freezing damage is discussed.

Assessing environmental sustainability of ornamental plant production: a nursery level approach in Pistoia District, Italy

ABSTRACT Ornamental plant production exerts considerable impacts on the surrounding environment. To assess the environmental sustainability within this sector, a set of impact indicators, which refer to specific management issues in environmental terms, was selected. By comparing the indicators with sustainable thresholds, we assessed the environmental sustainability of a pool of nurseries growing plants in container production (CP) and in open field production (FP) located in the Pistoia Nursery District of the Tuscany Region. Because of their peculiar production structure, the CP nurseries impacted the environment more than the FP nurseries, and hence need more improvements to reach the minimum level of environmental sustainability.