Ktisis Community: Σχολή Γεωτεχνικών Επιστημών και Διαχείρισης Περιβάλλοντος/Faculty of Geotechnical Sciences and Environmental Management

Cell wall physicochemical aspects of nectarine fruit related to flesh reddening symptoms

Sat, 29 Oct 2005 22:58:59 GMT

Title: Cell wall physicochemical aspects of nectarine fruit related to flesh reddening symptoms

Authors: Manganaris, George A.; Mignani, Ilaria; Vasilakakis, Miltiadis

Abstract: Flesh reddening (FR) symptoms are developed in many nectarine cultivars, without however having dissected its cell wall physicochemical aspects. ‘Caldesi 2000’ is a very susceptible nectarine to FR and was used as model cultivar in the current study. Two lots of 30 fruits were allowed to ripen for 5 d (shelf life) at 20°C either after harvest or after 4-week cold storage and the fruits with either white or reddish flesh surface were selected for cell wall analysis. Fruits with FR symptoms were characterized by a lower content of uronic acid in the insoluble pectin fraction, and therefore a lower proportion of uronic acid in the insoluble to water-soluble pectin fraction. The decrease of neutral sugar content was mainly attributed to cold storage. However, the fruits with FR symptoms were characterized by a lower content of total neutral sugars. Additionally, significant differences in glucose content were monitored between the white flesh fruits and the fruits with FR symptoms. The nectarine fruits subjected to cold storage were characterized by a decreased cellulose content, whereas the decrease was more intense in nectarines with FR symptoms.

Effect of pre-harvest and post-harvest conditions and treatments on plum fruit quality

Mon, 29 Oct 2007 22:58:59 GMT

Title: Effect of pre-harvest and post-harvest conditions and treatments on plum fruit quality

Authors: Manganaris, George A.; Vicente, Ariel R.; Crisosto, Carlos H.

Abstract: Plums belong to the Rosaceae family and include the European species (Prunus domestica L.), whichis consumed fresh or dried, and the Japanese species (Prunus salicina Lindell), mainly freshly consumed. Plums are considered climacteric, although some plum cultivars do not show the typicalincrease in ethylene production and respiration until late ripening. They respond to exogenousethylene, which is a key ripening regulator, while treatments with 1-methylcyclopropene (1-MCP),an ethylene action inhibitor, are effective in delaying fruit ripening. Plum fruit is characterized byhigh softening rate and, so far, the sequence of events leading to cell wall degradation, as well aschanges in the proteins responsible for these modiﬁcations, has not been thoroughly investigated.Post-harvest diseases (brown rot, grey mould and Rhizopous rot) are also a main concern in plumpost-harvest handling and storage. Prompt cooling and low-temperature storage (0 C) arerecommended to delay ripening and maintain plum fruit quality. However, when the fruit is heldfor long periods at low temperature, chilling injury (CI) symptoms, usually manifested as translucency, bleeding, ﬂesh browning and/or failure to ripen, might develop. Although softening can bedelayed by controlled and modiﬁed atmospheres, this technology is not widely used commercially,since the beneﬁts are not as pronounced as in other fruit species. Other post-harvest strategiestested to date with apparent usefulness at a laboratory scale include heat treatment, ozone,polyamine and calcium treatments, as well as fumigation with environmentally friendly compounds;such strategies might be useful under particular circumstances to complement other post-harvesttreatments. Pre-harvest treatments, such as application of synthetic auxins and calcium, regulationof canopy light conditions and orchard soil management, have been reported to affect plum fruitquality and its post-harvest behaviour. Overall, the present review discusses the inﬂuence of ﬁeldand post-harvest practices on plum fruit quality and market life.

Production of virus-free plant propagation material from infected nectarine trees

Tue, 29 Oct 2002 22:58:59 GMT

Title: Production of virus-free plant propagation material from infected nectarine trees

Authors: Manganaris, George A.; Economou, A.S; Boubourakas, I.N.

Abstract: Plum pox virus (PPV) is one of the major and common diseases in stone-fruit trees. The effect of thermotherapy in PPV-infected nectarine plants (Prunus persica var. nectarina Max, cv. Arm King) and plant regeneration from meristem-tip explants, as well as use of a reliable RT-PCR that detects extremely low virus titre of PPV in in vitro cultures were studied. Three weeks of thermotherapy at a maximum temperature of 35°C gave tender explants that used for meristem-tip culture. Meristem-tip explants first were established on WPM free of growth regulators and then for multiple shoot were subcultured on WPM supplemented with 8 µM BA and 0.8 µM IAA. Individual shoots produced from such meristem-tip cultures were tested for PPV presence with RT-PCR and gave ‘negative’ results (virus-free) at a frequency of 82.8%. Rooted in vitro microcuttings, derived from virus-free cultures, were established in the greenhouse conditions successfully.

Photorealistic large-scale urban city model reconstruction

Wed, 29 Oct 2008 22:58:59 GMT

Title: Photorealistic large-scale urban city model reconstruction

Authors: Poullis, Charalambos; You, C.

Abstract: The rapid and efficient creation of virtual environments has become a crucial part of virtual reality applications. In particular, civil and defense applications often require and employ detailed models of operations areas for training, simulations of different scenarios, planning for natural or man-made events, monitoring, surveillance, games, and films. A realistic representation of the large-scale environments is therefore imperative for the success of such applications since it increases the immersive experience of its users and helps reduce the difference between physical and virtual reality. However, the task of creating such large-scale virtual environments still remains a time-consuming and manual work. In this work, we propose a novel method for the rapid reconstruction of photorealistic large-scale virtual environments. First, a novel, extendible, parameterized geometric primitive is presented for the automatic building identification and reconstruction of building structures. In addition, buildings with complex roofs containing complex linear and nonlinear surfaces are reconstructed interactively using a linear polygonal and a nonlinear primitive, respectively. Second, we present a rendering pipeline for the composition of photorealistic textures, which unlike existing techniques, can recover missing or occluded texture information by integrating multiple information captured from different optical sensors (ground, aerial, and satellite).