Orange (Citrus sinensis L.) is one of the main fruit crops worldwide and its evergreen orchards may have a great potential for carbon (C) sequestration, but no data are currently available. In order to understand carbon fluxes in orange orchards, an experiment was undertaken on traditional and\ud intensive planting systems.\ud The experiment used C. sinensis scions grafted onto Citrus aurantium (bitter orange) rootstock. One orchard contained 14-year-old trees of the cv. Tarocco Scire` (a blood orange) grown in a traditional system with 494 trees/ha. The second orchard contained 12-year-old trees of the cv. Newhall (a\ud seedless navel orange) grown in an intensive system with 1000 trees/ha. Net primary productivity(NPP) was obtained by measuring the annual canopy growth of single orange trees and the above ground dry biomass of the ground cover; soil respiration seasonal pattern was measured with an infrared gas analyser (EGM-4, PP System) from June 2005 to May 2006, every 2 weeks from 12.00 noon to 15.00 h for maximum respiration and from 02.00 to 05.00 h for minimum respiration; a 24 h cycle measurement of soil respiration was made every 3 months.\ud Carbon fixation in the fruits and in the canopy of single trees was almost twice as much (10.7 kgC/tree) in the traditional than in the intensive system (5.5 kg C/tree); however, total NPP of the orchard did not change with planting density, being 5.3 t C/ha/year in the traditional system and 5.5 t C/ha/year in the intensive one. Carbon fixation by the ground cover was higher in the traditional (1.1 t C/ha/year) than in the intensive system (0.5 t C/ha/year). Annual soil respiration was 5.9 t C/ha/year in\ud the traditional system and 4.2 t C/ha/year in the intensive one. The carbon balance was almost four times higher in the intensive system (1.8 t C/ha/year) than in the traditional one (0.5 t C/ha/year), due\ud to large differences in soil respiration
Soil physical quality (SPQ) can be assessed by different experimental methodologies\ud and criteria and the optimal/critical values or ranges for SPQ\ud indicators are still approximate. Sampling soils with minimal anthropic pressures\ud should allow improvements in SPQ assessment. Different experimental\ud methodologies and criteria were applied to sample a Mediterranean oak forest\ud (Quercus ilex L.) and pasture land, in Sicily, with a varying degree of\ud anthropic disturbance. Soil water retention was determined in the laboratory\ud and the field, using the BEST (Beerkan Estimation of Soil Transfer parameters)\ud procedure of soil hydraulic characterization. Capacity-based indicators, the\ud S index, and location and shape parameters of the pore volume distribution\ud function were calculated for assessing SPQ. With the laboratory data,\ud only the criterion using the capacity-based indicators suggested that SPQ\ud increased as external pressures decreased. Therefore, this criterion appeared\ud to be more reliable than the other tested criteria in the sampled environment.\ud The field method was more prone to suggest good conditions and less able\ud to signal differences between plots as compared with the laboratory method.\ud A forest soil with a good SPQ has an ability to store and provide water to\ud plant roots similar to, but it is more aerated than, a good agricultural soil.\ud Developing BEST for SPQ assessment is advisable since parameters descriptive\ud of the soil water transport properties can be collected with a single\ud experiment. Simultaneous characterization of dendrometric and soil parameters\ud at other sites is recommended to explore the relationships between SPQ\ud indicators and characteristics of the forest cover
Ready-to-eat products are damaged by various factors, including exposure to O 2 and CO 2 , extreme temperatures, and rapid decay, due to trauma during processing. e use of natural antimicrobial agents and antioxidants might extend the shelf-life of the fruits. e aim of this work is to investigate the effects of four different antibrowning and gelling agents added into the Aloe vera gelbased edible coatings and applied to fresh-cut papaya. EC1 treatment consists of Aloe vera gel (30% v/v), EC2 contains CaCl 2 (5% v/v), EC3 contains K carrageenan (0.5% v/v), and EC4 contains sodium alginate (1.5% v/v) and K carrageenan (0.5% v/v). e fruits treated with EC2 showed the best results while maintaining high values in terms of firmness (that differ from the control of 42.5%), soluble solid content (that differ from the control of 14.6%), and titratable acidity (that differ from the control of 49%). Hence, the addition of CaCl 2 also reduces the ripening rate and loss of color without altering the product's sensory qualities. EC3 and EC4 treatments have provided an oxygen barrier and reduced respiratory rate, increasing the firmness retention and keeping a high C * value thanks to K carrageenan and sodium alginate.
Influence of within-tree and environmental factors on fruit quality of cactus pear (Opuntia ficus-indica) in Italy. Abstract-Introduction. Opuntia ficus-indica fruit quality was studied, in the main sites for cactus pear cultivation in Italy, with the ultimate goal of understanding the main sources of variability and increasing crop value. Materials and methods. A first study was carried out in 2006 on mature Opuntia ficus-indica trees, cvs. Gialla and Rossa, grown in ten commercial orchards located in the main sites for their cultivation in Italy. Trees were managed to produce an out-of-season crop in October, through the removal of the spring flush at bloom time, during the first week of June. Trees had a similar crop [(52 ± 10) kg of fruits•tree-1 ], and no more than six fruits were left on each of the fruiting cladodes. At commercial harvest time, indicated by the peel colour breakage, 75 fruits in each orchard and 750 fruits for each site were picked, analysed and evaluated by a consumer panel. A second experiment was carried out in 2006 on 8-year-old O. ficus-indica trees, cv. Gialla, grown in a commercial orchard. Within-tree factors, such as fruit position within the canopy, number of fruits per tree and per cladode, and cladode dry weight were studied. Results and discussion. Fruit weight, shape and total soluble solid content significantly changed with the environmental conditions, i.e., site and altitude, while flesh percent, pH and total titratable acidity did not. Cultivars had a significant influence only on fruit weight and seed content. Fruit weight changed greatly within the tree, while total soluble solid content and flesh percent variability was much reduced. Fruit weight decreased with fruit number per tree and both fruit weight and total soluble solid content decreased with more than six fruits per cladode. Light interception and cladode dry weight were the main sources of fruit dry weight variability and sugar content, while cladode surface area was poorly related to fruit quality. The role of cultivars in determining fruit quality did not change with site and, moreover, the sensory analysis was unable to discriminate for cultivar and environment. Italy / Opuntia ficus-indica / variety trials / fruits / yield factors / site factors Influence des facteurs intra-arbre et environnementaux sur la qualité des fruits du figuier de Barbarie (Opuntia ficus-indica) en Italie. Résumé-Introduction. La qualité des fruits du figuier de Barbarie a été étudiée, dans les principaux sites de culture de Opuntia ficus-indica en Italie, afin de comprendre les principales sources de variabilité et d'augmenter la valeur des récoltes. Matériel et méthodes. Une première étude a été réalisée en 2006 sur des arbres adultes d'O. ficus-indica, cvs. Gialla et Rossa, développés dans dix vergers commerciaux situés dans trois localités des principaux sites de cette culture en Italie. Les arbres ont été conduits de façon à produire en octobre, en contre-saison, par suppression des pousses de printemps au moment de la florai...
Water scarcity in the Mediterranean area is very common and understanding responses to drought is important for loquat management and production. The objective of this study was to evaluate the effect of drought on the growth and metabolism of loquat. Ninety two-year-old plants of ‘Marchetto’ loquat grafted on quince were grown in the greenhouse in 12-liter pots and three irrigation regimes were imposed starting on 11 May and lasting until 27 July, 2013. One-third of the plants was irrigated with 100% of the water consumed (well watered, WW), a second group of plants was irrigated with 66% of the water supplied to the WW plants (mild drought, MD), and a third group was irrigated with 33% of the water supplied to the WW plants (severe drought, SD). Minimum water potential levels of −2.0 MPa were recorded in SD plants at the end of May. Photosynthetic rates were reduced according to water supply (WW > MD > SD), especially during the morning hours. By the end of the trial, severe drought reduced all growth parameters and particularly leaf growth. Drought induced early accumulation of sorbitol in leaves, whereas other carbohydrates were not affected. Of over 100 leaf metabolites investigated, 9 (squalene, pelargonic acid, glucose-1-phosphate, palatinol, capric acid, aconitic acid, xylitol, lauric acid, and alanine) were found to be useful to discriminate between the three irrigation groups, suggesting their involvement in loquat metabolism under drought conditions. Loquat behaved as a moderately drought-tolerant species (limited stem water potential and growth reductions) and the accumulation of sorbitol in favor of sucrose in mildly-stressed plants may be considered an early protective mechanism against leaf dehydration and a potential biochemical marker for precise irrigation management.
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