Search results for "Citrus"
showing 10 items of 350 documents
Zygotic and nucellar embryo survival following dehydration and cryopreservation of citrus intact seeds.
2004
A cryopreservation procedure by dehydration and direct immersion in liquid nitrogen was developed for seeds of four polyembryonic Citrus species, and the sexual or nucellar origin of the recovered seedlings was investigated. Seeds of three species could be desiccated in a sterile air flow to 16 percent (C. sinensis) or 10 percent (C. aurantium and C. limon) moisture content with a negligible reduction in germination levels. Differently, the germinability of C. deliciosa seeds dropped to 50 percent after drying to 15 percent moisture content. Following dehydration treatments, a reduction in the average number of seedlings per germinated seed was always observed. However, all four species ben…
Ultrastructural and histochemical analysis reveals ethylene-induced responses underlying reduced peel collapse in detached citrus fruit
2010
Fruits from many citrus cultivars develop depressed areas in the flavedo (outer part of the peel) and albedo (inner part) following detachment. Although ultrastructural analysis may provide important information about multiple plant responses to stresses and external stimuli at the cell and tissue levels, and despite the proved efficacy of ethylene in reducing peel damage in citrus fruit, cytological responses of this horticultural crop to protective ethylene concentrations have not yet been reported. We show that applying high ethylene levels (2 mu L L(-1) for 14 days) causes sublethal stress as it favored the alteration of cuticle, vacuole, middle lamella and primary wall, especially in t…
Multiple-stage mass spectrometric analysis of six pesticides in oranges by liquid chromatography–atmospheric pressure chemical ionization–ion trap ma…
2004
Abstract Six pesticides were determined by liquid chromatography (LC) with positive ion (PI) atmospheric pressure chemical ionization quadrupole ion-trap tandem mass spectrometry (APCI–MS–MS). Ion fragmentation was studied by MS, MS 2 and MS 3 . Fragmentation of the pesticides produced ions formed by various losses from the side-chains and through heterocyclic ring opening, but without any common fragmentation pathway. Multiple reaction monitoring (MRM) of MS, MS 2 and MS 3 was used to identify and quantify the pesticides. The samples were extracted with ethyl acetate and dried over anhydrous sodium sulfate. Comparison of the three MS modes showed that MS 3 is slightly less sensitive but mu…
Matrix solid-phase dispersion extraction procedure for multiresidue pesticide analysis in oranges.
1996
A multiresidue extraction method based on matrix solid-phase dispersion (MSPD) is optimized for the extraction and gas chromatographic screening of eighteen insecticides (aldrin, carbophenothion, captafol, chlorpyriphos, chlorfenvinphos, diazinon, dicofol, alpha-endosulfan, beta-endosulfan, ethion, fenitrothion, folpet, methidathion, malathion, methyl-azinphos, methyl-parathion, phosmet, and tetradifon) from oranges. After optimization of different parameters, such as type of solid phase used and the amount of solid phase or eluent, recoveries ranged from 67 to 102% with relative standard deviations ranging from 2 to 10%. The limits of detection, calculated as 3 times the baseline noise ran…
Determination of abamectin in citrus fruits by liquid chromatography-electrospray ionization mass spectrometry.
2000
Liquid chromatography coupled to electrospray mass spectrometry (LC-ES-MS) with positive ion detection was used to determine abamectin in oranges. MS conditions were optimized to achieve maximum sensitivity. The main ion for abamectin was [M+Na]+ at a fragmentor voltage of 180 V. Abundant structural information can be obtained at different fragmentor voltages. The detection limit for the standard solution was 12 pg injected, and good linearity and reproducibility were observed. Abamectin residues were extracted using matrix solid-phase dispersion. Orange samples were homogenized with C18 bonded silica placed onto a glass column and eluted with dichloromethane. Recoveries of the abamectin fr…
Agricultural externalities and environmental regulation: evaluating good practice in citrus production
2006
Economic activity takes place in a scenario characterized by an increasing number of environmental regulations aimed at bringing under control the emission of contaminating wastes. In this paper, we evaluate the impact of transforming a code of good practice in nitrogen fertilization on Spanish citrus fruit farms into an environmental regulation of compulsory fulfilment. Using data envelopment techniques, we calculate unrestricted and environmentally regulated short-run maximum profits. Both profit values are then used to compute an index of the cost of regulation. Our results suggest that the cost of shifting from a merely recommended practice to a binding rule is low. On average, the loss…
The impact of winter flooding with saline water on foliar carbon uptake and the volatile fraction of leaves and fruits of lemon (Citrus limon) trees
2012
We investigated the consequences of recurrent winter flooding with saline water on a lemon (Citrus × limon (L.) Burm.f.) orchard, focussing on photosynthesis limitations and emission of secondary metabolites (isoprenoids) from leaves and fruits. Measurements were carried out immediately after flooding (December), at the end of winter (April) and after a dry summer in which plants were irrigated with optimal quality water (September). Photosynthesis was negatively affected by flooding. The effect was still visible at the end of winter, whereas the photosynthetic rate was fully recovered after summer, indicating an unexpected resilience capacity of flooded plants. Photosynthesis inhibition by…
Comparing conventional and organic citrus grower efficiency in Spain
2014
This paper compares the organic and conventional citriculture systems in Spain from the perspective of their technical efficiency. The primary objective of the research is to compare the relative efficiency of these two systems in relation to a metafrontier that envelops both technologies. In addition, the article analyses how efficient each growing system is at using its own technology, that is, when farms’ efficiency is benchmarked in relation to the best practices in their group. Contrary to conventional practice, farms’ performance is analyzed in terms of specific growing tasks: soil and plant cover management, pruning, fertilization and phytosanitary treatments. The results obtained hi…
Comparison of various liquid chromatographic methods for the analysis of avermectin residues in citrus fruits.
2001
Abstract Various liquid chromatographic (LC) techniques for analyzing avermectin (Abamectin) were compared after extraction of residues from citrus fruit samples by matrix solid-phase dispersion (MSPD). LC with UV and fluorescence detection were used as also was LC coupled to the mass spectrometer by an electrospray interface. The results obtained by the three methods were compared in terms of sensitivity and selectivity. The combination of MSPD extraction and LC with fluorescence detection have made it possible to quantify 0.5 μg kg −1 of Abamectin in 0.5 g of orange sample, with an overall average recovery of 94%. The procedure provides a simple and sensitive method for monitoring Abamect…
Sustainability evaluation of Sicily's lemon and orange production: An energy, economic and environmental analysis
2013
The island of Sicily has a long standing tradition in citrus growing. We evaluated the sustainability of orange and lemon orchards, under organic and conventional farming, using an energy, environmental and economic analysis of the whole production cycle by using a life cycle assessment approach. These orchard systems differ only in terms of a few of the inputs used and the duration of the various agricultural operations. The quantity of energy consumption in the production cycle was calculated by multiplying the quantity of inputs used by the energy conversion factors drawn from the literature. The production costs were calculated considering all internal costs, including equipment, materi…