158 research outputs found
Solar UV-B Radiation Influences Carotenoid Accumulation of Tomato Fruit through Both Ethylene-Dependent and -independent Mechanisms
The effect of UV-B shielding on ethylene production in ripening tomato fruits and the contribution of
ethylene and UV-B radiation on carotenoid accumulation and profile during ripening were assessed
to get more insight about the interplay between these two regulatory factors. To this aim, rin and nor
tomato mutants, unable to produce ripening ethylene, and cv Ailsa Craig were cultivated under
control or UV-B depleted conditions until full fruit ripening. The significantly decreased ethylene
evolution following UV-B depletion, evident only in Ailsa Craig, suggested the requirement of
functional rin and nor genes for UVB-mediated ethylene production. Carotenoid content and profile
were found to be controlled by both ethylene and UV-B radiation. This latter influenced carotenoid
metabolism either in an ethylene-dependent or -independent way, as indicated by UVB-induced
changes also in nor and rin carotenoid content and confirmed by correlation plots between ethylene
evolution and carotenoid accumulation performed separately for control and UV-B shielded fruits. In
conclusion, natural UV-B radiation influences carotenoid metabolism in a rather complex way,
involving ethylene-dependent and -independent mechanisms, which seem to act in an antagonistic
way
The residues of fruit and vegetable pro-cessing: From âwasteâ to âresourceâ of natural phytochemical compounds
The project of SantâAnna School, in line with the Italian legislation on limiting waste and promoting the redistribution of surpluses and unused goods, aimed to study the potential healthy value of residues obtained from the trans-formation of fruit and vegetable products that represent a cost, as they must be handled, stored and disposed according to stringent actual regulations. Two âmodelâ species (potato and apple) were considered to test the possibility of using industrial processing waste for food applications. The extracts, obtained with âgreenâ methods from potato and apple peels, were evaluated as natural antioxidants in the preparation of minimally processed freshÂcut apple. Results suggest the possibility to use these novel byproduct extracts as valuable alter-native treatments to traditional chemical additives employed for minimally processed apples
Solar UV-B radiation influences carotenoid accumulation of tomato fruit through both ethylene-dependent and -independent mechanisms
The effect of UV-B shielding on ethylene production in ripening tomato fruits and the contribution of ethylene and UV-B radiation on carotenoid accumulation and profile during ripening were assessed to get more insight about the interplay between these two regulatory factors. To this aim, rin and nor tomato mutants, unable to produce ripening ethylene, and cv Ailsa Craig were cultivated under control or UV-B depleted conditions until full fruit ripening. The significantly decreased ethylene evolution following UV-B depletion, evident only in Ailsa Craig, suggested the requirement of functional rin and nor genes for UVB-medlated ethylene production. Carotenoid content and profile were found to be controlled by both ethylene and UV-B radiation. This latter Influenced carotenoid metabolism either in an ethylene-dependent or -independent way, as indicated by UVB-induced changes also in nor and rin carotenoid content and confirmed by correlation plots between ethylene evolution and carotenoid accumulation performed separately for control and UV-B shielded fruits. In conclusion, natural UV-B radiation influences carotenoid metabolism in a rather complex way, involving ethylene-dependent and -independent mechanisms, which seem to act in an antagonistic way
Distinct mechanisms for aerenchyma formation in leaf sheaths of rice genotypes displaying a quiescence or escape strategy for flooding tolerance
Background and Aims Rice is one of the few crops able to withstand periods of partial or even complete submergence. One of the adaptive traits of rice is the constitutive presence and further development of aerenchyma which enables oxygen to be transported to submerged organs. The development of lysigenous aerenchyma is promoted by ethylene accumulating within the submerged plant tissues, although other signalling mechanisms may also co-exist. In this study, aerenchyma development was analysed in two rice (Oryza sativa) varieties, âFR13Aâ and âArborio Precoceâ, which show opposite traits in flooding response in terms of internode elongation and survival.
Methods The growth and survival of rice varieties under submergence was investigated in the leaf sheath of âFR13Aâ and âArborio Precoceâ. The possible involvement of ethylene and reactive oxygen species (ROS) was evaluated in relation to aerenchyma formation. Cell viability and DNA fragmentation were determined by FDA/FM4-64 staining and TUNEL assay, respectively. Ethylene production was monitored by gas chromatography and by analysing ACO gene expression. ROS production was measured by using Amplex Red assay kit and the fluorescent dye DCFH2-DA. The expression of APX1 was also evaluated. AVG and DPI solutions were used to test the effect of inhibiting ethylene biosynthesis and ROS production, respectively.
Key Results Both the varieties displayed constitutive lysigenous aerenchyma formation, which was further enhanced when submerged. âArborio Precoceâ, which is characterized by fast elongation when submerged, showed active ethylene biosynthetic machinery associated with increased aerenchymatous areas. âFR13Aâ, which harbours the Sub1A gene that limits growth during oxygen deprivation, did not show any increase in ethylene production after submersion but still displayed increased aerenchyma. Hydrogen peroxide levels increased in âFR13Aâ but not in âArborio Precoceâ.
Conclusions While ethylene controls aerenchyma formation in the fast-elongating âArborio Precoceâ variety, in âFR13Aâ ROS accumulation plays an important role
Physiological changes during postharvest life of cut sunflowers
The vase life of sunflowers (Helianthus annuus) is limited by early wilting of leaves and ray flowers. Vase life was positively correlated with stem length (5 days in 50 cm stems, 9 days in 70 cm stems). We also studied the vase life after a 24 h pulse treatment with a number of chemicals. It was significantly increased by treatment with 150 mg L-1 citric acid. Treatment with 10\u3bcl L-1 ethylene reduced vase life and induced both flower bending and abscission of ray flowers. In contrast, 2 mM amino-oxyacetic acid (AOA), an ethylene inhibitor, reduced ethylene production but did not increase vase life. 8-Hydroxyquinoline (8-HQS) at 150 mg L-1 did not lengthen vase life. Vase life was reduced by treatment with 2% sucrose combined with either 150 mg L-1 citric or with 150 mg L-1 8-HQS
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