Effect of u.v.-A on aging of wheat leaves and role of phytochrome

Joshi, Padmanava; Biswal, Basanti; Biswal, U. C.

doi:10.1016/0098-8472(91)90050-x

Cited by 36 publications

(9 citation statements)

References 21 publications

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“…Interestingly, however, in our experiment UV-A radiation increased (19%) lipid peroxidation in the oldest fully expanded leaves. This supports a study where wheat leaves exposed to UV-A radiation showed an increase in lipid peroxidation (Joshi et al 1991). In conclusion, UV-A exposure caused a low level of secondary metabolites and an increase in lipid peroxidation whereas enhanced UV-B increased secondary metabolite production and maintained a control level of lipid peroxidation.…”

Section: Secondary Metabolites and Lipid Peroxidationsupporting

confidence: 84%

Growth, structure, stomatal responses and secondary metabolites of birch seedlings ( Betula pendula) under elevated UV-B radiation in the field

Костина

Wulff

Julkunen‐Tiitto

2001

Trees

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Three-year-old birch (Betula pendula Roth.) seedlings were exposed, in the field, to supplemental levels of UV-B radiation. Control seedlings were exposed to ambient levels of UV radiation, using arrays of unenergized lamps. A control for UV-A radiation was also included in the experiment. Enhanced UV-B radiation had no significant effects on height growth, and shoot and root biomass of birch seedlings. Leaf expansion rate increased transiently in the middle of the growing period in enhanced UV-B-and UV-A-exposed plants; however, final leaf size and relative growth rate remained unaffected. Leaf thickness and spongy intercellular spaces were increased in UV-B-exposed seedlings along with increased density of glandular trichomes. At the ultrastructural level, enhanced UV-B increased the number of cytoplasmic lipid bodies, and abnormal membrane whorls were found. Both enhanced UV-B and UV-A radiation induced swelling of chloroplast thylakoids. Stomatal density and conductance were significantly increased by elevated UV-B radiation. UV-A radiation increased the length and width of stomata, whereas UV-B radiation had only a marginal effect on stomatal size. UV-A and enhanced UV-B radiation attenuated the appearance of necrotic spots in autumn, probably caused by the fungus Pyrenopeziza betulicola, suggesting a direct harmful effect of UV on pathogens or reduced susceptibility to pathogens in UV-exposed seedlings. Secondary metabolite analysis showed increases in (+)-catechin, quercetin, cinnamic acid derivative, apigenin and pentagalloylglucose in birch leaves under enhanced UV-B radiation. Negative correlations between apigenin, and particularly quercetin concentrations and lipid peroxidation levels indicated an antioxidant role of secondary metabolites in birch leaves exposed to UV-B radiation.

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Section: Secondary Metabolites and Lipid Peroxidationsupporting

confidence: 84%

Growth, structure, stomatal responses and secondary metabolites of birch seedlings ( Betula pendula) under elevated UV-B radiation in the field

Костина

Wulff

Julkunen‐Tiitto

2001

Trees

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“…Beside the DM accumulation the senescence processes might also contribute to the Chl reduction (Munné-Bosch and Alegre 2004). The leaf senescence is usually enhanced by several abiotic stress factors under field conditions, such as drought, high temperature, high irradiance, and UV-radiation (Pjon 1981, De Luca d'Oro and Trippi 1987, Joshi et al 1991. The lesser Chl content means a reduction in the amount of photons absorbed by leaves, and requires higher capacity to dissipate excess excitation energy per PFD absorbed (Munné-Bosch and Alegre 2000b).…”

Section: Resultsmentioning

confidence: 98%

Carotenoid composition and photochemical activity of four sandy grassland species

Veres¹,

Tóth²,

Láposi³

et al. 2006

Photosynt.

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The photosynthetic pigments and photochemical efficiency of photosystem 2 (PS2) were studied in four constitutive species (Achillea millefolium L., Festuca pseudovina Hack. ex Wiesb., Potentilla arenaria Borkh., and Thymus degenianus Lyka) of a semiarid grassland in South-eastern Hungary. Every species displayed typical sun-adapted traits and substantial plasticity in the composition and functioning of the photosynthetic apparatus. The contents of chlorophylls (Chls) and carotenoids (Cars) on a dry matter basis declined from May to July, however, the amount of total Cars on a Chl basis increased. This increase was the largest in Potentilla (48 %) and the smallest in Achillea (14 %). The pool of xanthophylls (VAZ) was between 25 % and 45 % of the total Car content and was larger in July than in May. The content of β-carotene increased by July, but lutein content did not change significantly. The Chl fluorescence ratio F v /F m was reduced by 3-10 % at noon, reflecting the down-regulation of PS2 in the period of high irradiance and high temperature. The occurrence of minimal values of ΔF/F m ' showed close correlation to the de-epoxidation rate of violaxanthin. Hence in natural habitats these species developed a considerable capacity to dissipate excess excitation energy in the summer period in their photosynthetic apparatus through the xanthophyll cycle pool and a related photoprotective mechanism, when the photochemical utilization of photon energy was down-regulated.

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“…Gamma irradiation could lead to an accumulation of free radicals such as O 2 .-and H 2 O 2 which unbalance the system of free radical elimination and thus induce lipid peroxidation. As a result, the cells of plants are injured and the MDA concentration increased (Murphy, 1990 andJoshi et al, 1991). In this concern, Štajner et al (2007) stated that the use of γ-irradiation at a dose up to 10 kGy did not provoke significant changes in lipid peroxidation and caused a slight increase which could be the consequence of the appropriate antioxidant response.…”

Section: Lipid Peroxidation Contentmentioning

confidence: 99%

Influence of ionizing irradiation on the antioxidant enzymes of <i>Vicia faba</i> L.

Aly¹,

El-Beltagi²

2010

Grasas y Aceites

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288SOD, but for GST enzyme at a dose level 10.0 kGy. For HeNe laser, with or without different doses (2.5, 5.0, 10.0 and 20.0 kGy) of γ-irradiation, enzyme induction was significantly stimulated and positively correlated with the dose levels of γ-irradiation in combination with the He-Ne treatment. There was a significant increase in the concentration of MDA and this increase was more pronounced at dose level 20.0 kGy (38.2 µmol/g d.w) compared to the control (3.9 µmol/g d.w). Laser treatment by He-Ne laser or diode laser only caused a slight increase (P<0.05) in MDA content (4.4 and 5.08 µmol/g d.w respectively) compared to the control (3.9 µmol/g d.w). H 2 O 2 content significantly increased in all treatments and this increase reached its maximum at dose level 20.0 kGy (36.3 µmol/g d.w) compared to the control (2.3 µmol/g d.w.). On the other hand, He-Ne or diode laser treatments combined with γ-irradiation significantly decreased in comparison with γ-irradiation treatments alone. In the case of glutathione content, there were significant increases by γ-irradiation at dose levels 2.5, 5.0, 10.0 and 20.0 kGy. Furthermore, with a combination of γ-irradiation and He-Ne or diode laser, a marked increase in glutathione content was found and was more pronounced than that of gamma irradiation alone. KEY-WORDS: Antioxidants enzyme -Gamma irradiationLaser irirradiation -Vicia faba L. INTRODUCTIONUnder natural conditions of growth and development, plants are inevitably exposed to different types of stress, which may cause an increased production of active oxygen species (ROS) (Smirnoff, 1993 ), which cause tissue injury. Plants have evolved various protective mechanisms to eliminate or reduce ROS. In plant cells, one such protective mechanism is an antioxidant system, composed of both non-enzymatic and enzymatic antioxidants (Foyer et al., 1994b). The capacity of the antioxidant defense system is often increased under stress conditions (Gressel and Galun, 1994), but in most situations the response is moderate (Foyer et al., 1994a). ROS are highly reactive in the absence of any protective mechanism, they can seriously disrupt normal metabolism through oxidative damage to membrane lipids, proteins, pigments and nucleic acids. These ROS are detoxified by the sequential and RESUMEN Influencia de la radiación ionizante en enzimas antioxidantes de Vicia faba L.Semillas de Vicia faba L. Giza 834 fueron expuestas a γ-irradiación a dosis de 2.5, 5.0, 10.0 y 20.0 kGy y después expuesta a una radiación laser de He-Ne (632.8 nm) o de diodo (650.0 nm) durante 5 minutos. Las actividades de las enzimas POD, APOX, CAT, SOD y GST fueron favorecidas significativamente, y éstas alcanzaron un máximo a una dosis de 5.0 kGy para las enzimas POD, APOX, CAT y SOD, y a 10.0 kGy para la enzima GST. Más aún, a diferentes dosis de γ-irradiación (2.5, 5.0, 10.0 and 20.0 kGy) con y sin laser de He-Ne, la inducción enzimática fue significativamente favorecida correlacionando positivamente con las dosis de γ-irradiación en combinación con tratamientos ...

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Effect of u.v.-A on aging of wheat leaves and role of phytochrome

Cited by 36 publications

References 21 publications

Growth, structure, stomatal responses and secondary metabolites of birch seedlings ( Betula pendula) under elevated UV-B radiation in the field

Growth, structure, stomatal responses and secondary metabolites of birch seedlings ( Betula pendula) under elevated UV-B radiation in the field

Carotenoid composition and photochemical activity of four sandy grassland species

Influence of ionizing irradiation on the antioxidant enzymes of <i>Vicia faba</i> L.

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