Increased antioxidant activity in Cassia seedlings under UV-B radiation

Agarwal, Sheela

doi:10.1007/s10535-007-0030-z

Cited by 67 publications

(30 citation statements)

References 33 publications

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“…At flowering and post-flowering stages UV-B produced almost the same results as those of NaCl. Agarwal (2007) reported a similar finding of increased ASA concentration in C. auriculata seedlings. Ascorbate may thus play a central role in nonenzymatic scavenging of superoxide and H 2 O 2 , and thus (2004) for C. angustifolia and mulberry plants (Sharma et al, 2003).…”

Section: Discussionsupporting

confidence: 61%

“…Decrease in chlorophyll concentration due to salinity and UV-B radiation has already been reported (Sairam et al, 2002;Garg and Singla, 2004;Agarwal, 2007). The reduced chlorophyll concentration may be due to increased chlorophyllase activity (Sudhakar et al, 1997).…”

Section: Discussionmentioning

confidence: 71%

“…It seems possible that the oxyreductases POX and PPO may play an important role as a defense against salt stress. Elevated activity under UV-B radiation has been reported in C. auriculata by Agarwal (2007). Increased activities of POX and PPO under water stress were observed in Cassia seedlings (Agarwal and Pandey, 2003a).…”

Section: Discussionmentioning

confidence: 96%

“…Increased CAT activity under water stress has been reported by Agarwal and Pandey (2003a) and Da et al (2005). The activity of CAT under UV-B stress was increased in other plant species (Ervin et al, 2004;Santos et al, 2004;Agarwal, 2007). The higher CAT activity under these stresses may be associated with tolerance of the plant to NaCl, UV-B and water stress.…”

Section: Discussionmentioning

confidence: 98%

“…To study the effect of salinity stress (75 mmol L -l NaCl) on different stages of plant growth, various components including carbohydrates, α and β-amylases, chlorophylls, carotenoids, chlorophyll stability index (CSI), nitrate reductase, glutamine oxaloacetate transaminase, glutamine pyruvate transaminase, and glutamine dehydrogenase were assayed (Agarwal and Shaheen, 2005a,b). Salinity, UV-B and water stress-induced changes in activities of the enzymic and non-enzymic antioxidant system have been reported by various workers (Hernandez et al, 2000;Sairam et al, 2002;Agarwal andPandey, 2003 a,b, 2004;Agarwal 2007). However, little is known about the effect of abiotic stresses in ROS metabolism in M. charantia.…”

Section: Introductionmentioning

confidence: 99%

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Stimulation of antioxidant system and lipid peroxidation by abiotic stresses in leaves of Momordica charantia

Agarwal

Shaheen

2007

Braz. J. Plant Physiol.

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The purpose of the present work was to evaluate both the antioxidant response system and oxidative stress in leaves from bitter gourd (Momordica charantia L) subjected to NaCl, UV-B and water stresses at three different stages of plant growth: pre-flowering, flowering and post-flowering. Except for peroxidase (POX), all enzyme activities including superoxide dismutase (SOD), catalase (CAT), polyphenol oxidase (PPO), glutathione reductase (GR), as well as concentrations of ascorbate (ASA), hydrogen peroxide (H 2 O 2 ) and thiobarbituric acid reactive substances (TBARS) exhibited maximum values at the flowering stage under all three stresses. All the enzyme activities, SOD, CAT, POX, PPO, GR and the concentrations of ASA, H 2 O 2 and TBARS were elevated under NaCl and UV-B stresses at all growth stages with the exception of H 2 O 2 concentration at the post-flowering stage under UV-B radiation. Greater quantities of the inorganic ions Na + and Cl -were accumulated at all growth stages under salt stress. Drought led to decreases in the concentrations of H 2 O 2 , ASA and activities of PPO and GR; conversely, it led to elevated concentrations of TBARS and activities of SOD, CAT, POX at all three stages in comparison with control values. The POX activity at the third stage was, however, reduced. The photosynthetic pigments decreased at all stages under all stresses. The chlorophyll stability index decreased under NaCl stress, accelerated only at the post-flowering stage under UV-B radiation and significantly increased at pre-and post-flowering stages under water stress. The protein concentration under NaCl stress decreased except at the pre-flowering stage and under UV-B and water stresses the protein concentration was higher than that of the control and NaCl treatment. It is suggested that M. charantia exhibits a protection mechanism against oxidative damage by maintaining a highly induced antioxidant system under all three stresses. Key words: antioxidative enzymes, environmental stresses, H 2 O 2 , ion concentration, thiobarbituric acid-reactive substances Estímulo do sistema antioxidativo e peroxidação de lipídios causados por estresses abióticos em folhas de Momordica charantia: O objetivo deste trabalho foi avaliar as respostas do sistema antioxidativo e o estresse oxidativo em folhas de plantas de Momordica charantia L. submetidas a NaCl, radiação UV-B e déficit hídrico, em três estádios de crescimento: pré-floração, floração e pós-floração. Com exceção da peroxidase (POX), as atividades das enzimas dismutase do superóxido (SOD), catalase (CAT), oxidase de polifenóis (PPO) e redutase da glutationa (GR), assim como as concentrações de ascorbato (ASA), H 2 O 2 e de substâncias reativas ao ácido tiobarbitúrico (TBARS) foram máximas no estádio de floração, independentemente do tipo de estresse aplicado. As atividades das enzimas e dos metabólitos supramencionados forma maiores sob estresses associados ao NaCl e à radiação UV-B em todos os estádios de crescimento, exceto a concentração de H 2 O 2 , que foi maior ...

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Section: Discussionsupporting

confidence: 61%

Section: Discussionmentioning

confidence: 71%

Section: Discussionmentioning

confidence: 96%

Section: Discussionmentioning

confidence: 98%