Ageing-induced changes in glutathione system of sunflower seeds

Abstract

Ageing-induced changes in glutathione system of sunflower seeds. -Physiol. Plant. 101: 807-814.The glutathione system is thought to be involved in defence mechanisms present in plant tissues. The efficacy of this system was evaluated in large seeds of sunflower {Helianthus annuus L. cv. Peredovik) in response to accelerated ageing (43°C/75% relative humidity from 1 to 11 days). Differences between the embryo axis and cotyledons in relation to the glutathione system were also investigated. Additionally, lipid peroxidation was determined by measuring the malondialdehyde (MDA) content. All assays were performed using dry seeds and seeds subsequently hydrated by imbibition in distilled water for 12 h at 25°C. Accelerated ageing caused a marked decrease in seed viability, accompanied by an increase in mean germination time. There were no changes in total glutathione in dry seeds. However, the distribution in its reduced (GSH) and oxidized (GSSG) forms revealed that ageing produced a slow conversion from GSH to GSSG. As the ageing period increased, this effect was accompanied by a decrease in glutathione reductase (GR, EC 1.6.4.2) activity. The results also indicated that the GSH system exerts a different response in the embryo axis as compared with the cotyledon: (1) the GSH levels decreased less in the cotyledons than in axes of aged seeds, and (2) the GSSG level in cotyledons was independent of ageing, while its amount increased in aged embryo axes. These different responses, in conjunction with the lower MDA levels in large as compared with small seeds, indicate a possible protective role of the reserve lipids. The efficacy of the GSH system in aged seeds was associated with seed viability, as revealed by multiple regression analysis. Upon imbibition, aged seeds were able to restore their GSH levels, reaching values approximating those of unaged seeds.

Stimulative influence of germination and growth of maize seedlings originating from aged seeds by 2,4-D potencies

“…3,4 The loss of seed vitality during long-term storage is the consequence of many spontaneous and damaging processes, 5 including production of reactive oxygen species, which damage the cell parts, leading to a slowing of respiration and membrane disintegration, 6 and glutathione oxidation. 7 Schafer and Buettener, for this reason, suggested a model based on relations of the GSSG/GSH couple (reduced/oxidised glutathione) for the quantification of physiological states. 8 In some cases, glutathione oxidation could lead to necrosis 9 and loss of germination ability.…”

Sunflower seed deterioration as related to moisture content during ageing, energy metabolism and active oxygen species scavenging

“…Lipid peroxidation has been demonstrated to be involved in seed ageing in soybean (Sung 1996), Norway maple (Pukacka 1991), peanut (Sung and Jeng 1994) and sunflower (Bailly et al 1996, Gidrol et al 1989), but it does not seem to play a key role in ageing in other species such as pigeonpea (Kalpana and Madhava Rao 1996), wheat (Girard and Le Meste 1992) and maize (Linn and Pearce 1990). In sunflower seeds, loss of viability during accelerated ageing is associated with an accumulation of malondialdehyde (MDA), suggesting that seed deterioration is associated with lipid peroxidation related to a decrease in the efficiency of the antioxidant defence system (Bailly et al 1996, Torres et al 1997). In addition, the work of Gidrol et al (1989) suggests that lipid reserves undergo peroxidation serving as a detoxifying trap thus protecting the membranes.…”

Natural Ultra Violet Radialtion on Field Grown Rice (Oryza sativa L.) Plants Confer Protection against Oxidative Stress in Seed during Storage under Subtropical Ambience

“…Ghani (2011) have also demonstrated a varietal difference in reduced glutathione content in aged Brassica napus seed. Age related reductions in glutathione have also been reported in naturally aged seeds of Chenopodium rubrum L. Mitrovic and Bogdanovic (2009) as well as in artificially (accelerated) aged seeds of Helianthus annuus L., Torres et al (1997). Glutathione, though a non-enzymatic antioxidant, being a tripeptide is subject to spontaneous UV radiation caused integrity loss of the linear bonds.…”

“…According to the method of Torres et al (1997) (Table 2), 200 mg embryo was extracted in sodium phosphate buffer pH 7.6 and diluted with 5% SSA (5-Sulfosalicylic acid dehydrate), 400mM sodium carbonate, Phosphate-EDTA dilution buffer and 5-5'-dithiobis (2-nitrobenzoic acid) (DTNB) was added to form the colored product 2-nitro-5-thiobenzoic acid, which was measured at 415 nm. S.D calculated for 6 replicates, P<0.001.…”