Effect of low-dose chronic gamma exposure on growth and oxidative stress related responses inArabidopsis thaliana

Abstract

Abstract. The biological responses induced by low-dose chronic gamma exposure of hydroponically grown Arabidopsis thaliana, irradiated during a full life cycle (seed to seed) were investigated. Applied dose rates were 2300, 375 and 85 Gray h −1 . Plants (roots and shoots) were harvested after 24 day (inflorescence emergence), at 34 days (∼50% of flowers open) and at 54 days (silice ripening). Gamma exposure significantly reduced root weight compared to the control but no clear effect of dose rate level on root dry weight was observed. Leaf weight was significantly reduced at the highest irradiation level, only after 54 days exposure. ED-10 was estimated at 10 Gy h −1 . Seed germination was not affected by gamma irradiation. For several of the stress enzymes studied enzyme capacity was generally stimulated at the low and intermediate gamma irradiation level compared to the control and highest irradiation level. No pattern was observed in concentration or reduction state of the non-enzymatic antioxidants, ascorbate and glutathione. Lipid peroxidation products in leaves were present highest at full flowering and decreased with exposure level at this growth stage. At the other two growth stages, lipid peroxidation products were unaffected by gamma treatment.

Effect of gamma radiation on morphological, biochemical, and physiological aspects of plants and plant products

“…The activities of POD, CAT, and SOD in radish (Raphanus sativus L.) leaves were enhanced by girradiation (10 Gy) treatment. Inhibition of CAT activity was also reported under irradiation stress (Ye et al 2000;Štajner et al 2009;Vandenhove et al 2009). The present increase in APX activity was reported to compensate for the progressive drop in catalase activity.…”

“…Lipid peroxidation products in leaves of Arabidopsis thaliana L. present highest at full flowering and decreased with higher g-exposure at this growth stage. At the other two growth stages, lipid peroxidation products were unaffected by g-treatment (Vandenhove et al 2009). The Malondialdehyde (MDA) content and HO˙quantities were observed only under the highest irradiation dose, in soybean (Glycine max Merill.)…”

Anti-oxidant modulation in response to gamma radiation induced oxidative stress in developing seedlings of Psoralea corylifolia L.

“…Such radiation practices, though within range of low doses (5e500 Gy) can elevate the physiological activities of cells in plants and photosynthetic microbes by ameliorating germination and growth rates (Thapa, 2004;Klarizze, 2005;Melki and Sallemi, 2008;Melki and Marouni, 2009;Jan et al, 2010) improving crop yields (Kim et al, 1998;Al-Safadi et al, 2000). However, irradiation with higher doses (2 kGye20 kGy) of gamma rays disturbs the synthesis of proteins (Xiuzher, 1994), enzyme activity (Zaka et al, 2002(Zaka et al, , 2004AlRumaih and Al-Rumaih, 2008;Vandenhove et al, 2009;Stajner et al, 2009;Jan et al, in press).…”

“…were reported to induce oxidative stress with overproduction of reactive oxygen species (ROS) such as superoxide radicals (O À 2 ), hydroxyl radicals (OH À ) and hydrogen peroxides (H 2 O 2 ) which react rapidly with almost all structural and functional organic molecules, including proteins, lipids and nucleic acids causing disturbance of cellular metabolism (Xienia et al, 2000;Al-Rumaih and Al-Rumaih, 2008). A varied response has been recorded in different plants even within same genera when exposed to gamma radiation (Wada et al, 1998;Zaka et al, 2002Zaka et al, , 2004Al-Rumaih and Al-Rumaih, 2008;Vandenhove et al, 2009;Stajner et al, 2009). Basically radiobiological tolerance may also be correlated with the content of antioxidant substances produced following gamma irradiation as observed in two species of Nicotiana (Wada et al, 1998;Stajner et al, 2007).…”

Effects of presowing gamma irradiation on the photosynthetic pigments, sugar content and carbon gain of Cullen corylifolium (L.) Medik

“…Such radiation practices, although within range of low doses (5-500 Gy) can enhance the physiological activities of cells in plants and photosynthetic microbes by ameliorating germination and growth rates (Thiede et al, 1995;AlSafadi and Simon, 1996;Lee et al, 1998;Thapa, 2004;Puzon, 2005;Melki and Sallami, 2008;Melki and Marouni, 2009;Jan et al, 2010), increase stress resistance (Zaka et al, 2002;Lee et al, 2002a;2002b; and/ or improving crop yields (Wiendl et al, 1995;Al-Safadi et al, 2000). On the erstwhile hand, high dose of gamma ray (2-20 kGy), applied to the seed before sowing, disturbs the protein synthesis (Xiuzher, 1994), results in improper hormone levels (Dwelle, 1975;Rabie et al, 1996), altered enzyme activity (Al-Rumaih and Al-Rumaih, 2008;Vandenhove et al, 2009;Stajner et al, 2009;Jan et al, 2011b), impaired leaf gas and water exchange (Stoeva and Bineva, 2001).…”