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41.
Mediouni Chamseddine Ben Ammar Wided Houlné Guy Chabouté Marie-Edith Jemal Fatma 《Plant Growth Regulation》2009,57(1):89-99
We compare cadmium and copper induced oxidative stress in tomato leaves and the antioxidative enzyme response during a time
course of 96 h. Plants were subjected to 25 μM of CdCl2 or CuSO4 and malondialdehyde (MDA) level and activity of guaiacol peroxidase, superoxide dismutase, catalase, ascorbate peroxidase
and glutathione reductase were determined. The results showed that there was an early increase in the MDA level and in the
guaiacol peroxidase activity more pronounced with copper exposure during almost all the time course of the experiment. The
activity of superoxide dismutase and catalase was induced very early after cadmium and copper treatment, reached a maximal
value after 12 h and then declined but it remained always slightly higher than the control at the end of the experiment. Ascorbate
peroxidase activity pathway was similar to superoxide dismutase or catalase with a maximal activity after 48 h of heavy metal
exposure. Induction of glutathione reductase activity observed only under copper exposure is maintained during almost all
the experimental time. The antioxidative activity developed by tomato leaves is more induced by copper treatment. This can
be related to the ability of this metal to induce more than cadmium an accumulation of reactive oxygen species (ROS) at the
cellular level. Decline in the antioxidative enzymes activity at the end of the experiment can be a consequence of cadmium-
and copper-inducing a further ROS formation that might affect enzymes activity. 相似文献
42.
The GGA functional PW91 were used in order to predict the structural, electronic, optical and elastic properties of α and β of d- Glucose. Such compounds, in their solid form, are widely used in chemical and pharmaceutical industry. The pure crystalline forms of glucose α-d-glucose and β-d-glucose have the same space group (McDonald and Beevers, 1950) [1]. We note that despite the fact that the two compounds have the same space group, upon cooling, the interatomic distances change and a new compound occurs. On the other hand, the cooling also influences the physical properties (structural, elastic, electronic and optical properties). The objective of this paper is associated with the control of the physical states of molecular materials when they are subjected to polymorphic changes. The laws and physical parameters that govern these transformations remain fundamentally misunderstood. 相似文献
43.
From probable Lower Jurassic of Pakistan the new ammonite genusKohaticeras with two new species is described and, despite some remarkable differences, is placed to the subfamily Bouleiceratinae (Toarcian). 相似文献