Visit our Expo - Redox and Inflammation signaling 2012

Session XV : Reactive oxygen species and cell signaling Poster XV, 3
Antioxidant enzymes during hypoxia-anoxia signaling events in Crocus sativus L. corm
Ezzatollah Keyhani(1,2), Jacqueline Keyhani(2), Mahnaz Hadizadeh(1), Lila
Ghamsari(1)
(1)Institute of Biochemistry and Biophysics, Univ. of Tehran, 13145 Tehran, Iran, and
(2)Laboratory for Life Sciences, 19979 Tehran, Iran. E-mail: keyhanie@ibb.ut.ac.ir
Saffron has been shown to have therapeutic and preventive effects for various cancers and
other ailments. The saffron plant (Crocus sativus L.) is propagated only via its corms. Thus a
better knowledge of the corm biochemistry and of its response to stresses is mandatory.
Reactive oxygen species (ROS) are involved in the response to hypoxia/anoxia (H/A), and it
was also shown that anoxia stress led to hydrogen peroxide formation in plants. H/A was
produced in Crocus sativus L. corms, either dormant or cultivated for 3 days, by flooding
them. Flooded corms were withdrawn after 1, 2, 3, 4, 8, 10 and 14 days under water and used
immediately, as well as control corms cultivated under normoxic conditions, for extract
preparation. ROS scavenging enzymes activity was studied in the obtained extracts. Catalase
activity was 2.5 times the control value in dormant corms flooded for 8 days, but exhibited a
four-fold increase compared to control in corms cultivated for 3 days and then flooded for just
1 day. The activities of o-dianisidine and ascorbate peroxidases decreased in dormant corms
maintained in H/A, while they consistently increased in corms cultivated for 3 days prior to
H/A. Superoxide dismutase (SOD) activity exhibited a two-fold increase in dormant corms
flooded for 2 to 4 days, then returned to the control value. In corms cultivated for 3 days
prior to H/A, SOD activity remained at the control level except for a two-fold increase at day
8. Glutathione peroxidase activity was consistently higher than the control, both in dormant
corm and in corm cultivated for 3 days prior to H/A. Data showed that 1) H/A stimulated
catalase, SOD and gluthatione peroxidase activities in dormant corms; 2) H/A stimulated all
five enzymes studied in corms cultivated under normoxic conditions prior to flooding with a
maximum stimulation for catalase, followed, in decreasing order, by o-dianisidine peroxidase,
ascorbate peroxidase, glutathione peroxidase and SOD; 3) there is a fine regulation of ROS
scavenging enzymes response depending on whether H/A occured in dormant corms, or in
corms grown for 3 days under normoxic conditions prior to H/A.
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