Abstract

HERRERA-SANTOYO, Josefina; LOPEZ-DELGADO, Humberto  and  MORA-HERRERA, Martha Elena. Stress in callus of Hippocratea excelsa: Catalase activity, hydrogen peroxide content and canophyllol accumulation. INCI [online]. 2007, vol.32, n.4, pp.253-256. ISSN 0378-1844.

Stress factors often induce oxidative stress in plant cells, generally leading to the synthesis of signal molecules that activate a range of signal transduction pathways and antioxidants. One of the signal molecules produced under stress is H₂O₂, which has been associated to production in vitro of secondary metabolites (SM) and to antioxidant activity. Canophyllol production by Hippocratea excelsa was used as an example to show the enhanced production of SM under stress. Seeds obtained from fruits were cultured in vitro. Two stresses were applied: nutritional, by reducing the amount of N₂, and osmotic, using polyethylene glycol. Canophyllol, H₂O₂ content and catalase activity were measured. Nutritional stress caused a different response than osmotic stress for catalase activity and canophyllol accumulation, whereas H₂O₂ contents increased under both stresses. The highest amount of canophyllol (8 times the control) was obtained under the nutritional stress, in the treatment with 25% of control N₂ strength. This work demonstrates that the responses of canophyllol production and catalase activity in H. excelsa callus are differentially signaled by the different stress factors.

Keywords : Canophyllol ; Catalase ; Hydrogen Peroxide ; Hippocratea excelsa ; Secondary Metabolites; Stress .