STUDY OF THE ANTIOXIDATIVE EFFECT OF FURASTANOL GLYCOSIDES UNDER IRRADIATION OF POTATO CALLUS TISSUE WITH VISIBLE AND UV LIGHT
L.A. Volkova, P.V. Lapshin, A.B. Burgutin
Institute of Plant Physiology, 127276, Botanicheskaya, 35, fax: (095)977-80-18, e-mail: burgutin@yahoo.com // 1/04/2003

During evolution, plant cells developed the effective mechanism of antioxidant protection from UV-irradiation. This mechanism includes various photoprotective compounds, among which there are several glycosides. We attempted to clarify whether some exogenic furastanol glycosides (FG) have a protective effect in cells of potato callus tissues (variety Tava) that were subjected to irradiation with visible or UV light at 0,4 W m^-2.

We tested the level of lipid peroxidation (LPO) estimating the content of TBK-active products that interact with thiobarbituric acid. The experiments were performed with both greening and white (light?) callus tissues that were exposed to UV-light for 4 hours.

The level of LPO increased two times in control green tissues (no FG) in 24 hours, and it increased 30% only in tissues supplied with FG at 5x10^-4 mg ml^-1. In 48 hours, the level of LPO returned to the original level (before irradiation) in both FG-supplied and unsupplied tissues, supposedly, due to the activity of reparation and antioxidation systems. White tissues did not show any significant increase in LPO.

Visible light caused a slight increase in LPO in greening tissues, and it had no effect on white tissues.

One can suggest that the main target of UV-irradiation are the pigments of cells, that generate the active oxygen species leading to the increase in LPO. FG promotes retardation of the peroxidation in greening tissues, where the maximum level of LPO was observed in contrast to white tissues.

Further we plan to elucidate the question: what is the mechanism of the protective effect of FG.