Poster: Oxidative stress

Abs # 77: Protective effect of selenium on wheat plants under drought stress

Presenter:	Kuznetsov, Vasilii V, vlkuzn@mail.ru
Authors	Kuznetsov, Vasilii V (A) (B)  Kholodova, Valentina P (A)   Kidin,  Viktor  V (B)   Kuznetsov, Vladimir V (A) (C)
Affiliations:	(A): Institute of Plant Physiology Russian Academy of Sciences (B): Timiryazev Moscow Agricultural Academy (C): Russian People Friendship University

During the last decades protective effect of selenium (Se) has been shown in animal and human organisms but it was not practically studied in plants. For the investigation, spring wheat (T.aestivum L.) plants were used grown under optimal watering or drought. Se was added to soil as sodium biselenite at 0.01-0.4 mM. After 8-12 days of water withholding, plant growth was strongly decreased, water content in leaves dropped by 12-14% despite the fact that transpiration was inhibited by 75%. Se prevented drought-induced inhibition of plant growth and decline in water content of leaves. Water status stabilization was not due to limitation of water consumption since Se did not affect significantly plant transpiration under drought. It depended on efficiency of water redistribution between root system and aerial parts of plants. The investigation of antioxidative defense systems proved that under drought, free proline having antioxidative properties was accumulated very rapidly exceeding its initial level 30-40 times but in plants grown in the presence of Se 2-3-fold inhibition of proline synthesis in leaves was observed. As to enzymes, drought induced SOD, CAT and POX activities by 20, 30 and 35% correspondingly. The highest activation reached 70 % was observed for POL measured as MDA formation. Strongly increased level of mRNA shown with the help of RT-PCR, witnessed in favour of rapid expression of LOX gene under drought. Se decreased practically to initial level mRNA of LOX and reduced activity of antioxidative enzymes investigated. Therefore it was proposed that protective effect of Se connected with its antioxidative properties seemed to be realized by decreasing reactive oxygen species and simultaneous suppression of proline synthesis.