Abstract
There have been accumulated reports that active oxygen may relate with plant injuries under draught and high salt stress. Superoxide dismutase (SOD) - and ascorbate peroxidase (APX) -transgenic tobacco plants were generated. The tolerance of two transgenic plants to draught and high salt-stress was evaluated.
By using chloroplast signal peptide gene of Arabidopsis glutathione reductase cDNA, transgenic tobacco with enhanced activity of SOD in chloroplasts and that with enhanced APX activity in chloroplasts were obtained.
APX-transgenic tobacco has 3.8 fold higher APX activity and 2 fold higher SOD activity than control tobacco. SOD-transgenic tobacco has 4.6 fold higher SOD activity and 2.5 fold higher APX activity than control tobacco. Both transgenic tobacco plants showed higher tolerance to active oxygen-forming chemicals, sulfite and paraquat in terms of visible injury, and also greater resistance to high salt, draught and 10% polyethylene glycol in terms of photosynthesis and growth than control ones.
