Stress and Senescence
Oxygen radicals frequently involved
Superoxide dismutase: O2 rad > H2O2
- Cu/Zn in chloroplasts
- Mn version in mitochondria
- Fe version also found in some plants
Cut flowers: wilting due to free radicals?
Salt stress or drought
- charged molecules: osmoprotectants
- betaine made by choline dehydrogenase gene: betA
- transgenic plants > 80% more salt tolerant