Effect of Stress Conditions Induced by Temperature, Water and Rain on Senescence Development

The effect of different stress conditions was studied in segments of oat leaves (Avena sativa L. cv. Suregrein). Temperature and water (water dificit and rain) stress conditions accelerated senescence development. Any stress condition leading to an increase in membrane permeability accelerated photooxidative phenomena in light, and senescence development including chlorophyll breakdown and hydroperoxides increase. On the contrary, in darkness, any stress condition prevented chlorophyll breakdown and senescence development except for proteolysis, despite an increase in permeability. Temperature stress did not increase proteolysis. Water stress induced in a humid chamber increased proteolysis, but it did not increase proteolysis when water stress was induced by floating in osmotic solution.