Supply of nitrogen can reverse senescence processes and affect expression of genes coding for plastidic glutamine synthetase and lysine-ketoglutarate reductase/saccharopine dehydrogenase.

Nitrogen availability has a strong influence on developmental processes in plants. We show that the time of nitrogen supply regulates the course of leaf senescence in flag leaves of Hordeum vulgare. The senescence-specific decrease in chlorophyll content and photosystem II efficiency is clearly delayed when plants are fertilised with nitrate at the onset of leaf senescence.

Successive maturation and senescence of individual leaves during barley whole plant ontogeny reveals temporal and spatial regulation of photosynthetic function in conjunction with C and N metabolism.

During ontogeny of barley plants (Hordeum vulgare, L. cv. Barke), a continuous developmental gradient of new leaves at the top and lower leaves undergoing senescence is maintained.