Senescence is a developmental stage of the plant life cycle, leading to the death of specific cells, organs for instance leaves, or whole organisms. Initiation of the leaf senescence and its normal process require expression of many specific genes, called senescence-associated genes sags. Different senescence-enhanced genes encoding degradative enzymes such as: proteases, nucleases, also enzymes involved in lipid and carbohydrate metabolism, enzymes involved in nitrogen mobilization, were identified.