Senescence is the age-dependent deterioration process at the cellular, tissue, organ, or organismal level, leading to death or the end of the life span (Nooden, 1988). Leaf senescence is an organ level senescence but is often intimately associated with cellular or organismal death (Lim et al., 2007). According to Betania et al. (2000), it is the last stage of leaf development. The senescence process is started by the breakdown of chloroplast (Gepstein, 2004). Next, it is followed by macromolecules