Decreases in the levels of P (78.4 %), K (85.3 %) and S (66.6 %) are seen during Arabidopsis leaf senescence. These nutrients appear to be targets of senescence-associated mo- bilization in many species including soybean, pine, pea and wheat (Mauk and Noodén 1992, Hocking 1994, Marschner
1995, Nieminen and Helmisaari 1996).