Accumulation and remobilization of amino acids during senescence of detached and attached leaves: in planta analysis of tryptophan levels by recombinant luminescent bacteria.

The process of leaf senescence is biochemically characterized by the transition from nutrient assimilation to nutrient remobilization. The nutrient drain by developing vegetative and reproductive structures has been implicated in senescence induction. The steady-state levels of amino acids in senescing leaves are dependent on the rate of their release during protein degradation and on the rate of efflux into growing structures.