Changes in tRNA methylase activity in senescing cob and stalk parenchyma tissue and the first developed leaf of corn ( Zea mays L.)

Abstract

tRNA methylase activity of corn cob parenchyma tissue, corn stalk parenchyma tissue, and the first developed leaf of corn was determined as a function of cell age during the period of senescence preceeding cell death. tRNA methylase activity of corn cob parenchyma tissue disappeared early in the study period and that of stalk parenchyma tissue declined to low levels in tissue containing older cells. Activity was also reduced dramatically in the first developed leaf. It is proposed that this loss of tRNA methylase activity is important in translational control of protein synthesis during senescence of these tissues.