Abstract
The concentration of chlorophyll decreased and the concentration of [alpha]-amino nitrogen and the absolute and specific activity of peptidase increased in disks of tobacco leaf incubated on water in darkness at 25[degree]. Although 6-furfurylaminopurine (kinetin) applied to the disks inhibited the increase in activity of peptidase after 4 days, this effect was too slow to account for the significant inhibition of increase in a-amino nitrogen after 24hrs. Treating with kinetin also delayed loss of chlorophyll and soluble protein, though not until 4 and 8 days respectively. The only significant effect of treating disks prepared from tobacco plants deficient in nitrogen with kinetin for 8 days was to inhibit the increase in [alpha]-amino nitrogen. Adding kinetin (5[mu]M to 5 [mu]M) in vitro did not affect the activity of peptidase extracted from tobacco leaf.