Effect of 4,6-Dinitro-o-sec-butylphenol on Phosphorus Accumulation and Incorporation in Tomato Leaf Disks

The accumulation and incorporation of externally applied P(32) into ATP and the effect of 4,6-dinitro-o-sec-butylphenol (DNBP) on these processes was studied, using tomato (Lycopersicon esculentum Mill.) leaf disks.P(32) was, in most part, actively accumulated into leaf disks with time and was incorporated into ATP and other organic phosphates. DNBP inhibited both P(32) accumulation and ATP generation. The amount of inhibition increased with time of incubation.It is concluded that P(32) accumulation is related to ATP generation. Even though DNBP greatly inhibits phosphorus accumulation, there is little or no effect on its retention.DNBP has the ability to uncouple oxidative phosphorylation. Therefore, it is assumed that its inhibitory effect on phosphate accumulation and generation of high-energy phosphorus esters is related to its inhibition of oxidative phosphorylation.A method is described which appears to be satisfactory to determine the relative amounts of ATP and ADP in leaf disks labeled with P(32).