Mechanism of peroxidase isoenzyme induction in pollinated Nicotiana alata styles

A comparative study on the induction of peroxidase isoenzymes, specifically number 10 (P-10) in Nicotiana alata styles revealed significant differences between the various plants of an inbred progeny. In some plants the ageing-induced increase in P-10 activity was very low, whereas in some others, it was relatively high. Pollination accelerated this increase, independent of the pollen genotype. Fertilization was followed by a considerable increase in the activity of several peroxidase isoenzymes, including P-10 in all the plants.Two plants that differed greatly with regard to P-10 induction were used in additional experiments in order to ascertain the mechanism involved in the induction of P-10. The increase in P-10 activity due to pollination or fertilization can partly be explained on the basis of auxin and auxin-induced ethylene activity. The differences in P-10 induction between various plants of the inbred progeny were probably due to differences in their sensitivity to ethylene.