EFFECTS OF COMPLEX FERTILISERS ON SOME OXIDOREDUCTASES ACTIVITY IN GROWTH AND DEVELOPMENT PROCESSES OF PEPPER PLANTS

Certain metabolic processes occurring in plants produce reactive oxygen species (ROS) which, besides their deleterious potential, may act as signalling molecules to control processes such as programmed cell death, abiotic stress responses, pathogen defense and systemic signalling. As catalase and peroxidase are parts of the antioxidant system of the cell, their activities can change drastically depending on the physiological conditions of the plant and the integration of different environmental, developmental and biochemical stimuli. This paper presents our studies on the influence of a non-conventional soil additive, Pennasoil, and a growth promoter, Cropmax, on greenhouse pepper (Capsicum annuum, Delta Fl hybrid) crops, from the seedling stage to the ripeness stage. In order to ascertain the correlation between growth and development, on the one hand, and the enzymatic detoxifying system, on the other hand, experiments were carried out to determine the catalase and guaiacol-peroxidase activities in pepper plants. The obtained data sustain the existence of a well-defined time course of catalase/peroxidase system activity during plant development, which is slightly modulated under the fertiliser influence. These results also suggest the protective effect of certain treatment schedules, pointing out the necessity to establish the optimum quantity and timing of fertiliser addition for each treated plant, in relation with the purpose of fertilisation.