Analyzing the variation of assimilation rate for the sunflower plants in the presence of the tested solutions it was noticed thatthe highest intensity was identified in the plants developed in the presence of spruce bark extract (SB1 with 58.43% and SB2 with54.25% higher than the assimilation rate registered for the control)and of deuterium depleted water (DDW- with 42% higher than the assimilation rate determined for the control). At the same time, for Fig