Abstract
The aim of this study was to evaluate the effect of polyphenolic extract and deuterium depleted water (DDW) as bioregulators in
maize (Zea mays L.) plant cultivation. The aqueous extract obtained from spruce bark (two levels of concentration), pure DDW
and DDW in combination with spruce extract were used. The test solutions were applied by spraying and the maize plant growth
and alelopatic effect on the development were studied. The following specific plants parameters were monitored: growth and
development of vegetative organs of the plant, photosynthesis rate, transpiration rate, sub-stomatal cavity CO2 concentration.
Photosynthetically active radiation (P.A.R.) incident on leaf surface, pigments photoassimilating content, total polyphenolic
content and individual polyphenolic compounds content in maize leaves were determined. It was observed that the solutions
applied triggers an intensification of metabolic processes in plants (photosynthesis, transpiration, pigments synthesis, substomatal
cavity CO2 concentration) with an increase in crop production. Highest percentage of stimulation was recorded in the
plant groups treated with only polyphenolic extract (130 mg/L) or in combination with DDW (96 mg/L). The supplementation of
the growth medium with polyphenolic extract cause an increase in the amount of catechine and synapic acid in leaves, increasing
defense capability and therefore improving plant growth and development.