Abstract:
The allelophatic effects of spruce bark extract on seed germination
and development of Lycopersicon esculentum plantlets were examined.
Spruce bark, provided by a Romanian pulp and paper company, was air
dried and ground in a mill. The phenolic compounds were separated with
NaOH 1.5%, for three hours at 90°C, at a liquor-to-wood ratio of 10, with a
preliminary extraction of lipophilic compounds with ethyl ether. After
treatment with ion-exchange resins and filtration, the neutralized extract was
dried, obtaining a brown colored powder. The experimental work included
seed germination in Petri dishes with various concentrations of bioactive
compounds. The biotests used aqueous solution of polyphenolic extract in
concentrations of 0.12, 0.16, 0.2, 0.24, 0.28, 0.32 and 0.36 mg/L. The
influence of the extractives was expressed through germination percentage,
elongations of roots and shoots. The effects of spruce bark on plantlets
growth were evaluated in laboratory conditions using vegetations pots with
sand. In the experiments a global extract was used at the concentrations of
0.04, 0.08, 0.16 and 0.32 g/L. The tomato plantlets were treated with
different additions in bioactive compounds: initial treatment with aqueous
solutions of spruce extract, then every 5 days with distilled water and
repeated treatment with aqueous solutions of spruce extracts every 5 days.
The influence of phenolic compounds on L. esculentum plantlets was
expressed through the number of established plants, their height and leaf
area. The natural phenolic compounds influenced the growth of L.
esculentum plantlets depending on the concentrations used and the
experimental design.
