Organic xenobiotics absorbed by roots and leaves of higher plants are trans
located by different physiological mechanisms. The following pathways of xe
nobiotic detoxication have been observed in higher plants: conjugation with
such endogenous compounds as peptides, sugars, amino acids, and organic ac
ids; oxidative degradation and consequent oxidation of xenobiotics with the
final participation of their carbon atoms in regular cell metabolism. The
small parts of xenobiotics are excreted maintaining their original structur
e and configuration. Enzymes catalyze oxidative degradation of xenobiotics
from the initial hydroxylation to their deep oxidation. The wide intracellu
lar distribution and inductive nature of oxidative enzymes lead to the high
detoxication ability. With plant aging, transformation of the monooxygenas
e system into peroxidase takes place. Once in the cells, xenobiotics are in
corporated into different cell organelles. All xenobiotics examined are cha
racterized by a negative effect on cell ultrastructure. The penetration of
high doses of xenobiotics into plant cells leads to significant deviations
from the norm and, in some cases, even to the complete cell destruction and
plant death. (C) 2000 Academic Press.