1022-7954/05/4105- © 2005 Pleiades Publishing, Inc.
Russian Journal of Genetics, Vol. 41, No. 5, 2005, pp. 539–544. Translated from Genetika, Vol. 41, No. 5, 2005, pp. 668–675.
Original Russian Text Copyright © 2005 by V. Titok, Yurenkova, M. Titok, Khotyljova.
Productivity as a complex quantitative trait is deter-
mined by cooperation of several elementary genetic
systems, which involve several levels of interactions
established and realized to affect the degree and charac-
ter of expression of the given trait in heterosis [1–3].
However, the dynamics and relationships of morpho-
logical, physiological, and bioenergy-related processes
in the formation of structural components of productiv-
ity during ontogeny are still incompletely understood in
the case of heterosis.
The formation of productivity is tightly associated
with growth rate, which depends on the activity of met-
abolic reactions in the course of plant development.
The metabolic control of ontogenetic processes
involves adenine nucleotides (AN) AMP, ADP, and ATP
and nicotinamide coenzymes (NC) NADP
, and NADH . Our studies with cultivars, lines,
hybrids of maize and tomato have shown that the
level of macroergic compounds and reducing equiva-
lents determines the rates of the formation and develop-
ment of morphogenetic traits in plants [5–7].
The objective of this work was to study the roles of
AN and NC in regulating the growth and development
hybrids and the parental cultivars in ﬁber ﬂax in
MATERIALS AND METHODS
We examined the F
hybrids and the parental culti-
vars of ﬁber ﬂax
Belinka) varied in the heterosis effect on stem
weight (–36.9, 9.9, 41.2, and 56.6%, respectively) and
ﬁber weight (–56.0, –1.8, 52.3, and 50.0%, respec-
tively). The effect of heterosis on productivity was esti-
mated as a percent increase in a trait in the F
compared with the most productive parent (as averaged
over two years). Biochemical experiments were carried
out with green leaves from the apical and donor parts of
the plant, since these parts contain metabolically active
tissues with intense functions of the photosynthetic and
mitochondrial energy-producing systems . Leaves
were collected at the following developmental stages:
“ﬁr,” fast growth, budding, ﬂowering, and green ripe-
AN (AMP, ADP, and ATP) and NC (NAD
, and NADPH) were assayed by reversed-phase
ion-paired high-performance liquid chromatography on
a KhZh-1311 unit equipped with a ﬂuorimetric detector
l ﬂow-cuvette . The adenylate energy
charge (AEC) was calculated as AEC = [ATP] +
0.5[ADP]/([ATP] + [ADP] + [AMP]) . In addition,
we estimated the NC and AN contents per plant .
All experiments were performed with three replicate
samples of ten plants each; each component was
assayed in triplicate for each sample. The signiﬁcance
of genotypic differences was evaluated by the least sig-
niﬁcant difference at
RESULTS AND DISCUSSION
Comparison of the genotypes under study with
respect to plant height and dry weight revealed differ-
ences at all ontogenetic stages (Table 1). At the ﬁr stage,
all hybrids surpassed their parents in plant height. At
later stages of ﬂowering and green ripeness, a higher
plant height was observed only in the heterotic hybrids.
Similar results were obtained for dry weight (Table 1).
Thus, individual features of plant development through
Characterization of Energy Metabolism during Ontogenesis
of Fiber Flax in Heterosis
V. V. Titok, S. I. Yurenkova, M. V. Titok, and L. V. Khotyljova
Institute of Genetics and Cytology, National Academy of Sciences of Belarus, Minsk, 220072 Belarus;
fax: (37517)284-19-17; e-mail: firstname.lastname@example.org
Received May 16, 2004
—The contents of adenine nucleotides and nicotinamide coenzymes, along with morphological traits,
were studied in ﬁber ﬂax cultivars and F
hybrids at various ontogenetic stages. The bioenergy parameters of
heterotic hybrids proved to be signiﬁcantly higher than in the parental cultivars, suggesting a higher activity of
energy-producing processes determining the intensity of plant growth and development. The character of the
heterosis effect on morphological, bioenergy, and productivity parameters was evaluated in the
ing in the extent of heterosis. Hybrids that displayed positive dominance or superdominance in productivity
parameters showed heterosis for most bioenergy traits.