ISSN 1021-4437, Russian Journal of Plant Physiology, 2006, Vol. 53, No. 1, pp. 68–74. © MAIK “Nauka /Interperiodica” (Russia), 2006.
Original Russian Text © V.F. Zabuga, G.A. Zabuga, 2006, published in Fiziologiya Rastenii, 2006, Vol. 53, No. 1, pp. 75–82.
The growing organs of forest plants manifest high
respiration rates [1–3], and their growth respiration
exceeds 3–10-fold the maintenance respiration .
Over three decades ago, such data led to the concept of
growth vs. maintenance respiration, and the further
development of this concept considerably expanded our
knowledge of whole plant respiration as a multicompo-
nent process with characteristic respiratory costs of
particular components [4–6].
Young shoots developed from dormant buds are
among the most rapidly growing organs of woody
plants. The growing shoots on the skeleton branches
and the boughs of higher branching orders constitute
the crown and determine crown growth and develop-
ment; these shoots affect relocation of photosynthates
in the whole tree and ﬁnally determine the photosyn-
thetic and total productivity of the whole tree. While
many aspects of the structure, growth and development
of young shoots [7, 8] and the crown as a whole [9, 10]
have been investigated in considerable detail, their res-
piration stays insufﬁciently studied.
In woody plants, the central shoot holds an excep-
tional position among the growing shoots of the crown
because it determines the height of the trunk, an inte-
gral index of tree productivity. The productivity of a
particular tree, including the increment in young shoot
biomass, is seen as a sum total of the production pro-
cess and an efﬁciency index respiration as a constituent
of the production process.
Our present goal was to relate the respiratory CO
exchange to the growth of young Scots pine shoots and
to evaluate quantitatively the total amount of CO
evolved by these shoots.
MATERIALS AND METHODS
Plant material was collected at the experimental plot
located 80 km to NE from Irkutsk, in the forest–steppe
zone of the lake Baikal region, with extreme continen-
tal conditions: the average annual temperature of
and annual precipitation of 271 mm. Besides, precipita-
tion was distributed most unevenly: 30–40 mm in win-
ter and spring and most of precipitation during the sec-
ond half of plant growth period, in July–September.
Low humidity in April–June, some times as low as 6–
10%, is a speciﬁc climate characteristic. The moisture
coefﬁcient according to the Ivanov’s formula partly
modiﬁed by Breken for the Irkutsk oblast conditions
 is equal to 0.6–0.8 and indicates insufﬁcient water
supply to this location.
Our observations were carried out in 1976–2004 at
the site represented by second class pine forest moving
into age class 3 (ﬁrst class bonitet). At the beginning of
this study, larch comprised 10% of pine forest (9P1L),
and by the end of it, the incidence of larch dropped down
to single trees (10P + L). Accordingly, the average height
and trunk diameter were 12.1 m and 18 cm at the begin-
ning and 22.2 m and 24 cm at the end of our study.
Respiration of the Growing Shoots of Scots Pine
V. F. Zabuga and G. A. Zabuga
Angarsk State Technical Academy, The Federal Education Agency of Russian Federation,
ul. Tchaikovskogo 60, Angarsk, Irkutsk oblast, 665830 Russia;
e-mail: firstname.lastname@example.org; email@example.com
Received May 30, 2005
—The respiratory CO
exchange and the growth of the annual shoots were followed in Scots pine
L.) trees growing under extreme continental forest–steppe conditions near the lake Baikal. The
temperature coefﬁcient of dark respiration (Q
) in growing shoots dropped down from 3.2–4.0 (in the temper-
ature range of 10–20
C) to 1.5–2.0 (in the temperature range of 20–30
C). The changes in averaged daily res-
piration rates correlated with the changes in shoot growth increments and temperature (with the multiple deter-
mination coefﬁcient of 0.94). Growth respiration of the axial shoots during the phenophase reached 80% of the
total respiration costs, with the coefﬁcients of growth respiration and maintenance respiration 0.32 and 0.021.
In young crown shoots, the average value of CO
evolution in the light combined for the whole observation
period (years 1976–2004) was about 1 kg/dm
, that is 9% of CO
evolution from the trunk surface.
Key words: Pinus sylvestris - growing shoot - growth respiration expenditure - total CO
—temperature coefﬁcient of respiration;
—total dark respiration;
—coefﬁcient of growth respiration;
—coefﬁcient of maintenance respiration.