ISSN 10214437, Russian Journal of Plant Physiology, 2013, Vol. 60, No. 6, pp. 812–820. © Pleiades Publishing, Ltd., 2013.
Original Russian Text © L.A. Ivanov, L.A. Ivanova, D.A. Ronzhina, P.K. Yudina, 2013, published in Fiziologiya Rastenii, 2013, Vol. 60, No. 6, pp. 856–864.
The plant pigment system is a basis for the photo
synthetic transformation of solar energy to the energy
of chemical bonds. The major photosynthetic pig
ments are chlorophylls (Chl), whereas carotenoids
(Car) transfer an additional energy to chlorophylls
(lightcollecting function) and take off excess energy
from chlorophylls (photoprotective function) [1–3].
The efficiency of the pigment system depends on con
formity between its structure and function and/or
environmental conditions (first of all, illumination).
Shade plants, growing under the forest canopy, usually
have the higher levels of Chl than sun plants [1, 4] and
the greater proportion of Chl
lecting ability of the leaf in the region of farred light
[4–6]. Under high insolation level, the proportion of
Car is often elevated because in this case they act as
protectors from photoinhibition .
The level of insolation is not the same in different
regions of the Earth surface, being reduced at the
higher latitudes where the altitude of solstice is lower.
In this case, a spectral distribution of solar energy and
the ratio between scattered and direct radiation
change . Latitudinal changes in the rate of solar
radiation must affect the pigment system of the leaves,
whose efficiency directly influences the photosyn
thetic productivity of plants. Adaptation to the insola
tion regime can affect both the content of photosyn
thetic pigments and the ratio between their forms. At
the same time, the data about changes in the plant pig
ment complex along the global latitudinal gradients
are not numerous. The majority of known works deal
with the content of plant pigments under extreme
environmental conditions (deserts, high mountains,
tundra, and farnorthern taiga) [8–11]. Available data
concerning the content of pigments in steppe plants of
Transbaikalia, Mongolia, and Volga region [8, 12–15]
did not suggest definite rules for changes in pigment
composition depending on the latitude of growing,
because they only dealt with certain forms of pigments
or a short gradient covering few locations.
In this connection, the aim of our work was to
investigate the content and ratios of different forms of
photosynthetic pigments in the leaves of plants grow
ing along the latitudinal gradient within the steppe
zone of South Ural.
MATERIALS AND METHODS
Investigations were conducted in 2008 in five
steppe regions of South Ural (within Orenburg, Che
lyabinsk, and Sverdlovsk regions), which form a latitu
dinal gradient from southern steppe to southern taiga
(Fig. 1, Table 1). Total length of the transect was
600 km. Mean annual parameters of climate in the
investigated regions are shown in Table 1 and Fig. 2.
Along the investigated latitudinal gradient from the
Changes in the Chlorophyll and Carotenoid Contents in the Leaves
of Steppe Plants along a Latitudinal Gradient in South Ural
L. A. Ivanov, L. A. Ivanova, D. A. Ronzhina, and P. K. Yudina
Botanical Garden, Ural Branch, Russian Academy of Sciences, ul. 8 Marta 202a, Yekaterinburg, 620144 Russia;
fax: 7 (343) 2103859; email: Leonid.Ivanov@botgard.uran.ru
Received September 18, 2012
—We studied the content of chlorophylls and carotenoids in the leaves of steppe plants of South Ural
growing along a latitudinal gradient from southern steppe to foreststeppe. The content of chlorophylls (
5–6 mg per 1 g of the leaf dry weight and did not depend on the latitude, whereas the content of carotenoids
in the leaves increased northward from 1.0 to 1.5 mg/g dry wt. At the same time, the greatest changes occurred
in the ratios between the forms of pigments: the chlorophyll
ratio increased from 1.8 to 2.8, and the chlo
rophyll/carotenoid ratio decreased from 5.6 to 3.5. The obtained results indicate that adaptation of the pig
ment apparatus of steppe plants growing along the latitudinal gradient occurs due to the transformation of the
: steppe plants, carotenoids, chlorophylls, latitudinal gradient, insolation, temperature, precipita
: Car—carotenoids; Chl—chlorophylls; Chl
ratio of Chl
; LHC—lightharvesting complex;PS—
photosystem; LMA—leaf mass per area.