ISSN 10214437, Russian Journal of Plant Physiology, 2011, Vol. 58, No. 1, pp. 185–189. © Pleiades Publishing, Ltd., 2011.
Published in Russian in Fiziologiya Rastenii, 2011, Vol. 58, No.1, pp. 156–160.
Seedling transplantation is the main cultivation
procedure for rice (
) production in many
areas. Transplantation has a considerable impact on
the rice growth. During transplantation, rice seed
lings, mainly roots, are often injured , and the seed
lings suffer from the misbalance between water uptake
and transpiration. As a result, some leaves of seedlings
wilt and could partly die due to water deficit , the
net assimilation rates are reduced, and leaf expansion
and plant tillering are delayed .
The investigation of the source–sink system and
regulation of source–sink relations provides for the
important information about plant growth adaptation
to environment [4, 5]. The transplantation injury and
shock effects on rice are well known [6, 7], but assim
ilate distribution and redistribution from the leaf
sheath during recovery period after seedling trans
planting remain unclear. We expected a change in the
direction and strength of source–sink relations in
transplanted rice plants.
The isotope tracer technique is useful for under
standing the source–sink relations between plant
organs and assimilate translocation and distribution
between tillers and the main stem or between repro
ductive and vegetative organs. For example, the trans
Clabelled assimilates between a tiller and its
parent shoot was examined in young plants of
This text was submitted by the authors in English.
, and a reciprocal exchange of radiocarbon
between the tiller and main shoot occurred principally
via a direct pathway through stem tissues rather than
via a pathway involving the roots .
The objective of this study was to characterize
translocation of sheath assimilates and their distribu
tion among seedling organs at the initial stage after
transplanting and to clarify the source–sink relations
in rice plants during recovery period after transplant
ing. Inside the plant, sucrose is the main transport
form of photosynthates; hexoses (including glucose
and fructose) can be involved in the formation of
sucrose carbon in leaves [9, 10].
Hglucose has a suit
able physical halflife, short biological halflife, and
high specific activity  to be used as a tracer in these
MATERIALS AND METHODS
Plant material and cultivation.
The hybrid rice
) combinations Gangyou 22, IIyou 162,
and Kyou 047 were used as plant material. Two pot
experiments were conducted in a greenhouse at the Iso
tope Research Laboratory of Sichuan Agricultural Uni
versity (Ya’an, Sichuan, China) during summer 2003.
Plastic boxes (25 cm in height and 25 cm in diameter)
were filled with 10 kg of airdry sand loam soil.
Seeds were sown on March 30; then five similar
seedlings (at the age of 38 days and 6.5 leaves) were
transplanted to the boxes on May 9. The soil in boxes
Analysis of Assimilate Distribution by
during Recovery Period after Rice Seedling Transplanting
W. J. Ren, T. Q. Lu, and W. Y. Yang
College of Agronomy, Sichuan Agricultural University, Xinkang str. 46, Ya’an, Sichuan, 625014 China;
emails: email@example.com; firstname.lastname@example.org
Received November 11, 2009
—In order to characterize assimilate distribution in rice (
L.) seedlings during recovery
period after transplanting, the experiments were conducted by using
Hisotope tracer technique with three
rice hybrid combinations. The label introduced into the leaf sheath was distributed and redistributed to young
roots, tillers, and young leaves, thus promoting these organs to grow at the initial stage after transplanting.
During period from 10 to 30 days after labeling,
Hassimilate redistribution occurred mainly from the sheath
of the main stem; some radioactivity moved to tillers and roots emerged after transplanting. The activity and
Hcompounds transporting to rooting nodes and roots emerged after transplanting were
higher in rootpruned plants than in control, indicating that growth of rootpruned seedlings more depended
on the export of the compounds from the sheath of the main stem than growth of control seedlings.
Keywords: Oryza sativa
Hglucose, root pruning, seedling, source–sink relations.