TY - JOUR
T1 - Hormonal changes in the grains of rice subjected to water stress during grain filling
AU - Yang, J.
AU - Zhang, J.
AU - Wang, Z.
AU - Zhu, Q.
AU - Wang, W.
N1 - This work was supported by the FRG of Hong Kong Baptist University, by the RGC of Hong Kong University Council, by the AOE Research Found of the Chinese University of Hong Kong, by the National Natural Science Foundation of China (project no. 39970424), and by the State Key Basic Research and Development Plan (grant no. G1999011700).
PY - 2001
Y1 - 2001
N2 - Lodging-resistant rice (Oryza sativa) cultivars usually show slow grain filling when nitrogen is applied in large amounts. This study investigated the possibility that a hormonal change may mediate the effect of water deficit that enhances whole plant senescence and speeds up grain filling. Two rice cultivars showing high lodging resistance and slow grain filling were field grown and applied with either normal or high amount nitrogen (HN) at heading. Well-watered and water-stressed (WS) treatments were imposed 9 days post anthesis to maturity. Results showed that WS increased partitioning of fixed 14CO2 into grains, accelerated the grain filling rate but shortened the grain filling period, whereas the HN did the opposite way. Cytokinin (zeatin+zeatin riboside) and indole-3-acetic acid contents in the grains transiently increased at early filling stage and WS treatments hastened their declines at the late grain filling stage. Gibberellins (GAs; GA1+GA4) in the grains were also high at early grain filling but HN enhanced, whereas WS substantially reduced, its accumulation. Opposite to GAs, abscisic acid (ABA) in the grains was low at early grain filling but WS remarkably enhanced its accumulation. The peak values of ABA were significantly correlated with the maximum grain filling rates (r=0.92**, P<0.01) and the partitioning of fixed 14C into grains (r=0.95**, P<0.01). Exogenously applied ABA on pot-grown HN rice showed similar results as those by WS. Results suggest that an altered hormonal balance in rice grains by water stress during grain filling, especially a decrease in GAs and an increase in ABA, enhances the remobilization of prestored carbon to the grains and accelerates the grain filling rate.
AB - Lodging-resistant rice (Oryza sativa) cultivars usually show slow grain filling when nitrogen is applied in large amounts. This study investigated the possibility that a hormonal change may mediate the effect of water deficit that enhances whole plant senescence and speeds up grain filling. Two rice cultivars showing high lodging resistance and slow grain filling were field grown and applied with either normal or high amount nitrogen (HN) at heading. Well-watered and water-stressed (WS) treatments were imposed 9 days post anthesis to maturity. Results showed that WS increased partitioning of fixed 14CO2 into grains, accelerated the grain filling rate but shortened the grain filling period, whereas the HN did the opposite way. Cytokinin (zeatin+zeatin riboside) and indole-3-acetic acid contents in the grains transiently increased at early filling stage and WS treatments hastened their declines at the late grain filling stage. Gibberellins (GAs; GA1+GA4) in the grains were also high at early grain filling but HN enhanced, whereas WS substantially reduced, its accumulation. Opposite to GAs, abscisic acid (ABA) in the grains was low at early grain filling but WS remarkably enhanced its accumulation. The peak values of ABA were significantly correlated with the maximum grain filling rates (r=0.92**, P<0.01) and the partitioning of fixed 14C into grains (r=0.95**, P<0.01). Exogenously applied ABA on pot-grown HN rice showed similar results as those by WS. Results suggest that an altered hormonal balance in rice grains by water stress during grain filling, especially a decrease in GAs and an increase in ABA, enhances the remobilization of prestored carbon to the grains and accelerates the grain filling rate.
UR - http://www.scopus.com/inward/record.url?scp=0034830837&partnerID=8YFLogxK
U2 - 10.1104/pp.127.1.315
DO - 10.1104/pp.127.1.315
M3 - Journal article
C2 - 11553759
AN - SCOPUS:0034830837
SN - 0032-0889
VL - 127
SP - 315
EP - 323
JO - Plant Physiology
JF - Plant Physiology
IS - 1
ER -