Use of the Stable Nitrogen Isotope to Reveal the Source-Sink Regulation of Nitrogen Uptake and Remobilization during Grain Filling Phase in Maize.
Although the remobilization of vegetative nitrogen (N) and post-silking N both contribute to grain N in maize (Zea mays L.), their regulation by grain sink strength is poorly understood. Here we use 15N labeling to analyze the dynamic behaviors of both pre- and post-silking N in relation to source and sink manipulation in maize plants. The results showed that the remobilization of pre-silking N started immediately after silking and the remobilized pre-silking N had a greater contribution to grain N during early grain filling, with post-silking N importance increasing during the later filling stage. The amount of post-silking N uptake was largely driven by post-silking dry matter accumulation in both grain as well as vegetative organs. Prevention of pollination during silking had less effect on post-silking N uptake, as a consequence of compensatory growth of stems, husk + cob and roots. Also, leaves continuously export N even though grain sink was removed. The remobilization efficiency of N in the leaf and stem increased with increasing grain yield (hence N requirement). It is suggested that the remobilization of N in the leaf is controlled by sink strength but not the leaf per se. Enhancing post-silking N uptake rather than N remobilization is more likely to increase grain N accumulation.
Center for Resources, Environment and Food Security, College of Resources and Environmental Science, China Agricultural University, Beijing, P.R. China.
Lan
L
Yang
Center for Resources, Environment and Food Security, College of Resources and Environmental Science, China Agricultural University, Beijing, P.R. China.|Soil and Fertilizer Research Institute Sichuan Academy of Agricultural Science, Chengdu, P.R. China.
Song
S
Guo
Center for Resources, Environment and Food Security, College of Resources and Environmental Science, China Agricultural University, Beijing, P.R. China.
Qinwu
Q
Chen
Center for Resources, Environment and Food Security, College of Resources and Environmental Science, China Agricultural University, Beijing, P.R. China.
Fanjun
F
Chen
Center for Resources, Environment and Food Security, College of Resources and Environmental Science, China Agricultural University, Beijing, P.R. China.
Lixing
L
Yuan
Center for Resources, Environment and Food Security, College of Resources and Environmental Science, China Agricultural University, Beijing, P.R. China.
Guohua
G
Mi
D018533:Biomass; D007553:Isotope Labeling; D009584:Nitrogen / Q000378:metabolism*; D009587:Nitrogen Isotopes; D009928:Organ Specificity; D012639:Seeds / Q000378:metabolism*; D003313:Zea mays / Q000254:growth & development / Q000378:metabolism*
D009587:Nitrogen Isotopes; D009584:Nitrogen