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Functional dynamics of the nitrogen balance of sorghum. II. Grain filling period

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van Oosterom, E. J., Chapman, S. C., Borrell, A. K., Broad, I. J. and Hammer, G. L. (2010) Functional dynamics of the nitrogen balance of sorghum. II. Grain filling period. Field Crops Research, 115 (1). pp. 29-38. ISSN 0378-4290

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Article Link(s): https://doi.org/10.1016/j.fcr.2009.09.019

Publisher URL: https://www.sciencedirect.com/science/article/pii/S0378429009002664

Abstract

Maintenance of green leaf area during grain filling can increase grain yield of sorghum grown under terminal water limitation. This ‘stay-green’ trait has been related to the nitrogen (N) supply–demand balance during grain filling. This study quantifies the N demand of grain and N translocation rates from leaves and stem and explores effects of genotype and N stress on onset and rate of leaf senescence during the grain filling period. Three hybrids differing in potential height were grown at three levels of N supply under well-watered conditions. Vertical profiles of biomass, leaf area, and N% of leaves, stem and grain were measured at regular intervals. Weekly SPAD chlorophyll readings on main shoot leaves were correlated with observed specific leaf nitrogen (SLN) to derive seasonal patterns of leaf N content. For all hybrids, individual grain N demand was sink determined and was initially met through N translocation from the stem and rachis. Only if this was insufficient did leaf N translocation occur. Maximum N translocation rates from leaves and stem were dependent on their N status. However, the supply of N at canopy scale was also related to the amount of leaf area senescing at any one time. This supply–demand framework for N dynamics explained effects of N stress and genotype on the onset and rate of leaf senescence.

Item Type:Article
Business groups:Crop and Food Science
Keywords:Demand Senescence Stay-green Supply Translocation
Subjects:Science > Botany > Genetics
Agriculture > Agriculture (General) > Fertilisers
Plant culture > Field crops > Sorghum
Deposited On:22 Dec 2021 05:56
Last Modified:22 Dec 2021 05:56

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