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Nitrogen and Carbon Accumulation and Remobilization during Grain Filling in Maize under Different Source/Sink Ratios
Author(s) -
Uhart Sergio Adolfo,
Andrade Fernando Héctor
Publication year - 1995
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci1995.0011183x003500010034x
Subject(s) - sink (geography) , shading , carbon sink , agronomy , biology , nitrogen , zoology , horticulture , chemistry , climate change , ecology , art , cartography , organic chemistry , visual arts , geography
The relative flow and remobilization of carbon (C) and nitrogen (N) to the grain during the grain filling period depends on the particular source/sink ratio of the crop. The objective of this work was to analyze the C and N accumulation and remobilization patterns of maize ( Zea mays L.) under a wide range of source/sink ratios. The experiment was conducted at Balcarce, Argentina, during 2 yr with both a shortand long‐season hybrid. The treatments consisted of two levels of source reduction (45 and 55% shading during the grain filling period), two levels of reproductive sink reduction (45 and 55% shading during a 30‐d period bracketing silking), and an unshaded control. The shading treatments had a variable duration (30=38 d) to ensure constant incident radiation. The source limitation produced increases in remobilization rates of leaf + stem reduced N (Nred) and stem nonstructural carbohydrates (CH) compared with the control. The sink limitation generated greater stem CI‐I accumulation and less Nred remobilization from the leaf and stem. Sink‐limited treatments had greater postanthesis N absorption and grain N concentration than the sourcelimited treatments. As the source/sink ratio decreased, N flow to the grain per unit of C flow decreased suggesting that N becomes more limiting for grain yield with increasing source limitation. Linear quantitative relationships between source/sink ratio and CH remobilization, N remobilization, relative C‐N fluxes to the kernel, and kernel N concentrations have been established.