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Relationship of source and sink in determining kernel composition of maize.

Seebauer JR, Singletary GW, Krumpelman PM, Ruffo ML, Below FE - J. Exp. Bot. (2009)

Bottom Line: Intermated B73xMo17 recombinant inbred lines (IBM RILs) which displayed contrasting concentrations of endosperm starch were grown in the field with deficient or sufficient N, and the source supply altered by ear truncation (45% reduction) at 15 d after pollination (DAP).The C/N ratio of the assimilate supply at 19 DAP was directly related to the final kernel composition, with an inverse relationship between the concentrations of starch and protein in the mature endosperm.The accumulation of kernel starch and protein in maize is uniform along the ear, yet adaptable within genotypic limits, suggesting that kernel composition is source limited in maize.

View Article: PubMed Central - PubMed

Affiliation: Department of Crop Sciences, University of Illinois Urbana-Champaign, 1201 W Gregory Drive, Urbana, IL 61801, USA.

ABSTRACT
The relative role of the maternal source and the filial sink in controlling the composition of maize (Zea mays L.) kernels is unclear and may be influenced by the genotype and the N supply. The objective of this study was to determine the influence of assimilate supply from the vegetative source and utilization of assimilates by the grain sink on the final composition of maize kernels. Intermated B73xMo17 recombinant inbred lines (IBM RILs) which displayed contrasting concentrations of endosperm starch were grown in the field with deficient or sufficient N, and the source supply altered by ear truncation (45% reduction) at 15 d after pollination (DAP). The assimilate supply into the kernels was determined at 19 DAP using the agar trap technique, and the final kernel composition was measured. The influence of N supply and kernel ear position on final kernel composition was also determined for a commercial hybrid. Concentrations of kernel protein and starch could be altered by genotype or the N supply, but remained fairly constant along the length of the ear. Ear truncation also produced a range of variation in endosperm starch and protein concentrations. The C/N ratio of the assimilate supply at 19 DAP was directly related to the final kernel composition, with an inverse relationship between the concentrations of starch and protein in the mature endosperm. The accumulation of kernel starch and protein in maize is uniform along the ear, yet adaptable within genotypic limits, suggesting that kernel composition is source limited in maize.

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Related in: MedlinePlus

The effect of ear decile position on individual kernel dry weight (A), and the concentrations of starch (B) and protein (C) along the ear for two IBM RILs with contrasting concentrations of starch and protein. The RIL M0116 is shown as closed circles, and M0288 as open circles. Data are the means ±1 SE (n=9). As determined by two-sample t test, RILs were significant (P <0.001) for all comparisons, and the percentile class difference was significant (P <0.001) for weight, starch, and protein concentration.
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fig1: The effect of ear decile position on individual kernel dry weight (A), and the concentrations of starch (B) and protein (C) along the ear for two IBM RILs with contrasting concentrations of starch and protein. The RIL M0116 is shown as closed circles, and M0288 as open circles. Data are the means ±1 SE (n=9). As determined by two-sample t test, RILs were significant (P <0.001) for all comparisons, and the percentile class difference was significant (P <0.001) for weight, starch, and protein concentration.

Mentions: Two RILs with contrasting starch levels differed in individual kernel weight, but not in how weight was affected by kernel decile position (Fig. 1A). Even though MO228 had slightly aberrant responses at the very base and tip of the ear, individual kernel weights tended to be highest at the base and decreased steadily towards the tip of the ear. The RILs differed as expected in starch and protein concentrations, exhibiting almost a 30 g kg−1 difference in starch, and a corresponding but opposite difference in protein (Fig. 1B, C). Except for some minor irregularities in starch, the concentrations of starch and protein were remarkably constant along the ear for both RILs. These results show that genotype plays a much larger role than kernel decile position in determining kernel composition, but not in final kernel weight.


Relationship of source and sink in determining kernel composition of maize.

Seebauer JR, Singletary GW, Krumpelman PM, Ruffo ML, Below FE - J. Exp. Bot. (2009)

The effect of ear decile position on individual kernel dry weight (A), and the concentrations of starch (B) and protein (C) along the ear for two IBM RILs with contrasting concentrations of starch and protein. The RIL M0116 is shown as closed circles, and M0288 as open circles. Data are the means ±1 SE (n=9). As determined by two-sample t test, RILs were significant (P <0.001) for all comparisons, and the percentile class difference was significant (P <0.001) for weight, starch, and protein concentration.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC2803218&req=5

fig1: The effect of ear decile position on individual kernel dry weight (A), and the concentrations of starch (B) and protein (C) along the ear for two IBM RILs with contrasting concentrations of starch and protein. The RIL M0116 is shown as closed circles, and M0288 as open circles. Data are the means ±1 SE (n=9). As determined by two-sample t test, RILs were significant (P <0.001) for all comparisons, and the percentile class difference was significant (P <0.001) for weight, starch, and protein concentration.
Mentions: Two RILs with contrasting starch levels differed in individual kernel weight, but not in how weight was affected by kernel decile position (Fig. 1A). Even though MO228 had slightly aberrant responses at the very base and tip of the ear, individual kernel weights tended to be highest at the base and decreased steadily towards the tip of the ear. The RILs differed as expected in starch and protein concentrations, exhibiting almost a 30 g kg−1 difference in starch, and a corresponding but opposite difference in protein (Fig. 1B, C). Except for some minor irregularities in starch, the concentrations of starch and protein were remarkably constant along the ear for both RILs. These results show that genotype plays a much larger role than kernel decile position in determining kernel composition, but not in final kernel weight.

Bottom Line: Intermated B73xMo17 recombinant inbred lines (IBM RILs) which displayed contrasting concentrations of endosperm starch were grown in the field with deficient or sufficient N, and the source supply altered by ear truncation (45% reduction) at 15 d after pollination (DAP).The C/N ratio of the assimilate supply at 19 DAP was directly related to the final kernel composition, with an inverse relationship between the concentrations of starch and protein in the mature endosperm.The accumulation of kernel starch and protein in maize is uniform along the ear, yet adaptable within genotypic limits, suggesting that kernel composition is source limited in maize.

View Article: PubMed Central - PubMed

Affiliation: Department of Crop Sciences, University of Illinois Urbana-Champaign, 1201 W Gregory Drive, Urbana, IL 61801, USA.

ABSTRACT
The relative role of the maternal source and the filial sink in controlling the composition of maize (Zea mays L.) kernels is unclear and may be influenced by the genotype and the N supply. The objective of this study was to determine the influence of assimilate supply from the vegetative source and utilization of assimilates by the grain sink on the final composition of maize kernels. Intermated B73xMo17 recombinant inbred lines (IBM RILs) which displayed contrasting concentrations of endosperm starch were grown in the field with deficient or sufficient N, and the source supply altered by ear truncation (45% reduction) at 15 d after pollination (DAP). The assimilate supply into the kernels was determined at 19 DAP using the agar trap technique, and the final kernel composition was measured. The influence of N supply and kernel ear position on final kernel composition was also determined for a commercial hybrid. Concentrations of kernel protein and starch could be altered by genotype or the N supply, but remained fairly constant along the length of the ear. Ear truncation also produced a range of variation in endosperm starch and protein concentrations. The C/N ratio of the assimilate supply at 19 DAP was directly related to the final kernel composition, with an inverse relationship between the concentrations of starch and protein in the mature endosperm. The accumulation of kernel starch and protein in maize is uniform along the ear, yet adaptable within genotypic limits, suggesting that kernel composition is source limited in maize.

Show MeSH
Related in: MedlinePlus