Assimilation, partitioning, and nonstructural carbohydrates in sweet compared with grain sorghum. [Sorghum bicolor (L. ) Moench]
- Texas A M Univ., College Station (USA)
Nonstructural carbohydrate concentrations in stems are greater for sweet than grain sorghums (Sorghum bicolor (L.) Moench). Knowledge of plant characteristics associated with high nonstructural carbohydrates in sweet sorghum will air efforts to increase nonstructural carbohydrates in grain sorghum stems. This study tested the hypothesis that variation of CO{sub 2} assimilation rate, leaf area, branching at upper nodes, and partitioning of {sup 14}C-labeled assimilate to main stems are associated with variation of stem nonstructural carbohydrates. A sweet (Atlas X Rio) and a grain (ATx623 X RTx5388) hybrid, stages near and after physiological maturity, and defoliation and gibberellic acid (GA{sub 3}) treatments provided sources of variation for study. Concentrations of nonstructural carbohydrates in lower and upper stems of the sweet hybrid were 1.4 and 2.7 times higher, respectively, than for the grain hybrid, after physiological maturity. Variation in branching, including {sup 14}C-assimilate partitioning to branches, was not consistently associated with hybrid differences in stem nonstructural carbohydrates. Increased recovery (twofold) of {sup 14}C-assimilate in roots and labeled leaves corresponded with lower percentages of {sup 14}C-assimilate and lower concentrations of nonstructural carbohydrates in stems of the grain hybrid. Leaf areas and leaf CO{sub 2} exchange rate were twice as great for the sweet hybrid. Although defoliation of the sweet hybrid minimized leaf area differences between hybrids, the sweet hybrid accumulated twice as much nonstructural carbohydrates in branches after physiological maturity. Greater potentials for CO{sub 2} assimilation and for {sup 14}C-assimilate accumulation in mature stem tissue were associated with higher levels of stem nonstructural carbohydrates in the sweet compared with the grain hybrid.
- OSTI ID:
- 5914458
- Journal Information:
- Crop Science; (USA), Vol. 30:5; ISSN 0011-183X
- Country of Publication:
- United States
- Language:
- English
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