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United States Department of Agriculture

Agricultural Research Service

Title: Sugars in Developing Cotton Squares

Authors
item Tarpley, Lee
item Sassenrath, Gretchen

Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: January 5, 1998
Publication Date: N/A

Interpretive Summary: The project objective was to determine the composition of particular sugars and starch during development of cotton (Gossypium hirsutum L.) flower bud (square) and flower developments. Soluble sugar ( about 86% of nonstructural carbohydrate weight 3 d before bloom), not starch, was the dominant nonstructural carbohydrate component of the buds throughout development. Sucrose and its hydrolysis products, but not starch hydrolysis, contributed to a more negative osmotic potential during rapid petal expansion. There is a sharp decline in soluble-sugar (glucose, fructose, plus sucrose) content of the flower during senescence, possible due to respiration climateric, and remobilization from petals to young boll or other plant parts.

Technical Abstract: During the last week of cotton (Gossypium hirsutum) flower bud (square) development, the increased rate of elongation is thought to involve a shift from cell division to cell expansion. During this stage, starch is possibly broken down into sugars. This increase in osmoticum would attract additional water into cells of the square, thereby increasing the turgor pressure. This allows the stretching of cell walls required during cell expansion. The objective was to provide an initial characterization of this sequence of events. The nonstructural carbohydrate composition was determined throughout development of first-position squares on Deltapine 50 plants grown in 1997 at Mississippi State University. Sugars were extracted with hot aqueous ethanol. After clean-up of the extracts, sugars were quantified colorimetrically through use of coupled-enzyme techniques. Preliminary results indicated that the extent of sucrose hydrolysis did not change with the time of day in younger buds.

Last Modified: 4/23/2014
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