Roper, Becky , Holaday, A. Scott .
Comparing synthesis of carbohydrate in xylem tissue of cotton during drought and recovery.
THE objective of this study was to determine the effects of drought on the metabolism of starch and soluble carbohydrates of the stem xylem in cotton, Gossypium hirsutum cv. coker-312 and cotton plants overproducing spinach sucrose phosphate synthase (SPS). At each of the three main growth stages (seedling, flowering, bolls), plants were slowly exposed to a soil water deficit and then re-watered. At the end of the drought period and after re-watering, extracts of xylem from the second or third node and the hypocotyls were taken and stored for activity rates and soluble carbohydrate measurements. Activities of sucrose-phosphate synthase (SPS), ADP-glucose pyrophosphorylase (AGPase), and sucrose synthase (SS) in the extracts were determined and compared with the contents of hexose, sucrose and starch. Preliminary experiments showed an increase in sucrose during the drought period, as well as the re-watering event. We hypothesized that enzyme rates associated with sucrose and starch synthesis would indicate a trend with decreasing plant water potential. Overproduction of SPS is expected to enhance the drought response to the extent of which starch in the xylem provides substantial hexose for sucrose synthesis during drought.
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1 - Texas Tech University, Biological Science, Box 43131, Lubbock, Texas, 79409-3131, USA
heterotrophic cotton tissue.
Presentation Type: Poster:Posters for Sections
Location: Auditorium/Bell Memorial Union
Date: Tuesday, August 1st, 2006
Time: 12:30 PM