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Plant Physiology 82:222-225 (1986) © 1986 American Society of Plant Biologists Cessation of Assimilate Uptake in Maturing Soybean Seeds 1Central Research and Development Department, Experimental Station, E. I. Du Pont de Nemours & Company, Wilmington, Delaware 19898
In vitro assimilate uptake and metabolism were evaluated in embryos of known age isolated from seeds at mid-podfilling through physiological maturity. The capacity of isolated Wye soybean embryos to take up exogenous [14C]sucrose dropped nearly 4-fold in less than 1 week at incipient cotyledon yellowing. This drop in rate of sucrose uptake coincided with cessation of seed growth as well as rapid decline in leaf photosynthetic rate that preceded leaf yellowing. Conversely, the rate of [3H]glutamine uptake by cotyledons increased as they yellowed. Yellow cotyledons also rapidly converted exogenous [3H]glutamine to ethanolinsoluble components, but converted little exogenous [14C]sucrose to ethanol-insoluble components, primarily because of greatly reduced sucrose uptake. Sustained import and metabolism of amino acids remobilized from senescing leaves may prolong seed growth beyond loss of photosynthetic competency and sucrose availability.
2 Present address: Haskell Laboratory, E. I. Du Pont de Nemours & Co., Inc., P.O. Box 50, Newark, DE 19714. 3 Present address: Agricultural Products Department, Crop Research Laboratory, E. I. Du Pont de Nemours & Co., Inc., P.O. Box 30, Newark, DE 19714. 4 Present address: 42 Duncraig Road, Applecross, Western Australia, Australia 6153. 1 Contribution No. 3932 from the Central Research and Development Department. This article has been cited by other articles:
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