Ethylene-Enhanced Transport of ^<14>C-Labeled Metabolites in Rice Seedlings in Relation to Ethylene-Stimulated Coleoptile Growth

概要

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To examine the effects of ethylene on sugar transport from endosperms to coleoptiles in rice (Oryza sativa L. cv. Sasanishiki) seedlings, the contents of free sugars in the coleoptiles of explants fed cold glucose and the distributions of ^<14>C-activities after feeding of ^<14>C-glucose to the scutella were determined at various times after ethylene application. Changes in sucrose, glucose and fructose in the cold glucose-fed explants exposed to ethylene were similar to those in the ethylene-treated intact seedlings having endosperms. Ethylene enhanced the transport of ^<14>C-labeled metabolites from the scutella to the coleoptiles. Most of the ^<14>C accumulated in the ethylene-treated coleoptiles were present as neutral substances in the ethanol-soluble fraction. Regardless of the presence or absence of ethylene, the incorporation of ^<14>C into sucrose preceded that into glucose and fructose. The glucose and fructose moieties of ^<14>C-sucrose in the coleoptiles were almost equally labeled, and the specific activities of l4C-sucrose were higher than those of ^<14>C-glucose and ^<14>C-fructose. These results suggested that sucrose synthesized in the scutella was exported to the coleoptiles, and cleaved there into glucose and fructose. Ethylene may accelerate the transport of ^<14>C-labeled metabolites by activating sucrose cleavage in the coleoptiles.
日本植物生理学会の論文