Effects of Sugars on Ethylene Production by Excised Sinapis Cotyledons

Ethylene production by excised Sinapis cotyledons in the lightwas increased 2–3 fold by exogenous 0–06 M sucroseafter a 6 h lag period and by glucose after a lag of 24–48h, whereas the non-metabolized glucose analogue 3-O-methyl -D-glucopyranosehad no effect on ethylene production. Sucrose enhancement of ethylene production occurred in boththe petiole and lamina of the cotyledon and was greater at highlight intensities than at low intensities, or in the dark. Enhanced ethylene levels in the petiole may be responsible forthe decline in petiolar protein, RNA and chlorophyll, and theregression of root primordia in cotyledons incubated in sucrose.