Localized Effect of Polyamines on Chlorophyll Loss

The effect of polyamines, spermidine and spermine, on senescenceof detached leaves of rice, wheat and soybean was investigated.The decline of chlorophyll in rice leaf segments was promotedby polyamines during the first three days and in soybean leafdiscs during the first day of incubation. However, the declinein chlorophyll was later retarded by polyamines. Polyamineswere more effective in retarding senescence of detached wheatleaves at a higher concentration (10 mM) or in narrower segments.The retardation of chlorophyll loss by polyamines was mainlylocalized in those areas around the cut edges of detached leavesor near large veins of soybean primary leaves. This suggeststhat polyamines are not readily transported in leaf cells. ¹ Supported by research grant to C. H. K. from the NationalScience Council of the Republic of China (NSC 72-0409-B002-18). (Received June 4, 1983; Accepted September 12, 1983)