Effects of polyamines on chlorophyll and protein content, and δ-aminolevulinate dehydratase(ALAD) activity were investigated during the greening of mung bean cotyledons. Polyamines stimulated chlorophyll formation in greening cotyledons, and this effect was enhanced by KCl. The changes in protein content were similar to the changes for chlorophyll content. The excision entailed an increase in ALAD activity. Then a decrease appeared after 48 h incubation on water in the dark. It was more precocious in the light, but was accelerated when the cotyledons were illuminated after a dark preincubation. Putrescine had little effect on ALAD activity in the dark. In the light, putrescine prevented the decrease in ALAD activity and enhanced this activity when a dark preincubation preceded illumination. KCl had a slight stimulating effect in the dark, but was uneffective in the light. The combination putrescine+KCl was devoid of stimulating effect. The results obtained suggest that plastid development of mung bean cotyledons during greening was affected by polyamines and light and that polyamines may play a role in the regulation of plastid development.

• Jung Hee Hong | 홍정희