Abstract: This paper concerns the photosynthetic characteristics of a yellow-green nucleus mutant ofricewhich was obtained in anther culture by us. The content of total chlorophyll, xanthophyll and β-carotene in the mutant leaves is about 31%, 40% and 75% of that ill normal leaves respectively; the chl a/chl b ratio of the mutant is much higher than that of normal leaves. The anal- ysis of SDS-solubilized extracts of the chloroplast lamellae shows that the major light-harvesting chl a/b protein complex of the mutant is extremely deficient, and its chl a/chl b ratio is more than 3. In the chloroplasts of mutant leaves, there are very few grana stacking, and more starch grains can be seen when leaves are exposed to sun light. The rate of CO2 assimilation of mutant leaves exposed to 20000 lux of sun light is 75% of that of normal leaves on a basis of leaf area, and is 185% on a basis of chlorophyll. The chloroplasts of the mutant may also show a much higher rate of ferricyanide Hill reaction on a basis of chlorophyll.

Key words: photosynthetic, characteristics, Yellow-green Rice, mutant