Abstract: The effects of three plant growth retardants paclobutrazol（PP333），uniconazole（S3307） and chlorcholinchlorid（CCC） and two methods of application（foliar spray and root drench） were studied on Zamioculcasz amiifolia plants of ages one，two and three years. PP333 and S3307 both significantly inhibited growth and their effects increased as the concentration applied increased. However，CCC did not significantly inhibit growth. PP333 reduced the average total length of leaf stalks，minimized the length petiolules（i.e. the stalk between leaflets）；shortened and thickened the petioles and also reduced the comparative growth speed of compound leaves. The optimal concentration of PP333 at different ages of Z. amiifolia varied with individual plant biomass. In contrast，the main effects of S3307 were on shortening and thickening petioles. Overall，the best control growth control of one-year-old Z. amiifolia plants was obtained with 300 mg · L-1 of S3307 applied as a foliar spray；of two-year-old plants with 300 mg · L-1 of S3307 or 600 mg · L-1 of PP333 applied as root drench；and of three-year-old plants with 1 200 mg · L-1 of PP333 applied as foliar spray.

Key words: Zamioculcasz amiifolia, plant growth retardant, dwarfing