摘要：

The effectiveness of uniconazole for height control of Hypoestes (Hypoestes phyllostachya Bak. 'Pink Splash') was determined, and the persistence of uniconazole with chlormequat and daminozide for limiting stem elongation in a low-light interior environment was compared. Spray and drench applications of uniconazole decreased plant height linearly with increased concentration. Two uniconazole sprays at 5.0 mg·liter -1 , 0.05 mg a.i./pot uniconazole drench, or two chlormequat sprays at 2500 mg·liter -1 resulted in equally aesthetic plant size for 0.4-liter pots. Chlormequat was more effective than uniconazole for reducing rate of growth in the postharvest envi-ronment. No difference in postproduction rate of growth occurred between two sprays at 5.0 mg·liter -1 and 0.05 or 0.10 mg a.i./pot drench treatments of uniconazole. Chem-ical names used: 2-chloro-N,N,N-trimethylethanaminium chloride (chlormequat chlo-ride); butanedioic acid mono(2,2-dimethylhydrazide) (daminozide); (E)-(S) -1-(4-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)-pent-l1ene-3-ol (uniconazole). Hypoestes is a perennial herb, native to Madagascar, with ovate leaves marked with lavender-pink spots. When grown as a potted plant, a growth regulator is normally used to control plant size. α -Cyclopropyl-α -(4-methoxyphenyl)-5-pyrimidinemethanol (an-cymidol) as a foliar spray at 200 mg·liter -1 was found to give good height control of Hypoestes (Armitage and Carlson, 1980). Reports of height control with daminozide vary from none or uneven control (Schultz, 1977), intermediate control (Armitage and Carlson, 1980), to good control (Sallee, 1989). Chlormequat was reported to be ef-fective at rates ranging from 750 to 5000 mg·liter -1 (Armitage and Carlson, 1980; Hentig, 1985; Sallee, 1989). Chlormequat as a 1% solution at 50 ml/pot caused phytotoxic yellowing of leaves of Hypoestes (Schultz, 1977) and needed to be applied two to four times to achieve a lasting effect (Sallee, 1989). Persistent effect of growth retardant use on Hypoestes would be desirable since well-grown, potted plants that are of suitable mar-ket height in the greenhouse often become excessively tall when placed in retail shops and home interiors. The objective of this re-search project was to determine the effec-tiveness of uniconazole on Hypoestes and to compare the effect and persistence of uni-conazole with chlormequat and daminozide for limiting stem elongation during post-Received for publication 17 June 1991. Accepted for publication 10 Feb. 1992. We thank Estella Auerswald for technical assistance. The cost of publishing this paper was defrayed in part by the payment of page charges. Under postal regula-tions, this paper therefore must be hereby marked advertisement solely to indicate this fact.

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