The influence of growth retardants and cytokinins on flowering of ornamental plants

Anna Pobudkiewicz

doi:10.5586/aa.2008.018

Abstract

Growth retardants are applied in order to obtain short and well compact plants. They usually inhibit stem elongation, but also can influence the flowering of plants. The aim of cytokinin application is to obtain well branched plants without removing the apical meristem. Cytokinins usually increase the number of axillary shoots but also can influence flowering. Growth retardants and cytokinins can affect flower size, pedicel length, number of flowers, flower longevity, abortion of flower buds and number of days from potting plants to the first open flower. Flowering of growth retardant and cytokinin treated plants might depend on the method of growth regulator used (foliar spray or soil drench), plant species or even a plant cultivar, but in the highest degree it depends on the growth regulator rate used. These growth regulators, when are applied at rates appropriate for height and habit control, very seldom influence flowering of ornamental plants, but applied at high rates can delay flowering, diminish flower diameter or flower pedicel length and also can decrease the number of flowers per plant. In cultivation of bulb plants, growth retardants, used at very high rates, also cause abortion of flower buds.

Highlights

It was reported that flurprimidol spray treatment increased days to flowering in oriental lily ‘Mona Lisa’, while soil drench unaffected flowering (Pobudkiewicz and Treder, 2006)
The results of other studies conducted on Dianthus (Pobudkiewicz and Nowak, 1994 a), Euphorbia (Pobudkiewicz et al 1995), Pelargonium (Pobudkiewicz and Nowak, 1999), Globba (Pobudkiewicz and Podwyszyńska, 1999), Cuphea (Pobudkiewicz, 2000 a), Streptocarpus (Pobudkiewicz, 2000 b) and Lilium (Pobudkiewicz and Treder, 2006) indicate that irrespective of growth retardant rate, plant species, or method of application, growth retardants had no influence on the number of days from potting plants to their flowering
In asiatic hybrid lily ‘Prima’ there was no bud abortion observed on the plants treated with flurprimidol at low concentration (10 mgdm–3) and on the control plants but higher concentrations: 20, 30, 40 and 50 mgdm–3 increased bud abortion by 8%, 25%, 50% and 58%, respectively (Pobudkiewicz and Nowak , 1992)

Summary

Introduction

Flurprimidol at high concentrations of 30–50 mgdm–3, delayed flowering of asiatic hybrid lily ‘Prima’ by a few days (Pobudkiewicz and Nowak, 1992) and at 22.5 mgdm–3 delayed flowering of dwarf alstroemeria (Pobudkiewicz et al 2000). Days to flowering of pot carnation ‘Snowmass’ (Pobudkiewicz and Nowak , 1994 a) were unaffected by double flurprimidol treatment at very high concentration (45 mgdm–3), but this retardant at very low concentration (7.5 mgdm–3) delayed flowering of chrysanthemum cvs.

Results

Conclusion