Paclobutrazol and Ancymidol Spray Applications Affect Production Responses and Subsequent Landscape Performance of Ornamental Cabbage, Calendula, and Pansy

Abstract

<jats:p>Previous experiments indicated that plant growth regulators applied during greenhouse production can have a negative effect on subsequent landscape performance of pansy (<jats:italic>Viola</jats:italic> × <jats:italic>wittrockiana</jats:italic> H. Gams `Crown Yellow'). Three experiments were initiated in September 2003 to determine the affects of paclobutrazol and ancymidol on production and landscape performance of ornamental cabbage (<jats:italic>Brassica oleracea</jats:italic> L. var. <jats:italic>acephala</jats:italic> A.P. deCandolle `Dynasty Pink'), calendula (<jats:italic>Calendula officinalis</jats:italic> L. `Bon Bon Orange'), and pansy. Seeds were germinated in plug trays (1.5 cm<jats:sup>3</jats:sup> inverted cone-shaped pockets) in a growth chamber with a 12 h photoperiod at 25/21 °C day/night. Plants were sprayed with paclobutrazol (formaulated as Bonzi) or ancymidol (formulated as Arest) at plug stage (cabbage, pansy, and calendula on 25 Sept., 2 Oct., 11 Nov., respectively), at 14 days after transplant into 0.73 L containers, or at both stages. Paclobutrazol was applied at 0, 5, 10 or 15 mg·L<jats:sup>-1</jats:sup> and ancymidol at 0, 2, 4, or 8 mg·L<jats:sup>-1</jats:sup>. Cabbage (30 Oct.), pansy (6 Nov.), and calendula (4 Dec.) were transplanted to landscape beds to assess residual effects on growth and flowering. Cabbage and calendula, showed minor differences in growth during greenhouse production due to varying rates of either paclobutrazol or ancymidol, but exhibited a greater response to application time. Only minor differences in growth occurred with pansy during greenhouse production due to rate or time of application using ancymidol, but exhibited major differences in response to both rate and time of application using paclobutrazol. Residual effects on growth and flowering during landscape performance phase will be discussed.</jats:p>

Evaluation of Abscisic Acid Analogs as Holding Agents for Bedding Plant Seedlings

“…In fi eld trials with tomato and pumpkin, treating seedlings with PBI 429 at 10 -4 M prior to transplanting provided excellent protection against transplanting stress but slowed subsequent plant development, resulting in fewer ripe fruits compared to PBI 365 (Sharma et al, 2006). McDonald and Arnold (2001) found that application of the plant growth retardant uniconazole to blue plumbago (Plumago auriculata) had long-term negative impact on subsequent growth and fl owering of the crop.…”

“…T he marketing period of bedding plants and vegetable transplants is limited due to the loss of aesthetic quality associated with undesirable growth and/or excess moisture loss during storage and handling. Plant growth regulators like paclobutrazol, uniconazole, and ancymidol are presently applied to container-grown ornamental and nursery plants to control growth, limit stem elongation, and slow moisture use, thereby producing more compact, easily maintained plants (Gibson and Whipker, 2000;McDonald and Arnold, 2001;Whipker and McCall, 2000;. Plant growth retardants also increase the stress tolerance of plants during shipping and handling and retail marketing, thereby improving shelf life and extending plant marketability (Latimer, 2001).…”

“…Plant growth retardants also increase the stress tolerance of plants during shipping and handling and retail marketing, thereby improving shelf life and extending plant marketability (Latimer, 2001). However, these products tend to have long-term negative effects on plant growth and development (Gibson and Whipker, 2003;McDonald and Arnold, 2001) and are not registered for use in vegetable crops (Cantliffe, 1993;Latimer, 1991). The effects of these plant growth regulators also vary among species and cultivars (White et al, 2005), making it diffi cult to develop appropriate application strategies.…”

Studies on the Impact of Spacing, Pinching and Growth Retardants on Vegetative Growth and Flowering Behaviour of Salvia

“…These retardants are applied for obtaining vigorous lateral growth of plants which are of small stature and is achieved by reducing the process of stem elongation [4,5]. They stimulate the plant branching habit that results in compact plants with reduced internodal length [6,7]. Growth retardants also influence plant flowering behavior, resulting in early flowering or more flowers per plant [8,9], enhancing the hue intensity of leaves and bracts [10], and improving the plant's ability to withstand various stresses encountered during transport and handling [11].The current study was conducted to determine the influence of spacing, pinching, and growth retardants on Salvia growth and flowering behaviour in order to generate beautiful pot plants by manipulating growth and promoting flowering by cultural or chemical approaches.…”