Growth retardants on development and ornamental quality of potted 'Lilliput' Zinnia elegans Jacq.

Abstract

Zinnias have good potential to be used as flowering, potted plants, being a quick source of novelty for the floriculture industry with the aid of growth retardants. This study evaluated the effect of growth retardants on development and production of short, compact and attractive plants of potted 'Lilliput' Zinnia elegans, a highly ornamental zinnia with low cost seeds. Trials were set up in randomized blocks, with ten treatments (control and three treatments of each retardant: daminozide, paclobutrazol and chlormequat) and four replications (two pots per experimental unit, with one plant per 0.6-L pot). Paclobutrazol (0.5, 0.75 and 1.0 mg a.i. per pot) and chlormequat (1.0, 2.0 and 3.0 g L -1 ) were applied as a single drench (40 mL per pot), and daminozide (2.5, 3.75 and 5.0 g L -1 ) as a single foliar spray to runoff (10 mL per pot), at apical flower bud stage. Daminozide (2.5 and 3.75 g L -1 ), paclobutrazol (0.5, 0.75 and 1.0 mg a.i. per pot) and chlormequat at 1.0 g L -1 significantly reduced plant height and side branches length, without affecting flower diameter, delaying production cycle and causing phytotoxicity symptoms. However, plants were not short and compact enough to meet market quality demand. Chlormequat (2.0 and 3.0 g L -1 ) caused phytotoxicity symptoms and daminozide (5.0 g L -1 ) delayed production cycle. Key words: floriculture, daminozide, paclobutrazol, chlormequat, flowering RETARDADORES DE CRESCIMENTO NO DESENVOLVIMENTOE NA QUALIDADE ORNAMENTAL DE Zinnia elegans JACQ. 'LILLIPUT' ENVASADA RESUMO: As zínias têm grande potencial como plantas floríferas envasadas e representam rápida fonte de novidade para a floricultura com o auxílio de retardadores de crescimento. Avaliaram-se os efeitos de retardadores de crescimento no desenvolvimento e na produção de plantas envasadas de porte baixo, compactas e atrativas de 'Lilliput' Zinnia elegans, cultivar altamente ornamental, com sementes de baixo custo. O delineamento experimental foi em blocos casualizados, com dez tratamentos (controle e três concentrações de cada retardador: daminozide, paclobutrazol e chlormequat) e quatro repetições (dois vasos por unidade experimental, com uma planta por vaso de 0,6 L). Paclobutrazol (0,5; 0,75 e 1,0 mg i.a. por vaso) e chlormequat (1,0; 2,0 e 3,0 g L -1 ) foram aplicados ao substrato (40 mL por vaso), enquanto o daminozide (2,5; 3,75 e 5,0 g L -1 ) foi aplicado através de pulverização foliar (10 mL por vaso), no estádio de gema floral apical visível. Daminozide (2,5 e 3,75 g L -1 ), paclobutrazol (0,5; 0,75 e 1,0 mg i.a. por vaso) e 1,0 g L -1 de chlormequat reduziram significativamente a altura das plantas e o comprimento dos ramos laterais, sem afetar o diâmetro dos capítulos, atrasar o ciclo de produção e causar fitotoxicidade. Entretanto, as plantas não se apresentaram suficientemente baixas e compactas para atender às exigências de qualidade do mercado. Chlormequat (2,0 e 3,0 g L -1 ) causou fitotoxicidade e daminozide (5,0 g L -1 ) aumentou o ciclo de produção.

Growth and Anatomical Responses in Xanthostemon chrysanthusas Influenced by Paclobutrazol and Potassium Nitrate

“…These results showed that PBZ inhibited the tree growth. Previous research also reported that PBZ resulted in plant height reduction (Ahmad Nazarudin 2012;Gent 2004;Pinto et al 2005;Taiz & Zeiger 2006;Williams et al 2003).…”

The influence of substrate type and chlormequat on the growth and flowering of marigold (Tagetes L.)

“…Similar results had been reported in the case of zinnia sprayed with different doses (500-1500 mg dm -3 ) of chlormequat (Asgarian et al 2013), which was explained by an early application of the regulator. However, chlormequat applied as a single drench at 1.0 g dm -3 significantly reduced the height of zinnia plants (Pinto et al 2005). Studies with marigold by Schroeter and Janowska (2003) reported shorter stems after the application of chlormequat (460 and 690 mg dm ).…”

Paclobutrazol or uniconazole effects on ethylene sensitivity of potted ornamental plants and plugs

“…This suppression of plant growth and more flowering on cuphea plants treated with 2-4 mg L −1 paclobutrazol was considered to be due to shorter internodal elongations rather than reduction in number of nodes (Arnold, 1998;Pinto et al, 2005). Moreover, increase in flowering by use of PGRs has also been reported (Bailey and Whipker, 1998;Karaguzel et al, 2004;Te-chato et al, 2009).…”