<b>The effect of plant growth regulators on height control in potted <i> Arundina graminifolia</i> orchids (Growth regulators in <i>Arundina graminifolia</i>)

Abstract

Orchids have become an important portion of the international floriculture market. Arundina graminifolia is a terrestrial orchid that produces attractive flowers, and, although the species could be a potential candidate for the floriculture market, its considerable height makes it difficult to transport and commercialize. A number of plant growth regulators have been utilized to control plant height in ornamentals and other species. Thus, the aim of this study was to evaluate the efficiency of growth regulators, paclobutrazol and chlormequat chloride on the vegetative development of containerized A. graminifolia orchid aiming at height control. Paclobutrazol (Cultar) was applied at 0, 5, 10, and 20 mg L -1 , and CCC (Cycocel) was applied at 0, 2000, 4000, and 6000 mg L -1 . The plants were assessed monthly for the plant height and number of shoots per container. CCC had no effect on the final height of plants at the concentrations applied. In contrast, paclobutrazol was effective in controlling plant height at a concentration of 5 mg L -1 , but higher concentrations (10 and 20 mg L -1 ) proved to be toxic to the plants, causing death to the new shoots. Paclobutrazol at lower concentrations offers a viable means for height control in A. graminifolia.Efeito de reguladores de crescimento no controle de altura da orquídea Arundina graminifolia em vasos (Reguladores de crescimento em Arundina graminifolia) RESUMO. As orquídeas tornaram-se parcela importante do mercado da floricultura nacional. Arundina graminifolia é uma orquídea terrestre, produz flores atraentes e uma espécie que poderia ser uma candidata potencial para o mercado da floricultura, entretanto, sua altura considerável torna difícil seu transporte e comercialização. Alguns reguladores de crescimento de plantas têm sido utilizados para controlar a altura em plantas ornamentais e em outras espécies. O objetivo desse estudo foi avaliar a eficiência dos reguladores de crescimento, paclobutrazol e cloreto de chlormequat no desenvolvimento vegetativo da orquídea A. graminifolia em vasos, visando o controle de altura. Paclobutrazol (Cultar) foi aplicado a 0, 5, 10 e 20 mg L -1 , e CCC (Cycocel) foi aplicado a 0; 2000; 4000 e 6000 mg L -1 . As plantas foram avaliadas mensalmente para altura de planta e número de brotos por vaso. CCC não teve efeito sobre a altura final das plantas nas concentrações aplicadas. Paclobutrazol foi eficaz no controle de altura da planta na concentração de 5 mg L -1 , mas concentrações mais elevadas (10 e 20 mg L-1) provou ser tóxico para as plantas, causando a morte em brotos novos. Paclobutrazol em concentrações mais baixas oferece um meio viável para o controle de altura em A. graminifolia. Palavras-chave: paclobutrazol, cloreto de chlormequat, desenvolvimento vegetativo.

Effects of water-deficit stress and paclobutrazol on growth, relative water content, electrolyte leakage, proline content and some antioxidant changes in Curcuma alismatifolia Gagnep. cv. Chiang Mai Pink

“…PBZ controls height as a cell and internode elongation inhibitor. It retards plant growth by inhibition of gibberellin biosynthesis (Fletcher et al, 2000, Hua et al, 2014, Wanderley et al, 2014). Burrows et al (1992) reported that PBZ reduced the height of Chrysanthemum cv.…”

“…When gibberellin production is inhibited, cell division still occurs, but the new cells do not elongate, resulting in stems with the same number of leaves and shorter internodes (Pinto et al, 2006, Francescangeli and Zagabria, 2008). For these reasons, PBZ is used to reduce plant height for potted plant production in several species (Pinto et al, 2006, Francescangeli and Zagabria, 2008, Hua et al, 2014, Wanderley et al, 2014). PBZ has been reported as an ameliorated compound when plants are subjected to salinity or water-deficit stresses.…”

Evaluation of paclobutrazol application method on quality characteristics of ornamental pepper

“…In addition to providing a suitable size for ornamental pot plant, the PBZ also favors the development of greener leaves, which is a desirable feature for an ornamental plant. Darker green leaves were also observed in the orchids Consolida orientalis and Arundina graminifolia treated with foliar spray and drench PBZ application method respectively, and 'Pitanga' pepper plants by both, foliar spray and drench PBZ application (MANSUROGLU et al, 2009;WANDERLEY et al, 2014;GROSSI et al, 2005). In this context, Berova and Zlatev (2000) reported that enhances in chlorophyll content is attributed to increases in phytyl content, which it is generated by the same terpenoid pathway as gibberellins.…”

Growth and quality of potted ornamental peppers treated with paclobutrazol

“…In the same work, the authors found that the reduction of plant height was proportional to the increase of PBZ concentration; however, no evaluation of the ornamental properties was performed. PBZ was also efficient in reducing the stem growth of sunflower and orchid plants (Wanderley et al, 2014a(Wanderley et al, , 2014b. Potted sunflowers soaked with PBZ reduced the stem extension, which was reversed by spray of GA 3 (Ribeiro et al, 2011).…”