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Advisor(s)
Abstract(s)
A necessidade de encontrar estratégias sustentáveis eficazes no controlo da altura da planta é actualmente um grande desafio que se coloca à horticultura ornamental protegida. Este estudo teve como objectivo: (1) analisar a informação disponível acerca dos factores que afectam a altura das plantas; (2) compreender os mecanismos fisiológicos envolvidos no processo de alongamento do caule; (3) definir alternativas sustentáveis para produzir plantas compactas, reduzindo ao mínimo a aplicação de „reguladores químicos de crescimento‟. Concluiu-se que manter uma temperatura nocturna superior à temperatura diurna (DIF negativa ou tratamento DROP) ou a alteração do espectro luminoso (elevado rácio vermelho/vermelho-longínquo) apresentam um forte potencial como métodos não químicos no controlo da altura de várias espécies de plantas ornamentais. Oaumento do rácio vermelho/vermelho-longínquo, poderáser efectuado de diferentes modos incluindo a utilização defilmes fotosselectivose/ourecorrendoa um conjunto de medidas facilmente aplicáveis tais como:(i) evitar densidades de plantação muito elevadas; (ii) utilização de luz suplementar com elevado rácio vermelho/vermelho-longínquo (ex. lâmpadas de assimilação em substituição de lâmpadas incandescentes); (iii) evitar a exposição das plantas à radiação do crepúsculo (devido à diminuição natural do rácio vermelho/vermelho-longínquo). O stress mecânico é também uma medida eficaz para a manutenção de plantas compactas em determinadas espécies. Paralelamente, o recurso ao Melhoramento de plantas no sentido de seleccionar cultivares ananicantes poderá ser bastante promissor. Porém, na maioria dos casos, não será uma medida única que permitirá a obtenção de plantas compactas, mas a combinação de várias estratégias.
Height control in ornamental plants: sustainable alternatives to growth regulators. The need to find sustainable and efficient strategies to control plant height is currently a great challenge in the protected cultivation of ornamental plants. The aim of this study was to: (1) analyse the available information on the factors involved in plant height; (2) understand the underlying physiological mechanisms behind stem elongation; (3) define sustainable alternatives for producing compact floricultural crops, reducing the application of chemical growth retardants to a minimum level. It was concluded that keeping a night temperature higher than the day temperature (negative DIF or DROP treatment) or changing the light quality (high red/ far-red ratio) have a high potential as non-chemical methods for controlling plant height in several species of ornamental plants. Increasing the red/ far-red ratio can be done in different ways including the use of photoselective films and/or using several easy to apply measures, including: (i) avoiding very high plant densities; (ii) using supplementary light with a high red/far-red ratio (e.g. assimilation lamps instead of incandescent lamps); (iii) avoiding plant exposure to the twilight period (due to the natural reduction of the red/far-red ratio). Mechanical stress is also an effective strategy for producing compact plants in some species. Furthermore, plant breeding might offer good possibilities for developing dwarf cultivars. Nevertheless, in most cases, it will not be one single measure that will result in compact plants, but it is rather the combination of several strategies.
Height control in ornamental plants: sustainable alternatives to growth regulators. The need to find sustainable and efficient strategies to control plant height is currently a great challenge in the protected cultivation of ornamental plants. The aim of this study was to: (1) analyse the available information on the factors involved in plant height; (2) understand the underlying physiological mechanisms behind stem elongation; (3) define sustainable alternatives for producing compact floricultural crops, reducing the application of chemical growth retardants to a minimum level. It was concluded that keeping a night temperature higher than the day temperature (negative DIF or DROP treatment) or changing the light quality (high red/ far-red ratio) have a high potential as non-chemical methods for controlling plant height in several species of ornamental plants. Increasing the red/ far-red ratio can be done in different ways including the use of photoselective films and/or using several easy to apply measures, including: (i) avoiding very high plant densities; (ii) using supplementary light with a high red/far-red ratio (e.g. assimilation lamps instead of incandescent lamps); (iii) avoiding plant exposure to the twilight period (due to the natural reduction of the red/far-red ratio). Mechanical stress is also an effective strategy for producing compact plants in some species. Furthermore, plant breeding might offer good possibilities for developing dwarf cultivars. Nevertheless, in most cases, it will not be one single measure that will result in compact plants, but it is rather the combination of several strategies.
Description
Keywords
Alongamento do caule DIF Espectro luminoso Flores de corte Plantas envasadas Cut flowers DIF Light quality Pot plants Stem elongation
Citation
CARVALHO, Susana M. P.; ALMEIDA, Domingos P. F.; HEUVELINK, Ep - Controlo da altura de plantas ornamentais: alternativas sustentáveis aos reguladores de crescimento. In V Jornadas Ibéricas de Horticultura Ornamental - Faro, Portugal, 13-15 Outubro, 2011 - Actas Portuguesas de Horticultura, n.º 19. [Lisboa]: Associação Portuguesa de Horticultura, 2011. p. 36-45
Publisher
Associação Portuguesa de Horticultura