Modulation of the initial growth of Eucalyptus clones using paclobutrazol: when smaller is better

Abstract

Modulating the growth rates of Eucalyptus during the initial vegetative phase via plant growth regulators can improve field establishment. The objective of this study was to verify the impacts of different concentrations of paclobutrazol (PBZ) on two Eucalyptus hybrids during the initial phase of growth. Experiments were conducted in a greenhouse using an E. urophylla x E. grandis hybrid (AEC 1528) and a spontaneous hybrid of E. urophylla (144 AEC). Both clones were subjected to PBZ concentrations of 0, 50, 100, 150 and 200 ppm active ingredient (a.i.) applied to the soil. The treatments were part of a 2x5 factorial design, and they were arranged into randomized blocks and consisted of five replicates. Cuttings were transplanted into 20-L pots; each pot contained one cutting and was considered an experimental unit. At90 days after the application of PBZ, the growth and development of both Eucalyptus clones subjected to all concentrations were inhibited. The inhibition effects intensified as the concentration of PBZ increased until approximately 90 to146 ppm and increased the plant sturdiness ratio (H/D; S//diameter) due to the inhibition of height caused by PBZ. Clone AEC 144 performed better than clone AEC 1528with respect to dry mass accumulation, LN and leaf area. However, clone AEC 1528 was superior with respect to resource partitioning due to a lower S/R ratio, aiding survival underwater deficit conditions.

Substrate Volumes and Application of Paclobutrazol for Ornamental Pepper Production

“…This variable indicates the balance of growth and relates these two variables to a single index, and the lowest values indicate robust changes. The use of PBZ to increase the robustness of seedlings was also observed by Santos et al (2018) in different clones of eucalyptus hybrids.…”

“…Plants under the effect of this inhibitor may present, in addition to the smaller size, more developed roots. These characteristics confer, in addition to a more exotic look, a greater rusticity to the vegetable, making it resistant to stress due to water deficiency and more adapted to explore the substrate in obtaining water and nutrients (Santos et al, 2018).…”

INDUÇÃO DE FLORESCIMENTO E FRUTIFICAÇÃO EM CAMPO DE Euplassa semicostata PLANA

“…A aplicação de paclobutrazol como estratégia para produção de fl ores e frutos tem sido utilizada principalmente para em plantios comerciais, como Anacardium occidentale (Mog et al, 2019), Eucalyptus spp. (Santos et al, 2018;Castro et al, 2021) e Mangifera indica (Oliveira et al, 2020). No entanto, esta técnica mostrou-se muito útil para fi ns de conservação, podendo ser expandida para outras plantas com difi culdade de fl oração, como E. semicostata.…”

“…A aplicação de reguladores de crescimento pode induzir a fl oração e frutifi cação de diferentes espécies (Gardner et al, 2016). O paclobutrazol, comumente utilizado em diferentes espécies de eucalipto (Santos et al, 2018) e frutíferas (Srilatha et al, 2016), antecipa a fase adulta e induz o fl orescimento das plantas (Soumya et al, 2017). As espécies nativas brasileiras Jacaranda mimosifolia e Schinus terebinthifolius fl oresceram após a aplicação do paclobutrazol (Mendes et al, 2020).…”

EFFECT OF THE APPLICATION OF GROWTH REGULATORS ON Peltophorum dubium

“…One way to promote physiological and biochemical changes in species with a medium life cycle such as in canafistula, in order to reduce the vegetative growth of plants and to anticipate their reproductive stage, is to use substances known as plant growth regulators (Kumar et al, 2011). Plant growth regulators are synthetic compounds essential for the improvement of forest species, to reduce the period preceding flower bud formation and fruit/ seed production (Santos et al, 2018).…”