Microcutting propagation of Eucalyptus grandis x E. urophylla through clumps of axillary buds using different containers and substrates

Abstract

This study aims to evaluate the microcuttings production in the micropropagation system via clumps of axillary buds in a clone of Eucalyptus grandis x E. urophylla, subjected to different types of containers and substrates. Clumps with six to eight differentiated buds of Eucalyptus grandis x E. urophylla established in vitro were used to test containers (polypropylene pot -500 ml, glass flask -250 ml; acrylic flask with gas exchange (AFGE) -250 ml; and test-tube -55 ml capacity) in a semisolid medium specific for Eucalyptus in a period of 35 days. For the substrates test, acrylic flask with gas exchange (AFGE) were used with different substrates (agar, average particle size vermiculite, and vermiculite: cellulose fiber in a 2:1 ratio) in a period of 35 days. The tests were installed in a completely randomized design (CRD). We evaluated the number of shoots larger than 0.5 cm per clump of bud, the number of microcuttings produced larger than 2 cm, the length of the longest microcutting (cm) and shoot vigor. Based on the obtained results, it was possible to observe that the best container to produce microcuttings larger than 2 cm was the polypropylene pot (500 ml). Glass flask (250 ml) was more advantageous to achieve greater production of microcuttings per square meter due to its capacity of better densification. The best substrates to produce microcutting larger than 2 cm using acrylic flask with gas exchange (AFGE) containers were agar or vermiculite. Keywords:In vitro propagation; plant tissue culture; vegetative propagation. Abbreviations: AFGE_acrylic flask with gas exchange, APDM_aerial part dry mass, APFM_aerial part fresh mass, BAP_6-benzylaminopurine, BIOAGRO_Institute of Biotechnology Applied to Agriculture, CO 2 _carbon dioxide, CRD_completely randomized design, JADS_culture medium specific for Eucalyptus (Correia et al., 1995), HCl_chloridric acid, IBA_indole-3-butyric acid, LMC_length of the largest microcutting (cm), NAA_naphthaleneacetic, NaOH_ sodium hydroxide, NMC > 2 cm_number of microcuttings larger than 2 cm, NMC > 2 cm m -2 _number of microcuttings larger than 2 cm m -2 , NS > 0.5 cm_shoots larger than 0.5 cm, NS> 2 cm m -2 _number of shoots larger than 0.5 cm m -2 , PVP-30_polyvinylpyrrolidone, RDM _root dry mass, RFM_root fresh mass, RT%_root percentage.

Spectral quality influence on in vitro morphophysiological responses of Eucalyptus dunnii Maiden and Eucalyptus grandis W.Hill ex Maiden × E. urophylla S.T.Blake

“…Adventitious rooting of Eucalyptus dunnii is a challenge in clonal propagation, varying from 3.0 to 46.5% (Brondani et al 2011;Oberschelp et al 2015;Souza et al 2019). In contrast, the Eucalyptus grandis × E. urophylla has shown 80.0 to 100.0% (Gallo et al 2017;Souza et al 2020b;Miranda et al 2020). Some species, such as Hevea brasiliensis are considered difficult-toroot because of the presence of an almost continuous cylinder of lignified tissue that, together with chemical barriers, hinder root emission (Almeida et al 2017).…”

Spectral quality and temporary immersion bioreactor for in vitro multiplication of Eucalytpus grandis × Eucalyptus urophylla

“…Studies focused on investigating the micropropagation of Eucalyptus grandis, Eucalyptus urophylla, and of their hybrids, have been important for the industrial forestry sector. These studies comprise in vitro establishment (Moura et al 2017;Keret et al 2018), bud multiplication (Businge et al 2017;Máximo et al 2018;Trueman et al 2018;Carvalho et al 2019), shoot elongation (Gallo et al 2017;Miranda et al 2020), as well as adventitious rooting and acclimatization phases (Nakhooda and Watt 2017;Brondani et al 2018).…”