Efficient regeneration of Eucalyptus urophylla from seedling-derived hypocotyls

Abstract

Seedling hypocotyls were used as explants to establish a regeneration protocol for Eucalyptus urophylla and N-phenyl-N'-[6-(2-chlorobenzothiazol)-yl] urea (PBU), one kind of di-substituted urea, was found useful growth regulator. The hypocotyls incubated on a modified Murashige and Skoog medium (SPCa), supplemented with 6.6 μM PBU and 0.57 μM indole-3-acetic acid (IAA) dedifferentiated and form calli (100 % after 7 d). Compared with other growth regulator combinations, PBU stimulated more vigorous calli and restrained their darkening. In addition, the calli induced by PBU showed high frequency of adventitious buds formation (57 %). Shoot proliferation and elongation was then stimulated on SPCa medium containing 0.44 μM 6-benzyladenine (BA), 0.54 μM naphthalene acetic acid (NAA) and 0.3 μM gibberellic acid (GA 3 ). For rooting, shoots were cultivated on root induction medium containing 2.5 μM indole-3-butyric acid (IBA). Plantlets were then successfully transplanted to greenhouse.

Efficient Regeneration of Eucalyptus urophylla x Eucalyptus grandis from Stem Segment

“…After this period, the calluses gradually became brown and no adventitious buds were observed. In a previous study PBU induced higher percentage of callus formation was observed than other plant growth regulators (Huang et al 2010). About 96% of the cut surface had grown calli on the 6th day when the explants were cultured on MS medium containing 13.2 µM PBU and 0.285 µM IAA (Table 1).…”

Alongamento in vitro de genótipos de Eucalyptus dunnii Maiden

“…Em Eucalyptus urophylla o comprimento médio das brotações alongadas foi de 25 mm após 40 dias de cultivo in vitro, de ANA e 0,1 mg L -1 de GA 3 (HUANG et al, 2010). Provavelmente, as diferentes espécies e idades das árvores tenham interferido na resposta observada, com o maior alongamento ocorrendo na presença da giberelina.…”

Tissue Culture of Corymbia and Eucalyptus

“…However, SP medium [108,[110][111][112], WPM minerals [113], WPM [114], B5 medium [115][116][117], N7 medium [86,118], JADS medium [98], EDM [119], and MS medium with White vitamins [89] have also been used. Callus is often induced in darkness, although basal organogenesis on shoots can occur in eucalypt shoot cultures that are maintained under light [45,46,64,98,120].…”

“…Thidiazuron (TDZ) and 2-Cl-PBU (i.e., 1-phenyl-3-(1,2,3-thiadiazol-5-yl) urea and N-phenyl-N -[6-(2-chlorobenzothiazol)-yl] urea, respectively) are potent promotors of callus formation in eucalypts. Organogenesis can be induced using 0.89 µM BA with 0.91 µM TDZ, or 0.5 µM TDZ with 0.2 µM 2,4-D for E. globulus [127,128], 2 µM TDZ, or 0.23 µM TDZ with 0.05 µM NAA, or 3 µM TDZ with 0.1 µM NAA for E. grandis × E. urophylla [89,123,128], and 2.27 µM TDZ with 0.54 µM NAA, or 1.14 µM 2-Cl-PBU with 0.57 µM IAA for E. urophylla [89,111,112]. Picloram (i.e., 4-Amino-3,5,6-trichloro-2-pyridinecarboxylic acid) has been used alone at 20.7 µM for E. urophylla organogenesis [86] or at 0.04 µM in combination with 2.25 µM BA for E. gunnii Hook.f.…”

“…Other media used for root induction have included WPM minerals or Knop's medium [159] for E. camaldulensis [16,113], B5 medium for E. globulus [117], SP medium with MS micronutrients for E. grandis × E. urophylla [110], Knop macronutrients, MS micronutrients, and de Fossard organics without KI and riboflavin for E. nitens [101], half-strength DKW medium for E. pellita F.Muell. [100], Hoagland's salts [160] for E. regnans [141], and SP medium for E. urophylla [111].…”