ABSTRACT
Colubrina glandulosa (sobraji) is a fast-growing timber species with a straight trunk, with the potential to form homogeneous reforestation, either by itself or associated with other species. In the view of this, we sought to establish a micropropagation protocol, using seeds and nodal segments, aiming at the production of seedlings on a commercial scale. The seeds were disinfected in NaClO 6% for 10, 20 or 30 minutes and sown in MS culture medium supplemented, or not, with 0.5 mL L-1 of Comet®. The nodal segments were disinfected in 2% NaClO and 5% PPM™ solution, introduced in WPM culture medium, supplemented with PPM™ (0; 0.2 or 0.4%) and 0.5 mL L-1 of Comet® associated with 0.75 g L-1 of sodium ampicillin or 2 mL L-1 Kasumin®. In multiplication, nodal segments were grown in WPM culture medium supplemented with BAP (6-benzylaminopurine) or mT (meta-topoline) (2; 4; 8 or 12 µM), combined with the presence or absence of ANA (naphthalenoacetic acid) (2 µM) in three subcultures. For rooting, the WPM/2 culture medium supplemented with IBA (indolbutyric acid) (0, 2 or 4 µM) was used, associated or not with 0.15% activated carbon. The rooted seedlings were acclimatized ex vitro. The highest percentage of germination (78.57%) was observed in seeds treated with 6% NaClO for 10 minutes, without fungicide in the culture medium. The 0.2% concentration of PPM™ provided the highest percentage of nodal segment survival (70%). The succession of subcultures significantly increases the rate of shoot induction and the highest number of shoots per explant (3.28 ± 1.8) occurred at a concentration of 2 µM mT. The formation of the largest number of roots was observed in the absence of activated carbon without the need for exogenous auxin and in acclimatization, there was a high percentage of seedling survival. In this way, it was possible to obtain a viable micropropagation protocol, constituting a promising methodology in the production of seedlings.
Keywords:
Sobraji; Micropropagation; Meta-topoline; PPM™
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Fonte: Autores (2020). Em que: semente germinada em meio de cultura MS, sete dias após a inoculação in vitro (A); plântula formada a partir de semente, 30 dias após a inoculação (B); segmento nodal 28 dias após a inoculação, evidenciando o alongamento da brotação (C); multiplicação de segmentos nodais estabelecidos a partir de plântula germinada in vitro no subcultivo 3 em meio de cultura WPM com 2 µM de mT, formando várias brotações (D); broto enraizado em meio de cultura WPM/2, na ausência de carvão ativado e sem aplicação exógena de auxina (E); aclimatização de mudas em tubetes com substrato Maxfertil® e casca de arroz carbonizada na proporção de 2:1 (v/v), armazenados em caixa de acrílico cobertas por filme de PVC (F).Source: Authors (2020). In where: germinated seed in MS culture medium, seven days after the in vitro inoculation (A); seedling formed from seed, 30 days after inoculation (B); nodal segment 28 days after the inoculation, showing sprout elongation (C); multiplication of nodal segments established from the seedling germinated in vitro in subculture 3 in WPM culture medium with 2 µM mT, forming several sprouts (D); sprout rooted in WPM/2 culture medium, in the absence of activated carbon and without exogenous application of auxin (E); acclimatization of seedlings in tubes with Maxfertil® substrate and 2:1 (v/v) carbonized rice husk, stored in an acrylic box covered with PVC film (F).
Fonte: Autores (2020)