Rooting ex vitro and acclimatization of micropropagated shoots of Eucalyptus grandis through a hydroponic system

DIGAUDIO ANABELLA; ESTEBAN TUBERT; AMODEO, GABRIELA; REGALADO GONZÁLEZ, JOSÉ JAVIER

CABA

Congreso; Reunión Conjunta de Sociedades de Biociencias, 13 al 17 de noviembre de 2017, Ciudad Autónoma de Buenos Aires, Argentina:; 2017

Sociedades Conjuntas (SAB SAIB SAN SAB etc)

Plant micropropagation can be critical in certain species for multiplication of interesting cultivars and breeding programs. Eucalyptus grandis is a very important wood crop in Argentina and its micropropagation is still an extensive process that requires long periods (six months). The objective of this work was to develop a faster micropropagation protocol adapted to E. grandis in order to properly satisfy local demand. To address this challenge, we rooted ex vitro and acclimated micropropagated shoots in a hydroponics system. We used nodal segments as initial explants to obtain the micropropagated shoots. The initial protocol for explant sterilization (24 g l-1 sodium hypochlorite during 5 min followed by three washes with sterile water of 5 min) was sufficient (sterilization rate 95.0 ± 1.8%). The sterile nodal segments were cultured in a MS medium supplemented with 1 mg l-1 butyric acid, sucrose 30 g l-1 and agar 0.6 g l-1, and incubated during four weeks at 25 ± 2°C under 16 h day photoperiod. Active carbon (1 g l-1) was added to MS medium to absorb the phenols produced by the eucalyptus explants. A 73 ± 8.7% of nodal segments grew generating 1.73 ± 1.03 micropropagated shoots per explant with a length of 0.76 ± 0.44 cm. Micropropagated shoots were transferred to a hydroponic system to allow ex vitro rooting and acclimatization (nutritional solution: Hoagland supplemented with 2 mg l-1 indol butyric acid). After four weeks the 11 ± 5.8% of micropropagated shoots had developed roots. All plantlets obtained were recultured to continue its growth in a new hydroponic system without plant growth regulators, after four weeks the plants were ready to transfer to soil. The protocol allowed to obtain micropropagated plants in 12 weeks. Although additional assays are necessary to improve the ex vitro rooting rate of the micropropagated shoots, our results show that traditional micropropagation Eucalyptus protocols can be substantially reduced to half of the time.