Respostas morfogênicas na micropropagação de bagassa guianensis aubl. (Moraceae): uma espécie amazônica com potencial ecológico

Abstract

Bagassa guianensis is a tree endemic to the Amazon rainforest that produces seeds with a low germination rate, rapid vigor loss, and recalcitrance. The species has ecological and economic importance and is suffering a rapid reduction in its natural populations due to anthropogenic pressures. The objective of this work was to establish a micropropagation protocol for B. guianensis. After asepsis, the seeds were inoculated in MS/2 medium with 0.5 mg L-1 of GA3 or AgNO3, and without regulator. The material was kept in a growth chamber under blue and red LED, white LED, or in the dark. Nodal segments were inoculated in MS medium with different concentrations of BAP (0; 0.5; 1; 2 and 4 mg L-1); and apical segments were inoculated in MS with different concentrations of IBA (0; 0.5; 1; 2 and 4 mg L-1). Plants originating from micropropagation underwent photoautotrophic cultivation in different substrates: commercial organic black soil or sand with 10 g L-1 of Basacote®. The seeds showed positive photoblastism, and cultivation in MS medium with GA3 using white LED produced longer plants; while the use of blue and red LED produced plants with more nodes and leaves. The highest number of shoots was obtained with the use of 4 mg L-1 of BAP; while the highest number of roots was obtained with 0.5 mg L-1 of IBA. However, the addition of growth regulators provided a high rate of callus formation. Photoautotrophic cultivation with commercial organic black soil provided 73.3% plant survival in a greenhouse. It is recommended to use blue and red LED for germination, 4 mg L-1 of BAP for shoot production, 0.5 mg L-1 of IBA for root induction, and organic black soil substrate for photoautotrophic acclimatization of Bagassa guianensis.