Histological and ultrastructural analysis of the Banana cv. Prata-Anã embryogenic calluses and cell suspension

Abstract

The analysis of the developmental stages during somatic embryogenesis has been essential to elucidate the in vitro plants embryogenesis process and can validate the somatic embryogenesis induction and progression. This work aimed to characterize the embryogenic calluses and cell suspension of Banana cv. Prata-Ana, anatomically and ultrastructurally, respectively. For the calluses induction and anatomical analyses, the male flower were disinfested and inoculated on MA1 solid medium. At intervals of 30 days up to 11 months, calluses were collected, fixed in FAA and prepared for analysis in optical microscopy. For the cell suspension and ultrastructural analyses, calluses4 months old calluses, obtained on the first experiment, were transferred to different liquids cultures mediums: MRT, MGM, CNPMF or MA2 and maintained in aggitation. At intervals of 30 days calluses were collected and prepared for analysis in scanning electron microscope. The male flowers showed, after three months on culture medium, heterogeneous calluses formed by clusters of small isodiametric cells that gave rise to globular structure with meristems tissues, clearly differentiated from other cells around the calluses. The globular structure, after ten months on the culture medium, developed to torpedo stage showing the meristematic tissues protoderm, ground meristem and procambium. The cell suspension cultivated on MRT culture medium showed embryos on globular and torpedo stage.