In vitro organogenesis of Cedrela fissilis Vell. (Meliaceae): the involvement of endogenous polyamines and carbohydrates on shoot development

摘要

Cytokinins are essential molecules involved in shoot induction during in vitro propagation. The addition of cytokinins into culture medium may modulate the endogenous metabolism of various compounds that play important roles during in vitro organogenesis responses, such as carbohydrates and polyamines (PAs). The effects of 6-benzyladenine (BA) and the type of explant (apical and cotyledonary nodal segments) on shoot development and the endogenous content of carbohydrates and free PAs were analyzed during the in vitro culture of Cedrela fissilis. BA addition (2.5 A mu M) into the culture medium was essential to increase both the number of shoots arising from the apical nodal segments and the length of the shoots arising from the cotyledonary nodal segments. Increased endogenous glucose was associated with an increased shoot length in the shoots derived from the cotyledonary nodal segments cultured with BA. On the other hand, increased endogenous sucrose was associated with reduced shoot production by apical nodal segments cultured without BA. Supplementation of the culture medium with BA increased the endogenous content of free putrescine in the apical nodal segments and increased the number of shoots produced compared to nodes cultured without BA. Total free PAs was increased in those treatments that increased the number of shoots produced. This work is the first to report the relationship between the addition of BA to the culture medium and the endogenous contents of soluble carbohydrates and free PAs during the in vitro propagation of tree species.