Polyamine effects on the endogenous polyamine contents, nitric oxide release, growth and differentiation of embryogenic suspension cultures of Araucaria angustifolia (Bert.) O. Ktze.

In the present work we determined the effects of exogenous polyamines (PAs), supplemented to the culture medium, on the endogenous PA contents, nitric oxide (NO) release, culture growth and organization of proembryogenic masses (PEMs), in embryogenic suspension cultures of Araucaria angustifolia. We observed that PAs (Putrescine (Put), spermidine (Spd) and spermine (Spm)) had a different effect on growth, morphological evolution and NO biosynthesis in embryogenic cultures. Spd (1.0 mM) and Spm (1.0 mM) supplemented into the culture medium reduced cellular growth and allowed a morphogenetic evolution of aggregates from PEM II to PEM III stages. Put increased NO release from the embryogenic culture, and Spd and Spm had an inhibitory effect on NO release when compared with the control treatment. In the control and Put (1.0 mM) treatments, it was observed that embryonic cells of A. angustifolia accumulated more NO than the suspensor cells, suggesting that NO biosynthesis might be related to the maintenance of the polarity (embryonic–suspensor cells) present at the PEM II stage.