Possible involvement of cyclic GMP in adventitious bud initiation in stem segments of Torenia
2004
Kawasaki, T. (Saga Univ. (Japan). Faculty of Agriculture) | Tanimoto, S.
Summary Adventitious bud initiation in epidermis of Torenia stem segments cultured in vitro, which is usually induced by cytokinin, could be induced by application of dibutyryl cyclic GMP (Bt sub2-cGMP) in the absence of cytokinin. Similar promotively effects on bud initiation were observed when various stimulating reagents to accumulate endogenous cGMP were added to the culture medium, such as inhibitors of cyclic nucleotide phosphodiesterase, theophylline and isobutyl methyl xanthine. Simultaneous addition of anticytokinin with Bt sub2-cGMP and/or above chemicals showed no effects on adventitious bud initiation. Endogenous content of cGMP in Torenia stem segments were increased by the application of the above chemicals . These results suggested that endogenous concentration of cGMP were involved in adventitious bud initiation of Torenia stem segments. Application of inhibitor for cGMP-dependent protein kinase inhibited bud initiation induced by cGMP-accumulating reagent. Furthermore, when the segments were cultured with Bt sub2-cGMP, ca.60 kDa polypeptide was phosphorylated.
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