Hormonal Regulation of Gametangial Formation in the Moss Bryum argenteum Hedw

Phytohormones such as auxins, cytokinins, gibberellins, andabscisic acid differentially affect gametangial induction inmale and female clones of Bryum argenteum. Both IAA and GA³increased the percentage of fertile gametophores in the maleclone, and inhibited the response in the female clone. GA₃ wasmore effective than IAA in eliciting the response in the maleclone. Cytokinins, on the other hand, increased the productionof fertile gametophores in the female clone, and inhibited itslightly in the male clone. The two cytokinins tested (kinetinand DMAAP) were almost equally effective for the female clone. An Interaction of IAA and kinetin nullified their individualinhibitory effects on the female and male clones, respectively.Cyclic AMP prevented the inhibitory effect of kinetin in themale clone; whereas, in the female clone, it stimulated theresponse elicited by kinetin. Abscisic acid (ABA) acted as ageneral inhibitor of vegetative growth and gametangial inductionin this moss. However, the inhibition of gametangial inductionwas greater in the female clone which is also more sensitiveto ABA than the male clone.     

Subcellular Localization of Adenylate Cyclase in the Shoot Apices of Bryum argenteum Hedw

Adenylate cyclase activity has been detected in the shoot apicesof Bryum argenteum at the ultrastructural level, using adenylylimidodiphosphate as substrate. Heavy deposits of the reactionproduct were observed along the plasma membrane, tonoplast andthe membranous system of developing plastids. No clear stainingwas associated with other subcellular membranes. Mosses, adenylate cyclase, Bryum, cyclic AMP     

Effect of Chelating Agents and Metal Ions on Gametangial Formation in the Moss Bryum argenteum Hedw

Chelating agents such as EDTA and EDDHA markedly stimulate theformation of gametangia in the dioecious moss Bryum argenteum,and the effect is more pronounced on male than on female clones.EDTA-stimulated gametangial formation is associated with significantincreases in endogenous iron and copper. Ferric citrate alsoenhances gametangial formation, but copper sulphate is inhibitory.The present findings are discussed in the context of earlierinvestigations on other plants in an attempt to explain thepossible involvement of chelating agents and metal ions in stimulatingthe onset of the reproductive phase in this moss. Bryum argenteum, gametangial formation, chelating agents, metal ions