Terpenoid evidences within three selected bryophyte species under salt stress as inferred by histochemical analyses

Histochemical analyses were applied to document the presence of terpenoids in three selected mosses. The species were chosen as bryo-halophyte, namely Entosthodon hungaricus (Funariaceae) and Hennediella heimii (Pottiaceae) and a model moss known to possess salt tolerance, Physcomitrella patens (Funariaceae). They were exposed to sodium chloride under axenic in vitro fully controlled conditions, with the aim to compare the terpenoid evidences among different moss developmental stages and species in various experimental treatments. The stress was simulated by addition of NaCl to the growth medium but also exogenously added ABA simulating the plantlets adjustment to increasing stress. The results obtained unequivocally indicate that the selected mosses respond to exogenous ABA as well as to NaCl in a different manner as indicated by histochemical staining of terpenes. Additionally, terpenoids were confirmed by colorimetric tests and in accordance with histochemical analyses. ABA seems to play role in pathways of terpenoid production in the two funaroid mosses, at least indirectly, implying these features to be evolutionary early developed in common funaroid ancestor. In contrast, the pottioid moss H. heimii differed in its response to stress by the constitutive presence of terpenoid compounds in all stress treatments.