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Sumnary. Subsequent production of amylase is severely inhibited if barban [4-chloro-2-btutynyl N-(3-chlorophenyl)carbamate] is added to embryo-free half seeds of barley within 4 to 5 hoLurs after gibberellic acid treatment of these seeds. Thirty to 50 mg/L concentrations of barban are effective. Barban inhibition is non-competitive with respect to gibberellic acid. Addition of barban 7 hours or more after gibberellic acid treatment is almost without effect.The delay between gibberellic acid treatment and amylase formation tends to become shorter with more prolonged imbibition periods. Regardless of imbibition period, susceptilbility to barban is lost within 7 hours after gibberellic acid treatment.Other herbicidally active phenylurethanes are also inhibitors, but none are as effective as barbanl. Phenethyl alcohol and 2 arylcarbamates can act as inhibitors.When gi,bberellic acid (GA) is added to embryofree half-seeds of cereals such as barley or wild oats, synthesis of a-amylase by the aleurone layers begins after a lag period (9,16,17). We now report a series of inhibitors which are much more effective when added within a few hours after gilbberellin addition, than when added later.These inhibitors consist primarily of herbicidally active carbamate compounds. One such group is composed of phenvlurethanes, which we will define chemically as Aryl-NH-CO-O-Alkyl compounds, an(l which are noted for severe inhibition of plant cell division. However, a nutmber of carbamates with somewhat' different structures are also effective inhibitors in the barley assay. These non-phenylurethane carbamates will be termed arylcarbamates. Materials and MethodsAll experiments reported here were performed with the Himalaya variety of barley, although we have obtained essentially identical results with the 2-rowed malting variety, Betzes. The first sample of Himalaya seed was supplied by Dr. James Bonner. Most of the experiments were performed with a larger sample generously stupplied by Dr. R. A. Nilan. The seeds were cut transversely and the embryo-containing halves were discarded.Half-seeds were sterilized for 10 minutes in a 1: 33 dilution of a commercial chlorine laundry bleach (Chlorox). They were rinsed with sterile distilled water, and then shaken for 8 hours (exceptions indicated in text) with distilled water containing 5 mg of penicillin and 5 mg of streptomycin per liter (2). Fifteen half-seeds were aseptically transferred into 25 ml Erlenmyer flasks containing 2 ml of antibiotic solution plus various addenda. Sterile technique was followed in transfers and in all subsequent manipulations. Most solutions were sterilized by autoclaving, but heatsensitive materials were filter-sterilized.www.plantphysiol.org on May 11, 2018 -Published by Downloaded from

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Salvia miltiorrhiza cell culture extract (SCE) was shown to produce dose-dependent hypotensive response in normo-tensive rats. The mode of this hypotensive action was studied both in vivo and in vitro. This vasodepressor effect was not due to the presence of cations (potassium, calcium and magnesium) in the extract. In pharmacological antagonist studies, the hypotensive effect was shown not being mediated via the alpha-, beta-adrenoceptors, histamine receptors and autonomic ganglion; nor via direct vasodilation and diuresis. However, the vasodepressor effect was probably angiotensin- and/or bradykinin-related since captopril infusion potentiated the hypotensive effect of SCE. Furthermore, data indicated that the vasodepressor effect might be accounted for by the positive inotropic and negative chronotropic effects of SCE, the latter via its modulation of cholinergic activity.