Studies of the order and rates of production of certain hydrolytic enzymes in the endosperm of germinating barley and in endosperm slices treated with gibberellic acid have shown that endo‐β‐glucanase formation precedes the formation of α‐amylase which, in turn, precedes the formation of protease. A rise in acid phosphatase appears to take place shortly after the induction of endo‐β‐glucanase. Although the order of induction of the enzymes is the same in slices and in grain germinating without additives, enzyme production begins some ten hours earlier in the slices. The response of isolated aleurone to gibberellic acid is qualitatively similar to that of the endosperm slices, but, though there is appreciable formation of enzymes, secretion is very slight. This suggests that the effect of gibberellic acid on hydrolase synthesis can be distinguished from any effect on secretion. Preliminary hydration of endosperm slices induces a much more rapid response to gibberellic acid.

When slices of barley endosperm are incubated with gibberellic acid in aseptic conditions the activities of salt‐soluble endo‐β‐glucanase and endopentosanase are greatly augmented and enzymes and soluble products of cell‐wall degradation (hexosan and pentosan) are secreted into the surrounding medium. This cytolytic action, together with the enhanced amylolytic activity which can be detected in isolated endosperms subjected to gibberellic acid, is sufficient to cause complete solubilization of the starchy endosperm in 3 days at 25° C. Gibberellic acid acts through the respiring aleurone layer; it has no effect on aleurone‐free endosperm or on endosperm slices in which the aleurone has lost the power of reducing tetrazolium salts. Gibberellic acid‐induced sugar secretion from endosperm slices is maximal at 30° C. and completely inhibited at 37° C. and secretion both of sugars and of endo‐β‐glucanase is unaffected in conditions which inhibit proteolysis. Excised barley embryos show no response to added gibberellic acid. It is suggested that, when barley germinates without additions of gibberellic acid, endogenous gibberellin present in the embryo is translocated to the aleurone where it induces secretion of hydrolytic enzymes from subcellular particles, so causing modification to proceed inwards from the aleurone; if this is so, then added gibberellic acid merely enhances the effects of the endogenous component.

Differential dissection of the embryo of barley grains, followed by observation of the extent of modification and assessment of α‐amylase production in the endosperm, has shown that the various organs of the embryo make the following different contributions to modification. The isolated scutellum has a very limited ability to produce α‐amylase and its powers of enzyme secretion are largely restricted to the peripheral region where aleurone cells are present. The stimulus which initiates enzyme formation in the aleurone is largely derived from the nodal region of the embryo, especially from the base of the node where subsidiary rootlets are formed; the scutellum apparently lacks the means of producing this stimulus. Translocation of the enzyme‐inducing hormone from embryo to aleurone takes place through the apical half of the scutellum in which vascular tissue develops; this preferred route of translocation partially accounts for the asymmetric pattern of modification normally observed. Removal of the first foliar leaf from within the coleoptile allows increased production of α‐amylase in the endosperm: this leaf can be regarded as a natural consumer of gibberellin.

An esterase (carboxylic acid hydrolase EC 3 1.1.1.) has been prepared from Saccharomyces cerevisiae. This esterase is active at pH 4 4 and, though it is unstable in solution, it can be main tained in an active form either by lyophilization or by coupling to an affinity gel. At pH 4 4, yeast esterase can hydrolyse between 20 and 40% of the esters commonly present in beer, and it is capable of synthesizing ethyl acetate from ethanol and acetic acid in a simple buffered solution without the provision of a co-factor. Different yeast strains yield different amounts of esterase, and there appears to be a positive correlation between the ability of the yeast to form esterase and the level of esters present in fermentations accomplished by that yeast.

(With I figure in the text) SUMMARY Qualitative and quantitative determinations have been made of the sugars, oligosaccharides and water-soluble polysaccharides of the seeds of twenty-two species of the Gramineae.Although in most species sucrose was the most plentiful free sugar, in Lolium perenne and in Festuca pratensis a trisaccharide which contained residues of galactose, glucose and fructose and which was chromatographically distinct from raffinose constituted the most abundant oligosaccharide; in Elytntis arenaritts and in Bromtts sterilis an homologous series of low-molecular fructosans represented the major simple carbohydrate. Similar fructosans were also present in Agropyron repens.Raffinose was present in fifteen of the seeds examined and stachyose in ten of these fifteen raflinose-containing seeds. The contents of raflinose and stachyose were positively correlated.Water-soluble polysaccbarides were obtained in yields approaching i per cent of the dry weight of the seeds from certain members of the Bromeae, the Hordeeae, the Festuceae and the Aveneae; yields from members of other tribes were low and predominantly dextrinous in nature.A pure p-glucosan, resembling that of cultivated barley, has been obtained from Bromus, from Avena and Arrhenatherum, and from Dactylis and other members of the Festuceae. The polysaccharide prepared from Nardus contained a high proportion of mannan and that from Molinia a high proportion of galactan.When the water-soluble carbohydrates of these seeds are considered in relation to the classification of the Gramineae, it is seen that Bromus is quite distinct from Brachypodium; that the members of tbe Festuceae here examined show underlying similarity in the composition of their water-soluble polysaccharides, though Eestuca pratensis and Lolium perenne are distinctive in containing an unusual trisaccharide; that Avena and Arrhenatherum differ from the other two members of the Aveneae examined (Holcus and Anthoxanthum) and that the members of the Hordeae constitute a natural group on the basis of their sugars content.