No abstract
those of numerous private individuals 8 had brought many varieties into the state before 1880. Even before this latter date the University of California had begun to view the viticulture industry with special consideration.Hilgard's Work.-Dean Hilgard, in his report 7 as the Professor of Agricul ture to the President of the University, remarked in 1879 that the industry was improving because of the introduction of varieties better than the pre viously used Mission and because of the adaptation of better methods of vinification to California conditions. 8 The real beginning of the work of the University on wine-grape varieties began in the fall of 1880, when the Legislature appropriated $3,000 for enological work at Berkeley. 9 A 20 by 46 foot brick cellar was constructed on the campus. Professor Hilgard was in charge of the experiments. His report for 1880 10 summarizes his aims and purposes :Included in this report were analyses of eleven musts of five common varie ties of grapes, including the Mission and Zinf andel, the two most important in this state at the time.Another report was made in 1882, based on the vintage of 1881. 11 A few more musts of common varieties were made into wine at Berkeley, and tasting of the wines produced had begun.
were cut between 7 and 8 A.A. and taken directlv to the laboratory. The leaves w-ere promptly stripped off, and comparatively large samples of young anid of mature leaves were taken. Then 4-to 6-incll sections were removed from the base, middle, and tip of each shoot. The base and middle sections were divided into wood and bark. All samples were quickly cut into small pieces, weighed, and rapidlv dried in a small fruit dlehvdrater with a verv strong air blast at 600 to 630 C. The vines were cane pruned so that mature shoots (canes) could be sampled in the same mannier, except that there were 414PLANT PHYSIOLOGY no tip samples. Two 3-inch sections were sawed or cut from each trunk, the bark was removed, and the wood was separated according to annual rings: one-year-old wood and the subsequent growth during the sampling period, two-year-old wood, and wood three years old and older (two years' growth, including the pith). As soon as the trunk was removed, the root.s in the vicinity of the vine were dug up. After washing and drying of the external moisture, three types of root samples were taken: small rootlets (3/32-inch and less), one-year-old roots (3/16-to 1/4-inch), and two-year+ roots (1/2-to 3/4-inch). The one-and two-year root sections were divided into wood and bark samples. The dried samples were ground in a Wiley mill.Analytical procedure To obtain the sugars, the samples were continuously extracted with 95 per cent. ethyl alcohol for 6 hours by letting the condensed alcohol fall directly from the condenser onto the sample contained in alundum thimbles, the liquid level being kept above the material to help prevent channeling. The alcohol extract was evaporated to a small volume. The residue, taken up in warm water, was subsequently treated with an excess of neutral lead acetate, and the precipitated material was centrifuged off. The excess lead was removed with oxalate. Invertase was used for the sucrose inversion. The alcohol-extracted residue served as the sample for determining starch. The sample, plus 50 cc. water, was placed in an enclosed steam bath for one hour. Subsequently, 10 cc. of a phosphate buffer of pH 5 (4) and 10 cc. of the Taka diastase solution (2.5 per cent.) were added. Taka diastase utilized was purified, to remove most of the blank, by precipitation from a saturated water solution through the addition of 2.5 times its volume of 95 per cent. ethyl alcohol. The precipitate was centrifuged off and redissolved.The sample was then transferred to a porcelain jar, several flint pebbles were added, and the whole was rotated on its axis for 16 hours at 250 r.p.m.This procedure reduced the material to a very fine state of division, facilitating complete hydrolysis. If starch was revealed by a microscopical examination, the samples were re-treated. The extract was clarified, using lead acetate, and brought to a definite volume; and sufficient hydrochloric acid was added to make 2.5 per cent. by volume. The samples were then hydrolyzed in an enclosed st.eam bath for 2.5 hours. To determine th...
This study is concerned directly with the first two factors only, although textural changes associated with the ma turity level of the fruit could possibly influence over-all sensory impressions. Flavor is defined as the complex reac tion of taste and olfactory receptors; the olfactory aspect is believed to be secondary with non-muscat varieties. In this study, only the taste aspect of flavor will be considered.There are four possible tastes in grapes: acidness (tart, or sour), sweet ness, saltiness, and bitterness. White grapes are very low in tannins and other bitter-tasting substances. Red grapes have more bitter-tasting substances, but these are mainly in the skins and unless skins are vigorously chewed little bitter taste is experienced. Grapes have very little salty taste, though tartrates give a reaction. Tartrates as buffer agents re pressing the ionization of malic and tartaric acids may, however, influence the acid taste.The characteristic gustatory sensation of grapes is their sweet-sour taste. The main sugars found in grapes, levulose and dextrose, are of very unequal sweet ness (about 1.5:1) and presumably the
Girdling has been practiced for years to produce large berries of Thompson Seedless grapes intended for table use. The operation, however, is expensive and occasionally results in the death of the girdled cane. In an effort to discover a better means of attaining results similar to girdling, applications of 4-chlorophenoxyacetic acid have been made (4, 5). These tests embraced separate and combined treatments of applications of 4-chlorophenoxyacetic acid, berry thinning (a practice usually employed to overcome compactness of cluster, 6), girdling, and girdling and berry thinning.Use was made of an irrigated vineyard located about one mile west of Davis, California. Mature vines of Thompson Seedless were pruned to four or five canes each of which had 9 to 12 buds. Each cane was tied horizontally on one wire of a 3-wire, flat-top trellis. Immediately after fruit set, the crop was reduced to five clusters per cane in tests made in 1950, and six in tests made in 1951.In 1950 an oil emulsion of 4-chlorophenoxyacetic acid was prepared, by dissolving 1 gm. of the compound in 5 ml. of an oil-base carrier (4), and then diluting to 1000 ml. with distilled water. This stock emulsion was diluted with water to make the desired concentrations. Aqueous solutions of 4-chlorophenoxyacetic acid were prepared in 1951 by adding sufficient ammonia to dissolve the compound. Dreft was used each year as a wetting agent.Clusters of berries were immersed momentarily into one of the formulations; clusters on one cane constituted a unit in these dipping experiments. Replicate canes were selected at random among the vines used. Berry thinning consisted of cutting off the apical half of the cluster, leaving five or six mnain branches of the rachis. Girdling consisted of removing a strip of bark three sixteenths of an inch in width near the base of canes with girdling pliers. For the spray applications of the growth regulator, each vine was divided into equal parts; one half was sprayed with a Craftsman sprayer, and the other half served as the untreated control. Cardboards were used to confine the spray to the intended area.At harvest, berries removed from the same parts of the clusters were thoroughly mixed and the weight of 100 or 200 was obtained in duplicate to indicate the size of the berry. . The remaining berries were crushed, and the percentage of total soluble solids in the juice was determined with a Balling hydrometer. Total acidity was determined by diluting 10 ml. of the juice
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