Search Results
Abstract
‘Elliot’ pear is resistant, but not immune, to the fire blight-inciting bacterium, Erwinia amylovora. ‘Elliot’ fruit has the shape and coloration similar to those of ‘Doyenne du Comice’ and ‘Tyson’ (Hedrick, 1921).
Abstract
The endosperm-nucellus of the almond increased in percentage dry weight as the volume decreased; the increase was accompanied by a textural change. Free GA increased from the time the embryo was microscopic in late April to a maximum when the embryo was partially developed, a period of approximately 3 weeks. GA decreased slightly from mid-May to early June when only the remnants of the nutritive tissues remained. GA-glucosides decreased while embryo development was occurring. Injection of 2-14C-mevalonic acid into the endosperm-nucellus resulted in rapid incorporation of label into presumptive GA precursors, suggesting that some gibberellins are synthesized in situ.
Abstract
Aqueous and ethanolic extracts of the Prunus endocarp were found to delay germination and subsequent growth of peach, almond, cucumber and plantago embryos. Constituents in the extracts were partially purified by chromatographic separation on paper and thin-layer plates. While there are several components in the inhibitor complex, one has been identified tentatively as abscisic acid by its Rf values in different solvent systems, reactions with chromogenic reagents and absorption of ultraviolet light. Most of the inhibitors in the endocarp were fixed on anion exchange resins but not on nylon or hide powder. Mild acid hydrolysis of the endocarp yielded no HCN which eliminates cyanoglucosides as having a role in the inhibition. The extractives induced a marked reduction in oxygen uptake by germinating pea seedlings and growth inhibition in cucumbers. The latter was reversible with gibberellic acid (GA).
Abstract
Yuzuhada is a Japanese term given to a fruit disorder which often occurs when certain cultivars of the oriental pear, Pyrus serotina are grafted onto seedlings of that species or of P. betulaefolia. A literal translation of the name, yuzuhada, is pomelo (citrus) skin disease because in severe cases, fruits of some varieties develop surface depressions similar to thick citrus rind. The disorder was described in 1928 by Mizuno (3), but it is practically unknown to American horticulturists. According to Hayashi (1), and Hayashi and Wakisaka (2), the symptoms of yuzuhada are similar to those of hard-end and black-end of Bartlett pear in that the fruits fail to soften normally and often manifest some darkening of the distal end near the calyx lobes. That these two disorders occur on the same rootstock species and that some of their manifestations appear to be similar suggest that a relationship might exist between the two disorders. This investigation dealing with stock influence on the scion variety was, therefore, undertaken to ascertain if there were any correlations between the potential of a rootstock to produce black- or hard-end of Bartlett and yuzuhada symptoms in varieties of P. serotina and two interspecific hybrids.
Abstract
‘Hayward’ kiwi fruit (Actinidia chinensis Planch.) samples collected at 20-day intervals after full bloom, May 18, until harvest in late October, were analyzed for carbohydrates, protein, organic acids including ascorbic and dehydroascorbic acids, tannins and polyphenolic substances, and cytokinin-like compounds. Starch is a predominant carbohydrate stored in the carpellary tissue which becomes hydrolyzed as the fruit approach maturity. Quinic acid was the main organic acid in young fruit which disappeared concurrently with the appearance of ascorbic acid. Mature fruit has low concentrations of tannins and polyphenolic substances but many raphides. Types of cytokinins changed as the fruit developed.
Abstract
Treatment of ‘Marianna 2624’ plum cuttings for 7 days with 1-14C-IAA with or without a pretreatment with 4000 ppm indolebutyric acid (IBA) for 5 sec revealed that the synthetic hormone inhibited IAA oxidase activity as measured by the decreased rate of 14CO2 evolution. KOH hydrolysis of different radioactive zones on paper chromatograms derived from alcoholic extractives of cuttings yielded presumptive IAA upon re-chromatography. Likewise, KOH and peptidase treatment of the alcohol insoluble residue yielded a radioactive substance with chromatographic properties characteristic of IAA. The presence of presumptive IAA and ninhydrin-positive substances in the peptidase hydrolyzate indicate that IAA was bound to protein(s). Appreciable radioactivity still remained in the alcohol insoluble residue after protein hydrolysis.
Abstract
Thirteen-year-old scions of ‘Bing’, ‘Black Tartarian’ and ‘Royal Ann’ on Vladimir (Prunus cerasus L.) grew to heights of 3 to 4 m while the same cultivars grafted about the same time on seedlings of P. avium L. or P. mahaleb L. or cuttings of Stockton Morello (P. cerasus L.) were 2 to 3 times as large. The trees on Vladimir tended to be willowy and were anchored poorly. Scions grafted on 2-year-old root suckers of dwarfing stock, when left unpruned, have borne crops continuously since the 2nd leaf. A training system utilizing these dwarfing and fruiting characteristics to advantage is described.
Abstract
Sweet cherry fruits covered with aluminum foil bags at the beginning of pit hardening were visibly larger than those exposed to light when examined 14 days later. With ‘Bing’ fruits this difference in size remained nearly constant until harvest while with ‘Royal Ann’ it continued to diverge during “final swell.” The size of covered fruits was larger at harvest, but soluble solids content was much less than in exposed fruits. The alcohol insoluble substances (AIS) of control mesocarp tissue of ‘Bing’ decreased from 15 to 7% during the 2 weeks prior to harvest; those of dark-grown fruits decreased from 13 to 10%. The trends for the ‘Royal Ann’ fruits were similar. About 45% of the AIS was hydrolyzable with pectinase. Comparisons of levels of gibberellins, auxin-like and ABA-like substances between covered and exposed fruits showed neither consistent trends nor differences correlative to size increase during 3 weeks before harvest wherein the possible roles of these hormones could be ascribed. Humidity and ambient temp were not effective factors compared to light in this growth phenomenon.
Abstract
Analyses conducted on acetone powder and extracts prepared from ‘Golden Delicious’ apples collected from late July to early September revealed that the polyphenoloxidase (PPO) activity increased during the maturation period while the substrate level decreased. Protein content decreased initially and then increased as the apple approached full maturity. Similar analyses on other cultivars revealed wide variations; ‘Tohoku #3’ had low PPO activity and substrate level which may make this cultivar a good candidate for mechanical harvesting provided it possesses other acceptable horticultural characteristics.
Abstract
When 14CO2 was administered to leaves on girdled ‘French’ prune spurs, the label was incorporated into sorbitol, sucrose, glucose, fructose, starch, and amylase-insoluble assimilates. The rates of export of soluble sugars and sorbitol and mobilization of starch from leaves were proportional to the rate of fruit growth. The deposition of amylase-inert assimilates in leaves exceeded that of starch, which may account for the gradual increase in specific leaf weight in prunes. The proportion of sorbitol to total sugars in leaf blades and petioles, stem, and peduncle was nearly constant during the 22-day experim ental period but changed abruptly in the fruit. 14C-sorbitol fed to fruits via their peduncles was metabolized to 14C-sucrose, but the reverse reaction was barely detectable.