Search Results
Abstract
Foliar applications of gibberellic acid (GA3) to mature ‘Lambert’ sweet cherry trees (Prunus avium L.) about 21 days before harvest increased fruit weight (fresh and dry), soluble solids (SS), alcohol-insoluble substances (AIS) (both concentration and per fruit), ash weight, and fruit firmness at harvest. Application of GA3 did not affect concentrations of ethylene diamine-tetraacetic acid (EDTA) or pectinase-soluble pectins and fruit Ca. GA3-treated fruit had lower concentrations of water-soluble pectins and reduced surface pitting. Fruits sampled at 3–7 day intervals (starting about 21 days before harvest) from control and GA3-treated trees showed that as an average response over a 29-day sampling period GA3 increased fruit weight, firmness, AIS concentration, AIS per fruit, pectinase-soluble pectins, and decreased water-soluble pectins. Neither total, residual, or soluble fruit Ca were affected by treatment with GA3. Fruit Ca levels remained constant, on a per fruit basis, during the last 3 weeks of fruit maturation but Ca concentration, expressed as fresh or dry weight, decreased as a result of increased fresh and dry weight. Higher Ca levels were not associated with firmer fruit (comparing GA3 and nontreated fruit), but were correlated positively with firmness in nontreated fruit.
Abstract
Firmer ‘Lambert’ and ‘Bing’ sweet cherry fruit (Prunus avium L.) was associated with higher soluble solids (SS), higher concentration of alcohol-insoluble solids (AIS), and pectinase-soluble pectic substances and less crop, surface pitting, and lower concentration of water-soluble pectic substances. Fruit Ca and ethylene diamine-tetraacetic acid (EDTA) soluble pectic substances were not associated with fruit firmness. Total pectic substances were lower in AIS extracted with 70% ethanol held at 70°C for 1 hour as compared with AIS extracted with 70% ethanol at room temperature plus 80% ethanol in 5% HCI (v/v) for an additional hour. The major differences between the 2 methods were less EDTA and more pectinase pectins in 70°C ethanol-extracted AIS.
Abstract
Aqueous ammonium fluoride (NH4F) sprays on ‘Early Improved Elberta’ peaches (Prunus persica (L.) Batsch) resulted in increased O2 consumption of suture tissue and inconsistent changes in O2 consumption of dorsal tissue as the spray concentration was increased. Flesh firmness on the suture side of treated fruit was less than non-sprayed fruit and decreased as either the NH4F spray concentration or number of sprays increased. The effect of the spray on the dorsal side differed from year to year. Levels of fluoride (F) in the fruit tissue were associated with F concentration and number of F sprays applied only within the same year.
Five-year-old `Napoleon' sweet cherry (Prunus avium L.) trees were treated with single-application basal drenches of paclobutrazol (PBZ) in an attempt to regulate growth and flowering. Increasing concentrations of PBZ at 0.05 to 0.30 g·cm-1 trunk diameter reduced terminal extension the year of treatment and for at least the following 3 years. Fruit count increased on wood grown before treatment but decreased as annual growth declined following treatment. Fruit/cm growth generally increased, whereas fruit per flower bud decreased as PBZ concentration increased. No differences were found in fruit size, soluble solids concentration (SSC; 13% to 14%), or firmness of cherries harvested at brine maturity. Chemical name used: β-[(4-chlorophenyl) methyll-α- (l,l-dimethylethyl) -l-H-l,2,4-triazo1e-l-ethanol (paclobutrazol, PBZ).
Abstract
In vivo pollen tube growth of apricot (Prunus armeniaca L. cv. Tilton) was unaffected by air concentrations of pyrene or fluoranthene ranging from 0 to 4.7 μg/m3 and times of exposure from 16 to 48 hours. At similar exposure times and pollutant concentrations, pollen tube growth of ‘Van’ sweet cherry (Prunus avium L.) in ‘Napoleon’ styles was reduced as In dose (hours exposure times pollutant concentration in μg/m3) of pyrene increased.
Abstract
Aqueous sprays of NH4F applied to ‘Early Improved Elberta’ peach trees significantly increased the % of abnormal fruits. Tissue firmness was increased on the dorsal side but decreased on the suture side. Suture tissues contained more F than dorsal tissues and both had higher F levels as the F spray concn increased. The climacteric of treated fruits was initiated before the untreated fruits at every sampling date where a climacteric occurred. Both malic and citric acids were decreased in the suture tissues of F treated fruits.
Abstract
Factorial combinations of 50 and 100 ppm (2-chloroethyl)phosphonic acid (ethephon) and 1000, 2000 and 4000 ppm succinic acid-2,2-dimethyl hydrazide (daminozide) sprayed on young ‘Napoleon’ sweet cherry trees (Prunus avium L.) for 3 consecutive years showed no antagonistic or synergistic effects on either growth or flowering, Daminozide, at 2000 and 4000 ppm, reduced terminal growth but had no effect on flower initiation or flower density. Ethephon significantly reduced growth only the first year applied and appeared to increase flower initiation on wood previously untreated. Daminozide at 4000 ppm reduced fruit set on all combinations of year-wood and years but when applied at a concentration of 2000 ppm reduced set only 2 out of 5 possible year-wood, year combinations. Ethephon reduced set 3 out of the 5 year-wood combinations but the average response was not significant.
Abstract
Fumigations with hydrogen fluoride (HF) decreased in vivo pollen tube growth of ‘Tilton’ apricot (Prunus armeniaca L.). Both tube lengths and percent of styles with pollen tubes that reached the base of the style were adversely affected more by high HF concentration for a short time than by low concentration for a longer time. Pollen germination was unaffected on agar containing sodium fluoride. Fumigations with hydrogen chloride had no effect on pollen tube growth at concentrations from 0.05 to 0.75 mg Cl/m3 and durations of exposure from 8.5 to 72 hours.
Abstract
Pollen tube growth of ‘Tilton’ apricot (Prunus armeniaca L.) was reduced by exposure to SO2. An empirical model, based on modified spline functions, described the decrease in pollen tube growth due to increasing dose (hours exposure × concentration of SO2) expressed on logarithmic scale. The response curve, based on this analysis, was “S-shaped” with a decrease from 98.5% pollen tube growth (PTG) for unexposed pollen tubes, based on percent of the style that the longest pollen tubes had grown to 91.6% at ℓ n dose 4.0. These was then a very sharp decrease in PTG to about 45% at ℓn dose 5.7, then a gradual curvilinear response to <1% PTG at the maximum ℓn dose of 7.7. There data strongly indicate that there is a threshold response to SO2 with respect to PTG. Response of ‘Van’ PTG in ‘Napoleon’ sweet cherry (P.avium L.) styles was similar to apricot, but not as definitive because of greater within year variation and differences between years. In one year (1979), a spline function model of PTG in cherry suggested a threshold value at about ℓn dose of 2.1, while in another year (1978), there was a nearly linear decrease in PTG with increasing ℓn dose.
Abstract
Six annual surveys indicated that % soluble solids and fruit weight were the only consistent predictor variables for fruit surface pitting in ‘Lambert’ sweet cherry (Prunus avium L.). Both were inversely related to pitting. Similar associations were found ‘Bing’ when fruit were handled excessively. In spite of tree-to-tree variation, the degree of pitting was relatively uniform in a given orchard in a given year. High and low percentage pitting orchards appeared to be fairly consistent over the 6 years, but intermediate ones were extremely variable. Postharvest factors (time delay prior to storage, hydrocooling temperature, or storage temperature) had little or no effect on surface pitting. Foliar sprays of gibberellic acid (GA3 or GA4+7) applied 3 weeks prior to harvest increased fruit firmness and reduced color. Gibberellic acid sprays reduced pitting when the disorder was present (1974 and 1976) or where the fruit were bruised. Mechanical bruising of cherries increased the incidence of pitting. Surface pitting of sweet cherries may be caused by bruising but fruit characteristics (% soluble solids, size and firmness) can indicate whether or not pitting may occur on bruised fruit.