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- Author or Editor: Floyd M. Woods x
Pectinesterase is present in green tomato fruit and increases several-fold during ripening. Several isoenzymes of pectinesterase can be separated by chromatography of tomato extracts on DEAE-Sephadex A-50. The predominant isoenzyme in most tomato cultivars including Better Boy has been designated PE IV. This isoenzyme accounts for most of the increase in total pectinesterase during ripening of these cultivars. The fruit of some cherry tomato cultivars such as Pixie and Short Red contain some PE IV, but the major isoenzyme is PE III which occurs only in these cultivars. PE III and PE IV were isolated from ripe fruit of Short Red and Better Boy, respectively, to further characterize differences between the isoenzymes. PE III binds more strongly to cation exchangers, indicating that it is more basic than PE IV, The molecular weights were estimated by gel filtration to be 26,900 and 25, 100 for PE III and PE IV, respectively. Polyclonal antibodies were raised against the two enzymes. Cross reactivity of the enzymes with the antibodies indicates that PE III and PE IV are immunologically identical.
Generalized recommendations for the southeastern U.S. would typically include soil testing well in advance of establishment. Lime, P, and K should be applied at least 2 weeks before planting. Nitrogen is either broadcast and incorporated before planting or sidedressed 2 to 4 weeks after planting at 30 to 70 kg·ha–1. Additional N at 30 to 65 kg·ha–1 is applied late August to mid-September. A late winter N application at 20 to 30 kg·ha–1 is suggested for sandy soils. On established plantings fertilization takes place at renovation, with P and K being applied based on soil test or foliar analysis results. Nitrogen rates are typically in the range of 35 to 60 kg·ha–1. Later season fertilization generally follows the rates and timings of fall and winter recommendations of the establishment year. Minor nutrients can be limiting on sandy soils and B may be required in a wider range of soil types.
Blueberries are an important fruit crop in the Ericaceae represented by multiple Vaccinium species and ecotypes. In addition to their economic value, blueberry fruit is known for an abundance of specialized metabolites with known human health benefits. Phenolic compounds, which include flavonoids and anthocyanins, are an important class of compounds found in blueberry that are known to contribute to fruit flavor and quality and for having health-promoting properties. Previous surveys of phenolic compounds in blueberry have demonstrated considerable variability in concentration of these metabolites, which is associated with differences in environmental factors and cultivars surveyed. This study expands this knowledge by surveying total phenolic, flavonoid, and anthocyanin content in ripe fruits of 71 blueberry cultivars from one growing season in Michigan. Included in this diversity panel are three ecotypes of blueberry (northern highbush, southern highbush, and half highbush). Rubel, Legacy, and Friendship were among the seven cultivars with the highest content of each compound. Total phenolic content showed a 5.03-fold difference among the lowest and highest cultivars, and total flavonoid content and total anthocyanin content demonstrated a 2.66-fold and 6.37-fold difference between the lowest and highest content across cultivars, respectively. There was no significant impact of ecotype on phytochemical composition of ripe fruits. This study also represents the first large-scale analysis of total phenolic content using the Fast Blue BB (FBBB) reagent. Data from this study have the potential to aid in future breeding efforts to enhance the human health benefits of this economically important fruit crop.
The use of soil solarization on 20-cm raised beds 30, 60, and 90 days prior to fall planting of `Chandler' strawberries was compared with soil fumigation with 269 kg·ha–1 98/2 methylbromide/choropicrin and with 562 liters·ha–1 metam-sodium (Busan). The clear plastic mulch was painted with white latex paint prior to planting on 15 Oct. Methylbromide/choropicrin treatment gave the best yields, followed by the metam-sodium treatment. Soil solarization on raised beds was complicated by weed growth on the top edges and sides of the bed. Soil solarization is a useful alternative for flat bed culture, but is practically limited on raised beds due to insufficient weed control.
Brown rot of peaches is one of the most devastating diseases that can occur before and after harvest. There has been extensive research that has shown that ultraviolet light (UV-C) kills the fungus that causes brown rot. However, it is has not been determined whether UV-C will also change ripening and fruit quality. We applied UV-C to `Loring' peaches that were harvested 10 days before normal harvest. We intentionally picked the fruit early because we wanted to make sure the fruit had not entered the climacteric. The fruit were treated with UV-C and ethylene, skin color, firmness, and soluble solids were measured. We also held fruit at three storage temperatures to determine whether there may be an interaction between UV-C treatment and storage temperature. Ethylene was slightly higher for UV-C treated fruit at 70 °F (20 °C) and 55 °F (12 °C), but not at 40 °F (4 °C). However, there was very little effect on firmness and soluble solids. There was a slight delay in development of red blush. UV-C had little effect on ripening and peach fruit quality.
`Navaho' erect thornless blackberry plants were subjected to a combination of three primocane summer topping heights and two winter lateral length pruning treatments. Plants were topped at 91, 122, 152 cm tall, and laterals were shortened to either 30 or 61 cm in length. Treatment effects on yield and plant structure were examined for four growing seasons. Lateral length had little effect on yield and any pruning height. Yield generally increased with increasing plant height. The 122-cm height appeared to optimize yield while still allowing for manageable floricane architecture.
A spectrophotometric assay for pyruvic acid in onion has been adapted to a microplate reader. Correlations between the spectrophotometer and microplate reader ranged from 0.991 to 0.997 for sodium pyruvate standards and 0.899 to 0.934 for onion samples. Onion pungency values were slightly higher with the microplate reader for both sample and background compared to the spectrophotometer when both are used in the single wavelength mode. Comparing the spectrophotometer in the single wavelength mode to the microplate reader in the dual wavelength mode resulted in no statistically significant difference between them. Standards for both the microplate reader and spectrophotometer followed a quadratic function.
Lotus (Nelumbo) is a highly valued plant with a long history for vegetable, ornamental, and medicinal use. Little information is available on the effects of planting time on performance of lotus, especially when grown in containers. The objectives of this study were to find a suitable planting time and to determine best management practices that are of importance for container lotus production. Effects of planting time and disbudding on plant growth indices in southeast Alabama were evaluated in a container production system for the ornamental lotus, N. nucifera ‘Embolene’. Results indicated that plant growth indices were little influenced by different planting dates in March, but were much influenced by planting dates with a difference over a month between February and May. Plants potted and placed outdoors in March and April performed best, and lotus planted in the greenhouse in February and planted outdoors in February and May performed worst. Flower number was not largely influenced by the planting time, but flowering characteristics, especially the flowering peaks, were different among treatments. Planting lotus outdoors between March and May produced the largest return. Influence of planting time on plant growth indices of lotus appeared to be explained by effects of growth-season climate conditions after planting. Disbudding had no impact on plant height but significantly increased underground fresh weight and the number of propagules. Therefore, disbudding should be considered a best management practice to maximize the yield of rhizomes or propagules. Positive linear, quadratic, or cubic relationships were detected among emerging leaf number, underground fresh biomass, and propagule number. Based on the regression models, the yield of lotus rhizomes or propagules can be predicted by the number of emerging leaves. This research provided a guide for nurseries, researchers, and collectors to select the best time to plant lotus outdoors.
`Chandler' strawberry plants (Fragaria Xananassa Duch.) were greenhouse grown under natural lighting and then placed into growth chambers at two constant temperatures of 16 and 26 °C and 2 daylengths of 9 h (SD) and 9-h photoperiod (NI) which was night interrupted with 3 hours of incandescent radiation at 30-45 μmol·s-1·m-2 PAR. Plants were given different numbers of inductive cycles in growth chambers and then moved to the greenhouse. Flowering and growth were monitored. Flowering was completely inhibited at 26 °C, regardless of pretreatment growing conditions such as pot sizes and plant ages, photoperiod, and inductive cycles. At 16 °C, SD promoted floral induction compared to NI under all inductive cycles except a 7-day induction. The minimum number of inductive cycles required at 16 °C for floral induction was dependent on photoperiod and prior greenhouse treatment. Flowering rate was also affected by greenhouse treatment, photoperiod, and inductive cycles. Runner production was affected by photoperiod and temperature × inductive cycle.
Sixteen sweet potato (Ipomoea batatas L.) genotypes were chilled for 36 hours at 5C with 85% RH and a 12 hour photoperiod. Transpiration, leaf diffusive resistance and visual scores for plant quality were taken before chilling and 2 days after the chilling treatment. Differences between the before and after readings were used to indicate the extent of chilling injury or tolerance. Visual score gave a better separation of the genotype for tolerance, however, the difference in transpiration was the most critical of the two objective measurements.