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Recently there has been an increased interest in the role of plants in human well-being and in the general public's perception of the value of plants. Knowing the nature and extent of the value of plants to people can affect the way plants are used in public and private landscapes, the amount of money invested in the establishment and maintenance of plants, and the satisfaction derived from the plantings. In conjunction with the annual National Gardening Association consumer market study, a question was asked to determine if observations from previous, limited studies were applicable to a wide range of American households.
Changes in the odor-active volatile compounds produced by `Gala' apples [Malus ×sylvestris (L.) Mill. var. domestica (Borkh.) Mansf. `Gala'] were measured after 4, 10, and 20 weeks storage at 1 °C in regular atmosphere (RA) or controlled atmosphere (CA), and 16 weeks in CA followed by 4 weeks in RA. Aroma was evaluated using the gas chromatography-olfactometry method Osme. Production of volatile esters decreased along with corresponding fruity aromas during CA storage. Hexyl acetate, butyl acetate, and 2-methylbutyl acetate were emitted in the largest amounts and perceived with the strongest intensities from RA-stored fruit. While hexyl acetate and butyl acetate concentrations and aroma intensities decreased during CA storage, 2-methylbutyl acetate remained at the RA concentration until apples had been stored 16 weeks in CA. Perception intensities of methylbutyrate esters with apple or berrylike odors decreased less than straight chain esters in CA-stored fruit. 4-Allylanisole, ß-damascenone, and 1-octen-3-ol, as well as an unknown compound with a watermelon descriptor, were perceived more in RA-stored fruit than in CA-stored apples. Factor analysis indicated the importance of these compounds in `Gala' apples stored 4 weeks in RA. Even though these compounds do not have an apple odor, they contribute to fresh `Gala' aroma.
Aroma and flavor characters of `Gala' apples [Malus sylvestris (L.) Mill. var. domestica (Borkh.) Mansf. `Gala'] were identified by 10 trained panelists. A vocabulary of 13 aroma descriptors and 16 flavor descriptors were used to characterize changes in controlled atmosphere (CA) and air, or regular atmosphere (RA) storage over 20 weeks. When compared with RA storage, the intensity of fruity (pear, banana, and strawberry) and floral descriptors decreased after 10 weeks in CA for whole and cut fruit aroma and flavor. During the entire storage period under CA, aroma of cut apples retained high vegetative and citrus characters but had a less intense anise aroma. Sourness and astringency were significantly higher for CA-stored apples, and sweetness was significantly lower. A musty note was perceived in whole apples stored in CA for 20 weeks. Aroma of whole fruit stored for 16 weeks in CA followed by 4 weeks in RA was higher in fruitiness, banana, floral, and anise characters when compared with apples stored 20 weeks in CA. There was no difference between fruit stored in CA followed by RA versus CA stored apples for flavor and aroma of cut fruit. Changes in descriptor ratings during storage are discussed in relation to gas chromatography and olfactometry data obtained with the Osme method.
`Gala' is an early season apple variety that has a distinctive aroma and flavor. Studies were conducted to identify volatile compounds that contribute to `Gala' aroma. `Gala' apples were harvested at optimum maturity in a commercial orchard. Volatile compounds were trapped on activated charcoal using dynamic headspace sampling and eluted with carbon disulfide. Odor profiles of the samples were determined using OSME, a method developed at Oregon State Univ. that combines gas chromatography and olfactometry with a time-intensity scale. Three trained panelists described odor characteristics of compounds eluted through a sniff port of a gas chromatograph. Compounds were identified by matching Kovats indices with those of standards and also by mass spectrometry. Butyl acetate, 2-methyl butyl acetate, and pentyl acetate were characteristic of `Gala' apple. Methyl-2-methyl butyrate, ethyl-2-methyl butyrate, pentyl acetate, and butyl-2-methyl butyrate carried apple-like descriptors.
`Gala' is an early maturing apple variety that has a distinctive aroma and flavor. Its storage season is short and flavor volatile production is reduced following controlled atmosphere (CA) storage. The aroma and flavor characters of `Gala' apples were identified by 10 trained panelists. A vocabulary of 13 descriptors for the aroma of whole and cut fruit and 16 descriptors for flavor were used to characterize the changes of apples stored in CA and/or regular atmosphere (RA) during five months. When compared to RA storage, intensity of fruity (pear, banana and strawberry) and floral characters decreased after 2.5 months in CA for whole and cut fruit aroma and flavor. During the entire storage period under CA, aroma of cut apples retained high vegetative and citrus characters but had a less intense anise aroma. Sourness, starchiness and astringency were significantly higher, however, sweetness was significantly lower. A musty note was perceived in whole apples stored in CA for 5 months. Differences in fruitiness of whole fruit and sourness only were found between fruit stored for 4 months in CA followed by 1 month in RA and fruit stored 5 months in CA. Relationships between panel ratings of specific characters and corresponding quantitative analysis will be discussed.
The effects of growth-retarding chemicals on stem anatomy were compared on poinsettia (Euphorbia pulcherrima Wind. `Annette Hegg Dark Red'). Micrographic examinations revealed that secondary walls of nonsclerotic phloem fiber cells were either completely or greatly reduced by retardant treatment. Wall thickening of phloem fiber cells was eliminated by paclobutrazol foliar sprays at 25 mg·liter-1. Fiber cell development was reduced, but not eliminated, by sprays of chlormequat and ancymidol at standard rates, while the triazole uniconazole at 10 mg·liter-1 permitted only limited fiber wall thickening. Chemical names used: (2-chloroethyl)-trimethyl ammonium chloride (chlormequat); α -cyclopropylα- (4-methoxyphenyl) -5-pyrimidine methanol (ancymidol); (E)-(p -chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl-1-penten-3-ol (uniconazole): and (R*,R*)- β -[(4-chlorophenyl)methyl]- α -(1,1-dimethylethyl)- 1 H-1,2,4,triazole-1-ethanol (paclobutrazol).
Abstract
Rooted cuttings of poinsettia (Euphorbia pulcherrima Willd. ex. Klotzsch cvs. Annette Hegg Dark Red and Eckespoint C-1 Red) were grown under a 16-hour photoperiod in aggregate culture to determine the influence of NH4-N and NO3-N on plant growth. Plant height, number of nodes, and shoot dry weight were reduced with NH4 in comparison to NO3.NH4:NO3 combinations containing more than 50% (6 meq) NO3 produced superior growth. Stunting, leaf chlorosis and abscission, and stubby brown roots were observed on plants receiving any level of NH4 in the nutrient solution and increased in severity as the NH4 concentration increased. Inferior growth observed with the NH4 treatments was not due solely to the higher levels of Cl and SO4 in those solutions.
`Gala' apples were harvested at weekly intervals for 6 weeks, refrigerated at 0C, and evaluated by a consumer panel monthly over a 6 month period for overall liking, firmness, sweetness, tartness and flavor intensities. Firmness, titratable acidity and soluble solids concentration were also measured. Initial analysis of sensory data revealed multicollinearity for overall liking, sweetness, and flavor. The five descriptors explained 75 % of the dataset variation in the first two factors. An orthogonal rotation separated overall liking, flavor and sweetness, and firmness and tartness into two independent factors. The distribution of mean scores along these independent factors showed that panelists could perceive changes due to ripening and maturation. The multivariate factor analysis was better than univariate ANOVA at illustrating how apple maturity stages were apparent to untrained panelists. Firmness was the only instrumental variable correlated to firmness ratings in the sensory tests. None of the analytical measurements could explain overall liking.
Several microsprinkler treatments were tested on 5-year-old satsuma mandarin orange (Citrus unshiu Marc.) trees to compare survivability of trunks and scaffold limbs in severe freezes. Three damaging freeze events occurred during winter, with two in 1995–96 and one in 1996–97. Air temperature dropped to –9.4, –5.6, and –6.7 °C, respectively. Almost 90% of the foliage was dead on the control plants after the first freezing event and 98% after the second. A single microsprinkler 1.6 m high in the canopy delivering 90.8 L·h–1 reduced injury; only 54% of the canopy was dead after the first freeze and 71% after the second. There was slightly more shoot-tip dieback on the plants in the microsprinkler treatments than on the control plants after the first two freezes. The amount of limb breakage by ice was minor. The third freeze killed 34% of the canopy in the control plants, but only 26% in the plants in the microsprinkler treatments. Use of microsprinklers increased yield in 1996, but yield for all treatments was very low. Yield for all treatments fully recovered in 1997, averaging 153 kg/tree. Although no death of scaffold limbs or trunks occurred, these results demonstrate that microsprinkler irrigation reduces damage to foliage and increases yield somewhat in severe freezes.
Eating quality of `Gala' and `Fuji' apples (Malus domestica Borkh.) from multiple harvests and storage durations was assessed using an untrained consumer panel. Apples were harvested at weekly intervals for 6 weeks and stored in air. Changes due to harvest maturity and storage for overall liking (OL), sweetness, tartness, firmness, and flavor intensity were evaluated over 8 months. A multivariate factor analysis revealed multicollinearity for OL, sweetness, and flavor intensity ratings in both cultivars. These attributes had the highest loadings in the first factor, explaining 51% and 52% of the variance of `Gala' and `Fuji' data sets, respectively, and were interpreted as a quality factor. Tartness and firmness had the highest loadings in the second factor for `Gala', explaining an additional 23% of the variability and reducing that cultivar's data set to two factors. For `Fuji', however, tartness and firmness were independent and included in factors 2 and 3, respectively. Factors 2 and 3 were interpreted as maturity factors, which explained 23% and 12% of the variance. The plots of the mean factor scores provided a multivariate technique to illustrate that panelists could differentiate between the stages of maturity of apples. Canonical correlations were calculated between the sensory and instrumental data. Only firmness measurements were correlated with sensory ratings for firmness (r = 0.53 and 0.44 for `Gala' and `Fuji', respectively).