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  • Author or Editor: S. Y. Wang x
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Abstract

Growth retardants [ancymidol (0.1-1.0 mg·liter−1), chlormequat (0.5-500 mg·liter−1), and paclobutrazol (0.1-1.0 mg·liter−1)] reduced shoot extension, promoted root initiation, and increased root weight in apple seedlings (Malus domestica Borkh ‘York Imperial’). The induction of root formation and increase in root weight were accompanied by a considerable increase in polyamine levels. Daminozide (0.1-250.0 mg·liter−1) and dikegulac (0.25-500 mg·liter−1) also inhibited apple seedling growth; however, these compounds did not promote rooting. Chemical names used: α-cyclopropyl-α-(4-methoxyphenyl)-5-pyrimidinemethanol (ancymidol); 2-chloro-N,N,N-trimethylethanaminium chloride (chlormequat chloride); butanedioic acid mono(2,2-dimethylhydrazide) (daminozide); 2,3:4,6-bis-O-(l-methylethylidene)-α-L-xylo-2-hexulofuranosonic acid (dikegulac); β-(4-chlorophenyl)methyl]-α-(l,l-dimethylethyl)-lH-1,2,4-triazole-l-ethanol (paclobutrazol).

Open Access
Authors: and

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.

Open Access

Fruit of the cultivated strawberry (Fragaria ×ananassa Duchesne ex Rozier) are a good source of natural antioxidants, which play an important role in protecting human health. Antioxidant levels vary considerably among strawberry genotypes. The cultivated strawberry is a hybrid of two very different wild progenitor species: F. virginiana Mill. and F. chiloensis (L.) Mill. The progenitor species are valued by strawberry breeders as sources of novel traits, but have not been evaluated for antioxidant capacity or levels of antioxidant compounds. The objectives of this study are 1) to evaluate the antioxidant contents and antioxidant activities in representatives of F. virginiana and F. chiloensis in comparison with representatives of the cultivated strawberry species (F. ×ananassa), 2) to determine which strawberry compounds are most closely correlated with antioxidant capacity among these three species, and 3) to identify wild strawberry genotypes with high antioxidant activity and bioactive compounds for use in cultivar development. Fruit of 19 accessions from each of the three species, cultivated strawberry plus the two progenitor species (F. ×ananassa, F. virginiana, and F. chiloensis), were evaluated for levels of antioxidant capacity (oxygen radical absorbance capacity), total phenolics, total anthocyanins, ellagic acid, quercetin 3-glucoside plus quercetin 3-glucuronide, kaempferol 3-glucoside, kaempferol 3-rutinoside, p-coumaryl–glucose, pelargonidin 3-glucoside, pelargonidin 3-glucoside–succinate, cyanidin 3-glucoside, and cyanidin 3-glucoside–succinate. Fruit of the 13 accessions tested from the wild progenitor species F. virginiana had significantly higher antioxidant capacity, total phenolics, and total anthocyanins than did the fruit of three accessions tested from the cultivated strawberry F. ×ananassa, or the three accessions tested from the other wild progenitor species (F. chiloensis), and will be valuable as a source of parent material for developing more nutritious strawberry cultivars. The high correlation with antioxidant capacity, relative efficiency, and lack of genotype-by-year interaction in this study suggests that the measurement of total phenolics may be the better assay to use for the later selection stages in a strawberry cultivar development program. Of the evaluated F. virginiana accessions, NC 95-19-1, JP 95-1-1, CFRA 0982, NC 96-5-3, and RH 30 fruit were highest in antioxidant capacity and should prove useful toward development of strawberry cultivars with high antioxidant capacities.

Free access

Abstract

Pollen tube growth in styles of ‘d’Anjou’ pear (Pyrus communis L.) is largely dependent on prevailing temp. At 21°C the process was completed within 24 hr, while at 15.5° and 10° growth was completed by 72 and 120 hr respectively. The initial fruit development 14 days following pollination was greatly influenced by day temp (ranging from 13° to 23.4°) during an thesis.

Open Access
Authors: and

Abstract

The physiology of dormancy in Lilium longiflorum ‘Ace’ was studied by determining the relationships between plant growth and composition and treatments such as bulb scale removal, cold treatment, field soil heating and chemical stimuli. Initiatory activity was continuous in the daughter bulb until its anthesis, but elongation of daughter axis leaves and internodes were normally inhibited until autumn. Inhibition of the daughter axis was high during the spring prior to anthesis of the mother, but progressively decreased following anthesis and disappeared completely by autumn. Balances of inhibitor-promoter growth substances were found in the bulb scales. Daughter scales were found to be the principal source of inhibitors. Treatments conducive to breaking dormancy included 40°F storage, GA3 treatment and field soil heating in early spring. Dormancy-breaking cold treatments were followed by changes in nitrogenous substances characteristic of dormancy removal in other species. The period of dormancy in the daughter portion of the lily bulb is of the correlated type and involves scale inhibition of axis elongation rather than initiatory activity in the apex.

Open Access

Micropropagated plantlets of Gerbera jamesonii H. Bolus ex Hook. F. `Terra Mix', Nephrolepis exaltata (L.) Schott `Florida Ruffles', and Syngonium podophyllum Schott `White Butterfly' were inoculated with two vesicular-arbuscular mycorrhizal (VAM) fungi, Glomus intraradices Schenck and Smith and G. vesiculiferum Gerderman and Trappe. They were potted in three peat-based media to determine the effects of mycorrhizal peat substrate on acclimatization and subsequent growth of micropropagated plantlets under greenhouse conditions. Symbiosis was established between the three ornamental species and VAM fungi within 4 to 8 weeks of culture in the greenhouse, but not during acclimatization. Mortality of Gerbera and Nephrolepis mycorrhizal plantlets was reduced at week 8 compared to the noninoculated control. A peat-based substrate low in P and with good aeration improved VAM fungi spread and efficiency. Mycorrhizal substrates had a long-term benefit of increasing leaf and root dry weight of Gerbera and Nephrolepis. Mycorrhizal Gerbera plants flowered significantly faster than non-mycorrhizal plants.

Free access

Abstract

Increased flouride (F) fumigation levels resulted in decrease in percent ‘Royal Ann’ pollen germination and pollen tube growth. As dose (hour x concentration in μgF/m3) increased, ‘Van’ pollen tube growth in vivo decreased. A linear relationship between increased dose and flouride residue in the flowers was shown.

Open Access
Authors: , , and

Abstract

A cyanide-resistant alternative pathway was found to exist in root tissue of apple (Malus domestica Borkh.). In the absence of potassium cyanide (KCN), an inhibitor of cytochrome electron transport, the alternative pathway did not contribute to overall root respiration. However, in the presence of KCN or carbonyl cyanide m-chlorophenyl hydrazone (CCCP), an uncoupler, active participation of the alternative pathway was detected. Inhibition of O2 uptake by salicylhydroxamic acid (SHAM) was observed in the presence of antimycin A (AA) or sodium azide (NaN3), but to a lesser degree than when KCN was present. The degree of inhibition by SHAM was greatest in the presence of KCN, followed by AA and then NaN3. The antioxidant n-Propyl gallate (PG) was found to be an effective inhibitor of the alternative pathway. The site of inhibition in apple root tissue by PG is very similar to that of SHAM. Sodium benzoate, another antioxidant and free radical scavenger, and tetraethylthiuram disulfide (disulfiram), a copper chelator, did not inhibit the alternative pathway in apple root tissue.

Open Access

Abstract

Foliar uptake of fluoride (F) resulting from hydrogen fluoride (HF) fumigations was linear with dose (concentration F in μg/m3 × duration of exposure in hours) at F concentrations lower than 17.5 μg/m3. Above this level, duration of exposure was the only important factor and uptake was non-linear with time. Higher leaf N levels resulted in greater F uptake. Production of CO2 was increased more by high F concentration for short periods than by low concentration for longer periods where leaf N was optimal or supraoptimal. Amino nitrogen (AN) levels increased more at low F concentration for longer periods than high concentration for shorter periods. The response patterns were similar at optimal and supraoptimal leaf N. Protein nitrogen (PN) decreased with increasing In HF dose at optimal and very low leaf N levels. Changes in PN and AN were significantly correlated in leaf tissue with optimal, but not in tissues with deficient or supraoptimal N.

Open Access

Fruit extracts from 17 to 18 representatives of three strawberry species [Fragaria virginiana Mill., F. chiloensis (L.) Mill., and F. ×ananassa Duchesne ex Rozier] were tested for the ability to inhibit proliferation of A549 human lung epithelial cancer cells. The fruit extracts also were tested for activities against free radicals, (peroxyl radicals, hydroxyl radicals, singlet oxygen, and superoxide radicals), the activities of antioxidant enzymes [glutathione peroxidase (EC 1.11.1.9), superoxide dismutase (EC 1.15.1.1), guaiacol peroxidase (EC 1.11.1.7), ascorbate peroxidase (EC 1.11.1.11), monodehydroascorbate reductase (EC 1.6.5.4), dehydroascorbate reductase (EC 1.8.5.1), and glutathione reductase (EC 1.6.4.2)], and the activities of nonenzyme antioxidant components, ascorbic acid and glutathione. Correlations between the proliferation of cancer cells and these antioxidant activities were calculated. At the species level, F. virginiana fruit extract inhibited the proliferation of A549 human lung epithelial cancer cells to a significantly greater extent (34% inhibition) than the extracts from fruit of either F. chiloensis (26%) or F. ×ananassa (25%) (P < 0.0001). Extracts from fruit of F. virginiana also had significantly greater antioxidant activities and higher activities of antioxidant enzymes and nonenzyme components than did extracts from the other two species. Among individual genotypes, there was a high positive correlation between antiproliferation of A549 cancer cells, antioxidant activities against free radicals, activities of antioxidant enzymes, and activities of nonenzyme components. Although all fruit extracts from all the strawberry genotypes inhibited proliferation of A594 cancer cells, fruit extracts from seven F. virginiana genotypes showed significantly greater antiproliferative effects than any of the F. ×ananassa or F. chiloensis genotypes. These genotypes, CFRA 0982, JP 95-1-1, NC 95-19–1, RH 30, NC 96-48-1, JP 95-9-6, and LH 50-4, may be especially useful in developing cultivars with greater anticancer potential.

Free access