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  • Author or Editor: J. Kelly x
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Dietitians and nutritionists have included vegetables among 4 of the 7 basic food groups used in planning meals. Because of the variety and quantity of vegetables we are able to furnish in this country, either fresh or processed, it is an easy task to prepare a well-balanced diet without too much concern for the differences in composition among vegetable types. It is no wonder, then that until very recently little attention has been directed to the differences which exist within vegetable types.

Open Access
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Horticultural crops play an important role in meeting the needs of man for vitamins and minerals. The serious problem of calorie-deficient diets can be relieved by many horticultural crops, although most of the world’s food energy is derived from grains. It is generally accepted that the most serious problem of underfed people in the less developed countries is one of protein-calorie malnutrition, particularly in infants, young children and pregnant and lactating women (1, 6). What part do horticultural crops play or what part might they play in closing the protein gap?

Open Access
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Euphorbia pulcherrima `Glory' were grown under natural photoperiods from 5 Oct. to 20 Dec. in specially constructed growth chambers equipped with clear double-walled polycarbonate panels filled with liquids that served as spectral filters. The filters were a blue dye that increased far-red/red FR/R) light, a CuSO4 solution that decreased FR/R, and H2O (control) which did not alter FR/R from natural light. The FR/R values were 1.01, 0.86, and 0.34 for blue dye, H2O (natural), and CuSO4, respectively. FR and R were measured at 725-730 and 655-660nm, respectively.

Plants grown under the CuSO4 filter were 32% shorter, with shorter internodes (48%), greater leaf chlorophyll (25%), and more lateral branches (17%) than controls. Plants grown under blue dye filters did not differ from controls. All plants developed normal bracts and flowers.

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`Spears' (nonpinched and pinched) and `Yellow Mandalay' (pinched) chrysanthemums were grown in growth chambers equipped with clear, double-walled polycarbonate panels filled with liquids that served as spectral filters. A blue dye raised FR/R by filtering out a portion of red light. A solution of CuSO4 lowered FR/R by absorbing a greater portion of far-red than red light. A red dye absorbed much of the blue/green portion of the light spectrum but did not change far-red to red (FR/R) light ratio. Two controls (H2O and air) were used. FR/R values were 1.01 for blue dye, 0.34 for CuSO4, and 0.86 for air, H2O, and red dye. FR and R were measured at 725-730 and 655-660nm, respectively.

All plants grown under CuSO4 filters had reduced height, reduced internode length, and increased chlorophyll content compared to controls. Red dye filtered pinched plants had decreased chlorophyll compared to controls.

Pinched plants grown under CuSO4 filters and long days developed fewer nodes than controls due to the formation of abnormal capitula. The controls and other treatments developed more nodes before producing similar capitula. Stem diameter and leaf area of controls did not differ from blue dye, red dye, or CuSO4 filter treatments.

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Potted Rosa × hybrida `Meijikatar' plants were produced at 350, 700, and 1050 μl·liter-1 CO2. At a stage of development where half of the flowers showed color, plants were placed into simulated shipping incubators for 5 days at 4 or 16 C.

Increased CO2 levels resulted in shorter production time, increased root dry weight, increased plant height, and reduced total chlorophyll in the upper leaves of the plants. Upon removal from simulated shipping, the number of etiolated shoots per plant increased with increased CO2 concentration. After 5 days in a simulated interior environment, higher shipping temperatures induced more leaf chlorosis, but there were no differences in leaf chlorosis due to CO2 enrichment.

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`Spears' chrysanthemums were grown in chambers fitted with double-walled exolite filled with spectral filtering solutions: a blue textile dye that absorbed red light, CuSO4·5H2O that absorbed far-red light, and H2O that was spectrally non-selective (control).

Leaves of `Spears' grown under CuSO4-filters had increased chlorophyll a (23%), chlorophyll b (26%), xanthophyll (22%), and β-carotene (24%) compared to plants grown under H2O or blue-dye filters. Ratios of total carotenoid: chlorophyll and chlorophyll a: chlorophyll b were not affected by filter.

Individual leaf area was reduced 25% under CuSO4 filters compared to other filters. Stomates per unit area were not affected by filters, however stomates per leaf were reduced 25% under CuSO4 filters because of leaf size reduction. Stomate length and width were not affected by filter. Leaves from plants grown under CuSO4-filters had an internal structure resembling that of sun-type leaves. Other filters induced a shade-type leaf.

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The growth of Rosa × hybrida and Exacum affine under different spectral filters was evaluated. Three filters that altered light quality were developed. One, a red textile dye, filtered out much of the blue/green portion of the light spectrum but did not change far-red to red (FR/R) light ratio. Another, a blue textile dye, raised FR/R by filtering out a portion of red light. The third, a salt (copper sulfate) lowered FR/R by filtering out a greater portion of far-red than red light. Two controls were used that did not alter light quality. The filters were installed in specally built growth chambers. Photosynthetic Photon Flux Density (PPFD) was adjusted to equal values in each chamber.

Plants of both species were significantly shorter and had higher leaf chlorophyll, when grown under the low FR/R filter.

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Sixty-two genetically diverse modern and traditional Phaseolus vulgaris L. cultivars from Brazil, the Dominican Republic, Honduras, Mexico, the Netherlands, and the United States, representative of the Andean and Middle American gene pools, were selected to study the interaction with distinct races of Colletotrichum lindemuthianum (Sacc. & Magnus) Lams.-Scrib. Principal component and phenetic analyses were conducted on the disease reaction to inoculation with 34 races of C. lindemuthianum from Argentina, Brazil, Colombia, Costa Rica, the Dominican Republic, Honduras, Mexico, Peru, and the United States. The principal component analysis revealed four clusters in which only one cluster consisted of cultivars from both gene pools. Bean genotypes clustered based on the gene pool origin of the resistance genes present, regardless of the actual gene pool of the host genotype. Middle American genotypes in cluster A carried Andean resistance genes. Further grouping of genotypes based on overall level of resistance within each gene pool was observed. Clusters A and C consisted of the most resistant genotypes from both gene pools. The distribution of genotypes generated by the phenetic analysis, placed the most resistant and susceptible genotypes of the anthracnose differential series at the extremities of the phenogram, providing support for the range in genotypic resistance exhibited by members of the differential series. Races of C. lindemuthianum isolated from Middle American genotypes showed broad virulence on germplasm from both gene pools, whereas races with Andean reaction showed high virulence only on Andean germplasm. The reduced virulence of Andean races on Middle American genotypes suggests selection of virulence factors congruent with diversity in P. vulgaris. In addition, races of C. lindemuthianum formed two clusters corresponding to the Middle American and Andean reaction groups based on the phenetic analysis. In the principal component analysis, most races with the Andean reaction were observed in the clusters C and D, except races 15 and 23 which clustered with Middle American races in cluster B. Only races 38, 39 and 47 from the Dominican Republic showed high similarity in both multivariate analyses and clustered based on geographic origin. Races from other countries showed no geographic effect. The overlapping of specific races, however, with races from different reaction groups might indicate that this group of isolates possesses factors of virulence to both host gene pools. Data based on virulence supports variability in C. lindemuthianum structured with diversity in P. vulgaris.

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Abstract

Supplemental night lighting of Easter lily (Lilium longiflorum Thunb) plants (2, 5-7) induces early floral initiation and reduces the number of leaves per plant, provided the bulbs (plants) have not been saturated with cold inductive temperatures <21.1°C, the upper limit of vernalization for Lilium ‘Ace’ (6). Also, ‘Ace’ bulbs respond to light during cold storage, which reduces the number of leaves formed before floral initiation and increases the percentage of plants that flower (4). Lighting Allim bulbs during cold storage was also shown by De Mille and Vest (1) to promote early flowering.

Open Access

Abstract

Seedlings of European birch (Betula pendula Roth.) grew rapidly (3.4 cm/week) in long days (8 hours of natural light plus 2 hours of supplemental light in the middle of the dark period). Two weeks of short days (8 hours of natural light) inhibited shoot growth and promoted the onset of dormancy. Daylength did not effect the rate of root growth. Root pruning suppressed the rate of root growth for 2 weeks, but once active tips were formed the rate of growth was similar to unpruned roots. Complete defoliation or covering of the foliage on short day dormant plants terminated root growth.

Open Access