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  • Author or Editor: D.M. Pharr x
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Abstract

Tomato leaf and fruit chlorophyll content of a dark green mutant (dg) of Lycopersicon esculentum Mill cv. Manapal was compared to +/+ and +/dg (within ‘Manapal’) and another high pigment line (hp/hp) from 111. 1252. The mutant dg/dg contained the highest chlorophyll a and total chlorophyll in the exocarp and mesocarp and per unit leaf area. The exocarp and mesocarp of hp/hp contained intermediate chlorophyll concentrations. The mutant dg/dg and hp/hp contained a greater mesocarp chlorophyll b concentration than +/dg or +/+.

Open Access

Abstract

‘New Hampshire Tiny Dill’, a dwarf cucumber (Cucumis sativus L.) was more responsive to applied gibberellins (GA) in terms of hypocotyl growth than ‘Gynoecious 3’ and ‘Chipper’, standard vine types. The dwarf gave a more prolonged response to GA3. Treatment of all lines with GA4+7 significantly increased both the fresh and dry weight of the hypocotyl and hypocotyl unit, but not of the cotyledons.

Open Access

Abstract

Five cultivars of cucumber (Cucumis sativus L.) were found to vary in chlorophyll/cm2 and total chlorophyll/leaf. Gibberellin (GA) treatments did not change the total chlorophyll content per leaf but all lines responded more to GA4+7 than to GA3 in terms of increased leaf area and leaf fresh weight. Treatment with GA4+7 stimulated the rate of leaf expansion, but caused a reduction in chlorophyll/cm2.

Open Access

Abstract

Aqueous extracts of thawed, transverse slices of cucumber fruit (Cucumis sativus L.) gave reliable measurements of reducing sugar and total carbohydrate concentrations. Fruit fresh weight increased throughout a 20-day sampling period, averaging 0.6, 13.4, and 389 g at anthesis, 5, and 20 days after anthesis, respectively. Reducing sugar and total carbohydrate concentrations were highly correlated (r=.97), but were not correlated with fruit fresh weight (r=.40) or commercial fruit size (r=.52). Reducing sugar concentration at anthesis averaged 6.3 mg/g fresh weight and increased to a plateau averaging 22.7 mg/g from 5 to 20 days after anthesis. Reducing sugar concentration of 585 plant introductions and cultivars ranged from 7.1 to 52.8 mg/g and averaged 31.1 and 22.6 mg/g at 2 harvest dates.

Open Access

Abstract

In the paper, Measurement and Variation of Sugar Concentration of Pickling Cucumbers by J. D. McCreight, R. L. Lower, and D. M. Pharr (J. Amer. Soc. Hort. Sci. 103(2):145-147. 1978), the first sentence of the introduction should read “Bloating of commercially brined cucumbers results in a 5 million dollar loss each year to the U.S. pickle industry (6).”

Open Access

Two cultivars of greenhouse tomato (Lycopersicon esculentum Mill.) were grown with ambient or 1000 μl CO2/liter during Jan.-June 1987 and 1988. In both years, CO2-enrichment increased foliar deformation and foliar starch, but during the season, foliar starch levels decreased while deformation increased. `Laura' had more deformation, while `Michigan-Ohio' had higher foliar starch concentration. During an entire season, there was no significant relationship between foliar starch concentration and deformation severity. Foliar C exchange rates in the lower canopy were not affected by severity of deformation. Data from these experiments do not support the hypothesis that excess foliar starch is responsible for foliar deformation at elevated CO2.

Free access

Abstract

Plants of sweet potato (Ipomoea batatas (L.) Lam) were exposed prior to harvest to 1 week of warm-dry, warm-flooded, cold-dry or cold-flooded soil conditions. Roots harvested from the warm-flooded soil showed more rotting during curing than roots from the other treatments, and rotting continued during storage. Roots harvested from the cold-flooded soil rotted to a lesser extent during curing but rotted rapidly during storage. Roots harvested from the cold-dry soil showed no rotting during curing; however after 52 days of storage, the number of roots with rot increased sharply. Root respiration rates from cold-flooded, cold-dry, and warm-flooded soils were not significantly different, but those rates were much higher than the rate in roots from warm-dry soil. ‘Jewel’ had a lower respiration rate than NC 317. The cold treatments stimulated sprouting of sweet potato roots during storage. ‘Caromex’ showed the highest sprouting followed by ‘Jewel’, NC 317, and ‘Centennial’.

Open Access

Abstract

Harvested roots of 2 cultivars of sweet potato [Ipomoea batatas (L.) Lam.] were submerged in water to simulate flooding damage and changes in the concentrations of carbon dioxide, oxygen, and nitrogen were followed in the internal gas atmospheres. The internal gas was almost exclusively CO2, 72 hours after submergence.

Open Access

Abstract

A 24 or 48 hour soak in gibberellins (GA) did not influence the total germination of open-pollinated rabbiteye blueberry seeds (Vaccinium ashei Reade, cv. Tifblue). GA4+7 at 100-500 ppm stimulated early germination of seeds from the 2nd to 4th week after sowing, with the maximum effect occurring after 3 weeks. The 48-hour, GA4+7, 100 ppm treatment stimulated germination from the 2nd to 5th week after sowing. Stimulation of earlier germination by GA4+7 hastened seedling transplanting by 2 to 4 weeks. Germination of mature seeds (large, filled) was significantly higher than immature (medium-size, filled) or imperfectly (partially-filled) developed seeds. GA4+7 did not increase germination of immature or imperfectly developed seeds.

Open Access

Abstract

The effect of 24, 48, and 72 hours of soil saturation on the ethanol concentration of roots at harvest and on postharvest storage loss was investigated for sweet potato [Ipomoea batatas (L.) Lam. cvs. Jewel and Centennial]. Ethanol accumulated rapidly with increasing time of soil saturation for both cultivars. Ethanol concentration was greater in roots taken from soil with slow drainage rates following saturation than from roots grown in soil with a fast drainage rate. The ethanol concentration in ‘Centennial’ roots did not increase beyond 48 hour saturation in soil with good drainage following saturation, while ethanol accumulated in ‘Jewel’ roots up to 72 hours. Weight loss in storage due to shrinkage and rotting was greatest for Jewel when subjected to 72 hours of continuous saturation followed by poor drainage, but as little as 24 hours of soil saturation followed by poor drainage caused significant storage losses.

Open Access