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  • Author or Editor: Richard N. Arteca x
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Abstract

Gibberellic acid (GA3) or 6-furfurylamino purine (kinetin), incorporated into a gel, was applied to the roots of 2 cultivars of tomato transplants (Lycopcrsicon esculentum Mill.), which were then potted and grown in the greenhouse. Kinetin significantly increased relative growth rate (RGR), leaf area, and total plant weight 3 weeks following treatment. GA3 treatment had no significant effect on plant growth. Antitranspirant significantly increased RGR, total leaf area, and plant weight independent of hormone treatments.

Open Access

Abstract

Immediately following vacuum infiltration of 45Ca into ‘Katahdin’ potatoes (Solanum tuberosum L.) the label was distributed within the tuber in the following manner: 45%, 20%, and 35% in the stem end, bud end, and middle section, respectively. Initially, the bulk of the radioactive calcium was localized 0–5 mm below the periderm layer. However, over a 60–day period, the calcium moved toward the center of the tuber. Temperature had no effect on this process.

Open Access

Abstract

Vacuum infiltration of 1 or 2% CaCl2 reduced chlorophyll accumulation in ‘Katahdin’ potatoes (Solanum tuberosum L.) 50 to 60% and 70 to 80%, respectively, relative to the controls. CaCl2 at 3 or 4% induced internal breakdown. Maximal uptake of CaCl2 was obtained by placing the tubers under vacuum (−0.9 atmospheres) for 30 minutes with a soak time of 15 minutes. Ca+ + infiltration helped maintain tuber quality in light allowing consumers maximum visibility of the product.

Open Access

Fast growing callus was derived from Cephalotaxus harringtonia stem explants placed on MS basal salt medium with B-5 vitamins, 3% sucrose, 1 μM kinetin and 4.5 μM 2,4-D. Callus placed on basal medium with 10 μM kinetin and 0.45 μM 2,4-D turned green and organogenesis was observed upon subculture onto basal medium without hormones. Shoots were excised and placed on 1/2 strength MS salts and 10% sucrose for further shoot development. During the process of organogenesis, we also observed the differentiation of roots. Rapidly growing root cultures were established by culturing them under a 24 hour light regime of 35 μM/m2/s. Two grams of root tip explants cultured on B-5 medium with 2% sucrose were capable of producing an average of 24 grams of roots within 11 days. A 20-fold increase in fresh weight was achieved within 3 weeks when 15 grams of these roots were cultured in a 3 liter air-sparged bioreactor. C. harringtonia contains a number of alkaloids that exhibit cytotoxicity and are being evaluated as chemotherapeutic agents. We are currently in the process of establishing growth characteristics for these roots and assaying roots for the presence of these alkaloids. All cultures were grown under a 12 hour light regime unless otherwise stated.

Free access

Cephalotaxus harringtonia plants produce alkaloid compounds possessing antitumor properties, the major one being homoharringtonine. The purpose of this study was to produce roots from callus cultures developed earlier. Fast growing callus cultures were placed on MS basal salt medium with B-5 vitamins, 2% sucrose, 10 μM kinetin, 0.45 μM 2,4-D and 0.2% Gelrite. Upon subculture onto basal medium without hormones, we observed organogenesis of both shoots and roots. Roots were excised and established on basal medium without hormones. By subculturing two 2-inch root tips containing numerous visible laterals in liquid medium we were able to harvest 30 g of roots/250 ml flask after 3 weeks and 50 g/250 ml flask after 6 weeks. A 20-fold increase in fresh weight was achieved within 3 weeks when 15 grams of roots were initially seeded into a 3 liter air-sparged bioreactor. However, most of these roots appeared to be fleshy/swollen while root cultures established from half inch root tips grew slower but were normal in appearance. We arc currently in the process of establishing growth characteristics for these roots and assaying roots for the presence of these alkaloids.

Free access

Four concentrations of GA, (0.05, 0.5, 5.0, or 50 mg·liter–1) were applied to the root systems of seven hydroponically grown geranium (Pelargonium × hortorum cv. Empress Irene, Glacier Crimson, Sincerity, Pink Fiat, Sybil Holmes, and Mrs. Parker and P. × domesticum cv. Lavender Grand Slam) cultivars. The relative growth rate of all cultivars tested increased with GA3 treatments. In conjunction with the increase in growth rate, each of the cultivars showed a reduction in the root: shoot ratio and chlorophyll content per unit leaf area with no change in the percent moisture. These Pelargonium cultivars are genetically diverse, showing that GA3 can stimulate growth over a wide range of cultivars. Chemical name used: gibberellic acid (GA3).

Free access

Abstract

Changes in phosphoenolypruvate carboxylase (PEP-Case) and ribulose-1,5-bisphosphate carboxylase (RUBP-Case) were evaluated in potato plants following CO2 enrichment of the root zone. There was a significant increase in PEP-Case activity in the roots of CO2-treated plants between 3 and 12 days following CO2 enrichment. Both PEP-Case and RUBP-Case in the leaves showed no significant change following CO2 enrichment of the root zone. Of 4 additional species tested, potato roots had the greatest PEP-Case activity.

Open Access

Abstract

Root systems of potato plants (Solanum tuberosum L. var. Russett Burbank) were treated with 14CO2 and translocation was evaluated by autoradiography. Treatments of less than 1 hour showed little radioactivity in the leaves. Between 1 and 6 hours, there was a substantial increase in radioactivity in both roots and leaves. The 14CO2 was translocated to the leaves as 14CO2 dissolved in the xylem sap and as components fixed in the roots then transported. Plant tissues were analyzed spearately for radioactivity as extractable, basic (amino acids), neutral (sugars), insoluble (starch), and acidic (organic acids and sugar phosphates) fractions. Between 70 and 80% of the total extractable radioactivity was in the acidic fraction; of this, 96% was found in malic acid with the remainder containing other organic acids, amino acids, and sugars.

Open Access

The purpose of this study was to evaluate physiological, biochemical and molecular changes which occur in unrooted Pelargonium ×hortorum cuttings during storage. Pelargonium cuttings of `Sincerity' (good shipper), `Wendy Ann' (moderate shipper), and `Snowmass' (poor shipper) were stored at 25°C and evaluated over a 5-day period. Following removal from storage, cuttings exhibited progressive declines in photosynthesis, respiration, carbohydrate, starch and protein over time which was significant in all three cultivars, however there was little difference among the cultivars. Ethylene levels produced by `Sincerity' and `Wendy Ann' began to increase 3 days following the initiation of storage, whereas `Snowmass' showed an increase after one day reaching a peak at 3 days and was followed by a sharp decline. When unrooted cuttings of `Snowmass' were stored for a 5-day period at temperatures from 4 to 25°C, it was observed that those stored at 4°C had a significantly higher visual rating, chlorophyll content, root and shoot weight than at higher temperatures tested. The decline in quality progressively became greater from 10 to 25°C. Changes in gene expression of two ACC synthases and an ACC oxidase were evaluated in `Snowmass' cuttings which were stored at 4 and 25°C. Correlations between ethylene and ACC levels with gene expression were observed.

Free access

The purpose of this study was to evaluate physiological, biochemical, and molecular changes that occur in unrooted Pelargonium ×hortorum cuttings during storage. Pelargonium cuttings of `Sincerity' (good shipper), `Wendy Ann' (moderate shipper) and `Snowmass' (poor shipper) were stored at 25 °C and evaluated over a 5-day period. Following removal from storage, cuttings of all cultivars exhibited steady and significant decline in photosynthesis, respiration, carbohydrate, starch, and protein over time. However, no significant differences were observed among cultivars for all of these parameters. Ethylene levels produced by `Sincerity' and `Wendy Ann' began to increase 3 days following storage; whereas, `Snowmass' showed an increase after 1 day, reaching a peak at 3 days, and then declined. When unrooted cuttings of `Snowmass' were stored for 5 days at temperatures ranging from 4 to 25 °C, it was observed that those stored at 4 °C had a significantly higher visual rating, chlorophyll content, and root and shoot weight than at higher temperatures tested. As temperature increased from 10 to 25 °C, quality of cuttings declined. Changes in gene expression of two ACC synthases and an ACC oxidase were evaluated in `Snowmass' cuttings stored at 4 and 25 °C. Correlations between ethylene and ACC levels with gene expression were observed. Chemical name used: 1-aminocyclopropane-1-carboxylic acid (ACC).

Free access