Search Results

You are looking at 21 - 30 of 77 items for

  • Author or Editor: William B. Miller x
  • Refine by Access: All x
Clear All Modify Search
Free access

Joseph P. Albano and William B. Miller

Our objective was to assess the susceptibility of seven marigold varieties to Fe toxicity. Marigold varieties included were one hedge type, `Orange Jubilee'; five semi-dwarf types, `First Lady', `Gold Lady', `Orange Lady', `Marvel Gold', and `Yellow Galore'; and one dwarf type, `Discovery Orange'. Plants were grown in a greenhouse in a soilless medium and treatments consisted of 0.018 mm (low) and 0.36 mm (high) Fe-DTPA incorporated into a nutrient solution. Plant height was not affected by Fe treatment and ranged from 32 cm in `Orange Jubilee', 13 to 14 cm in the semi-dwarf varieties, and 7.0 cm in `Discovery Orange'. Leaf dry weight per plant was not affected by Fe treatment and ranged from 1.15 g in `Orange Jubilee', 0.68 to 0.95 g in the semi-dwarf varieties, and 0.56 g in `Discovery Orange'. Symptoms of Fe toxicity only developed in the high Fe treatment, and the percent leaf dry weight separated at harvest as symptomatic ranged from 97% in `Orange Jubilee', 55% to 85% in the semidwarf varieties, and 15% in `Discovery Orange'. The Fe concentration in leaves in the high Fe treatment was 5.7-times greater in `Orange Jubilee', 2 to 3-times greater in the semi-dwarf varieties, and 1.6-times greater in `Discovery Orange' than in the low Fe treatment. Based on these findings, `Orange Jubilee' and `Discovery Orange' were the most and least susceptible varieties, respectively, to Fe toxicity of the seven marigold varieties evaluated in this study.

Free access

Anil P. Ranwala and William B. Miller

Easter lily flower buds at five stages of development (stage 1, 3–4 cm in length; stage 2, 6–7 cm; stage 3, 9–10 cm; stage 4, unopened buds, 13–14 cm; and stage 5, open flower one day after anthesis) were harvested, and flower organs were dissected for carbohydrate analysis. Extracting soluble sugars in distilled water at 70°C gave the optimum yield of soluble sugars among the several extraction methods tested including 80% ethanol, and distilled water at various temperatures. Separation of the extracted soluble sugars by alkaline high performance anion exchange chromatography revealed the presence of glucose, fructose, sucrose, and two other sugars of unknown identity. Glucose and fructose concentrations increased remarkably during the flower development in sepal (about 15-fold), style (about 10-fold), and filament (about 5-fold), while sucrose levels remained constant at low concentrations. In stigma, sucrose levels increased parallel to the increase of hexose sugars during development. Ovary had high sucrose levels relative to hexoses that remained constant while hexoses increased gradually. In anther, hexose concentrations increased at the stage 2 and then dropped at stage 3 and 4. Sucrose levels were higher than hexoses in anther, and it increased from stage 1 to stage 2, then dropped at stage 3, and increased thereafter. In addition to these sugars, anthers at stages 2 and 3 had a series of late eluting oligosaccharides. These oligosaccharides could be hydrolyzed to glucose with hot 1 m H2SO4 or with amyloglucosidase.

Free access

Anil P. Ranwala and William B. Miller

Three soluble invertase isoforms from Lilium longiflorum flower buds that had been separated by DEAE-Sephacel chromatography were purified to near homogeneity by further chromatography on hydroxylapetite, Con-A sepharose, phenyl agarose, and Sephacryl S-200 gel filtration. Nondenaturing polyacrylamide gel electrophoresis (PAGE) gave a single band in all three invertases that corresponded to a band of invertase activity in a duplicate gel. The SDS-PAGE of the purified invertase I resulted in a single band with apparent relative molecular mass of 78 kDa. Invertase II and III were resolved to a similar polypeptide pattern by SDS-PAGE with three bands of 54, 52, and 24 kDa. Antiserum of tomato acid invertase cross-reacted with all three invertase protein bands. Antiserum of wheat coleoptile acid invertase cross-reacted only with 54 and 52 kDa bands of invertase II and III but did not recognize invertase I protein. Con-A peroxidase was bound to invertase I protein and all three protein bands of invertase II and III, suggesting that all proteins were glycosylated. Invertase I protein could be completely deglycosylated by incubating with peptide-N-glycosidase F to result in a peptide of 75 kDa. Invertase II and III were partially deglycosylated by peptide-N-glycosidase F resulting proteins bands of 53, 51, 50, and 22 kDa.

Free access

Anil P. Ranwala and William B. Miller

Easter lily flower buds at five stages of development (stage 1, 3–4 cm in length; stage 2, 6–7 cm; stage 3, 9–10 cm; stage 4, unopened buds, 13–14 cm; and stage 5, open flower 1 day after anthesis) were harvested, and flower organs were dissected for invertase assay. On a fresh weight (FW) basis, anthers had the highest soluble invertase activity (about 10-fold greater) than all other organs reaching to 15 units/g FW by the stage 2. The activity dropped to about 3 units/g FW at stage 3 and 4, and then increased up to 10 units/g FW in open flowers. Specific activity (units per mg of protein) also showed the same trend. On a specific activity basis, sepal invertase activity steadily increased during bud development, but was relatively constant on a fresh weight basis. stigma, style, and ovary, soluble invertase activity expressed on a FW and specific activity basis steadily increased as bud development. Filament soluble invertase activity on FW basis dropped at the stage 2 and 3, while specific activity steadily increased during bud development. Cell wall-bound invertase activity (released with 1 m NaCl) was present in all flower organs. However, soluble activity accounted for the most of total activity in sepal, ovary and filament (about 90%). About 75% of total activity was soluble in anther and style, whereas nearly equal amounts of soluble and cell wall activities were present in the stigma. The cell wall bound invertase activity increased throughout the bud development in sepal, stigma, style, and ovary parallel to soluble activity. Anther cell wall-bound activity fluctuated in a similar pattern as the soluble activity.

Free access

Ted Whitwell, John Kelly, and William B. Miller

In 1993, Carolina Nurseries and the Department of Horticulture at Clemson Univ. entered into a partnership to create a research and development program to solve short and long term nursery production problems. Research is conducted on site at Carolina Nurseries in a specially designed 0.6-ha area built by the nursery. Faculty from the Depts. of Horticulture, Agricultural and Biological Engineering, Plant Pathology and Entomology have worked with graduate and undergraduate students located on site. The nursery staff is involved in overall planning and stay current with results so that research can be immediately implemented on the nursery. Yearly funding for the graduate student is provided by the nursery and grant funds are obtained from various companies for labor and supplies. Carolina Nurseries has committed to funding research to improve their production and also sharing the results with the rest of the nursery industry. Research findings are presented in peered reviewed articles, conference proceedings, abstracts, and oral presentations. Outstanding training opportunities for students and staff are available to also improve career development for future nursery managers. Faculty interaction with companies and the nursery industry are enhanced.

Free access

Joseph P. Albano and William B. Miller

Marigolds under iron deficiency stress exhibited characteristics associated with iron efficiency (e.g. induced reductase and rhizosphere acidification). Ferric reduction rates for roots of the minus Fe-DTPA treatment group was 0.97 μmol·g FW-1·h-1, 14 times greater than the 17.9 μM Fe-DTPA treatment group. Excised primary lateral roots from the minus Fe-DTPA and 17.9 μM Fe-DTPA treatment groups embedded in an Fe reductase activity gel visually confirmed an increased Fe reduction rate for the minus Fe-DTPA treatment group. The pH of the nutrient solution one week after initiation of treatments indicated that the minus Fe-DTPA treatment group was 1 pH unit lower than the 17.9 μM Fe-DTPA treatment group at 4.1 and 5.1, respectively.

Free access

Anil P. Ranwala and William B. Miller

Amylolytic activities extracted from scales of tulip (Tulipa gesneriana L. cv. Apeldoorn) bulbs stored at 4 °C for 6 weeks under moist conditions were characterized. Anion exchange chromatography of enzyme extract on DEAE-Sephacel revealed three peaks of amylolytic activity. Three enzymes showed different electrophoretic mobilties on nondenaturing polyacrylamide gels. The most abundant amylase activity was purified extensively with phenyl-agarose chromatography, gel filtration on Sephacryl S-200, and chromatofocusing on polybuffer exchanger PBE 94. The purified amylase was determined to be an endoamylase based on substrate specificity and end product analysis. The enzyme had a pH optimum of 6.0 and a temperature optimum of 55 °C when soluble starch was used as the substrate. The apparent Km value for soluble starch was 1.28 mg/ml. The inclusion of 2 mM CaCl2 in the reaction mixture resulted in a 1.4-fold increase in the enzyme activity. The presence of calcium ions also enhanced the thermo-stability of the enzyme at higher temperatures. The enzyme was able to hydrolyze soluble starch, amylose, amylopectin, and beta-limit dextrin, but it had no activity against pullulan, inulin, maltose, or p-nitrophenyl alpha-glucopyranoside. Only maltooligosaccharides, having a degree of polymerization of 7 or more, were hydrolyzed to a significant extent by the enzyme. Exhaustive hydrolysis of soluble starch with the enzyme yielded a mixture of maltose and matlooligosaccharides. This amylase activity was not inhibited by alpha- or beta-cyclodextrin upto a concentration of 10 mM. Maltose at a 50 mM concentration partially inhibited the enzyme activity, whereas glucose had no effect at that concentration.

Free access

Joseph P. Albano and William B. Miller

Our objective was to determine the effects on plant growth and physiology that a photodegraded Fe-chelate containing lab-prepared nutrient solution would have when used in plant culture. Plants grown hydroponically in the irradiated Fe-DTPA containing nutrient solution had ferric reductase activity 2.2 times greater, foliar Fe level 0.77 times less, and foliar Mn level 1.9 times greater than in plants grown in an identical but non-irradiated solution, indicating that plants growing in the irradiated solution were responding to Fe deficiency stress with physiological reactions associated with Fe efficiency. The youngest leaves of plants that were grown in the irradiated solution had symptoms of Mn toxicity. Restoration of the irradiated solution by removing the precipitated Fe by centrifugation and adding fresh Fe-chelate resulted in plants that were, in general, not different from those grown in the non-irradiated solution (control).

Free access

Anil P. Ranwala and William B. Miller

Our previous research has demonstrated preventive effects of foliar sprays of growth regulators containing GA4+7 (ProVide or Promalin) on cold storage-induced leaf yellowing and abscission in `Stargazer' hybrid lilies. Further research was conducted to investigate the effective concentrations of Promalin and appropriate timing of promalin sprays. Lilies at “puffy bud” stage were sprayed with promalin at concentrations of 10, 25, 50 or 100 ppm (each GA4+7 and BA) just before placing them at 4 °C for 2 weeks in darkness. Promalin concentrations of 25 ppm or above completely prevented cold storage-induced leaf yellowing occurring during the poststorage evaluation phase in a simulated consumer environment, whereas 10 ppm sprays only partially prevented it. Foliar spray of Promalin (100 ppm each GA4+7 and BA) just before storage at 4 °C for 2 weeks was compared with spraying 2 or 4 weeks before cold storage. While spraying 2 weeks before storage prevented leaf yellowing to the same extent observed in plants sprayed just before cold storage, spraying 4 weeks before storage had very little preventive effect on leaf yellowing. To investigate the effectiveness of promalin sprays with different cold storage durations, puffy-bud stage plants were stored at 4 °C for 1, 2, 3, 4, or 5 weeks in darkness with or without promalin sprays (100 ppm each GA4+7 and BA) before storage. Longer cold storage durations increased the severity of leaf yellowing occurring during poststorage phase. Although promalin was able to prevent leaf yellowing completely up to 2 weeks of cold storage, beyond 3 weeks of cold-storage, effectiveness of promalin diminished with no apparent preventive effect on plants stored for 5 weeks.

Free access

Jeff S. Kuehny and William B. Miller

The majority of Hippeastrum bulbs sold in the U.S. market are shipped from other countries. The shipping time and temperature varies by the country that the bulbs are shipped from and the storage time and temperature also varies by the company that packages the bulbs for retail sale. These packaged bulbs then sit on a shelf until they are purchased and forced by the consumer. These various storage times and temperatures can affect the longevity after packaging (premature emergence) and quality of the finished plant. The objectives of this research were to determine the effects of various storage temperatures and durations on emergence and forcing of Hippeastrum hybrids. Bulbs were stored at temperatures of 5, 9, 13, 21, and 29 °C for 6, 9, 12, and 15 weeks after which time one set was stored at 21 °C (packaged display temperature) and the other set forced in the greenhouse. Emergence of leaves and buds when stored at the 21 °C display temperature and during greenhouse forcing varied by specific hybrid according to storage duration at 5, 9 and 13 °C. Storage at 21 and 29 °C resulted in only leaf emergence and no flower bud emergence during the 21 °C display temperature and greenhouse forcing. Storage at 5 and 9 °C generally resulted in slower leaf emergence and quicker bud emergence. Results from this research can be used to help determine the best storage times and temperatures for preventing premature emergence of Hippeastrum based upon previous shipping times and temperatures.