Search Results
Abstract
Plants of Rhododendron × catawbiense Michx. cvs. Chionoides, Roseum Elegans, and Nova Zembla were cut back on May 14, 1974 and terminal buds removed at 2-week intervals throughout the summer starting on June 14 and examined microscopically for floral initiation and development. First evidence of floral initiation was found in samples taken on July 15 for ‘Chionoides’ and August 1 for ‘Roseum Elegans’ and ‘Nova Zembla’. Floral development continued in the buds of all cultivars into October, at which time buds were well developed and at the rest stage. The number of breaks resulting from removal of terminal buds was the greatest on plants pinched on August 1 and August 15. The percentage of breaks forming flower buds decreased on plants pinched after August 1 and no flower buds were formed on plants pinched after August 15.
Abstract
Leaf tissue carbohydrates of Ilex opaca cv. ‘Miss Helen’ extracted with alcohol and methylated with trimethylchlorosilane (TMCS) and hexamethyl-disilizane (HMDS) were assayed by gas chromatography. This empirical procedure involved a one-hour refluxing of 1 g of air dried plant tissue in 80% ethanol, followed by taking 2 ml of the alcoholic extract to dryness at 70°C. Upon dryness the material was taken up with 0.25 ml anhydrous pyridine, and methylated with 0.1 ml of TMCS and 0.1 ml of HMDS. After 30 min of reaction time a 2 µl portion of the mixture was assayed by gas chromatography. Five carbohydrates, D-fructose, D-galactose, alpha-D-glucose, beta-D-glucose and sucrose were identified. These carbohydrates extracted from the plant tissue were of a soluble nature. No apparent starch or cellulose hydrolysis was observed as a result of the extraction procedure. Reagent grade carbohydrates were observed to anomerize during the extraction procedure, however no indication of this phenomenon was noted with the plant tissue. Recovery was in the order of 90% with good associated reproducibility.
Abstract
Leaf samples of Ilex opaca ‘Miss Helen’ were collected over a 2-month period and analyzed on a mg/g basis for total nonstructural carbohydrates (TNSC), individual ethanol soluble sugars (IESS), total ethanol soluble sugars (TESS) and apparent storage carbohydrates (ASC). Samples were preserved for analysis by 4 methods: 1) liquid nitrogen killed freeze-dried (NFD); 2) liquid nitrogen killed oven-dried (NOD); 3) oven-dried (OD) and 4) ambient air-dried (AD). The samples showed significant decreases in TNSC between the NFD and NOD, NOD and OD and OD and AD methods; a significant decrease in TESS with the NOD and OD methods and a further significant decrease in TESS with the AD method. A significant increase in ASC was noted with the AD method. Gas liquid chromatographic analysis of the IESS revealed a significant decrease in D-fructose and D-galactose with the AD method, a significant decrease in α-D and β-D glucose with the OD method and an additional decrease in both sugars with the AD method. Sucrose was undetectable with the NOD method, and was significantly decreased with the OD and AD methods. TNSC, TESS and ASC all decreased significantly with leaf maturation and expansion. Time of day of sampling showed no significant differences in any carbohydrate fraction.
Abstract
Foliar sprays of succinic acid-2,2 dtmethylhydrazide (SADH) at 2500 ppm and (2-chlorethyl)trimethylammonium chloride (chlormequat) at 1500 ppm increased no. and size of tuberous roots of dahlias under short-day conditions. Root wt were frequently tripled, both in cultivars which normally form tuberous roots readily, and those which generally form slender, poor-quality roots. Plants grown from roots of treated plants were of excellent size, color, and quality. Similar treatments under long-day conditions caused formation of tuberous roots where untreated cuttings produced only fibrous roots.