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Abstract
Pimiento peppers from all ethephon treatments had a faster rate and a higher percentage of coloring than peppers receiving the ethylene treatment or the control. The completely green peppers, however, did not color to an acceptable commercial grade within 96 hr.
Ethephon induced a climacteric in the respiration of the treated detached peppers that was not present in the control fruits, indicating that metabolism was affected as the coloring rate was increased.
Abstract
Diffusive resistance decreased and chlorophyll content increased in leaves of Impatiens hybrida (shade tolerant) subjected to 14 days of low quantum flux density (QFD) compared with high QFD. There was no difference in diffusive resistance or chlorophyll content in Pelargonium X hortorum Bailey (sun tolerant) regardless of QFD treatment. Light saturation of net photosynthesis (Pn) occurred at higher light levels in impatiens treated with low QFD compared with those treated with high QFD. Light saturation in geraniums treated with high QFD was the same as in those treated with low QFD. Stomatal density in impatiens was greater, and stomatal area was smaller than in geranium. Physiological processes of impatiens appear to be more sensitive to changes in QFD than those of geraniums.
Abstract
Southern Magnolia, Magnolia grandiflora (L.), cuttings are difficult or impossible to root without growth regulators. Age of parent plant, terminal or lateral source of wood and specific growth regulators are factors in rootability.
The best growth regulator and concn was 2.0% IBA followed in decreasing effectiveness by 0.8% IBA, 0.1% Chloromone, 10 ppm 2,4-D, and 20 ppm 2,4-D. Young tissue produced a higher percentage of rooted cuttings than old tissue at all growth regulator concn tried. Also in young tissue, terminal shoots produced a higher percentage rooted cuttings than lateral shoots, while in old tissue the opposite was true.
Abstract
Chlorotic foliage of Euphorbia pulcherrima did not contain substantially higher levels of free amino acids than normal non-chlormequat treated foliage, and in some cases levels were lower indicating inhibition rather than protein degradation.
Free amino acids detected and measured in µ/g fresh wt included glycine, alanine, valine, leucine, isoleucine, serine, threonine, aspartic acid, glutamic acid, glutamine, lysine, arginine, histidine, cystine, proline and phenylalanine.
The high fertilizer rates stimulated chlorophyll regeneration after damage from phytotoxic spray application of chlormequat and was closely correlated with amino acids im portant in N metabolism.
Abstract
Chlormequat (Cycocel, CCC) sprays and drench reduced plant height of poinsettias. Sprays of 5000 ppm were most effective with 25% reduction after 32 days followed by 3000 ppm - 18%, 1000 ppm - 17%, and 5000 ppm drench 12%. Appearance as indicated by chlorophyll analyses and chlorosis ratings was most seriously affected by sprays of 5000 ppm followed by 3000 ppm. The spray application of 1000 ppm and drench of 5000 ppm showed no deleterious effect to appearance. High fertilizer rates stimulated chlorophyll regeneration following spray applications of chlormequat partially overcoming the induced chlorosis. Nitrogen and K in leaf tissue increased in all treatments as fertilizer of that mixture was increased but P decreased.
Abstract
A method is proposed for the germination of fungal-free seeds of Magnolia grandiflora as a source of tissue for in vitro experiments. A combination sequence of a 16 hour water-soak at 25°C, hot water (52°C) for 1 hour, and then surface sterilization for 1 hour in 1:1000 aqueous mercuric chloride was the best treatment. Dips in 2.5% chlorox, 95% ethyl alcohol and concentrated sulfuric acid soak for 20 minutes were unsatisfactory. If seeds are selected carefully and treated as described, 60 to 90% of the seeds will germinate aseptically within 30 days.
Abstract
Wax myrtle plants in 20 or 30 cm soil depths of peat, sand and soil mixture (1:1:1 v/v) were subirrigated for 75 days during January to April. Capillary watering maintained moisture adequate for plant growth in soil up to 30 cm depth. Plant growth improved in direct relation to the concentration of mineral nutrients applied to the medium surface as solutions of 20:8.6:16.6 (N-P-K) fertlizer. No toxic levels of soluble salts were detected even at the highest fertlizer rate. Adequate growth was produced in both soil depths but best with the 8× Solution and 20 cm depth and the 4× and 8× solutions with the 30 cm depth.
Abstract
Foliar application of 0.3% CCC applied to geranium (Pelargonium x hortorum Bailey) resulted in increased net photosynthesis (Pn), transpiration (Tr), chlorophyll concentration, and reduced photorespiration as measured by post lower illumination CO2 burst (PLIB) compared with plants treated with 0.5% SADH. Pn and Tr rates were enhanced beginning 2 to 3 days after the CCC treatment compared with control plants and remained elevated for a least 4 to 5 more days.
Abstract
Cineraria plants (Senecio cruentus DC) were transplanted into medium either with or without a hydrogel (polyethylene oxide). Half the plants in each medium were treated with a film-forming antitranspirant while half were not. Plants then were placed either in a clear glasshouse or a shaded glasshouse (40% shade), and no additional water was applied. Water loss was lowest for plants where both the foliage and medium were treated, whereas control plants (no treatment) lost water most rapidly regardless of light intensity. Plants which received only the hydrogel were similar in water loss to control plants at both light intensities. As water stress developed, net photosynthesis (Pn) decreased, reaching a zero rate at wilting; however, Pn measurements of treated leaves showed few significant differences due to treatment during the water stress period.
Abstract
Peach seed (Prunus persica (L.) Batsch, cv. Elberta) were stratified at 0°C in peat moss and analyzed for GA3 and GA7 at weekly intervals for 4 weeks and at 4 week intervals for 16 weeks. Percentage germination increased as GA3 and GA7 increased during stratification. The suggestion is made that there is a conversion of GA7 to GA3 during stratification and the biosynthesis is temperature dependent.