Abstract
The response of Chrysanthemum morifolium Ram. to drench applications of ancymidol was reduced if the potting media contained high quantities of ground pine bark. Aqueous movement of ancymidol was restricted by pine bark and sand in leaching tests. Bioassays with Setaria italica (L.) Beauv. indicated that the immobile ancymidol fraction in upper segments of pine bark and sand columns retained excellent biological activity.
Hosta (Hosta tokudama Makeawa `Newberry Gold') plantlets were micropropagated photoautotrophically (without sucrose in medium) or photomixotrophically (with 2% sucrose in medium) for 3 weeks at 23 °C under 80 μmol·m-2·s-1 photosynthetic photon flux (PPF) prior to long-term storage. Plantlets were stored for 4, 8, or 12 weeks at 5, 10, or 22 °C in darkness or under white (400-800 nm), blue (400-500 nm), or red (600-700 nm) light at or near light compensation points. Illumination during storage was necessary to maintain dry weight and regrowth potentials of plantlets in vitro, but light quality had no effect on these parameters. All photoautotrophic plantlets stored in darkness were of poor quality at the time of removal from storage and died when transferred to the greenhouse. Dark-stored photomixotrophic plantlets survived storage for 12 weeks at 5 °C, but declined in appearance (visual quality) as the storage duration increased. Decline in visual quality was greater when plantlets were stored at 10 and 22 °C. Leaf dry weight of illuminated plantlets increased and percentage of leaf yellowing decreased as storage temperature increased. Recovery of illuminated plantlets from photomixotrophic storage was best when plantlets were stored at 22 °C. These plantlets were characterized by increased visual quality (color and form) and increased dry weight compared with those in other treatments. After 60 days in the greenhouse, the dry weight of these plantlets was similar for 4-, 8-, and 12-week storage durations, indicating flexibility in storage time if specific light and temperature provisions are met.
Five cuttings from different node positions on stock plants were taken from each of 3 Clematis cultivars (Jackmani, Contesse de Bouchard, and Gypsy Queen) and Clematis purpurea plena elegans. Actively growing plants with 5 nodes were acquired. Node number increased from 1 at the base of the plant to 5 at the tip of the plant. Cuttings were treated with or without 0.1% IBA (indole-3-butyric acid) and placed in 1 of 5 different media: 100% washed sand (WS), 50% washed sand and 50% sphagnum peat (WP), 50% sphagnum peat and 50% perlite (SP), 100%) perlite (PT), or 50% sphagnum peat plus 25% perlite plus 25% vermiculite (PV). Rooting date, primary and secondary root number, and root dry weight were collected after 8 weeks. `Gypsy Queen' showed the earliest rooting with the greatest root development. Jackmani showed the worst rooting. Media WS and PT showed the best rooting whereas WP and SP showed the worst. Cuttings taken from the first 3 nodes rooted the best. As node position increased root number and dry weight decreased and time to root increased. Application of IBA had no significant effect on time to root or degree of rooting.
Hybrid lilies(4 oriental & 2 asiatic) species were grown in commercial potting media formulations containing various percentages of composted bark. Lilies were grown in greenhouse sections maintained at either 21C day temperature and 15C night temperature or 15C day temperature and 21 C night temperature from emergence until anthesis. The growth retardants Paclobutrazol (Bonzl) and Uniconazole (Sumagic) were applied as a media drench at 0.25 mg a.i. per pot. Final height, days to flower from planting, days to flower from visible bud, and flower number were recorded for each treatment. Plant height was significantly reduced by potting media formulation, growth retardant treatment, and temperature regime. The effects of these treatments on bud number, and days to flower will also be discussed.
Thermal properties of pine bark: sand container media as a function of volumetric water content and effectiveness of irrigation as a tool for modulating high temperatures in container media were studied. Volumetric water and sand content interacted to affect container medium thermal diffusivity. Adding sand to a pine bark container medium decreased thermal diffusivity if volumetric water content was less than 10 percent and increased thermal diffusivity if volumetric water content was between 10 and 70 percent. Thermal diffusivity was greatest for a 3 pine bark : 2 sand container medium if volumetric water content was between 30 and 70 percent. Irrigation was used to decrease temperatures in 10-liter container media. Irrigation water at 26°C was more effective if 1) volumes equaled or exceeded 3000 ml, 2) applications were made during mid-day, and 3) sand was present in the container medium compared to pine bark alone. However, due to the volume of water required to lower container media temperatures, nursery operators should first consider reducing incoming irradiance via overhead shade or container spacing.
Abstract
The addition of peat-perlite to backfill soil increased the initial root movement through the backfill of transplanted holly (Ilex crenata Thunb. cv. Green Luster) grown in a peat-perlite medium. Backfill composition had no effect on the initial movement of roots of plants grown in a soil-peat-sand or pine bark-sand medium.
Abstract
Tomato plants ‘Campbell 1327’ grown in peat with NH4 nutrition had no visible symptoms of NH4 toxicity, while severe symptoms of NH4 toxicity were displayed in solution or sand culture. Growth of plants was much better with NO3-N than NH4-N in sand, vermiculite, or solution culture; but in peat, growth of NH4-treated plants equalled or exceeded that of NO3-treated plants in sand, vermiculite, and peat. The total dry weight of NH4-treated plants grown in peat was 2, 2.5, and 3.4 times higher than plants grown in vermiculite, sand, and solution culture, respectively. Content of uncomplexed ASHS.109.3.406 in NH4-treated plants grown in peat was reduced markedly compared with other media. NH4-treated plants grown in sand, vermiculite, and solution culture, displaying NH4 toxicity symptoms, had a total amino acid:free NH4 + molar ratio < 2, compared to 6-8 with NO3. For NH4-treated plants grown in peat the ratio was similar to that of NO3-treated plants. Asparagine and glutamine in NH4-treated plants grown in peat were 3.5 and 11.3 times higher than with NO3-N, indicating a high efficiency in detoxification of NH4 through incorporation into these amino acids. The medium on which a plant is grown can have a marked influence on the plant response to N form.
Abstract
Semi-hardwood cuttings of Ligustrum japonicum Thunb. and Juniperus conferta Pari, were propagated in sand or sand-peat (1:1 volume/volume and top-dressed with 18-6-12 or 14-14-14 Osmocote (18N—2.6P—10.OK and 14N—6.OP—16.6K, respectively). Percent rooting was improved by Osmocote after 8 weeks although all L. japonicum cuttings were rooted after 12 weeks. Fresh weight of roots and dry weight of tops were improved by Osmocote treatment. N and P levels of leaf tissue increased with Osmocote top dressing compared to unfertilized controls. Percent rooting was initially superior in sand but after 10 weeks all cuttings were rooted and root development was greater in sand-peat.
‘Elizabeth’ and ‘Yellow Bird’ ( Biedermann, 1987 ). These studies indicated basal salt composition and plant growth regulators were important factors influencing in vitro propagation of magnolia. Culture media comprised of Murashige and Skoog (1962) basal
extract ( Robbins and Wiegand, 1990 ). Nutrient composition of media samples was determined by inductively coupled plasma (ICP) spectrophotometry after extraction using Mehlich 1 for P, K, Ca, Mg, and Na, DPTA for Cu, Zn, Fe, and Mn, and hot water for B