Abstract
Pine bark-filled containers were subjected to 10°, 20°, 30°, or 40°C for 24 days and fertilized periodically with 210 ml of a solution containing 100 ppm NH4-N. Every 6 days, medium solutions were tested for NH4-N and NO3-N concentrations and a NO3-N accumulation rate (NAR) was determined. Medium solution NH4-N concentrations were lower at 20° and 30° than at 10° and 40°, while those at 40° were considerably greater than at other temperatures and increased over time. In general, medium solution NO3-N concentrations at 10°, 20°, and 30° were comparable and higher than at 40°. Over time, the general order of NAR was 20° = 30° > 10° > 40°.
The most common components of soilless container media used by the nursery industry in the United States are bark from loblolly pine ( Pinus taeda L.) and douglas fir [ Pseudotsuga menziesii (Mirb.) Franco]. Loblolly PB is widely used by growers
In poplar (Populus deltoides) a 32kDa bark storage protein (BSP) accumulates during the fall, and is a major form of stored nitrogen during overwintering. This protein is induced by short-day (SD) photoperiod and may play an important role in nitrogen cycling in the plant. To determine the effect of plant nitrogen status upon BSP gene expression, poplar plants were grown in controlled environmental chambers under either SD or long-day (LD) photoperiods and watered with either 5, 10, 50, and 100 mM NH4NO3 for four weeks. [15N]-NH4NO3 was applied during the first and third weeks. SDS-PAGE and western blot analysis were used to detect the relative amounts of BSP. RNA gel blot analysis was used to determine the changes in BSP gene expression. BSP accumulation was enhanced by increasing levels of nitrogen under both photoperiods, however, SD photoperiod appears to moderate the response. These results indicate that BSP gene expression is dependant upon the nutritional status of the plant. [15N] analysis will also be presented.
Abstract
Suppressed growth and chlorotic leaves of Japanese holly (Ilex crenata, Thunb. ‘Hetzii’) when grown in hardwood bark, were caused by the uptake of excessive amounts of available Mn in bark leachates.
Abstract
Hardwood bark was used in combination with other materials as media for forsythia and juniper plants in containers with various growing procedures, bark sources, and fertility practices. Based on dry wt, the most rapid growth of forsythia was obtained in a bark and fine sand medium; whereas, the least growth was obtained in soil, peat, and perlite. However, pfitzer juniper plants under 2 different fertility regimes grew most rapidly in a bark, soil, and peat medium, slowest in a bark and torpedo #2 sand medium, and at an intermediate growth rate in soil, peat, and perlite. The standard mix (soil, peat, and perlite) was more acidic than the experimental mixes containing bark and sand. Chlorotic plants were more numerous in acidic mixes. Leaf tissue analyses from the plants grown in the peat amended bark and standard mix had higher Fe and Mn concn than plants grown in a bark-sand mix.
In recent years, several peat and pine bark (PB) alternative substrates have been developed and researched in the United States and throughout the world. The interest in new substrates is in response to the increasing cost and environmental issues
Abstract
Trunk bark thickness of 6 peach clones was significantly affected by seedling root-stocks of peach (Prunus persica (L.) Batsch). Of the 7 rootstocks tested, Siberian C invariably induced the thickest bark in the scion while Lovell and Halford induced the thinnest scion bark. However, Siberian C grown as unbudded seedling trees did not produce thicker bark than the other rootstocks, similarly grown. The effect was not site- or cultivar-dependent.
Abstract
Yields of greenhouse tomato (Lycopersicon esculentum Mill.) increased in bark or sawdust when the media had been prior cropped. Bark produced more marketable fruit than sawdust No unusual plant diseases were noted and root-knot nematode symptoms (a chronic problem in soil) were not observed on roots in either sawdust or bark.
Abstract
Internal porosity, availability of internally adsorbed water, and root growth within a pine bark particle were studied. Internal pore spaces comprised about 43% to 44% of the volume of a pine bark particle. Scanning electron microscopy (SEM) of Coleus blumei Benth. and Vaccinium ashei Reade showed roots anchored on the exterior surface and developing within the bark particle. Seedling development (Raphanus sativus L.) in water-saturated pieces indicated that internally adsorbed water was available provided that roots developed within the bark particle. The quantity of available water remains to be determined.
Abstract
When a 200 ppm N solution as (NH4)2SO4 was percolated through a wet pine bark medium, 6 times the medium volume of the N solution was required to reach an equilibrium of N in the bark. Once equilibrium was reached, the water added, leaching of the ammonium ion was rapid. When twice the medium volume of water was passed through the medium, 85% of the ammonium ions were leached. After analysis of the leachate indicated no N being leached from the bark, 60 ppm of N remained in the bark.