An approach to determine solution properties in micro pipes by near-field microwave microscopy

In this article, we propose a quantitative, non-destructive and noninvasive approach to obtain electromagnetic properties of liquid specimens utilizing a home-designed near-field microwave microscopy. The responses of aqueous solutions can be acquired with varying concentrations, types (CaCl2, MgCl2, KCl and NaCl) and tip-sample distances. An electromagnetic simulation model also successfully predicts the behaviors of saline samples. For a certain type of solutions with varying concentrations, the results are concaves with different bottoms, and the symmetric graphs of concave extractions can clearly identify different specimens. Moreover, we obtain electromagnetic images of capillaries with various saline solutions, as well as a photinia x fraseri Dress leaf.

Thermal Weed Control in Photinia x fraseri “Red Robin” Container Nurseries

A near-zero tolerance policy on weeds by markets for nursery crops calls for weed-free container-grown plants, and forces growers to frequently remove weeds. Thermal weed control could represent a novel method to control weeds in shrubs from container nurseries, thus avoiding the use of herbicides and mulches. The aims of this study were to develop custom-built machinery for thermal weed control in container nurseries and to test the weed control efficiency of flame weeding and steaming in Photinia x fraseri “Red Robin” containers. A liquefied petroleum gas (LPG) fed flamer and a steamer with a dedicated diffuser were built. Four treatments were applied for a total period of 24 months: steaming once every four months, steaming once every two months, flame weeding once every two months or once a month. Temperature values measured at different depths in the substrate after thermal applications were recorded and analyzed. Photinia x fraseri features (height, diameter, and dry biomass) and aesthetic parameters as affected by thermal treatments were also evaluated. The trend in temperature values of the substrate over time followed a two-phase exponential decay. All the thermal treatments lead to a continuous near-100% weed control level, which is the level required by growers for aesthetic reasons. No damages caused by heat on Photinia x fraseri were observed. Container nursery producers could thus adopt thermal methods as a substitute for chemical solutions for weed control management. Keywords: Container nurseries, ornamental plant production, Thermal weed control, Flame weeding, Steaming, Photinia x fraseri “Red Robin”, Two-phase temperature decay model.

BRANCHING AND VEGETATIVE GROWTH MODIFICATION OF PHOTINIA X FRASERI WITH EXOGENOUS PLANT GROWTH REGULATORS

Four rates of seven plant growth regulators were foliar-applied to 11.4 liter containers of Photinia × fraseri after initial root establishment. Growth regulators studied were uniconazole, paclobutrazol, dikegulac-sodium, ancymidol, 6-BA, GA4+7 and, 6-BA + GA4+7. Six months after application, plant height, plant width, growth index, and number of lateral and terminal branches were recorded. Applications of uniconazole (30 mg a.i./liter), 6-BA alone or in combination with GA4+7, and dikegulacsodium stimulated lateral branching. The number of lateral branches increased linearly as paclobutrazol rates increased from 60 to 180 mg a.i./liter. Growth index decreased with increasing application rates of uniconazole and paclobutrazol, while the growth index of photinia treated with other growth regulators wasn't affected by application rate. Plant height was increased in GA4+7 treated plants.

Growth Response of Photinia and Thuja and Nutrient Concentration in Tissues and Potting Medium as Influenced by Composted Sewage Sludge, Peat, Bark and Sawdust in Potting Media

Composted sewage sludge was blended with pumice and either bark, peat moss, or sawdust to form 6 potting media. Increasing the proportion of compost in media from 25 to 50% caused increased initial pH, electrical conductivity (EC), and airfilled pore space (AS) in all media, and increased growth of Photinia x fraseri Dress. and Thuja occidentalis L. ‘Pyramidalis.’ Sawdust-containing media had the highest pH, EC, and AS; sphagnum peat-containing media the highest water holding capacity and greatest shrinkage; bark-based media the highest bulk density. Plant growth in compost-based media containing peat or bark was equal to or better than that in two commercial media composed primarily of bark or peat.

Branching of Photinia x fraseri in Response to Growth Regulators and Fertilizer

Container grown photinia plants treated with 6-benzylamino purine (BA) or dikegulac (Atrinal) had 3 to 4 times as many branches as untreated plants. Branching was greatly increased by applying 10 to 15 gm (2-3 tsp) of Osmocote 18N-2.6P-10K (18-6-12) to supplement the fertilizer in the container mix. Application of Atrinal increased branching an additional 100% at the highest fertilizer level. Hand pinching the day before the first Atrinal application increased branching in one experiment, but hand pinching 11 days before the first Atrinal application had no effect on the response to Atrinal in another experiment. BA and N-(phenylmethyl)-9-(tetrahydro-2H-pyran-2-yl)-9H-purin-6-amine (Accel) increased branching when applied with Off-Shoot-O (OSO), and had less effect or no effect without OSO. Adding a phosphate buffer (Buffer-X) to prevent precipitation of BA further increased the response to the BA plus OSO treatment.