Plant Box Research Articles

A new root box for developing whole root systems in water culture

We have established a new plant box made of phenolic resin foam for developing whole root systems in water culture, and examined its application to the detection of changes in pH and the distribution of nutrients in the rhizosphere. The root box is light and soft, providing the cultures with ample air. In well-washed resin sheets, little NH4-N, NO3-N or K remained. Also CEC was low and the pH of the supplied solutions did not change in the resin. Therefore, culture using the root box allows for nutrient solutions to maintain their own pH and concentration of NH4-N, NO3-N and K. In addition, the root box allowed better visualization of changes in pH and the distribution of nitrate by image analysis in a representative whole root system. The pH values were detected with pH indicators, and the nitrate concentrations with a color reagent, sprayed onto profiles of the root system. The method described here offers a new approach for developing the whole system in water culture and a simple way to obtain an overall view of changes in pH and the distribution of nutrients in the rhizosphere under water culture conditions.

An in vitro microplant bioassay using clonal white ash to test for tall fescue allelopathy

Axillary shoots from three selected white ash (Fraxinus americana L.) clones were harvested from in vitro shoot cultures. Roots were initiated by pulsing excised shoots for eight days in the dark in MS medium supplemented with 2% sucrose, 0.7% agar, 5 μM NAA, and 1 μM IBA. Pulsed shoots were transferred to a root elongation medium consisting of 25% MS macrosalts, full-strength microsalts and organics, 1% sucrose, 0.7% agar and no auxins. When roots were visible (6–10 days after transfer to root elongation medium), microplants were transferred to vessels containing the same minimal medium and tall fescue (Festuca elatior var. arundinacea (Schreb.) Wimm.) leaf extracts, leaf leachates, or soil leachates from plant boxes with and without tall fescue sod. After four weeks in vitro, primary adventitious and secondary root growth was reduced by extracts obtained from 5 and 10 g ground leaves per 100 ml of medium. Leachates obtained from 5 g soaked leaves per 100 ml of medium stimulated primary root growth. Soil leachates from bare soil also stimulated primary root growth. Variation was observed among the clones for root growth when plantlets were grown in extracts or leachates from tall fescue.

Community dynamics of evergreen broadleaf forests in southwestern Japan. II. Species composition and density of seeds buried in the soil of a climax evergreen oak forest

The species composition and density of seeds in the soil of a climax evergeen oak forest in the Kasugayama Forest Reserve, Nara, Japan were studied by directly extracting seeds from soil samples and using soil samples in planting boxes as the basis of germination tests.