Sand Culture System Research Articles

Mass screening of Prosopis (mesquite) seedlings for growth at seawater salinity concentrations

The salt tolerance of Prosopis from highly saline environments of West Africa, Chile, Argentina, and the United States was compared to high-biomass-producing Prosopis identified in earlier field trials and to a Leucaena leucocephala cultivar. One hundred seedlings of each of ten accessions were grown in a hydroponic sand-culture system in the greenhouse in which the NaCl concentration of the nutrient solution was increased from 0.0%, 1.2%, 1.8%, 2.4%, 3.0%, to 3.3% (seawater). Prosopis tamarugo died early in the experiment due to fungal diseases. Leucaena leucocephala K67 and P. pubescens died at the 1.2% NaCl concentration. A Prosopis glandulosa var. glandulosa 1115 accession from Texas grew in the 1.2% NaCl but died in 3.0% NaCl. Prosopis alba 0166, P. alba/nigra 1117, P. articulata 0016, P. chilensis 0009, and P. juliflora 0044 all had seedlings which grew in the 3.3% NaCl treatment. Eighty of the seedlings which grew in the 3.3% NaCl have been repotted and propagated by rooting of cuttings. Each of the species which grew in 3.3% NaCl have been previously shown to fix nitrogen so these clones have potential for use as N-fixing halophytes. No other legume genus has been demonstrated to have such high salt tolerance, and Casuarina is the only other terrestrial N-fixing genus with equivalent salt tolerance.

Microsclerotial germination ofVerticillium dahliaeas affected by rape rhizosphere

The germination of nylon net-trapped microsclerotia of Verticillium dahliae pathogenic to rape (Brassica napus) was assessed in different systems by fluorescence microscopy using fluorescein diacetate. The influence of the culture's age and the size of the microsclerotia on germination percentages was assessed in water, mineral salts solution and mineral salts solution plus sucrose for 3 V. dahliae isolates. Large microsclerotia germinated better than smaller ones. The microsclerotia of 2 isolates showed decreased germination percentages with culture age over a 4–11-week period. Microsclerotial germination percentages were always higher in mineral salts solution plus sucrose than in mineral salts solution alone or water. In a sand culture system with the intact rape plant, microsclerotial germination percentages were high close to the root and decreased in a steep gradient to background levels within 5 mm from the root.

Microsclerotial germination of Verticillium dahliae as affected by rape rhizosphere

The germination of nylon net-trapped microsclerotia of Verticillium dahliae pathogenic to rape ( Brassica napus) was assessed in different systems by fluorescence microscopy using fluorescein diacetate. The influence of the culture's age and the size of the microsclerotia on germination percentages was assessed in water, mineral salts solution and mineral salts solution plus sucrose for 3 V. dahliae isolates. Large microsclerotia germinated better than smaller ones. The microsclerotia of 2 isolates showed decreased germination percentages with culture age over a 4–11-week period. Microsclerotial germination percentages were always higher in mineral salts solution plus sucrose than in mineral salts solution alone or water. In a sand culture system with the intact rape plant, microsclerotial germination percentages were high close to the root and decreased in a steep gradient to background levels within 5 mm from the root.

A Sand Culture System for Simulating Plant Responses to Phosphorus in Soil1

Abstract A sand medium containing activated alumina was developed to provide a range of stable, reproducible P concentrations in plant cultures. The lowest P levels compare favorably to concentrations found in soils. Activated alumina was “loaded” by absorption of phosphate from 0.01 m NaCl solutions containing KH2PO4. Phosphorus concentrations in solutions expressed from sand-alumina mixtures were dependent upon the P concentrations used to absorb P onto the alumina. Increasing the density of a specifically loaded alumina did not affect the average solution P concentration in the cultures but did result in substantial increases in total dry weight yields of tomato (Lycopersicon esculentum Mill.) plants grown in the cultures. Thus, diffusion of P to root surfaces seems to be a prominent limiting factor in this system as in soils. The sand alumina culture technique shows promise for simulating plant responses to P at concentrations and under conditions comparable to those found in soils.

Hydroponic sand culture systems for mycorrhizal research

Tomato plants were inoculated withGlomus fasciculatus mycorrhizal fungi while growing in sand through which recycled nutrient solution was automatically passed several times daily. Concentration of P and N in the solution were maintained at relatively low levels. Roots of inoculated plants became highly infected with mycorrhizal fungi, and yield parameters were significantly increased with inoculation over uninoculated control plants.

Effect of strength of nutrient solution on the growth and nutrient uptake of pistachio seedlings

Abstract In an effort to find the most appropriate nutrient solution for the growth of pistachio seedlings, three major Iranian pistachio cultivars, Badami and Fandoghi (Pistacia vera L.) and Beneh (Pistacia terebinthus L.) seedlings were grown in an automated sand culture system in a glasshouse for 8 weeks. Treatments included 0, 1/8, 1/4, 1/2, 1, 2, 4, 8, and 10 strength Hoagland solution. Aerial and root growth as well as the uptake of P, Na, K, Ca, Mg, Zn, Cu, Fe, Mn, and B were determined. Highest growth of aerial and root portions were associated with dilute (1 strength nutrient solution or lower) and tolerance of media salinity was higher by Badami and Fandoghi than by Beneh.

Physiological aspects of nitrate utilisation in a barley variety exhibiting high seed protein content

AbstractA barley variety (Hiproly) which exhibits high seed protein content, was compared with the commercial variety, Ymer. Plants were raised to the seedling stage using a sand culture system. The effects of humidity, nutrient NŌ3‐N level, and stage of development, on leaf and root protein and NŌ3‐N contents, were assessed. The major difference between varieties was observed when the regression of leaf NŌ3‐N (mg/plant), on root NŌ3‐N (mg/plant) was examined. Unit increase in total root nitrate results in a larger increase in leaf nitrate in Hiproly than in Ymer. Possible explanations for this difference are discussed.

Influence of Iron Supply on Peroxidase Activity and Peroxidase Isozymes in Corn (Zea mays)1

Plants of Oh43 ✕ Wf9 corn (Zea mays L.), grown in sand culture system, were watered daily with nutrient solution containing 0.025, 1.25, or 2.5 ppm Fe. Plants also were grown in a soil‐sand mixture. Leaf extracts were assayed quantitatively for peroxidase activity, and sampies of the extracts were subjected to gel dectrophoresis. A positive relationship was observed between Fe supply and proxidase activity. Numerous peroxidase isozymes were detected by gel electrophoresis. As judged by intensity of the hands, all isozymes appeared to be influenced by Fe supply.