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• 1. [Article] Growth rate and phosphorus uptake of wheat (Triticum aestivum VILL., Host) as a function of soil water suction and soil temperature

  The effect of soil temperature and soil water suction on the rate of phosphorus uptake and growth rate of wheat (Triticum aestivum VILL. , Host) was studied. Plants were grown in perlite slabs separated ...

  Citation × Citation Citation Abstract Copy Title: Growth rate and phosphorus uptake of wheat (Triticum aestivum VILL., Host) as a function of soil water suction and soil temperature Author: Fazilat, Mohammad The effect of soil temperature and soil water suction on the rate of phosphorus uptake and growth rate of wheat (Triticum aestivum VILL. , Host) was studied. Plants were grown in perlite slabs separated from an osmotic solution by a semi-permeable membrane. Measurements were made at temperatures of 10.0, 18.3, 23.9, 32.2, and 35.0°C, and soil water suctions of 0.35 and 2.5 bars. Five week old wheat seedlings were exposed to these conditions. The dry weight of shoots and roots was determined at two day intervals. Plant material extracted was analyzed for phosphorus concentration. The color intensity was measured on a Bausch and Lomb spectronic 20 spectrophotometer of 420 millimicrons. In general, a constant growth rate, which was approached exponentially during the experimental period was found in all treatment combinations. Growth rate for both shoots and roots was slow at low root temperatures and had a maximum rate at a root temperature of 24.0°C. High soil water suction was a limiting factor in growth rate. Phosphorus concentration of shoots and roots was found to approach a constant value during the experimental period according to the equation y = a+be[superscript]-0.07t[superscript]3/2 where y is the phosphorus concentration, t is the time in days, and a and b are constants. Over the entire range of soil temperatures considered the phosphorus concentration of the shoots increased linearlly with the root temperature, but the phosphorus concentration of the roots slightly decreased by increasing soil temperature and did not increase until the root temperature was about 32.0°C. There was no evidence of much variation in percent of total phosphorus uptake transported to the shoot in the experiments. Trans location of phosphorus from roots to shoots did not appear to be a limiting factor for phosphorus uptake at the low root temperature. It was suggested that the low rates of phosphorus uptake at the low root temperatures resulted from the low level of metabolic activity. Title: Growth rate and phosphorus uptake of wheat (Triticum aestivum VILL., Host) as a function of soil water suction and soil temperature Author: Fazilat, Mohammad The effect of soil temperature and soil water suction on the rate of phosphorus uptake and growth rate of wheat (Triticum aestivum VILL. , Host) was studied. Plants were grown in perlite slabs separated from an osmotic solution by a semi-permeable membrane. Measurements were made at temperatures of 10.0, 18.3, 23.9, 32.2, and 35.0°C, and soil water suctions of 0.35 and 2.5 bars. Five week old wheat seedlings were exposed to these conditions. The dry weight of shoots and roots was determined at two day intervals. Plant material extracted was analyzed for phosphorus concentration. The color intensity was measured on a Bausch and Lomb spectronic 20 spectrophotometer of 420 millimicrons. In general, a constant growth rate, which was approached exponentially during the experimental period was found in all treatment combinations. Growth rate for both shoots and roots was slow at low root temperatures and had a maximum rate at a root temperature of 24.0°C. High soil water suction was a limiting factor in growth rate. Phosphorus concentration of shoots and roots was found to approach a constant value during the experimental period according to the equation y = a+be[superscript]-0.07t[superscript]3/2 where y is the phosphorus concentration, t is the time in days, and a and b are constants. Over the entire range of soil temperatures considered the phosphorus concentration of the shoots increased linearlly with the root temperature, but the phosphorus concentration of the roots slightly decreased by increasing soil temperature and did not increase until the root temperature was about 32.0°C. There was no evidence of much variation in percent of total phosphorus uptake transported to the shoot in the experiments. Trans location of phosphorus from roots to shoots did not appear to be a limiting factor for phosphorus uptake at the low root temperature. It was suggested that the low rates of phosphorus uptake at the low root temperatures resulted from the low level of metabolic activity. Close