Air and Soil Temperature and Phosphorus Effects on Mineral Uptake and Distribution in the Pea Plant1

Abstract The effects of 4 air and soil temperature regimes and 3 levels of P on the concentrations and total contents of N, P, K, Ca and Mg in pea plant tissues were investigated in controlled environments. There were generally no significant interaction effects between temperature regimes and applied P when contents of these minerals were expressed as per cent of dry matter. When contents were expressed as total uptake into the various tissues there were significant interactions for all 5 minerals. At the pre-fruiting growth stages, tissue concentration of P generally increased with applied P, particularly at the highest rate. P concentration responses at the 10th node stage were similar to those at the 6th node, but there was a reversal of these effects at full bloom. The warm air temperature of 30°/21°C (day/night) generally increased P concentration but depressed total uptake compared with a temperature of 21°/13°. The increases were largely due to concentration effects resulting from smaller plants. Increases in P concentration at the high soil temperature of 18°, compared with 10°, were absolute because they occurred regardless of plant size. Applied P increased the total uptake of minerals as well as their translocation into the seed.