Effects of Temperature On Growth and Nutrient Uptake In Subterranean Clover During Recovery From Phosphorus Stress

Abstract

SummarySubterranean clover plants (Trifolium 8ubterraneum L., cv. Mt. Barker)were grown in nutrient solutions with a deficient and an optimum phosphorus supply in three temperature regimes (27°0 day/22°0 night, 21/16°0, and 15/10°0). They were then transferred to full nutrient solutions (optimum phosphorus) and plants from each pretreatment grown for a further 7 days in each of the three temperature regimes.Phosphorus uptake during the 7 days after transfer of the non·deficient plants, as well as its distribution to the shoots, was greater at high than at low temperatures, suggesting a greater demand for phosphorus at the higher growth rates induced by the higher temperatures. By contrast, the uptake of phosphorus by the plants recovering from phosphorus stress was little affected by temperature differences before or after transfer to complete solutions and was always greater than that by the non· deficient plants. However, the proportion of the phosphorus taken up during recovery which was distributed to the leaves was greatest for the plants raised at the highest temperature, possibly due to the greater severity of stress in these plants compared with those from lower temperatures.