ASPECTS OF THE PHOSPHORUS-NUTRITION OF WHITE CLOVER POPULATIONS .2. ROOT EXOCELLULAR ACID-PHOSPHATASE-ACTIVITY

The effect of phosphorus (P) level, solution pH, aluminium (Al) level on root exocellular acid phosphatase activity of white clover (Trifolium repens L.) populations was investigated in three experiments. Lotus peduculatus Cav. cv. Maku was also included in one experiment. Phosphatase activity increased with decreasing P and increasing Al supply, but was unaffected by the solution pH at which populations had been grown. There was usually a significant negative correlation between acid phosphatase activity and parameters measuring plant size, for plants grown at adequate P levels, but in only one of the three experiments were there significant differences between white clover populations for phosphatase activity. There was no clear correlation between the acid phosphatase activity of populations and the P status of soil from which they were collected.