Increases in phosphatase and β‐glucosidase activities in wheat seedlings in response to phosphorus‐deficient growth

The ability of plants to utilize P efficiently is important for crops growing in P‐deficient soils or on soils with a high P‐fixing capacity. The purpose of this work was to investigate early physiological changes which occur when wheat (Triticum aestivum L.) seedlings were grown under P‐deficient conditions. Wheat plants were grown in a greenhouse and watered with nutrient solution containing or lacking P. During the interval 12 to 18 days after planting, the dry weight of wheat seedlings was similar regardless of P treatment, although the P‐deficient plants had a greater proportion of the total plant weight in the roots. Sixteen days after planting, the roots and leaves of P‐deficient plants had only 20 to 30% the P content of P‐sufficient plants. After 16 days, plants grown under P stress had 41% more p‐nitrophenol phosphatase activity and 70% more β‐glucosidase activity in shoot homogenates than was found in P‐sufficient plants. Changes in both enzyme activities may be involved in the mobilization of plant resources during the early stages of P‐deficient growth.