Respiration and plasma membrane ATPase in strawberry stolons

The biochemical, physiological and anatomical properties of strawberry (Fra garia ananassa Duch.) cv. 'Cambridge Favourite' stolons were studied during growth. ATPase activity was measured, in microsomal and plasma membrane fr actions, along with chlorophyll determination, in-situ photosynthesis measu rements and scanning electron microscopy (SEM) and X-ray microanalysis of s tolon cross-sections. Potassium-stimulated ATPase activity and proton-pumpi ng, both together indicating the presence of plasma membrane ATPase, was gr eatest in the stolon tip, the tissue with the fastest growth and respirator y activity. The enzyme activity and respiration gradient from the tip of th e stolon to the base was concomitant with xylem development which was more differentiated in the base than in the tip. These cross-sections also showe d 30% greater amounts of calcium and potassium of the cryo-preserved basal part relative to the stolon tip. This gradient existed independent of the p resence of daughter plants. A hypothesis is presented which suggests that f or the long-distance longitudinal transport of nutrients this gradient betw een stolon tip and base is likely to be involved in stolon growth.