Zinc Levels in Pecan Leaflets Associated with Zinc Deficiency

摘要

LEAFLET ANALYSIS is widely used by pecan growers to determine the Zn (zinc) status of pecan trees. In most diagnostic laboratories, the zinc concentration of the leaflet of 50 to 100 or 60 to 100 parts per million zinc is considered sufficient. Pecantrees with less than 20 ppm Zn in the leaflets are zinc deficient. Thus, the reported sufficiency ranges are well above the deficiency range. However, in practice, leaflet samples are usually composite samples which rarely contain only zinc-deficient leaflets. Therefore, zinc values of up to 40 parts per million have been reported for zinc-deficient trees.