The 17 essential elements
Form used by plants:
Cu+ or Cu2+
Important enzyme component (laccase and other oxidase enzymes) and in the production of vitamin A
Critical in the role of photosynthesis, protein and carbohydrate metabolism, and respiration
Contributes to the color and flavor development in fruits and vegetables
Necessary in the formation of seed and chlorophyll
Involved in the use of Fe by plant
Stimulates lignification of all plant cell walls
Ideal foliage range for apple leaves:
Ideal fruit concentration:
Ideal soil range:
>0.6ppm (using DTPA method; this is not total Cu but available Cu).
Soils deficient in Cu are rare.
Copper is strongly sorbed by soil components and is not readily mobile.
Mobility in plant:
Not remobilized within plant
Vegetation symptoms: “Wither tip” occurs. Leaf margin chlorosis of young leaves first. Shoots grow normally at first but in mid-June the terminal leaves turn yellow, wither and fall. Dieback of terminal shoots; stunted growth; poor pigmentation; wilting and eventual necrosis of leaf tips. Can occur over part or most of the tree.
Fruit symptoms: undersized fruit and reduced yield
Increased risk of deficiencies:
Availability decreases as pH increases but more closely associated with organic matter content
Excess problems/Interactions with other elements:
- Excess Cu may reduce Mo (molybdenum) and Mn (manganese) uptake by plants
- Excess Cu encourages Fe (iron) deficiency
- Excess phosphate may encourage Cu deficiency
- Heavy nitrogen fertilization increases Cu deficiency
July 13, 2004