The 17 essential elements
Form used by plants:
Component or regulator cofactor of enzymes (dehydrogenase, proteinase, and peptidase enzymes)
Influences plant hormone proteins, for example auxin development, especially IAA (i.e., aids in the normal growth and fruiting processes).
Promotes starch formation
Ideal foliage range for apple leaves:
Ideal fruit concentration:
Ideal soil range:
0.5-0.75ppm (available Zn not total Zn levels)
Zinc is not very mobile in soils.
Mobility in plant:
Not remobilized within plant
Young leaves are affected first.
Leaves are smaller and narrower than normal ("little leaf").
Rosetting of leaves occurs.
Increased risk of Zn deficiencies on:
Excess problems/Interactions with other elements:
- Excess phosphate may encourage Zn deficiency
- Heavy N fertilization intensifies Zn deficiency. However, application of N fertilizer can stimulate plant growth and increase Zn requirements. Acid-forming N fertilizers will increase the uptake of both native and supplemental Zn. Neutral to basic products are known to depress Zn uptake.
- Excess Zn encourages iron deficiency and reduces manganese absorption
- Other metal cations, including copper(Cu2+), iron(Fe2+), and manganese (Mn2+), inhibit zinc uptake
- Application of calcium sulfate added to a slightly acid soil can increase the Zn and Fe concentrations in plants.
July 13, 2004