Rosette and little leaf at the shoot tip are the most characteristic symptoms of Zn defi-Rosette and little leafat the shoot tip are the most characteristic symptoms of Zn deficiency in fruit trees (Swietlik, 2002). In marginally Zn deficient soils,yield and quality
can be affected without the obvious appearance of symptoms; this is called ‘hidden’
(or ‘latent’) deficiency (Alloway,2008, 2009). Some studies have reported that dry
matter production is reduced by 40% or more by hidden Zn deficiency (Carroll
and Loneragan, 1968). Given these circumstances, the understanding to the intrinsic
changes in the physiological processes of leaves affected by hidden Zn deficiency
may be helpful to determine the initial damages caused by Zn deficiency along with
the final development of deficiency symptoms.