Immunolocalization of cytokinin bases within
vegetative shoot apices. The location of cytokinin bases in
longitudinal sections was determined using immunohistochemistry.
Nitroblue tetrazolium/5-bromo-4-chloro-3-indolyl phosphate was used as
chromogenic substrate for the AP, resulting in a purple reaction
product. Immunolocalization of zeatin (a and d), DHZ (b and e), and IP
(c and f) in vegetative shoot apices at developmental stages I1 (a, b,
and c) and I2 (d, e, and f) (Fig. 1). Purple staining is present for
zeatin (a and d) in the nucleus and cytoplasm, whereas for DHZ (b and
e) and IP (c and f) a more perinuclear purple staining is visible.
Arrows in a, b, d, and f point to staining in the lateral zones of the
meristems. g and h, Sections (from stage I1, see Fig. 1) incubated with
anti-zeatin (g) and anti-DHZ (h) antibodies saturated with zeatin and
DHZ as a control, respectively. Bars = 90 μm (a, b, d, e, g, and
h); 45 μm (c); and 22 μm (f).