from plants excised 5 s after spraying with L(+)-adenosine,
the first 20 pL contained about 40% more Ca2+ and 20%
more Mg2+ than exudate from controls sprayed with water
(Fig. 1). These same exudates from L(+)-adenosine plants
contained significantly less K+ compared to control plants.
However, Kf concentration increased dramatically and exceeded
the control by more than 2 mM in the fourth, fifth,
and sixth 20-pL fractions (Fig. 1). In contrast, when stem
excision was delayed for 24 min, K+ concentrations were less
in exudates from the control than from L(+)-adenosinetreated
plants. The CaZ+ and Mg2+ concentrations in the
exudates of both controls and treatments increased in successive
fractions, whereas the K+ concentration decreased in the
controls. Twenty-four minutes after treatment with L(+)-
adenosine, there was little difference in Ca2+ and Mg2+ concentration
in exudates from controls and treatments, which
indicated that L(+)-adenosine had caused a transient increase
in ion concentration (Fig. 1).
In a study where tomato shoots were excised 5 s, 1 d, and
7 d after treatment with water or L(+)-adenosine, only the 5-
s L(+)-adenosine treatment showed significantly higher Ca2+,
Mg2+, and K+ concentrations (Table 11). In contrast, the K+
concentration was higher in the controls than in the L(+)-
adenosine plants harvested 1 and 7 d after treatment. Plants
from the same population that showed the rapid cation
response (5 s) to L(+)-adenosine also grew more rapidly than
controls, as measured by shoot dry weight 1 and 7 d after
treatment (Table 11).