Figure 1. The effect of abscisic acid (ABA) (A), after-ripening
(B,C) and class I ß-1,3-glucanase (ßGlu I) sense and antisense
transformation on the kinetics of testa and endosperm rupture during tobacco
seed germination. The incidence of testa and endosperm rupture is expressed
as the percentage of sense-ßGlu I (TKSG7), antisense-ßGlu I
(TKAG4) and empty-vector (TCIB1) seeds scored with time after the start
of imbibition in continuous light. (A) The effect of ABA on testa
and endosperm rupture of after-ripened seeds incubated in medium without
(Control) and with 10 µM ABA added. (B,C) The effect of after-ripening
on testa rupture (B) and endosperm rupture (C) investigated
by comparing fresh and after-ripened TKSG7, TKAG4 and TCIB1 seeds incubated
in control medium. Note that ßGlu I is over-expressed in TKSG7 seeds,
but that TKAG4 seeds express TCIB1-like levels of ßGlu I during endosperm
rupture. The antisense-ßGlu I transformation therefore only affects
testa rupture of TKAG4 seeds and the delay in endosperm rupture is attributed
to the delay in testa rupture. Means of single line mean values from several
independent lines are presented; the single line mean values ± SE
are published in Leubner-Metzger and Meins (2000),
Leubner-Metzger and Meins (2001) and
Leubner-Metzger (2002).
© Gerhard Leubner-Metzger, Seed
Science Research 13: 17-34 (2003)
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CABI Publishing