Plant Journal 23: 215-221 (2000)

Sense transformation reveals a novel role for class I ß-1,3-glucanase in tobacco seed germination

Gerhard Leubner-Metzger and Frederick Meins, Jr.

Model relating afterripening, ßGLU I and endosperm rupture

Figure 2. A speculative model relating afterripening, class I ß-1,3-Glucanase (ßGLU I) and endosperm rupture.
According to the model, ßGLU I, which is transcriptionally down-regulated by ABA, contributes to endosperm wall weakening and breaking of coat-enhanced dormancy. ABA accumulated during seed maturation is sufficient to delay ßGLU I induction and endosperm rupture. Afterripening decreases ABA levels and possibly sensitivity to ABA allowing the induction of ßGLU I during imbibition, which helps modulate coat-enhanced dormancy. The model does not exclude the possibility that other factors contribute to afterripening and modulation of coat-enhanced dormancy, or that ABA has additional functions, e.g. in photodormancy.
© Leubner-Metzger and Meins, Plant J 23: 215-221 (2000)

Article in PDF format (280 KB)
Figure 1 Figure 2 Table 1               Glucanase constructs
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