Planta

, Volume 215, Issue 6, pp 959–968

Seed after-ripening and over-expression of class I β-1,3-glucanase confer maternal effects on tobacco testa rupture and dormancy release

  • Gerhard Leubner-Metzger
Original Article

DOI: 10.1007/s00425-002-0837-y

Cite this article as:
Leubner-Metzger, G. Planta (2002) 215: 959. doi:10.1007/s00425-002-0837-y

Abstract.

'Coat-imposed' seed dormancy of many non-endospermic and endospermic species is released during after-ripening. After-ripening-mediated promotion of tobacco (Nicotiana tabacum L.) seed germination is mainly due to a promotion of testa rupture and a similar promotion of subsequent endosperm rupture. Treatment of after-ripened or freshly harvested mature seeds with abscisic acid (ABA) delays endosperm rupture and inhibits the induction of class I β-1,3-glucanase (βGlu I) in the micropylar endosperm, but does not affect the kinetics of testa rupture. After-ripening-mediated release of photodormancy is correlated with a decreased gibberellin (GA) requirement for testa rupture during dark-imbibition. Reciprocal crosses between wild-type tobacco and sense-βGlu I transformant lines showed that βGlu I over-expression in the seed covering layers can replace the promoting effect of after-ripening on testa rupture in light, but only if the mother plant is a sense-βGlu I line. This maternal effect supports the model of two sites for βGlu I action: (i) βGlu I contribution to the after-ripening-mediated release of dormancy in the dry seed state, which is manifested in the promotion and ABA-insensitivity of testa rupture during imbibition. (ii) ABA-sensitive expression of βGlu I in the micropylar endosperm, which contributes to endosperm rupture. The importance of GA-signaling and testa characteristics appear to be a common feature during the after-ripening-mediated release of coat-imposed dormancy in endospermic and non-endospermic seeds.

After-ripening Gibberellin requirement β-1,3-Glucanase Maternal effect Nicotiana (seed dormancy) Testa rupture

Copyright information

© Springer-Verlag 2002

Authors and Affiliations

  • Gerhard Leubner-Metzger
    • 1
  1. 1.Institut für Biologie II, Albert-Ludwigs-Universität, Schänzlestr. 1, 79104 Freiburg i. Br., Germany