caa a22 4500 477101992 CHVBK 20180405111544.0 cr unu---uuuuu 170330e19960601xx s 000 0 eng 10.1007/BF00196570 doi (NATIONALLICENCE)springer-10.1007/BF00196570 Effects of gibberellins, darkness and osmotica on endosperm rupture and class I β-1,3-glucanase induction in tobacco seed germination [Elektronische Daten] [Gerhard Leubner-Metzger, Corinne Fründt, Frederick Meins Jr.] The "Havana 425” cultivar of Nicotiana tabacum L. is photodormant. Gibberellins (e.g. 10−5 M GA4 or GA7) can substitute for light in releasing dormancy. Measurements of β-1,3-glucanase activity, mRNA accumulation and the activity of the class I β-1,3-glucanase B promoter indicated that class I β-1,3-glucanases are induced by GA4 in the dark in association with germination. As in the light, this induction occurred prior to endosperm rupture and was localized exclusively in the micropylar region of the endosperm where the radicle will penetrate. Abscisic acid (ABA, 10−5 M) did not appreciably affect GA-induced release of photodormancy or seed-coat rupture, but it delayed endosperm rupture and inhibited the rate of class I β-1,3-glucanase accumulation. Seeds imbibed in the light in the presence of osmotica, e.g. 0.04 M polyethylene glycol 6000, showed delayed seed-coat and endosperm rupture, delayed onset of β-1,3-glucanase induction, and decreased rates of β-1,3-glucanase accumulation. These delays were shortened by GA4 treatment. Our results suggest that GAs and ABA act at two distinct sites during germination and that expansive growth of the embryo acts in two ways by triggering β-1,3-glucanase induction and by providing force for endosperm penetration. This provides further support for our working hypothesis that class I β-1,3-glucanases promote endosperm weakening and facilitate radicle penetration. Springer-Verlag, 1996 Endosperm nationallicence Germination nationallicence Gibberellin nationallicence β-1,3-Glucanase nationallicence Nicotiana nationallicence Photodormancy nationallicence ABA : cis-S(+)-abscisic acid nationallicence GA : gibberellin nationallicence GUS : β-glucuronidase nationallicence PEG : polyethylene glycol nationallicence Leubner-Metzger Gerhard Friedrich Miescher-Institute, P.O. Box 2543, CH-4002, Basel, Switzerland aut Fründt Corinne Friedrich Miescher-Institute, P.O. Box 2543, CH-4002, Basel, Switzerland aut Meins Jr. Frederick Friedrich Miescher-Institute, P.O. Box 2543, CH-4002, Basel, Switzerland aut Planta Springer-Verlag 199/2(1996-06-01), 282-288 0032-0935 199:2<282 1996 199 425 https://doi.org/10.1007/BF00196570 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00196570 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Leubner-Metzger Gerhard Friedrich Miescher-Institute, P.O. Box 2543, CH-4002, Basel, Switzerland aut NATIONALLICENCE 700 1- Fründt Corinne Friedrich Miescher-Institute, P.O. Box 2543, CH-4002, Basel, Switzerland aut NATIONALLICENCE 700 1- Meins Jr Frederick Friedrich Miescher-Institute, P.O. Box 2543, CH-4002, Basel, Switzerland aut NATIONALLICENCE 773 0- Planta Springer-Verlag 199/2(1996-06-01), 282-288 0032-0935 199:2<282 1996 199 425 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer