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

Leubner‐Metzger, Gerhard

doi:10.1007/s00425-002-0837-y

Cited by 72 publications

(58 citation statements)

References 37 publications

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“…The complete hydrolysis of b-glucans is facilitated by several enzymes, including endo-(1-3)-b-glucanase (Leah et al, 1995). Recent studies in tobacco seeds revealed that an up-accumulation of b-1,3 glucanase correlated with the release of seed-coat imposed dormancy during after-ripening (Leubner-Metzger, 2002, 2005. Here, Leubner-Metzger et al (2005) proposed that hydrolysis of b-glucans contributes to release the seed-coat barrier to facilitate radicle protrusion.…”

Section: An Accumulation Of Energetic Metabolism and Hydrolytic Enzymmentioning

confidence: 99%

Proteomic Analysis of Seed Dormancy in Arabidopsis

et al. 2006

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The mechanisms controlling seed dormancy in Arabidopsis (Arabidopsis thaliana) have been characterized by proteomics using the dormant (D) accession Cvi originating from the Cape Verde Islands. Comparative studies carried out with freshly harvested dormant and after-ripened non-dormant (ND) seeds revealed a specific differential accumulation of 32 proteins. The data suggested that proteins associated with metabolic functions potentially involved in germination can accumulate during after-ripening in the dry state leading to dormancy release. Exogenous application of abscisic acid (ABA) to ND seeds strongly impeded their germination, which physiologically mimicked the behavior of D imbibed seeds. This application resulted in an alteration of the accumulation pattern of 71 proteins. There was a strong down-accumulation of a major part (90%) of these proteins, which were involved mainly in energetic and protein metabolisms. This feature suggested that exogenous ABA triggers proteolytic mechanisms in imbibed seeds. An analysis of de novo protein synthesis by two-dimensional gel electrophoresis in the presence of [ 35 S]-methionine disclosed that exogenous ABA does not impede protein biosynthesis during imbibition. Furthermore, imbibed D seeds proved competent for de novo protein synthesis, demonstrating that impediment of protein translation was not the cause of the observed block of seed germination. However, the two-dimensional protein profiles were markedly different from those obtained with the ND seeds imbibed in ABA. Altogether, the data showed that the mechanisms blocking germination of the ND seeds by ABA application are different from those preventing germination of the D seeds imbibed in basal medium.

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Section: An Accumulation Of Energetic Metabolism and Hydrolytic Enzymmentioning

confidence: 99%

Proteomic Analysis of Seed Dormancy in Arabidopsis

et al. 2006

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“…Taken together, we can conclude from these results that ABA does not inhibit endosperm rupture and transition to postgermination growth by affecting TAG mobilization. Compared to freshly harvested seeds, after-ripened tobacco seeds have lower ABA contents, decreased ABA sensitivity, and enhanced bGlu I expression during imbibition (Grappin et al, 2000;LeubnerMetzger and Meins, 2000;Leubner-Metzger, 2002, 2005. ABA-sensitive expression of bGlu I in the micropylar endosperm causally contributes to endosperm rupture.…”

Section: Aba Does Not Inhibit Tobacco Seed Oil Mobilizationmentioning

confidence: 99%

“…This experimental advantage was used to study the hormonal regulation and to pinpoint the sites for class I b-1,3-glucanase (bGlu I) action (e.g. Leubner-Metzger and Meins, 2000;Leubner-Metzger, 2002, 2005. ABA inhibits the induction of bGlu I in the micropylar endosperm just before its rupture but does not affect testa rupture of tobacco.…”

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confidence: 99%

Water Uptake and Distribution in Germinating Tobacco Seeds Investigated in Vivo by Nuclear Magnetic Resonance Imaging

et al. 2005

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The regulation of water uptake of germinating tobacco (Nicotiana tabacum) seeds was studied spatially and temporally by in vivo 1 H-nuclear magnetic resonance (NMR) microimaging and 1 H-magic angle spinning NMR spectroscopy. These nondestructive state-of-the-art methods showed that water distribution in the water uptake phases II and III is inhomogeneous. The micropylar seed end is the major entry point of water. The micropylar endosperm and the radicle show the highest hydration. Germination of tobacco follows a distinct pattern of events: rupture of the testa is followed by rupture of the endosperm. Abscisic acid (ABA) specifically inhibits endosperm rupture and phase III water uptake, but does not alter the spatial and temporal pattern of phase I and II water uptake. Testa rupture was associated with an increase in water uptake due to initial embryo elongation, which was not inhibited by ABA. Overexpression of b-1,3-glucanase in the seed-covering layers of transgenic tobacco seeds did not alter the moisture sorption isotherms or the spatial pattern of water uptake during imbibition, but partially reverted the ABA inhibition of phase III water uptake and of endosperm rupture. In vivo 13 C-magic angle spinning NMR spectroscopy showed that seed oil mobilization is not inhibited by ABA. ABA therefore does not inhibit germination by preventing oil mobilization or by decreasing the water-holding capacity of the micropylar endosperm and the radicle. Our results support the proposal that different seed tissues and organs hydrate at different extents and that the micropylar endosperm region of tobacco acts as a water reservoir for the embryo.

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“…Anybody is familiar with the swelling of a wet grain, which breaks the outer hull and thus enables or eases the seedling's growth. But water entering the grain also starts physiological and developmental processes necessary for the early development of the embryo [1,78,194,259]. It is influenced among other parameters crucially by temperature and water supply [35,344].…”

Section: Moving Interfacesmentioning

confidence: 99%

Imbibition in disordered media

Alava

Dubé

Rost

2004

Advances in Physics

285

333

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The physics of liquids in porous media gives rise to many interesting phenomena, including imbibition where a viscous fluid displaces a less viscous one. Here we discuss the theoretical and experimental progress made in recent years in this field. The emphasis is on an interfacial description, akin to the focus of a statistical physics approach. Coarse-grained equations of motion have been recently presented in the literature. These contain terms that take into account the pertinent features of imbibition: non-locality and the quenched noise that arises from the random environment, fluctuations of the fluid flow and capillary forces. The theoretical progress has highlighted the presence of intrinsic length-scales that invalidate scale invariance often assumed to be present in kinetic roughening processes such as that of a two-phase boundary in liquid penetration. Another important fact is that the macroscopic fluid flow, the kinetic roughening properties, and the effective noise in the problem are all coupled. Many possible deviations from simple scaling behaviour exist, and we outline the experimental evidence. Finally, prospects for further work, both theoretical and experimental, are discussed.

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

Cited by 72 publications

References 37 publications

Proteomic Analysis of Seed Dormancy in Arabidopsis

Proteomic Analysis of Seed Dormancy in Arabidopsis

Water Uptake and Distribution in Germinating Tobacco Seeds Investigated in Vivo by Nuclear Magnetic Resonance Imaging

Imbibition in disordered media

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