A single-seed assay for endo-beta-mannanase activity from tomato endosperm and radicle tissues

Completion of germination (radicle emergence) is an all-or-none developmental event for an individual seed. Variation in germination timing among seeds in a population therefore reflects variation among seeds in the rates or extents of physiological or biochemical processes prior to radicle emergenc...

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Bibliographic Details
Published in:Plant physiology (Bethesda) 1997-01, Vol.113 (1), p.13-20
Main Authors: Still, D.W. (University of Arizona, Yuma, AZ.), Dahal, P, Bradford, K.J
Format: Article
Language:English
Subjects:
ACTIVIDAD ENZIMATICA
ACTIVITE ENZYMATIQUE
ANALISIS CUANTITATIVO
ANALYSE QUANTITATIVE
Biochemistry
Biological and medical sciences
COMPOSICION QUIMICA
COMPOSITION CHIMIQUE
Development and Growth Regulation
Endosperm
ENDOSPERMA
ENDOSPERME
Enzyme activity
Enzymes
ETAPAS DE DESARROLLO
EXPERIMENTACION
EXPERIMENTATION
Fundamental and applied biological sciences. Psychology
Gels
GERMINACION
GERMINATION
GLICOSIDASAS
GLYCOSIDASE
Imbibition
LYCOPERSICON ESCULENTUM
Metabolism
Plant physiology and development
Plants
PROTEINAS
PROTEINE
RADICULA
RADICULE
Seeds
STADE DE DEVELOPPEMENT
Sugars
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Description
Summary:Completion of germination (radicle emergence) is an all-or-none developmental event for an individual seed. Variation in germination timing among seeds in a population therefore reflects variation among seeds in the rates or extents of physiological or biochemical processes prior to radicle emergence. For tomato (Lycopersicon esculentum Mill.) seeds, correlative evidence suggests that endo-beta-mannanase activity weakens the endosperm cap tissue opposite the radicle tip to permit radicle emergence. To test whether endo-beta-mannanase activity is causally related to germination rates, we have developed a sensitive assay suitable for use with individual radicle tips or endosperm caps. We show that endo-beta-mannanase activity varies at least 100-fold and often more than 1000-fold among individual inbred tomato seeds prior to radicle emergence. Other sources of variation (tissue size and experimental error) were evaluated and cannot account for this range of activity. Endo-beta-mannanase activity was generally 10-fold greater in leachates from endosperm caps than from radicle tips. Release of reducing sugars from individual endosperm caps also varied over a considerable (9-fold) range. These extreme biochemical differences among individual tomato seeds prior to radicle emergence indicate that results obtained from bulk samples could be misleading if it is assumed that all seeds exhibit the "average" behavior
ISSN:0032-0889
1532-2548
DOI:10.1104/pp.113.1.13