The re-establishment of desiccation tolerance in germinated radicles of Medicago truncatula Gaertn. seeds

Germinated seeds of Medicago truncatula Gaertn. with a protruded radicle length of 2.7 mm did not survive drying below 0.2 g H2O g–1 dw, as indicated by vital stain assays and the absence of growth resumption after rehydration. The re-establishment of desiccation tolerance was achieved using an osmo...

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Bibliographic Details
Published in:Seed science research 2003-12, Vol.13 (4), p.273-286
Main Authors: Buitink, Julia, Ly Vu, Benoit, Satour, Pascale, Leprince, Olivier
Format: Article
Language:English
Subjects:
abscisic acid
Alfalfa
cold treatment
cotyledons
dehydrins
Desiccation
desiccation tolerance
drought tolerance
Drying
fluridone
gene expression
germination
Life Sciences
Medicago truncatula
osmotic shock
osmotic treatment
polyethylene glycol
rehydration
Seedlings
seeds
sucrose
water
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Summary:Germinated seeds of Medicago truncatula Gaertn. with a protruded radicle length of 2.7 mm did not survive drying below 0.2 g H2O g–1 dw, as indicated by vital stain assays and the absence of growth resumption after rehydration. The re-establishment of desiccation tolerance was achieved using an osmotic treatment with polyethylene glycol (PEG), combined with a cold treatment. The ability to regain desiccation tolerance after germination was restricted to a period of growth characterized by radicle lengths between 1 and 3 mm. After PEG treatment of germinated seeds with 2.7 mm long radicles at –1.7 MPa at 10°C for 3 d and subsequent drying to 0.04 g H2O g–1 dw, 90% survived and developed into normal seedlings after rehydration. Desiccation tolerance could also be re-established in excised radicles, demonstrating that cotyledons were not essential for this process. Upon PEG incubation, sucrose accumulated rapidly prior to the re-establishment of desiccation tolerance in germinated radicles, regardless of the presence of cotyledons. Induction of MtDHN (a dehydrin) gene expression was correlated with the re-establishment of desiccation tolerance. Furthermore, the PEG-induced expression of MtDHN was repressed when fluridone was added to the PEG solution.
ISSN:0960-2585
1475-2735
DOI:10.1079/SSR2003145