Sensitivity cycling and mechanism of physical dormancy break in seeds of Ipomoea hederacea (Convolvulaceae)

Sensitivity cycling to physical dormancy (PY) break in seeds is known to occur in some Fabaceae and Convolvulaceae species. PY in seeds of species of Convolvulaceae and of some other angiosperm plant families can be broken by storing them dry. However, the mechanism of opening the water gap in the s...

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Bibliographic Details
Published in:International journal of plant sciences 2009-05, Vol.170 (4), p.429-443
Main Authors: Jayasuriya, K.M.G. Gehan, Baskin, Jerry M, Baskin, Carol C
Format: Article
Language:English
Subjects:
buried seeds
Convolvulaceae
Desorption
dormancy breaking
Fabaceae
Flowers & plants
Ipomoea hederacea
Ipomoea hederacea var. hederacea
Plant sciences
seed dormancy
seed germination
seed scarification
seed storage
Seeds
storage conditions
testa
Water
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Summary:Sensitivity cycling to physical dormancy (PY) break in seeds is known to occur in some Fabaceae and Convolvulaceae species. PY in seeds of species of Convolvulaceae and of some other angiosperm plant families can be broken by storing them dry. However, the mechanism of opening the water gap in the seed coat (dormancy break) during dry storage has not been investigated. In research reported here, we determined whether sensitivity cycling occurs in seeds of Ipomoea hederacea (Convolvulaceae) and investigated the effect of dry storage on opening of the water gap. Seeds can cycle between insensitive and sensitive states to dormancy break, and dormancy can be broken in sensitive seeds by storing them dry at high to moderate temperatures. Seeds with the lower part of the hilum blocked lost a minimal amount of water during storage. Percentage water loss was significantly correlated with percentage dormancy break. Desorption of water through the hilar fissure during dry storage reduced the vapor pressure below the bulges (water gap), which caused slits to form around the bulges (opening of water gap). The amount of water desorption was low in insensitive seeds because the hilar fissure remained closed and thus the water gap did not open.
ISSN:1058-5893
1537-5315
DOI:10.1086/597270