Journal Article

Role of Seed Coat in Imbibing Soybean Seeds Observed by Micro-magnetic Resonance Imaging

Mika Koizumi, Kaori Kikuchi, Seiichiro Isobe, Nobuaki Ishida, Shigehiro Naito and Hiromi Kano

in Annals of Botany

Published on behalf of The Annals of Botany Company

Volume 102, issue 3, pages 343-352
Published in print September 2008 | ISSN: 0305-7364
Published online June 2008 | e-ISSN: 1095-8290 | DOI: https://dx.doi.org/10.1093/aob/mcn095
Role of Seed Coat in Imbibing Soybean Seeds Observed by Micro-magnetic Resonance Imaging

More Like This

Show all results sharing these subjects:

  • Ecology and Conservation
  • Evolutionary Biology
  • Plant Sciences and Forestry

GO

Show Summary Details

Preview

Background and Aims

Imbibition of Japanese soybean (Glycine max) cultivars was studied using micro-magnetic resonance imaging (MRI) in order to elucidate the mechanism of soaking injury and the protective role of the seed coat.

Methods

Time-lapse images during water uptake were acquired by the single-point imaging (SPI) method at 15-min intervals, for 20 h in the dry seed with seed coat, and for 2 h in seeds with the seed coat removed. The technique visualized water migration within the testa and demonstrated the distortion associated with cotyledon swelling during the very early stages of water uptake.

Key Results

Water soon appeared in the testa and went around the dorsal surface of the seed from near the raphe, then migrated to the hilum region. An obvious protrusion was noted when water reached the hypocotyl and the radicle, followed by swelling of the cotyledons. A convex area was observed around the raphe with the enlargement of the seed. Water was always incorporated into the cotyledons from the abaxial surfaces, leading to swelling and generating a large air space between the adaxial surfaces. Water uptake greatly slowed, and the internal structures, veins and oil-accumulating tissues in the cotyledons developed after the seed stopped expanding. When the testa was removed from the dry seeds before imbibition, the cotyledons were severely damaged within 1·5 h of water uptake.

Conclusions

The activation of the water channel seemed unnecessary for water entry into soybean seeds, and the testa rapidly swelled with steeping in water. However, the testa did not regulate the water incorporation in itself, but rather the rate at which water encountered the hypocotyl, the radicle, and the cotyledons through the inner layer of the seed coat, and thus prevented the destruction of the seed tissues at the beginning of imbibition.

Keywords: Dry seeds; Glycine max; MRI; seed coat; soaking injury; soybean; testa; role of inner layer of seed coat; water uptake

Journal Article.  6299 words.  Illustrated.

Subjects: Ecology and Conservation ; Evolutionary Biology ; Plant Sciences and Forestry

Full text: subscription required

How to subscribe Recommend to my Librarian

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content.