Pre-sowing Seed Treatments, Seed Coats, and Metabolic Activity of Lehmann Lovegrass Seeds1
- Marshall R. Haferkamp,
- Gilbert L. Jordan and
- Kaoru Matsuda2
Data from both field and laboratory studies have suggested germination of Lehmann lovegrass (Eragrostis lehmanniana Nees.) caryopses (seeds) can be improved by various pre-sowing seed treatments. Effective treatments include moistening and drying, oven-drying, scarification, and pre-chilling on a moist substrate. The increased germination may be due to improved seed-coat permeability or to a change in the metabolic state of the seed. A growth chamber study was undertaken to determine if pre-treating air dry Lehmann lovegrass seeds with moistening, oven-drying, or mechanical scarification increased: (1) inetabolic activity upon remoistening; (2) seed-coat permeability relative to moisture imbibition; and (3) percent germination in low concentrations of oxygen (O2).
Lehmann lovegrass seeds were pre-treated and immediately following treatment samples were either: (1) imbibed in darkness at 24 C and analyzed after 9 hours for adenosine triphosphate (ATP) content and after 24 hours for percent germination; (2) imbibed in darkness at 24 C and analyzed after 0, 6, and 18 hours for moisture content; (3) imbibed for 37 hours at 24 C in atmospheres containing either 5, 10, or 21% O2 and analyzed for percent germination; or (4) viewed with a scanning electron microscope to evaluate damage to seed coats.
Treated seeds germinated better and contained more ATP than untreated seeds. Oven-dried, scarified, and moistened plus oven-dried seeds germinated the best, while scarified and moistened plus oven-dried seeds contained the most ATP.
Rate of moisture imbibition was increased by pretreatments. After 6 hours of imbibition, scarified, ovendried, and moistened plus oven-dried seeds contained significantly more moisture than air-dried seeds. After 18 hours the differences were not as large.
Treated seeds germinated best in atmospheres of 5, 10, and 21% O2, but germination was poorest in the 5% O2.
Seed coats appeared affected by treatments. Scarified seeds appeared scratched and the gelatinous coating surrounding the seeds appeared loosened and torn from moistening and oven-drying.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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