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Copyright
© 2001, CAB International |
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BA: |
19930321854
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ET: |
Watermelon
seed germination. 2. Osmomanipulation of photosensitivity. |
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AU: |
Thanos,
C. A.; Mitrakos, K. |
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AA: |
Institute
of General Botany, University of Athens, 15784 Athens, Greece.
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SO: |
Seed
Science Research, 1992, Vol.2, No.3, pp.163-168, 22 ref. |
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AB: |
Seed
germination of watermelon cv. Sugar Baby was fully suppressed by
intermittent far-red (FR) irradiation (1 min every 30 min). When the
intervening dark period was increased, percentage final germination
increased linearly. However, a 4-day intermittent FR treatment induced
phytochrome-controlled dormancy and the longer the dark interval the
deeper was the dormancy of the non-germinated seeds. When seeds were
soaked in a fully inhibitory osmotic solution (0.6 M mannitol), no
dormancy was imposed. However, a single FR pulse at the time of transfer
induced partial, secondary dormancy; the kinetics of the imposition of
dormancy followed a negative exponential curve (half-life 1.5 days; 3 days
for cv. Crimson Sweet). Seeds treated osmotically for 10 days in darkness
and subsequently dehydrated (with and without a final FR pulse) acquired
germination characteristics similar to those in light-requiring and
dark-germinating achenes, respectively, of lettuce cv. Grand Rapids. In
the light-requiring osmomanipulated seed population, the induction of
germination was brought about by the low-energy reaction of phytochrome,
chilling, dry storage and decoating. The transformation through
osmomanipulation of the dark-germinating watermelon seeds (the inhibition
of which required prolonged exposure to light) to positively or negatively
photosensitive seeds (that responded to brief light pulses), might be
attributed to the slow relaxation of existing meta-Fa and meta-Rb
phytochrome intermediates to Pfr upon hydration. |
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DE: |
Watermelons;
seeds; germination; light; seed treatment; treatment; osmotic
pretreatment; far red light; Phytochrome; metabolism; plant physiology;
mannitol; water relations; Dormancy; Temperature; tropical fruits; fruit
crops |
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OD: |
Citrullus
lanatus |
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UP: |
Citrullus;
Cucurbitaceae; Violales; dicotyledons; angiosperms; Spermatophyta; plants
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IS: |
0960-2585
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CC: |
FF060; |
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RY: |
69-65-8
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LA: |
English
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DT: |
Journal
article |
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SC: |
Horticultural
Abstracts; Seed Abstracts; Crop Physiology Abstracts |