 Laboratory
Evaluation of Lettuce Seedlings
The
objective of the germination test is to determine the percentage
of normal seedlings in the test. The ultimate purpose of making
the test is to determine the value of the seed for planting.
Description of a normal lettuce seedling tested for 7 days at
constant 68°F.
Seedling
Description
The following
is from Association of Official Seed Analysts (AOSA)
Seedling Evaluation Handbook, 21-2002 (with permission)
ASTERACEAE,
Sunflower family I - Lettuce (Lactuca sativa)
Seedling type:
Epigeal dicot
Food reserves:
Cotyledons which expand and become thin, leaf-like, and
photosynthetic. Some varieties develop elongated petioles at the
base of the cotyledons.
Shoot system:
The hypocotyl elongates and carries the cotyledons above the
soil surface. The epicotyl usually does not show any development
within the test period.
Root system:
A long primary root
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