Lab 6 Worksheet.pdf - .J Laboratory Exercse 6 A I I...

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Laboratory Exercse 6
PhotoPeriodism
As discussed
in chapter 10,
photoperiodism
is the response
of plants
to.changes
in daylength' Pho-
toperiodism
alows
prants
to respond
to
seasonar
changes
that may
result
in more favorable
or
unfa-
""'tlh?Til[:;3Xt:',1"Ji;
etzeas a
guid",.119ll-:-':if
if
:::H:Till*:x3::";L';i#
o,,t
the
ror-
lowing
table
that i[ustrates
th;;;;poir"
of flowering
to
.nu"giig
photoperiod'
In each case' show
*t
"tti"t
the
plant will
flower
or
remain
vegetative'
Table
6-1 Flowering
response
to photoperiod'
Environment
Long-day
PlantTYPe
Short-daY
Day-neutral
Long
daY-short night
Short
daY-long
night
Short
day-night broken
by a
short period
of light
24 hours
continuous
light
Lto,;er/
W
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Light and Seed
Germination
some
seeds,
especially
weed seeds,
are
photoperiod
sensitive
which assures
that
they
will
not germi-
nate
during the
wrong
season.
However,
many
other seeds
utu
iigt'i
sensitive
but
are
not photoperiod
sensitive.
These seeds
require
rignt Lf
u
rrury
ihort
duration
to ge"rminate.
lhllochrome
also
functions
in
this system,
but
germination
ii
triggered
when-p,
is
convol"a
to
Pg,
by
light' This
light requirement
for germination
o.Jr*
mostly
in
smatt seeds
,u"n'as pigweed and
tedtucl, and assures
the seed
that
it
is
crose
enough
to
reach the
soil surface
with its limited
food reserves.
TEMPERATURE
Read
remperature onpages
161-163.
Temperature
affects
nearly
all of
the physiological
processes in
the
plant including
growth,
flowering una
"'rr"n
photoperiodic
response.