3
RESEARCH
NOTES
TGC
REPORT
No
.
31,
1981
generating
larger
progenies
in
order
to
verify
the
true
locus
position
(see
Table)
.
La
(LA
335,
chromosome
7L
-
48)
is
currently
shown
to
map
8
cM
distal
to
not
.
Thus,
although
it
seems
likely
that
this
mutant
is
an
allele
of
La,
non
-
complementation
may
be
confirmed
only
by
making
crosses
with
the
new
homozygotes
and
scoring
large
separate
F
1
progenies
.
The
general
problem
of
allele
tests
between
dominant
mutants
that
are
homozygous
lethal
was
considered
by
Rick
and
Bosland
(TGC
28:17)
.
Homozygous
La
-
like
segregates
of
the
M
1
plant,
while
viable
plants,
have
yet
to
set
fruit,
but
homozygous
F
2
segregates
from
the
above
mentioned
cross
to
LA
1164
have
very
small
flowers
and
set
elongated,
beaked
fruits
(see
illustration)
.
Four
elongated,
triangular
seeds
produced
in
these
fruits
gave
rise
to
plants
with
the
homozygous
La
-
like
phenotype
.
This
variant
constitutes
the
third
La
-
type
mutant
in
our
collection
.
The
original
La
mutant
arose
spontaneously
in
a
hairy
cherry
background
(LA
335),
and
a
narrow
-
leaf
mutant
derived
from
Hildering's
EMS
survey
with
the
cv
.
Moneymaker
(3305);
in
both,
the
'La/La'
genotype
is
lethal
.
Mathan
(TGC
6:19)
obtained
subvital
La/La
segregates
by
backcrossing
La/+
F
1
plants,
produced
by
hybridization
of
heterozygotes
with
normal
plants,
to
La/+
mutants
.
These
homozygotes
did
not
bear
seeds
.
This
led
Mathan
to
postulate
a
contribu
-
tion
of
one
or
more
modifiers
by
the
normal
stock
.
Modifiers
might
likewise
contribute
to
seed
production
in
this
mutant
.
Farrell,
M
.
Phenylalanine
ammonia
lyase
Phenylalanine
ammonia
lyase
(PAL)
activity
in
anthocyaninless
mutants
.
(E
.
C
.
4
.
3
.
1
.
5),
a
bridging
(regula
tory)
enzyme
discovered
by
Koukol
and
Conn
in
1961,
catalyzes
the
deamination
of
phenylalanine
to
yield
trans
-
cinnamic
acid,
a
precursor
for
anthocyanin
pigments
as
well
as
other
phenylpropanoids
.
Five
different
anthocyaninless
mutants
and
the
isogenic
anthocyanin
-
plus
lines
in
which
they
arose
--
are
and
aw
in
cv
.
V36
(La
490);
C545
(ah),
E128
(ah),
and
G146
in
cv
.
VFNTCh
(LA
1221);
and
of
in
cv
.
Cal
Red
Cherry
(LA
337)
--
have
been
assayed
for
the
activity
of
the
PAL
enzyme
.
Seeds
were
germinated
in
blotter
-
lined
sandwich
boxes
maintained
under
a
uniform
temperature
(25
0
C)
and
light
(12
hr)
regime,
and
supernatant
extracts
of
seedlings
were
assayed
at
8
to
17
days
.
Older
material
did
not
provide
a
sufficiently
clear
solution,
and
shoot
material,
in
addition
to
being
more
cloudy,
reacted
with
the
substrate
at
lower
rates
than
did
the
root
material
(Fig
.
1)
.
Five
additional
assays
of
ah
roots
showed
a
reduction
in
enzymic
activity
when
compared
to
the
isogenic
anthocyanin
-
plus
roots
raised
in
the
same
incubator
for
the
