Effect of Soaking, Moist Chilling, and Temperature on Germination

of Striped Maple (Acer pensylvanicum) Seed

Anthony Bourgoin and Dale SimpsonCanadian Forest Service

Fredericton, NB

Range of Striped Maple

Silvics

• Small tree up to 10 m tall• Grows on well-drained, cool moist soils• Shade tolerant• Flowers in late May; seed falls mid October• Trees are monoecious and/or dioecious

Identification

Dormancy

• Embryo – inhibitors• Testa – reduces imbibition

– reduces leaching of inhibitors– restricts radicle elongation

• Pericarp

Experimental Design

• 5 Seed lots – 3 single-tree, 2 bulk• 4 Soaks – 0, 48, 72, 96 hours• 3 Chill times – 16, 24, 32 weeks• 2 Germination temp. regimes – 5/15°C, 20/30°C• 4 Replications of 25 seed each

Germination

• Assessed every 7 days for 56 days (8 weeks)• Successful germinants had properly developed

cotyledons, hypocotyl and radicle• Cutting test done on ungerminated seed

Data Analysis

• Total germination at 8 weeks• Data transformed by arcsin square root• Data analyzed using SAS

Impact of Soaking Time on Seed Moisture Content

Soaking time (hrs) Seed MC (%)

0 7.9

48 58.7

72 63.5

96 65.8

Results

Results

Seed lot

Mean germ.

Soak

time

Mean

germ.

Chill

time

Mean

germ.

Germ.

temp.

Mean

germ.

117 * 65 a1 0 52 a 16 48 a 5/15 90 a

120 58 a 48 57 b 24 59 b 20/30 23 b

118 * 53 b 72 59 b 32 62 c

119 68 c 96 58 b

123 * 39 d

1 means with different letters are significantly different at P=0.05

* single-tree collection

Results

0102030405060708090

100

16 24 32Chilling Time (Weeks)

% G

erm

inat

ion

0 hr 48 hrs 72 hrs 96 hrs

5/15°C

0102030405060708090

100

16 24 32Chilling Time (Weeks)

% G

erm

inat

ion

0 hr 48 hrs 72 hrs 96 hrs

20/30°C

Results

0

10

20

30

40

50

60

70

80

90

100

1 2 3 4 5 6 7 8Weeks

Germ

inatio

n (%

)

0 soak 5/15 48 soak 5/15 96 soak 5/150 soak 20/30 48 soak 20/30 96 soak 20/30

16 weeks chill

0

10

20

30

40

50

60

70

80

90

100

1 2 3 4 5 6 7 8Weeks

Germ

inatio

n (%

)

0 soak 5/15 48 soak 5/15 96 soak 5/150 soak 20/30 48 soak 20/30 96 soak 20/30

32 weeks chill

Conclusions

• Soaking seed for 48 hours was sufficient to promote high germination

• Moist chilling for 16 weeks was adequate to promote high germination

• Seed germination was maximized at temperatures of 5/15°C

• Secondary dormancy was induced at germination temperatures of 20/30°C