Eila Tillman-Sutela, Anu Hilli and Anneli Kauppi

Finnish Forest Research Institute and University of Oulu

Oulu

Muhos

Helsinki

Arctic CircleRovaniemi

Germination changes of Picea abies seeds

at water-based pretreatments

INTRODUCTIONPretreatments are a prerequisite for a mechanized seedlingproduction in modern forest tree nurseries.

The goal is to achieve a homogenous seed lot -germination capacity and rate of at least 95 %.

Seed extraction is only the first step in a multi-phased procedure preceding sowing.

Conifer species have a high genetic control over germination attributes and their differences between and within species.

Structural differences in the seed coat and nucellus cause functional differences between moistened spruce and pine seeds.

Results of ecological studies suggest that pretreatment conditions should be customized for different seed species.

Highly mechanized treatments tend to be homogenized using water and elevated temperatures to accelerate the process.

Pretreatments of spruce seeds have been reduced to a minimum due to unpredictable results.

The aim of our study was to find out:

1. changes in the germination attributes of Norway spruce seeds during the multi-phased pretreatment chain,

2. impact of seed structures on the changes of germination attributes from cone collection to storage

3. effect of storage on germination attributes of IDS-treated spruce seeds.

1200 l of conescollected in February 2001

Extraction

using water 580 l

in airflow 20 ºC 40 l, control

without water 580 l

38 ºC

• De-winging• Water cleaning• Drying• Mechanical cleaning

• Storage 90 d, -3 ºC

MATERIAL AND METHODS

IDS-treatment:• Moistening, 20 ºC, 16 h• Incubation, 5 ºC, 24 h • Desiccation, 20 ºC• Separation 11 fractions• Drying, 20 ºC• Storage, -18 ºC--------------------------- 11 phases

by hand, 20 cones

• Radiography• Germination tests, ISTA• Moisture content

measurements• Floating tests• Microscopy

• Tukey’s multiple comparison test

• paired t-test

1 = Initial germination

2 = Extraction

3 = Dewinging 4 = Water cleaning 5 = Drying 6 = Mechanical cleaning

7 = Storage 90 d, -3 ºC

8 = Initial moistening 9 = Incubation 24 h, 5 ºC10 = Desiccation 45 min11 = Storage drying Fr 112 = - "- Fr 213 = - "- Fr 314 = - "- Fr 4 -10 15 = -"- Fr 11

Changes in germination parameters of dry-extracted spruce seeds at different pretreatment phases

Germination Germination rate

Changes in germination parameters of water-extracted spruce seeds at different pretreatment phases

0

20

40

60

80

100

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

%

0

20

40

60

80

100

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

%

IDS

Opened seed coat in a moistened fungi-infected spruce seed.

Opened micropyle of the seed coat in amoistened spruce seed.

Spruce

Large nucellar cap covers about ¾ of the length of the micropylar end of the spruce seed.

The changes of germination parameters in dry-extracted, IDS-treated seed fractions

after one year’s storing at –18 C

The changes of germination parameters in water-extracted, IDS-treated seed fractions

after one year’s storing at –18 C

0

20

40

60

80

100

1 2 3 4-10 11

%

Fr

2001 2002

2001 2002

Germination capacityGermination rate

-01 -02-01 -02 -01 -02 -01 -02 -01 -02

-01

-02

0

20

40

60

80

100

1 2 3 4-10 11

%

Fr

2001 20022001 2002

Germination capacityGermination rate

-01 -02 -01 -02 -01 -02 -01 -02 -01 -02

-01 -02

CONCLUSIONS

• Separation of spruce seeds succeeded well according to the

principles of the IDS-method, even if the germination parameters in

the

fungi-infected seed lot did not reach 95 %.

• The result was achieved using a surprisingly

short incubation time compared to the

experiences in pine seeds.

• Short incubation time may be favourable to Norway spruce seeds

because of the rapid opening of the seed coat in moistened seeds.

• Restriction of water and lowering of temperature

at least at the extraction phase of winter-collected spruce cones

should be considered.

• The results need verification using good quality seeds collected in

consecutive months.

Mechanical cleaning

Pretreatment of forest tree seeds from cone collection to nursery sowing

Cone collection Storage

Seed extraction De-winging

Water cleaning

SowingStorageDrying

PREVAC   IDS

(Incubation· Desiccation· Separation· Storage drying)Sowing in nurseries