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Eila Tillman-Sutela, Anu Hilli and Anneli Kauppi

Arctic Circle. Rovaniemi. Oulu. Muhos. Helsinki. Eila Tillman-Sutela, Anu Hilli and Anneli Kauppi Finnish Forest Research Institute and University of Oulu. Germination changes of Picea abies seeds at water-based pretreatments. INTRODUCTION.

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Eila Tillman-Sutela, Anu Hilli and Anneli Kauppi

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  1. Arctic Circle Rovaniemi Oulu Muhos Helsinki Eila Tillman-Sutela, Anu Hilli and Anneli Kauppi Finnish Forest Research Institute and University of Oulu Germination changes of Picea abies seeds at water-based pretreatments

  2. INTRODUCTION Pretreatments are a prerequisite for a mechanized seedling production 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.

  3. The aim of our study was to find out: • changes in the germination attributes of Norway spruce seeds during the multi-phased pretreatment chain, • impact of seed structures on the changes of germination attributes from cone collection to storage • effect of storage on germination attributes of IDS-treated spruce seeds.

  4. MATERIAL AND METHODS 1200 l of cones collected in February 2001 Extraction by hand, 20 cones in airflow 20 ºC 40 l, control using water 580 l without water 580 l 38 ºC • Radiography • Germination tests, ISTA • Moisture content measurements • Floating tests • Microscopy • Tukey’s multiple comparison test • paired t-test • De-winging • Water cleaning • Drying • Mechanical cleaning • Storage 90 d, -3 ºC • 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

  5. Changes in germination parameters of dry-extracted spruce seeds at different pretreatment phases Changes in germination parameters of water-extracted spruce seeds at different pretreatment phases Germination Germination rate IDS 1 = Initial germination 8 = Initial moistening 2 = Extraction 9 = Incubation 24 h, 5 ºC 3 = Dewinging 10 = Desiccation 45 min 4 = Water cleaning 11 = Storage drying Fr 1 5 = Drying 12 = - "- Fr 2 6 = Mechanical cleaning 13 = - "- Fr 3 14 = - "- Fr 4 -10 7 = Storage 90 d, -3 ºC 15 = -"- Fr 11

  6. Opened seed coat in a moistened fungi-infected spruce seed. Opened micropyle of the seed coat in a moistened spruce seed. Spruce Large nucellar cap covers about ¾ of the length of the micropylar end of the spruce seed.

  7. Germination capacity 2001 2002 % Germination rate 2001 2002 100 -01 80 -02 60 40 20 0 -01 -02 -01 -02 -01 -02 -01 -02 -01 -02 1 2 3 4-10 11 Fr The changes of germination parameters in dry-extracted, IDS-treated seed fractions after one year’s storing at –18 C Germination capacity 2001 2002 Germination rate % 2001 2002 100 80 -01 60 -02 40 20 0 -01 -02 -01 -02 -01 -02 -01 -02 -01 -02 1 2 3 4-10 11 Fr The changes of germination parameters in water-extracted, IDS-treated seed fractions after one year’s storing at –18 C

  8. 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.

  9. Cone collection Seed extraction Water cleaning De-winging Storage Mechanical cleaning Storage Sowing Drying PREVAC   IDS (Incubation· Desiccation· Separation· Storage drying) Sowing in nurseries Pretreatment of forest tree seeds from cone collection to nursery sowing

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