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Shiro TSUYUZAKI
Plant community ecology / Environmental conservation

Mount Usu / Sarobetsu post-mined peatland
From left: Crater basin in 1986 and 2006. Cottongrass / Daylily

(Update on Dec. 9, 2003. Last revision at Oct 20, 2006)

Seedbank estimation

Types

Table 1. Types of seedbank estimation. (After Tsuyuzaki 1990)
Type Germination Hand sorting Sieving Flotation
Principle Sowing soil on pot Power play under a binocular stereomicroscope Seiving with various mesh sizes Seeds floated by a high-concentration solution
Merit Easy way Easy way Easy way
Quick treatment		 Qucik treatment
High seed recovery
Demerit Waste long time (occasionally more than 6 months)
Low accuracy (all species do not always germinate)		 Restricted sample volume
Boring job		 Difficult to extract all sedds, in particular, small seeds Complicated manipulation
Seeds damaged by flotation solution
Recovery rate Low in general High Depending on the soil sample Very high

Improved germination test

(Ter Heerdt et al. 1996)

Washing soil samples by coarse and fine sieves

Coarse = 4.00 mm mesh width
Fine = 0.212 mm

= concentrated samples [and greenhouse space]
[Sample soils = clay, peaty, and sandy soils]

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Spreading in a 3-5 mm thick layer on sterilized potting compost

  1. Seedling emerged more than by unconcentrate samples
  2. Hand-sorting afterwards shows that the germination rates vary between 81 and 100% of the viable seeds present
  3. 95% seedlings emerge within 6 weeks

Concentrating samples can lead to seed losses in soil bank estimations

(Traba, et al. 1998)

Concentration, C

Traba et al. (1998) = 0.100 mm-diameter sterile nylon mesh

[ter Heerdt et al. (1996) = 0.212 mm in mesh width]

vs

Non-concentration, NC

Seedling emergence (/432 cm3)
C NC
199.7 ± 79 161.5 ± 11.8

P < 0.001 (paired t-test, n = 10)
No significant difference in the number of species per sample (P = 0.153, n = 10)

Seven species (Crassula tillaea, Hernaria hirsuta, Sagina apetala, Teesdalia coronopifolia, Trifolium arvense, Tuberaria gutata and Vulpia spp.)

NC > C (Wilcoxon range test, P < 0.05)
Those species produce small seeds.

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References

  • seedbank
  • seed dormancy
  • seed dispersal
  • Ter Heerdt GNJ, Verweij GL, Bekker RM & Bakker JP. 1996. An improved method for seed-bank analysis: seedling emergence after removing the soil by sieving. Functional Ecology 10: 144-151
  • Traba J, Levassor C. & Peco B. 1998. Concentrating samples can lead to seed losses in soil bank estimations. Functional Ecology 12: 975-976
  • Tsuyuzaki, S. 1990. Methods on the researches of buried seed populations - as teaching materials. Biological Materials 25: 9-20 (in Japanese)

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