The effects of sowing density and substrate texture on the survival of yellow horned-poppy Glaucium flavum, a glass house experiment, eastern England

  • Published source details Walmsley C.A. & Davy A.J. (1997) The restoration of coastal shingle vegetation: effects of substrate composition on the establishment of seedlings. Journal of Applied Ecology, 34, 143-153


Shingle beach vegetation at Sizewell, Suffolk, eastern England, was extensively damaged during construction of a power station. The feasibility of restoring vegetation and identification of best techniques to employ was undertaken in a series of experiments. Summarised here are the results of a glasshouse experiment which examined the effects of sowing density and substrate texture on the survival of yellow horned-poppy Glaucium flavum.

Study site: The glasshouse experiment used yellow horned-poppy Glaucium flavum seed collected from the beach at Sizewell, Suffolk, eastern England (National Grid ref: TM 475635).

Poppy seed and sowing substrate: Yellow horned-poppy seed, 18 months old, was stratified at around 2ºC in sand for 23 weeks to break dormancy. On 24 January 1993, the seed was sown in 9-cm square pots (10 pots, five seeds each, thinned to one/pot after germination; five pots 10, 25, 50 and 100 seeds) containing either 100% washed horticultural sand or, 1 1:4 mix of sand and 5 mm grade shingle. The seed was sprinkled on the surface and covered in 2-4 mm of sand. The pots were kept in a heated (15ºC) illuminated (400 W sodium lamps 16 h/day) glasshouse. Pots were regularly watered and fed with liquid fertilizer.

Seedling emergence and survival: Seedling emergence and survival were recorded at first three times/week, and then at reduced frequency. The experiment ran over 22 weeks, at the end of which plants were dried and weighed to obtain shoot and root dry mass.

Percentage emergence was quite low, 51% in the sand substrate, and 44% in the shingle sand mix. The lower emergence in the latter is attributed to less water and seed retention in the surface shingle. However the surviving density of plants was greater in sand-shingle mix throughout the range of sowing densities. Seedlings also grew much less in the sand than in the sand-shingle mixture.

On shingle, survival was negatively density-dependent, but the much lower survival on sand was density-independent. Consequently, the higher mortality on sandy field plots was probably directly associated with substrate effects.

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