title: Effects of burial in sand and water supply regime on seedling emergence of six species.
abstract: OBJECTIVE
  Air seeding has long been regarded as a quick and successful measure for vegetation rehabilitation in China. However, seedling emergence of often-used species including Agriophyllum squarrosum, Artemisia sphaerocephala, Artemisia ordosica, Hedysarum fruticosum, Caragana korshinskii and Medicago sativa is low. Experiments were conducted under controlled conditions to study the effects of sowing depth and water supply on seedling emergence, in order to understand the requirements for increasing seedling emergence.
  
  
  METHODS
  Seeds were exposed to different environments of burial and water supply regimes in PVC pots (7 cm in diameter and 11 cm in height) under the same light intensity and alternating temperature regimes in a growth chamber.
  
  
  RESULTS
  Seedlings of three species (Agriophyllum squarrosum, Artemisia sphaerocephala, Artemisia ordosica) with relatively light seeds emerged well at a 0.5 cm sowing depth under a 7.5 and 10 mm water supply regime. However, few seedlings of these species emerged when the sowing depth was over 1 cm or when water supply was 5 mm. Seedlings of Caragana korshinskii, Hedysarum fruticosum and Medicago sativa emerged from sowing depths of 0.5-4 cm, 0.5-3 cm, and 0.5-4 cm, respectively, under both 7.5 and 10 mm water supply regimes. Under a 5 mm water supply regime, seedlings of these species also emerged at over 1 cm sowing depth. Seeds of all six species sown on the surface of sand did not germinate, and seedlings did not emerge when they were sown at depths greater than 6 cm.
  
  
  CONCLUSIONS
  Based on these experiments, a 0.5 cm sowing depth resulted in the highest seedling emergence and it is concluded that this is the optimal sowing depth for seedling emergence of all six species.
authors.affiliation: Laboratory of Quantitative Vegetation Ecology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China. zhengyuanrun@hotmail.com
authors.forename: Yuanrun
authors.initials: Y
authors.lastname: Zheng
authors.forename: Zhixiao
authors.initials: Z
authors.lastname: Xie
authors.forename: Yi
authors.initials: Y
authors.lastname: Yu
authors.forename: Lianhe
authors.initials: L
authors.lastname: Jiang
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Shimizu
authors.forename: Glyn M
authors.initials: GM
authors.lastname: Rimmington
mesh_terms: D018525:Germination / Q000502:physiology*; D063245:Plant Development; D036226:Seedlings / Q000254:growth & development; D012822:Silicon Dioxide; D012987:Soil; D013045:Species Specificity; D013997:Time Factors; D014867:Water
chemical_list: D012987:Soil; D014867:Water; D012822:Silicon Dioxide