AOBPreview originally published online on April 8, 2005
Annals of Botany 2005 95(7):1237-1245; doi:10.1093/aob/mci138
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Effects of Burial in Sand and Water Supply Regime on Seedling Emergence of Six Species
1 Laboratory of Quantitative Vegetation Ecology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China, 2 Geography and Geology Department, Florida Atlantic University, Boca Raton, FL 33431, USA, 3 National Institute for Environmental Studies, Tsukuba, 305-8506, Japan, 4 Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China and 5 Office for Global Learning, Wichita State University, Wichita KS 67260-0013, USA
* For correspondence. E-mail zhengyuanrun{at}hotmail.com
Received: 29 October 2004 Returned for revision: 13 December 2004 Accepted: 25 February 2005 Published electronically: 8 March 2005
• Background and Aims 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.
• Key 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.
Key words: Air seeding, desertification, Mu Us sandy land, seedling emergence, semi-arid area, sowing depth, vegetation rehabilitation