Seedling emergence of three Chenopodiaceae annuals in response to different sand burial depths and irrigation regimes
LUO Ya-yong1,2,ZHAO Xue-yong1,HUANG Ying-xin1,2,ZUO Xiao-an1,2,WANG Shao-kun1,2,ZHANG Yong-feng3(1.Naiman Desertification Research Station,Cold and Arid Regions Environmental and Engineering Research Institute,Chinese Academy of Sciences,Lanzhou 730000,China;2.Graduate University of Chinese Academy of Sciences,Beijing 100049,China;3.High School of Lingtai County in Gansu Province,Pingliang 744403,China)
The interactive effects of irrigation and seed burial depth in sand on seedling emergence and seedling survival in 3 annuals(Agriophyllum squarrosum,Corispermum macrocarpum and C.elongatum) which commonly grow on sand dunes in the experimental region of Inner Mongolia were investigated.Seedling emergence was examined for seeds sown on the surface,or at depths of 10,20,30,40 and 50 mm in sand-filled pots.There were 4 different watering regimes in pots was: Treatments A(30 mm,initial irrigation),B(10 mm),C(10 mm),and D(30 mm).Subsequently,water equivalent to 5 mm of irrigation at 1,2,or 6-d intervals was added to treatments A,B,and C,respectively,but no further irrigation was applied to treatment D.No seed dormancy was found in any species.A.squarrosum and C.elongatum seedling emergence was most favoured when seeds were buried at a depth of 10 mm,but for C.macrocarpum 30 mm was the most favourable depth.The average of the 4 different irrigation regimes for the 3 species was 50.63%(A.squarrosum),77.29%(C.macrocarpum),and 75.21%(C.elongatum).When seeds sown on the sand surface were irrigated,seed germination of A.squarrosum,was considerably suppressed,but many seeds of C.macrocarpum and C.elongatum,germinated though few seedlings survived due to water deficiency.The effectiveness of sand burial depth was decreased in the order C.macrocarpum,A.squarrosum and C.elongatum.The more irrigation,the greater the seedling emergence in all species but it was more after one heavy irrigation than after an accumulation of several light irrigations for A.squarrosum and C.macrocarpum,but was vice versa for C.elongatum.It is suggested that precipitation is the most crucial factor in determining the seasonal emergence of seedlings of the three species tested in the field.The vertical distribution of seeds in sand determines the proportion of seeds that germinate after precipitation and acts to maintain seed banks over multiple years.
【Fund】： 国家自然科学基金项目(40601008);; 中国科学院资环局方向性项目(KZCX2-YW-431);; 中国科学院寒区旱区环境与工程研究所创新课题(O65044400)资助
【CateGory Index】： Q945
【CateGory Index】： Q945