Effects of Sand Burial on Survival, Growth, Gas Exchange and Biomass Allocation of Ulmus pumila Seedlings in the Hunshandak Sandland, China

作者：L. SHI, Z. J. Zhang, Chunhan Zhang, J. Z. Zhang · 发表于：Annals of Botany · 年份：2004 · DOI：10.1093/aob/mch174 · 被引用次数：86 · 研究领域：Seedling growth and survival studies、Aerospace, Electronics, Mathematical Modeling、Environmental and Agricultural Sciences

BACKGROUND AND AIMS: In the last decade, the number of young plants of Ulmus pumila in the Hunshandak Sandland has decreased sharply because of severe sand burial, and their ecological protective function has been weakened. In order to develop an understanding of the tolerance of U. pumila to sand burial and to suggest reasonable measures to protect the sparse-elm-grassland ecosystem, the effects of burial on the survival, growth, photosynthesis and biomass allocation in U. pumila were studied. METHODS: Seedlings were buried at five different depths in pot experiments: no burial (control), partial burial (33 % and 67 % stem height), and complete burial (100 % and 133 % stem height). Growth analyses and measurements of photosynthesis were carried after the plants had been uncovered. KEY RESULTS: All the plants survived partial burial, but about 30 % and 80 % of the seedlings died as a result of the 100 % and 133 % sand burial treatments, respectively. The numbers of newly produced leaves and branches, and the height of the stems of the seedlings in the 33 % and 67 % burial treatments during the period of the experiment were significantly greater than those in the control. Furthermore, net photosynthetic rate, transpiration rate and water use efficiency were also elevated by the partial burial, but not affected by burial time. This might be attributed to the increased root length, which improved water acquisition. The biomass and biomass allocation of the seedlings were signifi...