The Natural Regeneration And Adaptability Of Seed Germination Of Ulmus Pumila Var. Sabulosa In Hunshandake Sandland

The Ulmus pumila L. var. sabulosa J. H. Guo Y. S. Li et J. H. Li is only of the best suitable plant in Hunshandake sandland, it is concentrated in Zhen Lan country. This article has carried out the investigation of Ulmus pumila L. var. sabulosa J. H. Guo Y. S. Li et J. H. Li in the different habitat of Hunshandake sandland. The content includes both the seeding density and the seeding growth under the forest,and studies the seeding density of dispersal both under the single-tree and under the edge of forest. The test analyzes its natural regeneration. In this research the temperature, light, the soil moistures and soil thickness that influenced the seed germination and seedling development were studied, analyzes its seed germination adaptability. with main conclusions being achieved as follows:The young tree of quantity are few, the density is 7 young trees per hectare in shifting dune, the density is 240.12 in semi-fixed sandy land, the density is 93.05 in fixed sandy land;The seeding density is shifting dune >semi-fixed sandy land > fixed sandy land,the seedings grow badly in the fixed sandy land and in the shifting dune, seedling death phenomenon is serious in the shifting dune. the seedings grow well in the semi-fixed sandy land,The semi-fixed sandy land which compared to the fixed sandy land and the shifting dune is suitable habitat of natural regeneration;The scope of seedings main centralism dispersal is apart from the edge of forest 20m, outside 20m the density of seedling it reduces obviously.The wind direction has the tremendous influence on the the seeding density dispersal, the density of seeding is the Northwest > the Southeast >the Southwest > the Northeast. The optimal temperature for seed germination was 15℃to 35℃. When the temperature was lower than 10℃and higher than 45℃, seed could not germinate;The light on seed germination was not significante in 15℃～35℃,but at 40℃,exactly darkness more suitable seed germinate;The optimal sand water content for seed germination was 4% to 20%. If sand water content was less than 1% or more over 30%, seed could not germinate;Seed germination needed sand bury. The optimal sand thickness was 0.5cm to 1cm. However, when the sand that buried seed was thicker 0cm and than 6cm seed would not germinate; and died finally.