Study On Inter-annual Variation And Altitudinal Gradients Distribution Patterns Of Soil Seed Bank In Picea Schrenkiana Forest

Soil seed bank is summation of vigor seed both in soil and on its surface. The papermainly research objective is Picea schrenkiana Forest. It was studied by the methods ofgermination in greenhouse and soil samples to analyze the different altitudinal gradient (1450-2750m) in the year of2011and interannual variability (2004-2011) community structurecharacteristics of P. schrenkiana forest from1800-2205m in soil seed banks, through theburied test check the germination rate attenuation P. schrenkiana seed bank. The conclusionshows as follows: There is a huge interannual change in the seed density of soil seed bank and the seeddensity of P. schrenkiana, which is not synchronous. The seed bank density maximum (2009)was953.75±66.12ind./m2and the maximum density (2008) was186.50±20.37ind./m2.Moreover, the community of P. schrenkiana maximum density (2006) was584.50±42.86ind./m2, maximum density (2005) was0.25±0.26ind./m2. The seed density belongs toinconstantly soil bank, which was mainly affected by good harvest or low production inprevious year. With the altitude rising, the number of species composition of P. schrenkiana forest soilseed bank shows a declining trend in the fluctuation as a whole. At the altitudinal of2000m(1950-2050m) is the maximum, reached to30species; The common species first increasedand then decreased and finally stabilized between neighboring altitudinal gradients. The seeddensity in soil seed bank presented single peak distribution pattern, the maximum density(1813.80±154.00ind./m2) appearing at the altitudinal of2000m (1950-2050m). Piceaschrenkiana seed density in the soil seed bank also presented single peak distribution pattern,the maximum density (190.00±16.80ind./m2) appearing at the altitudinal of1800m (1750-1850m). After half a year buried into the soil, the seed vitality of P. schrenkiana is decreased, butthe decline is not obviously except litter layer; compare with the first half year, the seed whichis buried one year, the vitality decrease significantly; compare with the first half year, the seedvitality decrease sharply. According to a preliminary inspectionit P. schrenkiana seed bank isinstantaneous soil seed bank. Buried depth has significant role to keep the seed vitality of P.schrenkiana in short-term (half a year), but not significant in long-term (one year and one anda half year).