呼伦贝尔沙地樟子松落种与种子库特征

采用生态学方法对呼伦贝尔沙地樟子松Pinussylvestrisvar．mongolic0土壤种子库和落种情况进行调查和分析。结果表明：沙地樟子松土壤种子库中种源丰富，种子扩散主要受风的影响，长距离传播的沙地樟子松种子对其斑块化边缘的维护以及林一草一沙过渡带天然生态系统的恢复起到十分积极的作用。土壤种子库主要分布在凋落物层中，平均种子密度可达614粒·inz；种子密度随与母树距离的增加而减少。在距母树约3m左右范围内，存在一个明显的环状峰值区域。该区域中心位于母树北偏东方向．在这个区域内土壤中的种子密度明显高于其他部位．从空间分布格局来看，种子多飞落在距母树树干0～8m距离内，在东、南、西、北和主风方向，种子密度均随与距母树距离的增加而减少：而且东、北向落种密度明显高于西向和南向。风向在当地樟子松种子在地面的扩散中发挥了重要的作用。形成了沙地樟子松种子在母树下呈侧环状分布的格局．图4表1参18

Seed falling and seed bank research on natural Pinus sylvestris var.mongolica individual plant in the Hulun Buir sandy land

Pinus sylvestris var. mongolica is adaptive to cold, drought and barren environment, with promi- nent regeneration ability to wind erosion control and shifting sand fixed. The natural regeneration process of P/- nus sylvestris var. mongolica in the sandy land is important to vegetation rehabilitation, degraded ecosystems reconstruction, sustainable sandy ecosystem benefit development, as well as the establishment of green eco- logical barriers in north of China. In order to explore seed bank and seed falling of Pinus sylvestris var. mon- golica, inoculators （specification： 1.0 m x 1.0 m x 0.1 m） were installed at 4, 8, 12 m in easdsouth/west/ north direction from the mature tree and grids （specification ： 1 m x 1 m） were arranged around the mature tree, and with the vectoring technology get the spatial distribution graph which X axle is north direction axle is east direction. The results showed that Pinus sylvestris vat. mongolica seeds disperse mainly in the litter layer with an average seed density of 614 seeds·m-2 and in the 0-5 cm horizon with an average seed density of 469 seeds·m-2. The amount of seeds in different direction respectively is 6.67 （east） 〉6.07 （north）〉5.53（west）〉 4.63 （north）. The primary dispersal concentration was up to about 3 m from the mature tree. Temperate andspatial characteristics of seed falling showed that most seeds were in a region near the mature tree, especially in the 0-8 m range. Conclusions were drawn that the seeds of Pinus sylvestris var. mongolica dispersal density near the observed tree was fan-shaped and composed by winds from the south and west. The horizontal distri- bution characteristics of seed bank from a nature tree shaped a ring region where seed density was largest from the north tothe east with seed density decreasing as the distance increased from the mature tree. [Ch, 4 fig. 1 tab. 18 ref. ]