庞泉沟自然保护区河岸林群落的土壤种子库特征

以人工拣种结合种子萌发法研究了庞泉沟自然保护区9种河岸林群落的土壤种子库特征,结果表明: 9种群落的土壤种子库密度间于684±108 - 2 696±266粒·m^-2,69.27% - 88.65%的种子留存于0 - 5 cm的层次,沙棘灌丛的种子库密度最大,乌柳灌丛最小;离河岸10 m和20 m处的种子库密度大于岸边、离河岸30 m和40 m处;种子库包含的40种植物以多年生草本为主,灌木和草本种多为耐干扰种,存在典型的湿地植物,但种子储量以先锋种白桦最丰;辽东栎无完整种子,白桦、华北落叶松、云杉和油松的种子活力保持期为1 - 2年,多数草本的种子活力保持期超过2年;按照群落土壤种子库的相似性,将群落划分为林分开始期、林分排除期、下层再现期和老熟期4个演替阶段。演替后期群落的种子库密度、丰度以及与地上植被的相似性都小于前期群落。土壤种子库是森林自然更新及种群恢复的重要基础,本文对于研究地区河岸林的保护和重建具有重要的理论意义。

Soil Seed Bank of Mountain Riparian Forests in Pangquangou Nature Reserve

In this paper, a research about soil seed bank of 9 typical riparian forests in Pangquangou Nature Reserve was conducted. Seeds in soil were separated by soil analysis sieves (0.5 mm), and then germinated in laboratory. The results showed that the soil seed bank densities of 9 communities were among 684±108 - 2 696±266 seeds per square meter, about 69.27% - 88.65% seeds were saved in the layer of 0 - 5 cm. The seed density of Hippsphae cheilophila bush was the highest, and which of Salix cheilophila bush was the lowest. Among 5 level lines of different distances away riparian, the seed densities of 10 m and 20 m were higher than that at riparian and 30 m and 40 m from the riparian. The soil seed banks of all the 9 communities were composed of 40 species, which mainly were perennial herbs. Most shrubs and herbs were interference-resistant species. In addition, there were some typical wetland plants. Pioneer species Betula platyphylla was of the highest seeds density. Among 5 tree species of soil seed bank, no viable seeds of Quercus liaotungensis was found, the seeds of other tree species could remained viable in soil for 1 - 2 years. The seeds of most herbs could remain viable more than 2 years. According to seed banks similarity indexes, 9 communities were classified into 4 succession stages: stand initiation stage, stems exclusion stage, under-story initiation stage and old growth stage. The soil seed banks of 4 succession stages were different: seeds densities, species number and similarity between soil seed bank of latter stages were smaller than earlier stages. The soil seed bank is important for regeneration and restoration of forest in nature. This research would provide references for protection and reconstruction of riparian forests of Pangquangou Nature Reserve.