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| Soil seed bank of Pinus tabulaeformis f/i>.shekannesis natural forest in the Ziwuling mountains |
| He Zhaowan1,Cheng Jimin2,Wan Hui'e2,Xiong Chuqiao3,Chen Li3,Han Tianfeng3,Yang Xiaomei2 |
| 1.College of Resource and Environment,Northwest A&F University;2.Institute of Soil and Water Conversation of Chinese Academy of Sciences and the Ministry of Water Resources;3.College of Animal Science and Technology,Northwest A&F University: 712100,Yangling,Shaanxi,China |
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Abstract The soil samples of 54 quadrates in 4 sample plots which included 3 plot on different position of slope and 1 plot of contrast in the Pinus tabulaeformis f.shekannesis natural forest of Ziwuling Mountains were collected.It was studied combing the germination methods in house and investigation in ground,in expectation of opening out the characters of soil seed bank and the relationship with the aboveground communities.The result showed: 1) The average soil seed density was 1 496.7 seed/m2,the minimum density was 1 240.0 and the maximum density was 1 785.0 seed/m2.The seed density in the comparison zone of barren hill was 510.0 seed/m2.2) The vertical distribution pattern of seed bank showed that it is nearly 90% of seeds stored in litter layer and 0-7.5 cm upper layer of soil.3) 32 plant species were recorded which belonged to 20 families.Among them,perennial herbs and evergreen shrubs had the highest proportion in seed banks,which accounted for 48.3% and 41.9%.4) The species richness ranged from 2.523 to 3.082 and the species diversity ranged from 1.458 to 1.781 in the slopes.Among them,the middle slope had the maximum of the richness,and the minimum of the diversity,the upper slope had the maximum value of both the diversity and the evenness of the soil seed bank.5) The dominant plants of the aboveground communities on slope,such as Ostryopsis davidiana Decaisne,Cotoneaster acutifolius Turcz,Sanguisorba officinalis Linn and so on hadn't been recorded in the seed bank,except Carex rigescens(Franch) V.krecz,Carex lanceolata Boott,Lespedeza bicolor Turcz,and Thalictrum alpinum Linn accounted for 19.7%,2.1% & 0.8%,1.7% & 3.1%,and 0.4% of the soil seed bank in the corresponding slope.The plant species composition of soil seed banks did not closely reflect the composition of aboveground communities.Some plant species not emerged out owing to their own characters of germination.6) The proportion of Pinus tabulaeformis f.shekannesis seeds was about 0.6%.In the investigation of aboveground communities,it was discovered that there were a few seedlings of Pinus tabulaeformis f.shekannesis on the forest floor,and about 5-7 seed/m2 which indicate that the seed banks have potential germination and the forest ever has some abilities of self-renewal.
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Received: 27 February 2009
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