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题名	塔里木河下游土壤种子库特征及其在植被更新过程中的作用
作者	王增如
学位类别	硕士
答辩日期	2008
授予单位	中国科学院．新疆生态与地理研究所
导师	尹林克，中国科学院新疆生态与地理研究所
关键词	塔里木河下游
其他题名	Contribution of Soil Seed Bank to Regeneration of Vegetation in in the lower reaches of the Tarim River
中文摘要	以塔里木河下游为研究区，采用植被定位监测与野外激活土壤种子库相结合的研究方法，于2006年选择了5个不同退化程度的断面，进行土壤种子库样品采集和植被调查，并开展了野外土壤种子库激活实验，对塔里木河下游土壤种子库的萌发需水规律、基本特征及其在植被更新中的贡献等进行了研究。综合运用繁殖生态学、植物生态学、恢复生态学和土壤学等多学科理论，对土壤种子库在植被恢复中的潜力进行了探讨，旨在为塔里木河下游退化植被的恢复与重建提供科学依据，并促进荒漠生态系统土壤种子库研究方法及恢复生态学理论的发展。主要结果如下：（1）在野外自然条件下，不同水分处理对激活土壤种子库具有显著影响。大部分物种随着供给水量的减少，萌出物种数和幼苗数量逐渐降低，且各物种萌发高峰期向后推迟了2-3天。对于塔里木河下游激活土壤种子库的适宜水分选择，土壤含水量介于23-28%为宜。（2）土壤种子库激活实验总共出现了12个物种, 生活型组成以多年生草本和灌木为主，表层土壤0-2cm种子密度占0-5cm深度的70%以上。土壤种子库特征具有较大的空间变异性，随着退化程度的加剧，土壤种子库的物种丰富度、密度以及多样性指数呈明显下降的趋势；多年生草本和灌木的种子库密度比重略有增加，一年生草本比重呈降低趋势，但退化程度对土壤种子库密度的分布格局无显著影响。（3）土壤种子库对漫溢区幼苗库的物种组成和密度具有显著影响，土壤种子库与实生幼苗库在物种组成上具有较高的相似性，在密度特征上具有很好的正相关性，实生幼苗有80%以上来源于土壤种子库。这表明了土壤种子库对幼苗库的形成具有重要贡献。（4）从土壤种子库物种组成和密度特征及其在幼苗库中形成的作用等综合分析，表明土壤种子库对塔里木河下游植被更新具有很大潜力。在适度漫溢干扰下，土壤种子库对植被恢复与重建具有重要促进作用。 本研究的创新之处在于：通过改进土壤种子库萌发法，在野外自然条件下，验证了土壤种子库萌发的最佳需水量；探明了塔里木河下游土壤种子库特征及其随退化程加剧的变化趋势；揭示了漫溢区幼苗库的形成机制以及土壤种子库对幼苗库形成的贡献度。Over the last 50 years the desert riparian vegetation in the lower reaches of the Tarim River in western China degraded due to improper management regimes. Little is known about the effects of the level of vegetation degradation on the structure and performance of soil seed banks in desert riparian vegetation. A field experiment was established in 33th Regiment to test the effects of different levels of vegetation degradation on the structure and performance of the soil seed bank. The importance of the soil seed bank was evaluated by determining the characteristics of soil seed bank and its role in resorting floodplains vegetation. It’s found that:(1)the seedling species and amount decrease gradually in response to the descending of the water supply, except several unique species that the most seedling amount doesn’t appear in the most water supply. (2)Different species present different germination characteristics. The whole species show two germination types: fast-germination and slow-germination. Every species has its own climax period of germination which is postponed by 2 to 3 days with the descending of the water supply. Therefore, the choice of soil moisture is vital to the germinating experiment, and different water treatment should be chosen when we study the characteristics of soil seed bank or in allusion to certain species. In the research of soil seed bank in lower reaches of Tarim River, the theoretical optimal soil moisture ranges from 23% to 28%, and the seedling conservation should be strengthened in the climax period of germination.(3)The results showed a significant effect of the level of vegetation degradation on the characteristics of the soil seed bank. An increase in the level of vegetation degradation negatively affected the species abundance, density and biodiversity index of soil seed bank. There was no significant impact of intensity of vegetation degradation on vertical density distribution of soil seed bank. However, over 70% of seeds were concentrated in upper most soil layer (0-2cm). Plots with extreme vegetation degradation showed a greater proportion of annual herbs compared to plots with heavy or moderate vegetation degradation, while perennial herbs and shrubs followed the inverse trend. These results indicate that the potential of the natural vegetation to restore naturally decreases with increasing levels of vegetation degradation.(4)the soil seed bank has a significant effect on seedlings species and density of the floodplains, which 84.7% and 99.4% of seedlings emerged from the seed bank and the positive correlation between the density of seedlings and seed bank density was significant. It can be concluded that soil seed bank may play an important role in promoting the natural regeneration of vegetation during primary stage of.the vegetation.
语种	中文
学科主题	植物生态学
公开日期	2010-11-12
页码	共61页
内容类型	学位论文
源URL	[http://ir.xjlas.org/handle/365004/8002]
专题	新疆生态与地理研究所_中国科学院新疆生态与地理研究所(2010年以前数据)
推荐引用方式 GB/T 7714	王增如. 塔里木河下游土壤种子库特征及其在植被更新过程中的作用[D]. 中国科学院．新疆生态与地理研究所. 2008.

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