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The Research Development of Soil Seed Bank and Several Hot Topics

土壤种子库的研究进展及若干研究热点


土壤种子库是指存在于表层土壤(包括凋落物)中的有生命的种子。土壤种子库的研究已是植物生态学研究不可缺少的一部分,现已成为植物种群生态学中比较活跃的领域。土壤种子库时期是植物种群生活史的一个重要阶段,有人称之为潜种群阶段。土壤种子库对一年生植物来说尤其重要。土壤种子库简单地可分为瞬时土壤种子库和长久土壤种子库,即使给予理想的萌发条件如季节、温度、湿度等,土壤种子库中也仍有部分种子保持休眠状态,休眠的种子组成了土壤长久种子库的成分。时空异质性是土壤种子库的基本特性之一,不仅不同植被类型的土壤种子库具有不同的组成、大小和多样性,而且微环境也影响土壤种子库的分布格局。由于萌发、捕食和衰老等原因,土壤种子库具有季节动态,一般在旧种子萌发之后,新种子散布之前达到最低点。在高等植物占据的大多数生境中,以休眠繁殖体形式存在的个体远远超过地上植株的数量;土壤种子库、幼苗库和成年植被相互联系相互影响。由于各种原因如群落类型的差异、群落的演替阶段、取样的时间等,地上植被和土壤种子库之间关系大体上可分为两种情况,即相似性和差异性;研究土壤种子库的方法通常有萌发法和物理分离法。土壤种子库能部分反应群落的历史,对退化生态系统的恢复起着重要的作用。目前土壤种子库的主要研究热点问题可分为以下几个方面:1)土壤种子库的研究方法,2)土壤种子库的分类问题,3)土壤种子库分布的时空格局,4)地上植被和土壤种子库的关系,5)土壤种子库的动态等。

All viable seeds present on or in the soil or associated litter constitute the soil seed bank. Seed bank input is determined by the seed rain. Seed rain comes from seed dispersion from mother plants and also from secondary dispersion. Seed losses result from germination, animal predation, deep burial, redispersal, natural senescence and death caused by pathogens and some animals. Seeds in the soil display horizontal and vertical dispersion, reflecting initial dispersal onto the soil and subsequent movement. Investigation of the seed and spore bank has become a recognized and indispensable part of plant ecology now and has been an active research area. The soil seed bank is one of the life history stages of plant populations, which is called subpopulation stage. Some soil seed bank classification methods had been provided by scientists, but simply the soil seed bank can be classified into the transient soil seed bank, with seeds that germinate within a year of initial dispersal, and the permanent soil seed bank, with seeds that remain in the soil more than one year. Even given ideal germination conditions such as season, temperature and moisture, some seeds in the soil still remain dormant; these comprise the persistent soil seed bank. Temporal and spatial heterogeneity is the basic characteristic of the soil seed bank. Not only are the floristic composition, size and diversity of the soil seed bank different in different plant communities, but microsites or microhabitats greatly affect the distribution patterns of the soil seed bank. The number of reproductive individuals existing in a dormant state is significantly greater than that of aboveground individuals in most habitats dominated by higher plants. Because of reasons such as germination, predation and decay, soil seed banks have seasonal dynamics. The soil seed bank, seedling bank and adult vegetation can interconnect and interact with each other. The relationship between soil seed banks and their aboveground vegetation is similar or dissimilar because of different plant community types, different succession stages and different sampling time. Germination in the greenhouse and physical separation methods were used to research the soil seed bank. The soil seed bank can partly reflect the history of communities, and plays an important role in the restoration of degraded ecosystems.The main hot topics about soil seed bank research are summed up as following: 1) the research methods about soil seed banks; 2) the classification of soil seed banks; 3) the temporal and spatial distribution patterns of soil seed banks; 4) the relationships between aboveground vegetation and soil seed bank; 5) the dynamics of soil seed banks.


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