【作者】 李胜平；

【导师】 王德利；

【作者基本信息】 东北师范大学 ， 生态学， 2010， 硕士

【摘要】 全球变暖与氮沉降增加是全球变化领域内的热点问题,草地作为陆地生态系统的主要类型之一,对全球变化的反映与调节占有重要地位。植被繁殖体库既是这些生态学事件的被迫变化者,也是改变和影响植被演替方向的重要驱动因素。因此,开展全球变化下草地植被繁殖体库响应机制的研究,是揭示草原生态系统对全球变化的响应与适应过程的关键环节,对解释和预测草原生态系统与全球变化相互关系及植被更新理论有十分重要的意义。本论文以东北松嫩草原羊草群落为研究对象,采用原位处理实验方法,即利用红外线加热模拟大气升温,人工施氮肥模拟氮沉降获得对照、增温、施氮、增温+施氮四个处理,经过2008年及2009年的野外测定和室内分析,完成了对种子雨、种子库、幼苗再生的研究工作。结果发现:(1)增温处理下,禾本科种子雨及种子库含量减少,克隆苗出生数/实生苗出生数减少较多;杂类草种子雨及种子库含量增加,克隆苗出生数/实生苗出生数增加;植被总的种子雨及种子库含量增加,克隆苗出生数/实生苗出生数增加,丰富度及辛普森指数减少,植被最终的密度减少,地上植被、种子雨、种子库、实生苗之间的相似性系数与对照比无规律变化。(2)施氮处理下,羊草群落禾本科种子雨含量变化不大,种子库含量减少,克隆苗出生数/实生苗出生数增加;杂类草种子雨种子库含量增加,克隆苗出生数/实生苗出生数减少;植被总的种子雨及种子库含量增加,克隆苗出生数/实生苗出生数减少,丰富度基本不变,辛普森指数减少,植被最终密度变化较小,地上植被、种子雨、种子库及实生苗之间的相似性系数较对照增加。(3)增温+施氮作用下,禾本科种子雨含量几乎不变,种子库含量增加,克隆苗出生数/实生苗出生数增加;杂类草种子雨及种子库含量增加,克隆苗出生数/实生苗出生数减少;植物总的种子雨增加,种子库含量变化不大,克隆苗出生数/实生苗出生数减少,丰富度减少,辛普森指数显著减少,植被最终密度增加,地上植被、种子雨、种子库及实生苗之间的相似性系数较对照减少。(4)不同处理下,禾本科克隆苗出生数/实生苗出生数与杂类草克隆苗出生数/实生苗出生数的变化呈现相反的趋势,植被最终克隆苗出生数/实生苗出生数的变化更依赖于杂类草。更多还原

【Abstract】 Globe warming and Nitrogen addition are the hot issues in the realm of global change, and as one of the main types of the ecological system of the land, the grassland has an important role in the response and regulation to the globe warming .The propagule bank of the vegetation is forced to change in these ecological incidents, as well as the key driving factor to impact and change the succession of vegetation. Therefore, the research on the the mechanism of the response of the propagule bank to globe change is the key step to reveal the response of grassland to globe change and also of significance to explain and predict the interaction of grassland ecosystem with globe change and the theory of vegetation regeneration.This thesis focuses on Leymus chinenisis(Trin.)Tzvel. Grassland in Songnen plain.We simulated warming by achieving with Infrared Radiator and nitrogen (N) application by receiving ammonium nitrate in vivo. We examined seed rain, seed bank and seedling regeneration responses to manipulations of four treatments: ambient, warming, N application, and warming plus N application during the year 2008 and the year 2009. The result showed that:Under warming treatment, for the herbaceous plant functional group, the quantity of seed rain and seed bank was decreased, the ratio of the number of seedling that from clonal growth with sexual growth was decreased; for the weed plant functional group, the quantity of seed rain and seed bank was accelerated, the ratio of the number of seedling that from clonal growth with sexual growth was accelerated; for the whole vegetation, the quantity of seed rain and seed bank was accelerated, the ratio of the number of seedling that from clonal growth with sexual growth was accelerated, the richness of plant species and the simpson parameter was decreased, the density of the vegetation was decreased, the variation of the coefficient of similarity among standing vegetation, seed rain, seed bank and seedling regenerating from seed was not inerratic when compared with the control treatment.Under N application, for the herbaceous plant functional group, the quantity of the seed rain and seed rain was a little changed, the quantity of seed bank was decreased, the ratio of the number of seedling that from clonal growth with sexual growth was accelerated; for the weed plant functional group, the quantity of the seed rain and the seed bank was accelerated, the ratio of the number of seedling that from clonal growth with sexual growth was decreased; for the whole vegetation, the quantity of the seed rain and seed bank was accelerated, the ratio of the number of seedling that from clonal growth with sexual growth was accelerated, the richness of the plant species was almost not changed, the simpson parameter was decreased, the density of the vegetation was changed a little, the vaule of the coefficient of similarity among standing vegetation, seed rain, seed bank and seedling regenerating from seed was accelerated when compared with the control treatment.Under warming plus N application, for the herbaceous plant functional group, the quantity of seed rain was almost not changed, the quantity of the seed bank was accelerated, the ratio of the number of seedling that from clonal growth with sexual growth was accelerated; for the weed plant functional group, the quantity of the seed rain and seed bank was accelerated separately, the ratio of the number of seedling that from clonal growth with sexual growth was decreased; for the whole vegetation, the quantity of the seed rain was accelerated, the quanlity of seed bank was almost not changed, the richness of the plant species was decreased, the simpson parameter was decreased significantly, the density of the vegetation was accelerated, the vaule of the coefficient of similarity among standing vegetation, seed rain, seed bank and seedling regenerating from seed was decreased when compared with the control treatment.The change mode of the ratio of the number of seedling that from clonal growth with sexual growth for gramineae and the weed is opposite under different treatment, and the response of the ratio of the number of seedling that from clonal growth with sexual growth for the vegetation is more dependent on the response of the seed.更多还原