【作者】 张作亮；

【导师】 张世挺；

【作者基本信息】 兰州大学 ， 生态学， 2009， 硕士

【摘要】 以青藏高原东部高寒草甸弃耕地种子大小不同的3个常见物种:2个一年生物种鼬瓣花(Galeopsis bifida Boenn)和菊叶香藜(Botrydium schraderi Spach)及1个二年生物种四数獐牙菜(Swertia tetraptera Maxim)为试验材料,通过单播、2个、3个物种的混播,分别以2个密度(高密度和低密度),按照随机或者种内积聚的空间格局形式播种,研究空间格局、物种组合对不同种子大小植物行为的影响。结果表明:1>空间格局和物种组合对3物种的出苗率没有显著影响,但在一定程度上影响着物种竞争能力等级。大种子鼬瓣花在种间竞争中占据着优势地位,小种子菊叶香藜在种内集聚格局下获益;四数獐牙菜的种子大小介于二者之间,其种间竞争的结果表现复杂;2>集聚格局下菊叶香藜的幼苗死亡率低,地上生物量比随机格局下显著高;集聚格局下鼬瓣花死亡率高,通过密度—格局作用,高密集聚下表现出显著较低的地上生物量;3>与其他物种混播相比,鼬瓣花单播下死亡率高,地上生物量低;当混播中存在四数獐牙菜时,菊叶香藜的死亡率比单播下高,物种组合对其地上生物量没有显著影响;四数獐牙菜与鼬瓣花混播时死亡率最低,三个物种混播时其死亡率最高;4>空间格局对鼬瓣花和菊叶香藜的株高和分枝数都没有显著性的影响(P＞0.05),但通过密度—空间格局作用,大种子物种鼬瓣花在高密集聚下的株高较高,分枝较少;菊叶香藜则在高密随机格局下表现出显著较高的株高,显著较少的分枝数;5>物种组合显著性的影响着两物种的株高和分枝数。鼬瓣花单播时株高较高而分枝少,而小种子物种菊叶香藜则在三个物种混播时株高较高,分枝少,密度—物种组合作用下,这种效应更明显:6>大种子鼬瓣花和四数獐牙菜单播下根冠比高:小种子物种菊叶香藜则在三个物种的混播中根冠比最高。通过空间格局—物种组合作用,随机格局下菊叶香藜与另外两物种共同混播时的根冠比最高。更多还原

【Abstract】 In order to test that the effects of spatial pattern and species combinations on the plant performances with different seed mass,the seeds of two annuals Galeopsis bifida Boenn and Botrydium schraderi Spach and a biennial Swertia tetraptera Maxim which occur commonly in the abandoned fields of the eastern Tibetan plateau,were sown by the treatment combinations,spatial pattern(aggregated vs.random)×density (low vs.high)×species combination(monocultures,two and three species combinations).The results indicated that:1> Spatial pattern and species combinations had no significant effects on the emergence rate of three species,but on the competition rank in a certain extent. Galeopsis bifida Boenn which has the large seed mass had the advantaged status in the interspecific competition;Botrydium schraderi Spach,having small seed mass,could benefit from aggregated pattern;Swertia tetraptera Maxim,which seed mass is in the middle rank,had the complex results of interspecific competition.2> Compared with random pattern,the death rate of small-seed species Botrydium schraderi Spach was lower in the aggregated pattern,and had the higher aboveground biomass;But the death rate of Galeopsis bifida Boenn was higher in the aggregated pattern.Compared with low density-aggregated pattern,the aboveground biomass of Botrydium schraderi Spach were lower in the high density-random pattern.3> Compared with other mixtureculture,Galeopsis bifida Boenn had the highest death rate and the lowest aboveground biomass in the monoculture treatment; Botrydium schraderi Spach had higher death rate when mixed with Swertia tetraptera Maxim comparing with monoculture treatment.Species combinations had no significant effects on the aboveground biomass of Botrydium schraderi Spach;Swertia tetraptera Maxim had the lowest death rate when mixed with Galeopsis bifida Boenn,and the highest when three species mixed together.4> Spatial pattern had no significant effects on the plant height and branch of Galeopsis bifida Boenn and Botrydium schraderi Spach(P＞0.05),but density-spatial pattern had significant difference on plant height of Galeopsis bifida Boenn,which had the highest plant height in high density-aggregated pattern,and the lowest branch,however,small-seeded species Botrydium schraderi Spach had the highest plant height in high density-random pattern,and the lowest branch.5> Species combinations had significant effects on the plant height and branch of Galeopsis bifida Boenn and Botrydium schraderi Spach.In monoculture, large-seeded species Galeopsis bifida Boenn had higher plant height but less branch;Small-seeded species Botrydium schraderi Spach had higher plant height, less branch when three species mixtureculture together,and the effects showed more obviously though density-species combination effects.6> Galeopsis bifida Boenn and Swertia tetraptera Maxim had higher root-shoot rate in monoculture comparing with mixtureculture;Small-seeded species Botrydium schraderi Spach had the highest root-shoot rate when mixed with two other species together.In random pattern,Botrydium schraderi Spach also had the highest root-shoot rate when mixed with two other species together.更多还原